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Nouveaux poissons acanthodiens

du Dévonien du Spitsberg

Pierre-Yves GAGNIER

Grande Galerie de l'évolution, Muséum national d’Histoire naturelle,

36 rue Geoffroy Saint-Hilaire, F-75231 Paris cedex 05 (France)

Daniel GOUJET

Laboratoire de Paléontologie, Muséum national d’Histoire naturelle,

8 rue de Buffon, F-75231 Paris cedex 05 (France)

Gagnier P.-Y. & Goujet D. 1997. — Nouveaux poissons acanthodiens du Dévonien du

Spitsberg. Geodiversitas ^9 (3) : 505-513.

MOTS CLÉS

acanthodicn.

Dévonien,

Spitsberg,

systématiouc,

Mesacanthus,

Xylacanthus.

RÉSUMÉ

Une description de deux nouvelles espècc.s de poissons acanthodiens est don¬

née. Mesacanthusgrandis n.sp. est représentée par un spécimen articulé mon¬

trant bien les écailles du corps, les écailles modifiées de la tête et une scapula.

Xylacanthus minutus n.sp. est représentée par une hémi-mandibule droite en

vue linguale. Les affinités phylogénétiques de ces poissons acanthodiens sont

discutées, ainsi que leur signification paJéoejivironnementale.

KEYWORDS

acanthodian,

Devonian,

Spitsberg,

Xylacanthus.

ABSTRACT

Two new acanthodian species are described from the Spitsbergen Old Red

Sandstone. Mesacanthus grandis n.sp. is represented by an articulated spéci¬

men showing unornamented body scales, elongate modified rectal scales, and

a mesacanthid type of scapula. The second species, Xylacanthus minutus n.sp.

is represented by a right branch of the mandible in lingual view, showing a

single row of triangular striated reeth with an anterior flange. Phylogenctic

affinities of these forms are discussed as well as their paleoenvironmencal

significancc.

505 1

• 1997 • 19 ( 3 )

Gagnier P.-Y. & Goujet D.

INTRODUCTION

MATÉRIFI, FT Mf^THODFS

Le matériel consiste en deux spécimens de pois¬

sons acanthodiens. Le premier est articulé et fos¬

silisé dorso-ventralement, le second est formé

d’une hémi-mandibule droite.

La gangue ne réagissant pa.s à l’acide (ôrmique ou

acétique, le spécimen articulé a été préparé méca¬

niquement par l'un de nous (D. G.) à Taiguille

montée. L’hémi-mandibulc a etc dégagée en

négatif par dissolution de fos à l'acide chlorhy¬

drique (R J.). Le matériel ainsi préparé a ensuite

été étudié a partir d‘un moulage en élastomère.

La figuration a été essentiellement réalisée à la

chambre claire. Le spécimen articulé était place

sous immersion dans une eau contenant de

l'alcool pour le.s prises de vues photographiques,

et les reliefs de riiémi-mandibule ont été accen¬

tués par pulvérisation à la fumée de magnésium

(oxyde de magjiésium).

Localisation CE-:oGRArHiQUt*.

Ix)rs de Texpédiiion au Spitsberg de 1969, orga¬

nisée par le CNRS et le Muséum national

d'Histoire naturelle de Paris, de nombreux verté¬

brés dévoniens ont été récoltés. Parmi eux^ beau¬

coup d'acanthodiens furent découverts, dont les

deux formes décrites ici.

Ces spécimens proviennent de deux localités de

la rive est, au fond du Wüodf]ürd. Elles sont

situées de part et d'autre de Woodfjurddalen, la

première sur le versant nord-est du mont Wagner

et la seconde sur le versant sud-sud-ouest du

mont Nidhogg (Fig. lA, B).

GtoLOtilH

Les sédiments dévoniens de cette région sont

dominés par le faciès Vieux Grès Rouges sem¬

blable à celui des roches plus ou moins contem¬

poraines de Grande-Bretagne ou de Podolie. Ce

faciès esc câtactcrisé par la prédominance des

sédiments arénaccs détritiques plus ou moins

grossiers dont la couleur varie du rouge brique au

gris-vert (Goujet 1984).

Les affleurements fossilifères font partie de la

Formation de Wood Bay (Dévonien inférieur).

Le matériel du mont Nidhogg, comme celui du

mont Wagner, appartient à la division faunique

Rg. 1. — Carte des affleurements de la formalion de Wood Bay

au nord du Spitsberg. A, vue générale avec les trois divisions

fauniques principales, extrait de Goujet 19ô4a (modifié de

Ffiend Moody-Stuan 1972|; B, tocalisaiton géographique.

Échelle : 20 km.

506

GEODIVERSITAS • 1997 • 19(3)

Nouveaux acanthodiens du Dévonien du SpiLsberg

de Lykta (Fig. lA ; Goujec 1984 : 26^ fig. 2).

Ourre sa riclif.sse en vertébrés fossiless la découver¬

te, dans la Formation de Wood Bay, de traces de

trilobites {Cntzuina et Rtuophycus) et de Unguia

remet eu doute les conclusions sédimentologiques

de plusieurs auteurs Goncernanr la Formation de

Wood Bay. Il ressort de l'analyse sur le paléomilieu

de cette formation par Goujet (1984 : 32) et

Goujct & Emig (1985 : 945) quelle correspon¬

drait à un milieu marin côtier, sub-tidal.

SYSTÉMATIQUE

Classe ACANTHODII Owen, 1846

Ordre ICHNACANTHIFORMES Berg, 1940

Famille ICHNACANÎlfîÜAt Woodward, 1891

Genre Xylacamhus 0rvig, 1967

XyLicanthus mimitus n.sp.

(Eig. 2)

HoloTYpf. — Le seul matériel de ce nouvel

Ischnacanthidae est un os deinigere portatn six dents.

MNHN P SVD 247 est l'holorype de Xvlacanthits

mirmtm n.sp. Il représente une hcmi-mandirtule droite,

en vue linguale. Ce spécimen fut récolté lors de la der¬

nière expédition CNRS-Muséum en 1969 au Spitsberg.

Niveau- n'PK. — Formation de Wood Bay (I^ivîsion

faunique de Lykta), I.ochkovien sup. (Siegcnien).

LüCAUrÉ-TlTE. — "laïus, flanc NE de Wagnerfjcllet,

Andrée Land, Vestspiisborgçn, Svalbard (Fig, lA).

ÉTYMOLOGir . — Le nom spécifique, minutus, esc

donne en raison de la caille (86 mm) de la mandibule

de cette nouvelle espèce, beaucoup plus petite que

celle de l’autre espece du genre (350 mm).

Diagnose. — Xylacamhus inimmis est un Ischnac-an-

thiformes possédant un o.s dentigère à une seule ran-

ée de dents. Les dents sont réunies, le long de la

ordure labiale de la lame dentigère, par une crête

ponant de quatre à cinq deiiticules réguliers. Les dents

portent de trois h cinq cretes aigues sur leur lace

mcdialc, séparées par de profondes cannelures. Lllc.s

sont aplaties, presque rriaugulaires en section para-

basale. Le champ médial de h» mâchoire est pourvu de

petits uiberailcs sur sa mihtié proximale.

La forme de Lo.s dentigère, les siriaiions marquées des

dents, la forme des denticules portés par la crête entre

les dents principales, et la forme du processus postéro-

dorsal de la région articulaire permettent d’attribuer

ce spécimen au genre Xylacanthus. Il diffère de

Xylni'urulms grandis par sa peritc taille, par la forme,

latéralement comprimée, de sc.s dents et par la mor¬

phologie de la crête labiale.

Descriition et remarques

La mandibule nesr représentée que par son os

dentigère, qui mesure 86 mm de longueur. La

transposition, à partir de ccr os, des proportions

à'Isihnacanlbus gmcilis, dont on possède des spé¬

cimens en connccuon, permet d'estimer que

l'individu complcr devait mesurer plus de 50 cm

de long.

Los dentigère esr étroit et haut postérieurement.

Sa forme générale rappelle celle de XyUcanthus

grandis (0rvig 1967b). L’ossification des champs

dentaires (os dentigère) est peu importance,

contrairement à celle de Gomphonchus (Gross

1957) ou ^Acanthodopsh.

Los dentigère possède une rangée de six dcius

principale.s, aplaties latéralement (presque rrian-

gulaircs en section parabasale) cr courbées média

lement, comme celles Âtopacanihm (0rvig

1957),. A'Ai'anthodopsis (Miles 1966) et de

Yïschnacanthida indet. de Séripona (Gagnier et

al. 1988). l es dents sonr élancées et portent rrols

à cinq crêtes verticales sur leur face médiale. Une

ou deux perires cu-spides apparaissent à la base de

ces creres. Les dents sont reliées par une longue

crête portant de quatre à cinq petits denucules

entre les ciispidcs principaux. 0rvig (1967a,

pi. 2, fig. 3) figure une srrucrurc similaire chez

Xylacanthus grandis. Il y décrit également une

rangée de quatre à cinq denticules formant une

crête entre les dents.

Sur la face linguale, à la ba.se des dents, un sillon

antéro-posterieurT bordé d’un champ dentaire

secondaire, s'élargit antérieurement comme chez

la ntajofité des Ischnacanthidae, sauf Ischna-

canthus et YIschnacajithida indet. de Séripona

(Gagniez et ai 1988). Ce champ dentaire (lin¬

gual) n'est que peu marqué. Bien qu’il porte des

dents ou des tubercules dans la majorité des

espèces. Ü est lusse chez Atopacanlhus ou Persa-

canthus par exemple. Xylacanthtis minutus n.sp.

montre une situation Intermédiaire puisqu'il ne

porte de petits tubercules que sur la moitié posté¬

rieure (proximale), comme chez l'Ischnacanthi-

formes indet. d'Iran (Blieck et al, 1980) et, de

façon plus développée, cY\ez Xylacamhus grandis.

GEODIVERSITAS • 1997 • 19(3)

507

Gagnier P.-Y. & Goujet D.

Fig. 2. — Xylacsnthus minutus n,sp., monl Wagner, SpÜsberg, MNHN P SVD 247 • fragment dentifère de mandibute droite en vue

linguale, cu.p., cuspide principal ; d.s.. dentîcule secondaire ; fo.ac., fossette accessoire : pr.p., processus postéro-dorsal. Échelle ;

1 cm.

La régioa articulaire de Vos dendgère possède un

processus bordant postérieurement une encoche

dorsale qui correspond à une fossette accessoire,

mais pas à rarticulaiion principale de la mandi¬

bule. Elle est entourée par un petit bourrelet

comme chez Taemasamnthus (Long 1986). Le

processus est élevé dorsalement comme celui de

Xylacantbus grandis.- La fosse articulaire propre¬

ment dite était en position latérale par rapport à

ce processus qui marque le côté lingual.

Le processus postérieur de l'os dentigère se pro¬

jette latéralement. Sa cavité postérieure» « en

cuillère», conespondaïc à la limite antérieure de

la zone articulaire de la mandibule.

Ordre ACANTHODIFORMES Berg. 1940

Famille Mesacanthidak Moy-Thomas, 1939

Genre MesacanthusTïa.<\\xd\v, 1888

Mesacanthus grandis n.sp.

(Figs 3. 4)

Holotype. — Le seul spe'cimen d'acanthodien articu¬

lé connu de la série des Vieux Grès Rouges du

Spitsberg, MNFIN P SVD 246. est riiolorypc de

Mesavanwiis gran^ n.sp. Il est conserve en vue doisale

partielle. la tète, incomplète, est courbée suivant un

angle de 90*^ environ par rapport à Taxe du corps. Line

partie de la ceinture pectorale, Taiguillon dorsal et la

nageoire caudale sont visibles.

Initialement, la couverture écailleuse était transparente

à l’observation sous liquide. Pour la préparation et

l'ctudc. le spécimen a été coloré à l'alizarine et préparé

manuellement. Cette préparation a nécessité plus de

sept mois de travail (D. G.).

Nivuau-TYPE. — Formation de Wood Bay (division

faunique de Lykta), Lochkovien supérieur (Siegenien).

LocALIT^-TYI'E. — Talus, flanc nord de Nidhogg

dans une vallée à Test de Woodf|orddalen (Fig. lA).

Étymologie. — Le nom spécifique signifie que cette

nouvelle espèce est très grande pour le genre.

DlAGNO.SE. — Acanihodiforme, atteignant plus de

10 cm de longueur et dont le rapport de la hauteur

estimée sur la longueur rotalc est d'environ 0,11. Les

écailles du corps sont de forme rhombique, plates et

sans ornementation. La tète est couverte de tessères

allongées disposées dans le plan longitudinal.

508

GEODIVERSITAS • 1997 • 19 (3)

Nouveaux acanthodiens du Dévonien du Spitsberg

Fig. 3. — Mesacanîhus grandis n.sp., mont Nidhogg, Spitsberg, MNHN P SVD 246. a.d., aiguillon dorsal ; n.c., nageoire caudale ;

r.c., région céphalique ; Sc. Scapula. Échelle : 1 cm.

Ce spécimen est attribué aux Acanthodiformes par la

présence d'une seule nageoire dorsale et par la forme

des écailles à base mince et couronfic lisse et plate, aux

Mesacanthidae par la présence d'un aiguillon dorsal

superficicllcmeiir inséré dan.s le corps.

Il est attribué au genre AfesacaNthus et non à

Triazeugacanthits du Fait de la dimension réduite des

écailles et par la présence de icsstrcs oblungues sur le

sommet de la tétc. Ce spécimen diffère de

Mesacanthiis mitchtlii par sa grande taille, la position

postérieure de sa nageoire dorsale cl la présence d'un

.seul sillon latéral sur taiguillon dorsal.

Description ft remarquer

Mesacanthîisgrandis n.sp. (Fig. 3) est un acantho-

dien de forme très allongée. Le rapport estimé de

la hauteur sur la longueur totale du corps est

d’environ 0,11 alors qu’il esr de 0,14 pour les

Mesacanthidae, Mesacanthîis er Triazeugacanthits,

Compte tenu du mode de présentation du fossi¬

le, cette différence nexclut pa.s une erreur d’éva¬

luation de la longueur du spédmen redressé. On

peut e.stimer que la longueur de la tête (du

museau à la scapula) occupait une partie impor¬

tante de ranimai (0,18) comme chez

Mesacanthîis mitchelli.

Nageoire

La nageoire dorsale est nettement postérieure,

étant donné la forme de la caudale, notamment

le développement de son lobe ventral. La nageoire

anale, non visible sur le fossile, devait probable-

GEODIVERSITAS • 1997 • 19(3)

509

Gagnier P.-Y. & Goujet D.

ment être franchement antérieure par rapport à

la dorsale. La nageoire caudale est courte, avec

un lobe hypochordal bien développé.

Le fragment du cégumeni correspondant à la

région dorsale de là tête comprend des tessères

allongées. Ces tessères se raccourcissent et se

confondent avec les écailles du corps en arrière

de la position présumée de la chambre bran¬

chiale. Les tessères semblent s’organiser en ran¬

gées longitudinales dans la région antérieure, un

arrangement particulier semblable à celui de

Mesacanthus rnitchelli d’après les remarques de

Watson (1937 : 75). Les écailles de la tête et du

corps ne sont pas ornementées.

Ecailles

Les écailles sont petites (0,4 mm), lisses, rhom-

biques et ne semblent pa.s imbriquées. Elles sonr

proportionnellement plus petites que celles du

genre Triazéugacarithus et rappellent, par leurs

proportions, celles de Mesacantlms mitcbellL De

raille uniforme sur le tronc, clics sont plus petites'

antérieurement. Elles sont alignées en rangées

obliques sur les flancs. Au niveau de la nageoire

caudale, elles recouvrent le voile. En forme de

petits reaangles, elles vont en se réduisant vers le

bord distal, iorrnant des rangées parallèles au

bord d’attaque, perpendiculaires à l'axe du corps.

Sur les fragments de tégument de la région de la

tête, on repère une série d'éléments écailleux

allongés qui correspondaient vraisemblablement

à des tessères. Compte tenu de leurs dimensions

et de leur type de conservation, il n'a pas été pos¬

sible de les figurer : elles sont en effet partielle¬

ment transparentes et ne réagissent que

partiellement à la coloration par l’alizarine, aussi

le contour de ces éléments qui demeure en partie

flou ne peut-il être tracé avec une précision suffi¬

sante.

Ceinture scapulaire

La ceinture scapulaire de Mesacanthus grandis

n.sp. n’est représentée que par sa scapula (Fig. 4).

Cet élément est forme d’une ossification péri-

chondrale, qui comprend une tige dorsale s'éva¬

sant vers le bas en une expansion triangulaire. En

largeur, cette base correspond environ au tiers de

la hauteur de la tige scapulaire. La base de la sca¬

pula possède, comme celle de Tnazeugâcanthus

Fig. 4. — Mesacanthus grandis n.sp., mont Nidhogg. Spitsberg,

MNHN P SVD 246 ; scapula droite en vue mésiale. Echelle :

2 mm.

ajjinisy une fosse glénoïde très marquée (Fig. 4),

mais qui semble proportionnellement plus petite

que chez ce dernier. Cette fosse glénoïde se situe

sur la face postérieure de la lame latérale. Une

seconde petite lame, probablement post-

branchiale, est en continuité avec la tige scapu¬

laire, perpendiculairement à la lame latérale. Elle

forme, avec la fosse glénoïde de la lame latérale,

une dépression dont la ba.se est mal définie,

comme chez tous \ts exemplaires connus de

Mcsacanthidac. Il .se pourrait néanmoins quelle

puisse servit de marge radialis. La tige scapulaire

est peu élancée comparativement à celle de

Iriazeugacanthus affinis (Miles 1966 : scap,

pl. 5-9). Sa forme générale rappelle la scapula de

Mesacanthus Tnitchelli, mais dans cette dernière

espèce, elle n'a été que succinctement décrite

(Miles 1973: 159, fig. 23).

Aiguillon dorsal

Seule la partie proximale de raiguillon dorsal est

conservée en place. D’après la forme de la base, il

est clair que cet aiguillon nétait pas profondé¬

ment inséré dans le corpSj une caractéristique des

Mesacanrhidae parmi les Acanthodiformes. Une

section transversale ne montre qu un seul sillon

510

GEODIVERSITAS • 1997 • 19(3)

Nouveaux acanthocliens du Dévonien du Spitsberg

profondément marqué de chaque côté de

laiguillon. Il marque l'avant de la nageoire dor¬

sale qui occupait donc une position très posté¬

rieure. Le rapport de la distance du museau à

laiguilJon dorsal sur la longueur torale du corps

devait être d’cnvirmi 0,65, tandis que ce rapport

se rapproche de 0,53, tant chez Tnaz-cugacantbiu

que chez Mesacanthus mitchelli.

Nageoire caucLile

Uaxe de la nageoire caudale semble peu relevé. Le

lobe hypochordal esr petit, triangulaire, et ne

s’étend pas jusqu'à rextrémiré de Taxe caudal. Le

rapport de la nageoire caudale à la longueur totale

du corps esc égal à 0,23, tandis qu’il correspond a

0,28 chez Mesacmrthns mitchelli et à 0,32 chez

Triazeugacanthiis ajfmis. Le rapport de la hauteur

maximale de la nageoire caudale sur sa longueur

au pédoncule représente 0,4 chez le Mesacanthus

du Spitsberg candis qu'il approche 0,5 chez

l'espèce d’Écosse.

CONCLUSIONS

Xylacanthus minutus n.sp. est connu par un os

denrigère unique, présentant la morphologie clas¬

sique des Ischnacanthifocmes. Il est mince, élargi

pour le support du cartilage de Meckel, et ses

dents sont lusionnées. Aucune spirale den-taite

n'est connue ; les dents fusionnées sont plus

grosses à l’avant. Ccci suggère, comme Orvig

(1973 : 127-130) Ta montré, que de nouvelles

dents, sur une nouvelle base, sont périodique¬

ment ajoutées à l’exTrémité antérieure de la

mâchoire, comme chez les placodermes (voir aussi

Valiukevickis 1992 : fig. SA, pis 1, 4, fig. 3).

L'extrémité postérieure de l’os dentigère chez

Xylacanthus (Fig. 2) est simple comme chez les

Ischnacanrhidae hchnurambusj Persacanthus^

(Janvier 1977 )t Rockycampacantbm ou Taemasa-

canthus (Long 1986), alors.que Pariiculaiion est

géncralemenr double chez les Climatiiformes et

Acanthodiforracs. Un grand processus postéro-

dorsal marque l’avant de la région articulaire. Ce

processus, en continuité avec la bordure linguale

chez Taernasacanthus, Aiopjicanthm (0rvig 1957)

et Persacanthus. esi bien individualisé chez

Xylacanthus. Chez ce dernier, la fossette accessoire

du procc.s.sus po.stéro-latéral est basse alors qu’elle

est haute chez Atopiicanthus et Taemasacanthus.

Gro.ss (1957) suggère d utiliser la forme des dents

pour séparer les os dentigères de Climatiiformes

de ceux des Ischnacanthiformes. Cependant,

Denison (1976), après une étude histologique,

considère que le seul os dentigère attribué aux

Climatiiformes [Nostokpis ; Gross 1957 ; 0rvig

1973) se rapporterair au genre GomphonctnLs, un

Ischnacanthiformes. Toutefois, les caractères rele¬

vés par Gross restent intéressants : par exernple,

« présence de cuspides secondaires attachées à la

cuspide principale », caractère repris par 0rvig

(1967a) sous la forme « présence de cuspides

secondaires latérales plus nombreuses à l’arrière

de la dent » Chez Xylacanthus (Fig. 2),

Persacanthus et Taemasacanthus, une crête posté¬

rieure est visible sur chaque dent- La présence de

tubercules secondaires ou de crêtes est probable¬

ment liée à des types de synchronissation du déve¬

loppement différents pour Pos denrigère et pour

le champ morphogénétique des dents.

Un autre caractère présenté par Gross (1957) et

qui existe chez la majorité des Ischnacan-

thiformes est la présence d’un champ dentigère

labial (champ dentigère secondaire), U est géné¬

ralement garni de tuHercqIes mais peut être lisse,

comme chez Persacanthus, ou finement denticulé,

comme chez Xylacanthus.

La présence de stries sur les dents, leur crête pos¬

térieure tubcrculée, la largeur du champ lingual

très finement denticulé, et la finesse de J’os denti-

gère du genre Xylacanthus permettent d'y voir un

intermédiaire morphologique entre Persacanthus

et le Nostolepis de 0rvig (1973). Ce dernier est

probablement un Ischnacanthiformes (Denlson

1976).

Le spécimen articule d’acanthodien, Mesacanthus

grandis n.sp., ne possède qu'une seule nageoire

dorsale, caractère di.stinciif des Acanthodiformes.

Ses écailles non ornementées sont égaleincni clas¬

siques dans cet ordre. L’insertion superficielle de

l'aiguillon dorsal, la forme des tessèrcs rectales ci la

morphologie de la ceinture scapulaire plaident en

faveur d’un Mesacanthidae. Toutefois, la préseitce

d’éperons intermédiaires — jusqu'ici considérés

comme une exclusivité de la famille au sein des

Acanthodiformes — n’a pas été mise en évidence.

GEODIVERSITAS • 1997 • 19(3)

511

Gagnier P.-Y. & Goujet D.

Dcnison {1979 : 47) écrit que le genre

Mesacanthus correspond à des petits poissons

acanrhodieiis minces et élancés, dont la tête est

recouverte d'écailles inégulîères, et qui peuvent

posséder de larges plaques inter-orbitaires. Chez

TnazeugiU'anshuü (Miles 1966 ; Gagnier 1996), la

tête est couverte d'écailles régulières cr représente

probablement un stade primitif à panir duquel la

tendance à la tonnation des plaques inter-

orbitaires a pu évoluer. La forme allongée des tes-

sères rectales est un caractère partagé entre

Mesacanthus mitchelli et A/, ^indh n.sp.

Toutefois, les tessères reaalcs existent chez tous

les Climatiiformes, Euthaamthm. Watson

(1937), Novitskaya Obruchev (1964 : 272) et

Miles (1965 : 247 ; Miles in Moy-Thomas &

Miles 1971 ; 74) considèaenc que l’évolution des

acanchodiens mène à une réduction du squelette

dermique. La présence de tessères cbez les

Climatiiformes serait donc primitive. Miles

(1971) interprète les plaques inter-orbitaires de

Mesacanthus ou encore Los riasal de Triazeu-

gacanthus ajpaiis comme des stades régressifs

secondaires. En revanche, Denison (1979 : 5) fait

remarquer que les Climatiiformes considérés

comme les moins évolues ont des tessères plus

petites ou des écailles peu modifiées (cl*. Eiuha-

canthus). De plus, les tessères rectales des

Climatiiformes sont en général des écailles modi¬

fiées, élargies, qui partagent une base commune.

Nous partageons l’opinion de Denison qui consi¬

dère deux voies possibles de spécialisation au sein

des acanthodiens. Une première voie se traduirait

par rélargissement des formations osseuses ; la

seconde, par la diminution de l’écaillurc chez

certains Acanthodidae tels que Tra^juairichthys et

Acanthodes, Il s’agirait alors d’une régression

secondaire.

La scapiila de Mesacanthus^ comme celle de

Triazeugacanthus, possède une haute tige dorsale

(Fig. 4). Cette tige est circulaire ou ovale en sec¬

tion comme celle des autres acanthodiens. Chez

Mesacanthus gtandh n.sp., la base de la scapula

semble s’étendre vciuralement, couvrant la partie

latérale de f aiguillon pectoral (Fig. 4). Chez

Triazeugacanthns affinis, la base de la scapula est

petite et ne couvre probablement pas la partie

latérale de l'aigmllon. Il semble toutefois exister

une concavité pour la réception de ce dernier et

une autre pour farriculation d’un procoracoïde.

Cependant, aucune trace de certe ossification

n’est visible.

Bien que la scapula des Mcsacanchidac reste assez

mal connue, elle montre des caractères qui lui

sont propres, tels que la présence d’une tige dor¬

sale (supra-scapulaire) très haute et une fosse

postéro-médiale associée à la lame latérale plutôt

qu’à la tige dotsale comme c’est le cas chez les

autres acanthodiens. Contrairement aux

Chciracanrhidae, la scapula des Mesacanthidae

posséderait une portion basale qui enserrait

l'aiguillon.

Dans les Vieux Grès Rouges de la Formation de

Wood Bay, les acanchodiens apparaissent comme

des raretés comparées aux placodcrmes, aux

agnathes ou aux porolepilormes. En fait, on les

rencontre en abondance dans les niveaux de base

de la formation (division launique de

Sigurdfjellet) où d'emblée ils .sont représentés par

de grandes formes, pui.sque des aiguillons de

l'ordre de 10 cm de long ne sont pas rares. Plus

haur dans la série, leurs restes sont plus clairse¬

més. La découverte d’un individu complet de

A'îesacanthus artesre cependant qu'ils vivaient à

proximité du lieu de leur découverte ou dans la

tranche d’eau immédiatement sus-jucentc. !>a

nature du sédiment témoigne d'un environne¬

ment momentanément curbide probablement lié

à une décharge sédimentaire soudaine et brutale.

On notera que Mesacanthus grandis a été décou¬

vert dans les niveaux supérieurs de la Formation

de Wood Bay et que, plus haut dans la série stra-

tigraphique, les influence.s marines évidentes s'ac¬

compagnent d'accumulations d'écailles parmi

lesquelles celles d'acanthodiens sont les plus

abondantes. En conclusion, contrairement à ce

que pourrait faire croire une première impres¬

sion, les acanthodiens, prédateurs actifs à cette

époque, seraient ici des indicateurs d'influences

marines plutôt que des témoins de l'apport d'eau

douce. Il est probable qu’une incursion à proxi¬

mité des côtes leur fut accidentellement fatale et

qu'ils y trouvèrent le lieu de leur ensevelissement.

Remerciements

Les auteurs tiennent à remercier H. P. Schultze et

512

GEODIVERSITAS • 1997 • 19(3)

Nouveaux acanthodiens du Dévonien du Spitsberg

V. T. Young pour leurs remarques et commen¬

taires qui ont grandement contribué à améliorer

le texte initial de cette note.

RÉFÉRENCES

Blieck A. R. M., GoJshani F., Goujet D., Hamdi A.,

Janvier P., Mark-Kurik E. & Martin M. 1980. —

A new vcrtebratc locality in the Eifelian of the

Khush-Ycilagh Formation, Eastern Alborz, Iran.

Palaeovertehrata 9'V: 133-154.

Denison R. H. 1976. — Notes on a dentigerous jaw

bones of Acanthodü. Neues Jahrbuch fiir Géologie

und Paliiomologie Monatshefie, 395-399.

— 1979. — Acanthodü. Handbook of Palcoichthyo-

loQ/^ volume 5, 62 p.

Gagnier P-Y. 1996. — Acanchodiir 149-164, in

Schultze H. P. & Cloutier R. (eds), Devonian Fishes

and Plaîits of Miguasha, QuebeCj Canada,

Dr Friedrich Pfeil Verlag, München.

Gagnier P.-Y.. Turner S., Suarez-Riglos M.,

Friman L. & Janvier P. 1988. — The vertebrates

and bivals from the Devonian Catavî Formation at

Seripona, Chuquisaca. BoÜvia. Nettes Jahrbuch Jttr

Géologie und Palàontologie Abhandlung B 176 (2):

269-297.

Goujet D. 1984, — Les poissons Placodcrmes du

Spitsberg. Arthrodires Dolichothoraci de la

Formation de Wood Bay (Dévonien inférieur).

Cahiers de Paléontologie (sec. vert.), CNRS éditions,

Paris, 284 p.

Gouiet D. &C Emig C. C. 1985. — Des Lingula fos¬

siles, indicateurs de modifications de l’environne¬

ment dans un gisement du Dévonien inférieur du

Spitsberg. Comptes Rendus hebdomadaires, Séance de

lAcadémie des Sciences^ Paris, tome 301, série II,

13:945-948.

Gross W. 1957. — Mundzahne und Hautzahne der

Acanthodier und Arthrodiren. Palaeontographica, A

109; 1-40.

Long J. A. 1986. — New ichnacanthid acanthodians

from the early Devonian of Australia, with com-

ments on acanthodian interreJarionships. Zoological

Journal ofthe Linneati Society 87'. 321-339.

Miles R. S. 1965- — Some features in the cranial

morphology of acanthodians and the relationships

of Acanthodü. Acta Zoologica 46; 233-255.

— 1966. — The acanthodian fishes of the Devonian

Plattcnkalk of the Paffrath trough in the

^'xtycVànd. Arkiv for Zoologi (1), 18 (9): 147-194.

— 1973. — Articulatcd acanthodian fi.shcs from the

Old Red Sandstone of England, with a review of

the structure and évolution of the acanthodian

shoulder-girdle. Bulletin of the British Muséum

(Natural History, Geology) 24: 113-213.

Moy-Thomas J. A. Miles R. S. 1971. — Palaeozoic

fishes. Second ed., Chapman and Hall, London,

259 p.

Novitskaia L. L & Obrucliev D. V. 1964. — Class

Acanihodei, in Fundamentals of Paleontology,

Academy Nàuk SSSR 11: 175-194.

0rvig T. 1957. — Notes on somc Palcozoic lower

vertebrates from Spitsberg and North America.

Norskgeologisk tidskrifi^l: 285-353.

— 1967a. — Phylogeny of tooth ris.sues: évolution of

some calcifîed tissues in early vertebrates, in

Miles A. E. W. (ed.), Structural and chemical orga¬

nisation of teethy Academie Press, New York 1 :

45-110.

— 1967b. — Some new acanthodian material from

the Lower Devonian of Europe, in Panerson C. &

Greenwood P. H. (eds), Fossü Vertebrates, Zoolo¬

gical Journal of the Linnean Society 47 (31 1):

131-153.

— 1973. — Acanthodian dentition and its bearing on

the relationships of the group. Palaeontographica

143: 119-150.

Valiukevicius J. 1992. — First articulatcd

Poracanthodes from the Lower Devonian of

Severnaya Zemiya, in Mark-Kurik E. (ed,), Fossil

fishes as living animais. Academia 1: 193-213.

Watson D. M. S. 1937. — The Acanthodian fishes.

Philosophical Transactions of the Royal Society of

London 228B: 49-146.

Soumis pour publication le 22 mai 1996;

accepté le 17 février 1997.

513

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes (Vertebrata, Piacodermi)

from the Late Devonian Gogo Formation,

Western Australie, with a révision of the

Européen genus Ctenurella Ory'ig, 1960

John A. LONG

Department of Earth and Planetary Sciences, The Western Australian Muséum,

Francis Street, Perth, Western Australia, 6000 (Australia)

Long J. A. 1997. — Ptyctodontid fishes (Vertebrata, Piacodermi) from the Late Devonian

Gogo Formation, Western Australia, with a révision of the European genus Ctenurella

Orvig, I960- Geodiversitas 19 (3) : 515-555.

KEYWORDS

Ptyctodontida,

Devonian,

Piacodermi,

Coco,

Australia,

Austroptyctodus n.g.,

Ctenurella,

Chelyophortis.

ABSTRACT

A new, almost complété specimen of the ptyctodontid placotierm

Campbellodus decipiens Miles Young, 1977 enables description of the skull

roof, trunk shield, viscéral skeleton, pelvic girdie, dermal scale cover, and

parts of the vertébral column. A new reconstruction of the head shield of

Ctenurella gladhachensis 0rvig. I960 from Bergisch-GJadbach permits thk

taxon to be generically defined from the Gogo species previously referred to

that genus. The Gogo foriTi is hea* referred to Austroptyctodus n.g. A new spe¬

cimen o\ Austroptyctodus gardineti Miles ^^/^Young, 1977» together with new

observations of Chelyopborus vernmtli Agassiz,, 1844 and Ctenurella gbdba-

chensis 0rvig, 1960, shows new information for the endocranium, the hyoid

arch and viscéral skeleton, identifying the previously identified ‘^metaptery-

goid” éléments as paired nasal bones. The large viscéral skeleton bone poste-

rior to the jaw joint in ptyctodontlds is here identified as an elongated

interhyal.

MOTS CLÉS

Ptyctodontida,

Devonien,

Piacodermi.

Gogo,

AustraRc,

Austroptyctodus n.c.,

Ctemirella,

Chelyophortis.

RÉSUMÉ

Une nouvelle description du toit crânien, de la cuirasse thoracique, du sque¬

lette viscéral, de la ceinture pelvienne, de Técaillure et de quelques éléments

de la colonne vertébrale est proposée à partir d’un nouveau spécimen sub¬

complet du ptyctodonte Campbellodus decipiens Miles et Young, 1977. Une

nouvelle reconstitution du toit crânien de Ctenurella gLidbachensts 0rvig,

I960 (Frasnicn de Bergish-Gladbach, Allemagne) permet de redéfinir le

genre Ctenurella^ en y incluant les formes de Gogo qui y sont rapportées. Un

nouveau genre Austroptyctodus. est créé. A partir du maicrici qui définit

Austroptyctodus gardineri, espèce-type du genre, et d’une révision de

Chelyophonis vemeuilli Agassiz, 1844 et de Ctenurella galdbachemky de nou¬

velles informations sur l’endocrâne. Tare hyoïde ei le squelette viscéral dc.s

pryctodontes sont fournies. Ainsi le n métapcerygoïde >> est interprété comme

des os nasaux pairs, de même Tes du squelette viscéral situé en arrière de

l'articularion de la mandibule serait un interhyal de forme allongée.

GEODIVERSITAS • 1997 • 19(3)

515

Long J. A.

INTRODUCTION

The ptyctodontid placoderms hâve for many

years been a problematic and poorly-known

group of extincc flshes. Early workers idencified

ptyctodontids only from their characterisnc cooth

plates and chus allied then^ lo rhe holocephalans

(Pander 18S8; Woodward I891)t although when

the cxoskeletal trunk armour was described by

Jaekel (1907) he compared ir fàvourably with the

sturgeon Acfpensc7\ an osteichrhyan fish. Roth

Dollo (1907) and Goodrich (1909) rejectcd this

view and argucd that chey were placoderm fishes.

Watson (1934) described more complété macerial

of a new form he called Rhamphodopsis and fur-

cher characterised chem as placoderm fishes, and

this view was strengthened by further discoveries

of well-preserved specimens (Watson 1938).

Major discoveries of complété, well-preserved

ptyctodontids from the Bergi.scb-Gladbach région

of Germany described by 0rvig (1960, 1962,

1971, 19S0) led him to revive the carlicr hypo-

thesis of a holoccpltalan affinity between ptycto¬

dontids and holocephalans, proposing them to bc

ancestral to the holocephalans, an opinion loUo-

wed by Stenski (1963, 1969) and Jarvilc (1980).

However, many researchers working wirh placo¬

derm fishes or chondrichthyans opposed this

view, regarding ptyctodontids as placoderm fishes

{e.g. Patterson 1963; Stahl 1967; Miles 1967;

Miles Young 1977; Denison 1978; Forey &

Gardiner 1986; Young 1986). Today this view is

widcly held, and the placoderm affinity of ptycto¬

dontids has been borne out by several recent

computer analy.ses of placoderm incerrelation-

ships {e.g. Forey & Gardiner 1986; Carr 1991,

1995; Goujet & Young 1995).

The problematic position ol the group wîthin

the Placodermi has been raised. Tbey hâve been

proposed as a primitive sisrer group to other pla¬

coderms (Miles & Young 1977: Young 1980), as

a primitive group more derived than acantho-

thoracids plus rhenanids, but plesiomorphic to

ail other placoderms (Forey & Gardiner 1986),

or as a sister taxon to the petalichthyids (Goujet

1984; Goujet & Young 1995; Carr 1995).

Most of che kaown ptyctodontid taxa (some

forty-seven species, Carr 1995, amended) are

based solely on tooth-plates (Denison 1978),

although rhe following species hâve been descri-

bed from relacively complété, well-preserved

marerial of head and trunk armour: Ctenurella

gladbachensii (0rvig 1960, 1971), Àustro-

ptyctodm gardineri n.g. (Miles & Young 1977,

here erected as a new genus), Rhampbodùpns

tbreiplandi and R. trispmatîi^ (Watson 1934,

1938; Vliles 1967), Rhynchodus tetradon

(Newberry 1 873; Jaekel 1903; Gross 1933;

Stensio 1959 ; Miles 1967). Cbelyophonn ver-

mieili (Agassiz 1844; EichwaJd 1859; Obrucheva

1983), and Ptyctodopsis menzeli (Denison 1985).

Recenr new discoveries of other relatively com¬

plété ptyctodontids hâve been made in

North America from the Frasnian Mt. Eldetr site

in. Arizona (Johnson ât Elliott, in press) and

from the Pînicon Range Formation, lowa

(Hickerson 1993; work in prep.).

The superb three-dimensionally preserved mate-

rial of ptyctodontids Irom rhe Frasnian Gogo

Formation of We.stern Australia has provided the

most detailed knowledge ot the group to dare.

Miles & Young (1977) described several spéci¬

mens of a new species they ;tsslgned to the genus

Ctenurella 0rvig, I960. Two incomplète speci¬

mens were placed in the new genus and species,

Camphellodus decipiens. Further observations on

the structure ot the Gogo ^CtenutrlLi' were descri¬

bed by Gardiner (1984a) and Forey & Gardiner

(1986). New finds of Gogo fishes made dunng

expéditions in 1986-1989 by rhe auchor include

many new arthrodires (Long 1987, 1988a, I9S8b,

i990K 1994a, 1995b) as well as two nearly com¬

plété, articulated specimens of ptyctodontids,

which belong to the previously described taxa.

The aim of this paper was originally to describe

this new material of the Gogo ptyctodontids in

detail, by comparison with other specimens of

ptyctodontids, made avajlable for che author to

study at the Muséum nanonal dTüstoire natu¬

relle. The wcll-pceserved nature of the Gogo spe¬

cimens has permitred new further interprétations

of the structure of these other taxa. Compari.sons

with the Bergisch-Gladbach Ctenurella indicared

that its skull roof and viscéral skeleron could be

reinrerpreted. It soon became apparent that this

species differs in several major features from the

Gogo species, and chus a new genus, AiistrO'

ptyctodus n.g., is here erected for the Gogo species.

516

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

DERMAL BONE TERMINOLOGY

IN PTYCTODONTIDS

The central médian bone thac bears the X-sha-

ped confluence of the two main dorsal

senson^-linc canals lias bcen previously called the

centro-nuchal (0rvig I960)> the cenno-median

(Miles 1967), the nuchaJ {e,g. Miles & Young

1977; Long 1988a} or the postpineal (Dcnison

1978, 1985; Johnson & Elliott 1996).

Confusion over the nume of this bone has ariscn,

largely due to the supposed presence of a small

posterior médian clement in Rhamphodopsis

which was termed the nuchal. Examination of

specimens of Rhamphodapsh threiplandi in the

collections ol the Natural History Muséum,

London, and in the Ficid Muséum, Chicago,

shows that the posterior nuchal élément is not

présent in this genus, but was misinterpreted by

Watson due to rhe crushed and fractured nature

of the Edderton specimens. The area of exposed

bone immediately behind the paired central

plates is most likely the crushed occipital ossifica¬

tions of the braincasc, as this région lacks any

trace of dermal ornamentation on the Edderton

specimens.

In other placodcrm groups that hâve the supraor-

bital sensory line cariais as well as posterior pic-

line canals converging mcsially onto one médian

bone, as in ptyctodontids, this bone is generally

identified as the nuchaL espccially so when it

extends ail the way to the posterior margin of the

skull roof {e.g. as in petalichthyids; Woodward

1941; Gross 1963; Young 1985; Lia 1992). This

condition is aiso seen in the primitive arthrodire-

like form Wuttagoanaspis (Rîtehie 1973) and in

phyllolcpids. whcrc the nuchal plate is broad

rather than clongate. bur still bears rhe confluen¬

ce of several .scnsory-line canals (Long J 984b). In

many primitive ariltrodireît this bone has a .simi-

lar elongatc shapc and also has similar contact

relationships wich neighbouring paranudial, cen¬

tral, and poscorbital or prcorbital bunes,

although the convergence of the sensory-line

canals is lacking.

l'hus the médian caual-bearing bone in ptycto-

doniids is incerpreted here as homologous to the

nuchal of other primitive placoderms, rather

then a postpineal as this élément, where présent

in some placoderm groups, is always a médian

bone lacking sensory-llne canals {e.g. as in an-

tiarchs, Denison 1978), or maybe represented by

a sériés of irregularly-shaped onamestic bones (as

in the rhenanid AsterosteuSy Stensiô 1969, fig 92).

For chc other bones m the head shield and cheek

of ptyctodoniids, papers published since Miles 6C

Young (1977) use a consistant lerminology.

However, the large paired ventral bones in the

rrunk shield that hâve bcen called either the

anterior vcnrrolaterals (Gross 1933; Miles 1967)

or chc intcrolatcrals (Watson 1938; Denison

1978, 1985) require discussion. 0rvig (1960)

regarded them as a combination of both élé¬

ments and termed them the interolateral-anterior

ventrolarerals The anterior vcnrrolaceral plates in

primitive placoderms, such as petalichthyids

{Lumspis, Gross 1961), early arthrodires (actino-

lepids, phlyctaenaspids, Gou)ec 1984b)> phyllole-

pids (Long 1984b) and Wuttagoonaspis (Ritchie

1973) are named so because there is also a poste¬

rior ventrolatcral plate présent posterior to them.

Ail of these forms also beat paired interolateral

plates forming the anterior ventral margin of ihc

shield and meeting the spinal plates dorsally, and

in ail cases having an expanded anteriorlyTacing

postbranchial lamina wiih rows of triangular

rubcrcles. In acanthothoracids (e.g. Romundinay

0rvig 1975) and rhenanids (e.g. Jagorina^

Sien.sio 1969) there is only one pair of large ven¬

tral plates and ihese also form the anterior mar¬

gin of the ventral lamina of ihe rrunk shield and

hâve a postbranchial lamina which in life presum-

ably formed the posterior wall of rhe branchial

chamber. However, it is known that ihe position

of the scapulocoracoid in arthrodires generally

sits between the anterior latéral, the spinal and

the anterior ventrolatcial plates (and also be¬

tween rhe interolateral in Dtcksoîiostezis, Goujet

1984b). Similarly, in antlarchs, it lies within the

bounds of the anterior vcnirolateruls, even

though only remnants of it hâve beeii tound in

primitive forms (e.g. Procondylolepis^ Young ÔC

Zhang 1992). Thus its condition in ptyctodon-

tids would impiy that the interolateral has expaii-

ded ventnilly to include the scapulocoracoid, or

that ic has indeed fused with the anterior ventro-

lateral lo he a compound bone (as suggested by

0rvig 1960, also Stensiô 1959). The identifi-

517 1

GEODIVERSITAS • 1997 • 19(3)

Lx)ng J. A.

cation of ihe bones in pryctodonrids cornes

down to i;he overall shape in ihat ürey are narrow

bones without posieriorly extended ventral lami-

nae, bordering, in che irunk shield, die anterior

ventral margin ol the trunk and contacting ihe

spinal plaie dorsally» and ihe faci chat tbey bear

rhe well-developed postbranchial lamina wiih

rows of triangular tubercles, a featurc never

found in any placodcrm anterior vcntrolatcral

plate (bccause interolacerals are aJso présent in

the same armour). Thtis ic is here su^ested that

they represent interolateral plates. This hyporhe-

sis implies that ihe ptyctodontid trunk shield is

more specialised than those of other placoderms

in the secondary loss of both anterior and poste-

rior ventrolaterals.- In this respect they could par-

rallel the évolution of phyllolepids, now regarded

as derived arthfodirrs in the loss of postenor dor-

solateral plaies and the fusion of upper jaw élé¬

ments (based on materials of a new phyllo-lepid

from New South Wales iindcr study by

Dr. A, Ritchic, pers comm. 1995).

MATERIALS AND METHODS

The ptyctodontids from Gogo were prepared by

the standard acetic acid technique using about

5-10% concentration, strengthcned with dilute

B30 Mowital in acétone solution (from

Hoescht). The délicate nature of the Austroptyc-

todus specimen callcd for epoxy resin transfer

préparation. Before embedding the specimen in

resin, a latex peel of rhe exposed surface derail

was made. Ail photographs are ofspecimens whi-

tened with ammonium chloride, excepi for the

Bergisch Gladbach specinieiis which were phoio-

graphed under alcohol.

The new Gogo speciraens were compared with

the following ptyctodontid material. These

results will form the basis ol a future révision of

the Euramexican ptyctodontids:

— Austroptyctodus gardineri n.g. (Miles et Young,

1977). Ail specimens held in theNatural History

Muséum, London. Upper Devonian (Frasnian),

Gogo Formation, Western Australia.

— Chelyophorus verneuili Agassiz, 1844. Original

Agassiz collection held in the Palacontological

collections of the Muséum national d’Histoire

naturelle, Paris. Llppcr Devonian (Fammenian),

Dankov-Lebedyan beds, LISSR.

— CtcntAteUa gladhachensb 0rvig> I960. Five

nearly complété well-preservcd specimens held in

rhe Palaeontological collections of the Muséum

national d'Hiscoire naturelle, Paris; other spéci¬

mens in the Natural Histor}' Muséum, London.

Middlc-Upper Devonian (Upper Giveuin/Lower

Frasnian), Obérer Plartenkalk, Germany.

— Pt)fctodopsis menzelli Denison, 19S5. Type spe¬

cimen held (on display) in the County Museqrn,

lowa City, lowa; additional specimens held in

the Geology Department collection, L^niversity

of lowa, lowa City. Middie Devonian (Upper

Givetian), Cedar Valley Limestone, USA.

— Rhamphodopiis threiplandî Warson, 1934.

Specimens in the Field Muséum, Chicago and in

the Natural History Muséum, l.ondon. Middie

Devonian (Eifelian), Middie Üld Red Sandstone,

UK.

— Rhynchodus tetrodon. CasL of the holor}'pe held

in the Nntural History Muséum. London. Upper

Devonian (Frasnian). Kellwasserkalk, Germany.

— Specimens of an undescribed new genus of

ptyctodontid from the Spring Grove Meniber

(Givetian), northern Illinois, held by the

Geolog)^ Department, Augustana College, Rock

(sland, Illinois.

— Specimens of an undescribed new genus of

ptyctodontid from the Gneudna Formation

(Upper Givetian-Lower Frasnian), Western

Australia, collected by the authc>r and

K. Trinajstic in 1995.

Al! specimens described or cited in this paper are

reposited in the palaeontology collections of the

following institutions as denoted by these abbre-

viations:

MNHN Muséum national d’Histoire naturelle,

Paris;

NHM Natural History Muséum, London;

WAM Western AustraÜan Muséum, Perth,

Western Australia.

SYSTEMATIC DESCRIPTIONS

Genus Campbellodus Miles Young, 1977

Type SPECIES. — Campbellodus decipiens Miles et

Young, 1977.

518

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

AaiIiNDED DiAGNOsiS. — A inotleraicly large ptycto-

domid haviiig a PtyctuduS‘\\\<£: crushing dendeion with

high dorsal process on the upper tooihplate, head

shield having a breadth/lengrh ratio of 90, che nuch-al

is subrectanguiar, almosi as broad as long and j)artici-

pates in the posterior margm of tht skull-rool-, cxclu-

ding the centrais from mcsial contact; submargin-al

plate is much deeper postcriorly tban anterlorly.

Trunk shield wlth three médian dorsal bones, the

dorsaimost bcing a broad, fiat splne. Spinal plate very

small; anterior médian ventral plate more tlian twice

as broad as long, fail covered with large overlapping

scalcs.

Campbellodus decipietu Miles er Young, 1977

Campbellodus decipiens Miles et Young, 1977:

145-155, figs 8-14, pis 1, 2A, B, 4A. - Denisoii 1978:

28. - Long 1987a: 203; 1988a: 443-4, fig. 7; 1988c;

141.143,144, fig. 2B; 1991: 366, 367. fig. 20H;

1995a: 108-110.

Ptyctodiis Gardiner et Miles, 1975.

“tooth-plates rescmbling those of Rhynchodus"

(Brunion, Miles &L Rolfe 1969)

“toodi-plates whlch recall those of Ptyctodus** (Miles

1971)

Holotype. — WAM 70.4.252. This number is nor

published in the Miles &c Younç (1977) as the spéci¬

men had then been alIocatetT by the provisional

British Muséum of Naturai History number P50905.

On 1ER MAITtRlAl.. — NHM P50907. compristng the

lefr spinal plate, left upper toothpiate, incomplète Icft

interolatera! plate, partial dorsal spine, a dermal scalc

and parts ol perichondral ossifications of the endocra-

nium (Miles & Young 1977). WAM 86.9.672, an

almost complète individual, shows the head shield

mostly complété, missing only pan of ihc posterior

margin on me riglu side and a small part of che left

posterior margin. It shows weli che three-dimensional

form of the entire arriculated trunk shield. the pelvic

girdic and endogirdlc. body .scalc.s and axial skelcral

cléments. WAM 95.6.112 shows the left upper and

lower tooth plates, mirror opposites ro those scen in

the holotypc.

Remarks. — The new material is regarded as cogene-

nc with the holotypc as the dorsal spine is of the same

broad based sbape with sirailar ornamenraiion, and

the isolarcd prcorbital, postorbital and submarginals

of the Holotypc are ail of similar shape ;md idcncical

proportions in WAM 86.9.672. This genus ha.s bcen

redefined in the light of nearly complète material of

the dcrmal armoun axial skelcton and squamation.

Long (1988a) figured a reconstruction ofthe dermal

armour, and conimentcd briefly on iis ovcrall mor-

phology, but it is only wichin the framework of stu-

dying the oihcr Gogo ptyctodontid with the compara¬

tive material of ocher European généra thar the com¬

plète description, and new reconstruction provided

here, could be undertaken.

Descwition

Head shield

The exceptional préservation of WAM 86.9.672

(Figs lA-C, 2) bas enabled the head shield of

Campbellodm to be restored in its natural three-

dimensional fdrm. This is unique for pryaodon-

tids in which restorarions usually show the head

shield flattcned in dorsal aspect, the one excep¬

tion bcing Ptyctodopsis (Denison 1985) which is

preserved in latéral view. Overall rhe head shield

is 90% as broad as long, being broadest across

the püscorbital places posterior to the large orbir.

The preorbical plates are cxceptionally large,

about iwice the size of the other skull roof boites,

which are approximately the same size as each

other. An unusual feature of the skull roof is rhat

the prcorbital place.s are not in rnesial contact

with apparcntly an open pineal notch for rhe

pineal organ. No pineal plate was recovered

during the préparation of the specimen, and, as

most of the dclicace gill arch clemencs of both

sides werç found, it is assumed rhat a pineal plate

was ci cher very small (as in Austroptyaodus n.g.),

or absent. In latéral view, the skull roof shows a

slii-like opening at che junction of the postorbi¬

tal, marginal and submarginal plates, referred ro

previously by Miles & Young (1977) as rhe post-

orbital fenestra and by Long ( 1988a) as the spira-

cular slii.

Marginal plate. le was apparently not tightiy

connccted with the lacerai margin of the head

shield: as its précisé dorsal border does not cor¬

respond CO the well-preserved ventral margin on

the lacerai face of the head shield, it is presumed

to hâve been looscly atcached. The submarginal

was probably aiso free in the skin of the cheek

région, bur anteriorly contained ihe opercular

cartilage which acticulated with the ethmoid

ossification of the braincase.

Preorbîtal plates. (PrO; Figs lA-C, 2) These are

che largest bones of the head, being just over half

the total length of the skull. Miles & Young

(1977, fig. 8) dcscribed and figured une of these

plates but wrongly identified it as the right ele-

GEODIVERSITAS • 1997 • 19(3)

519

Lx)ng J. A.

Fig. 1. _ Campbellodus decipiens Miles et Young, 1977. WAM 86.9.672. A-C, head shield; A, dorsal view. B. ventral view; C. right

latéral view, 0. E. nght marginal plate: D,, latéral view; E. mesial view F-H. médian dorsal plates in right latéral view; F. médian dor¬

sal spine: G, médian dorsal plate 2; H, médian dorsal plate 1.1, J. prepelvic bone and attached endoskeletaJ pelvic girdie: I, ventral

view; J, dorsal view. K, right quadrate in mesial view. Ail photos whitened with ammonium chloride.

520

GEODIVERSITAS • 1997 • 19(3)

Ptyccodontid fishes from che Late Devonian Gogo Formation

ethm. ri

1 cm

Fig. 2. — Campbellodus decipiens Miles ef Young, 1977, WAM 86.9.672. A-D, sketch of head shield; A, dorsal view; B, ventral view;

C. right latéral view: D, posterior view, art.fl, articular flange ot neck joint on PNu plate; Ce. central plate; dep, dépréssion; ethm.rl,

ethmoid ridge; for. foramen; gr. groove; Mc. main latéral line canal; Nu. nuchal plate (posterior element); orb, orbil or orbital margin;

P, pineal plate or space provided for it in the head shield; pit, pit for insertion of eye muscles: PNu, paranuchal plate; pp, posterior

sensory-line canal on head shield; ppr. posterior process of PNu plate: PrO, preorbital plate: PtO, postorbital plate; soc. supraorbita!

sensorydine canal; spir, spiracuiar sllt; suov, supraorbital vauit

ment when in face it is die lefc preorbital place, as

verified by direct comparison witb rJie arriculatcd

head shield of WAM 86.9.672. The preorbital

plates are subrectangular in form, having a

breadch/length index of berween 56-60, for both

specimens. They show a weakly concave latéral

margin, gently convex anterior margin, strongly

convex posterior margin, and gently concave

mesial margins witb a well-defined anterior

Dotch for ihe pineal foramen. In latéral view

(Figs IC, 2C), the preorbital plates are weakly

curved, flexing over the mid-point of che orbit.

The path of the supraorbital sensory-line canal is

only visible in dorsal view Iti die posterior parr of

che plate, faindy seen mainly through a single

row of minute pores opening from within the

spaccs of the reticulatc ornamentation. In viscéral

viev^v the tubular sen.sory-line canals are clearly

seea (Fig. 2B, soc, pp, lie), disappearing within

the centre of die boue at the os.sification centre

of the plate. The main latéral line sensory-Üne

canal that cornes oif the marginal plate enters the

GEODIVERSITAS • 1997 • 19(3)

521

Long J. A.

PNu

ppr

Fig. 3. — Campbellodus decipiens Miles et Young,

1977, WAM 86.9.672. Left paranuchal and postorbital

plates in mesiai view, showing spiracuiar sût. PNu,

paranuchal plate: ppr. posterior process of PNu plate;

PtO, postorbital plate; spir, spiracuiar slit; suov,

supraorbital vault.

preorbital at its posteroventral corner and runs

directly into thc ossification centre of tlie plate.

In viscéral view, the preorbital sJiows areas of

cancellous spongy bonc above the orbits, lor-

ming a supraorbital vault (suov, Fig. 2B), and

smooth areas of bone surface for contactlng the

endocramum, presumed here to be mostly card-

laginous. An anteriorly facing dépréssion

(Fig. 2B, ethm.ri) is posieriorly bounded by the

raised supraorbital sensory-linc canal (soc) and a

mesially direcced ridge, Presumably, this région

braced the dorsal wall of rhe ethmoid division of

the braincasc as it docs in arthrodines. The latéral

sides of thc supraorbital scnsoiy-linc canal has a

pit (Fig. 2B, pit) just posterior to the cthmoidal

ridge, possibly a myodome for eycmuscle attacli-

ment. Thcrc is a broad triangular dépréssion

(Fig. 2B, dep) defined by the mesiai margin of

the supraorbital canal and the raised mesiai edge

of the supraorbital vauk> and a simiJar postenor-

ly facing dépréssion between the cwo converging

sensory-llne canals in rhe posterior half of the

plate. The ornament of the preorbital plate is largc-

ly reticulate with patches of very fine tubercles

over the orbits and towards the anteriar margin.

Postorbital plate. (PrO; Figs lA-C, 2, .3) It is

only parcially visible in dorsal view, showing its

largest area in latéral view. 1rs dorsal lamina

contacts the central posteriorly and is notched

into the preorbiral anteriorly. In latéral view, it

has a smoothly concave anterior margin for the

orbir and an irregularly convex posterior margin

which in part forms thc margin for thc spiracuiar

slit (spir; Figs 2C, 3). In viscéral view, it shows

no unusual features apart from Ünear thickenings

of bone running out from the ossification centre

CO the margin of ihc spiracuiar .slit (Fig. 3). These

chickening of bonc aroiind the spiracuiar slit pre-

sumably assisted to direct lhe flow of water from

outside into thc spiracuiar groove.

Nuchal plate. (Nu; Figs lA. B, 2A. B, D) This

central niedian bone of theskull roofis contacted

ainerolaterally by the preorbitals, laterally by rhe

centrais, and forms the posterior indenced margin

of thc skull roof, It is a relativcly small but broad

bone for ptyctodontids, about half as long as che

preorbital, and only a little longer than its

bteadeh. It is quite fiat. lis margins arc ail complè¬

te and gencly concave to mect che surtounding

boncs which it ovcrlaps. The confluence of che

sensoiy-linc canals on the nuchal ai*e well-defined

in dorsal view and, in ventral view, arc clearly

seen by the raised tubes of bone chat carried che

sensory-lines (pp; Fig. 2B), Weak ridges of bone

radiate outwards from its ossification centre.

Left central plate. (Ce; Figs lA-C, 2A) li is

well-preserved in this speetmen although only

part of the righr élément is présent, but neither

shows the posteromesial margin completely pre-

served, Ir has a strongly concave anterior margin

for the preorbital plate, straight contact of latéral

margin where it meets the macginals, a strongly

convex latéral contact margin with the paranu-

cha) plate, and a relarively straight mesiai margin

where it lies in contact with the nuchal. The

short région of thc po.steroinc.sial margin is also

quite straight and forms part of the indented

posterior margin of thc skull roof.

522

GEODIVERSITAS • 1997 • 19 (3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

Paranuchal plate. (PNu; Figs lA-Q 2A'D> 3) It

is well prescrvcd on the left side of the skull roof,

and partly preserved on the right sidc. k has an

irregular shapc, dominated by concave margins

where it contacts the postorbital anteriorly and

the central anteromesially. It has short contact

wich the posiorbiial before beiiig indented for

the spiracular slii (spin Fig. 3). The posterior

margin of the paranuchal has a large, unorna-

mented posieriorly-facing flange of bone (art.fl;

Fig. 2D) for contact wiïh che siniilarly fiat pro-

cess on the anrerior donsolateral plate (art.conj

Figs 13, 14). The ventral margin of this articula-

tory flange has a smaJl foramen (for; Fig 2B),

corrc5ponding well to che position of rhe endo-

lymphatic duct opening on the viscéral surface of

the place in artlirodircs. Yct as the plate lacks an

external (dorsal opening), I conclude ir is possi-

bly just a nutritive canal. As rhe rwo arciculatory

surfaces of rhe paranuchal and rhe anterior dor-

solaceral plates do not precisely fir together. a

chin pad of cartilage probably divided the cwo

fiat processes to allow some sUght degree of verti¬

cal flexibility in the neck joint. There is also a

smooth process of dermal bone (ppr; Fig. 2B)

which projeers posteriorly from che latéral mar¬

gin of the paranuchal,. and weakly overlaps the

anrerior margin of che arcicular process of the

anterior dorsolareral plate. Thcrc is a groove

along rhe poscerovencral margin of the para¬

nuchal plate in posterior view (Fig. 2D, gn Fig. 6).

Marginal plate. (M; Figs ID, E, 4, 6) It is well-

preserved on the riglir side only. It is a wedge-

shaped bone, slighcly longer than the preorbirals

and, with a breadch/length index of about 37* is

narrower ihan for most other pryctodontids. It

lacks the strong inflection seen in some oiher

forms, such as Rhynchodus and Rhaynphodopshy

and is proportionarely much smallcr relative to

the head shield than for chose généra, k has an

almost stralght dorsal margin bordering the

orbic, and relatively straight, short margins for

concacting che postorbital and paranuchal plates.

The viscéral surface shows a pair of mesially

dirccted laminae extending our from che centre

of the plate (Fig. 4A, C, D). These laminae are

criangular în dorsal view and hâve a roughened

surface betw^een them presumably for contact

wirh che orbital ossification of the braincase.

This structure in pryctodontids is becter prescr-

Fig. 4. — Campbellodus decipiens Miles et Young, 1977, WAM 86.9.672. A-D, right marginal plate; A, mesial view; B, latéral view;

C, anterior view; D, dorsal view, mes.lam, mesial perichondral lamina extending from marginal plate: ov.PtO, overlap surfaces for

postorbital plate.

GEODIVERSITAS * 1997 • 19(3)

523

Long J. A.

ved in the new Gogo specimen oiAustroptyctodiis

and is descfihtrd in further detail below (see

Figs 28, 29)- The posterior division of the viscé¬

ral surface of the marginal plate has a smooth

triangular région emanating Irom behind the pai-

red laminae. The overlâp area for the postorbitàl

plate is Nvell-developed on the latéral surface

(Fig. 4 B);

Submarginal plate. (SM: Figs 5, b) It is preser-

ved only for the left side, but is also well-prescr-

ved in the holotype and was figured and

dcscribed by Miles & Young (1977, fig, 10). Tr is

broad, posteriorly, nartowing to a slighrly up-

turned, well-roundcd anterior end. It is propor-

tionately deeper in its posterior end than in ail

other ptyciodontids for which it is known, as in

most other piyctodontid gênera it is almost

bar-like. l’he viscéral surface is smooth with the

anterior end having the perichondral she|l of the

opercular cartilage in situ. In ventral view, this

perichondral lamina is niesially developed into a

strong process (mes.pr; Fig. 5C), which is inter-

preted to hâve supported a thick and presumably

large opercular cartilage (Fig. 6).

Fig. 5. — Campbellodus decipiens Miles et Young. 1977, WAM

86.9.672. A-C, left submarginal plate; A, mesial view; B. left

latéral view; C. ventral view, showing opercular cartilage ossifi¬

cation. mes.pr. mesial process or\ opercular cartilage; op.car.

opercular cartilage.

Viscéral skeleton

Scveral paired and one unpaired perichondral

ossification of the viscéral skeleton werc recox'er-

ed from chc specimen. Numerous viscéral arch

bone.s should bc Ibund in the skeleton of any fish

that had them well-ossified, yet only a few bones

have been found in this specimen, and in other

arciculated specimens of the Gogo form

Austroptyctodus^ and the German Ctenureila. This

suggesrs that only some bones of the anterior gill

arches in ptyctodonrids were ossified. .Schulc7-e

( 1993; 213) points out that in elasmobranchs the

dorsal hyoid arch éléments are the first to chon-

drify (epihyal, ceratohyal), follnwed by the pha-

ryngobranchials, epibranchials and cerato-

branchiaU, then lastly by the hypobranchials and

basibranchiab. It is possible that only rhose élé¬

ments of the first gill arch and possibly one pos¬

terior to it were invesred with perichondral hone

in ptyctodonrids. This could be explained by the

need to strengthen the bones in direct contact

with the strong jaw mcchanlsm, chc more distal

arch cléments rcmaining as cartiJaginous units.

The provisional identification of rhese gill arch

éléments is based on comparîsons with articulat-

ed matcrial of the other Gogo ptyctodontid,

AmtroptyctodiLu as weJI as articuJated specimens

of Cteinirella gladbachensis in the MNlfN, Pans.

Therc is no direct évidence, because none of the

smaller cléments arc preserved in life position in

any specimen examined. The position and iden¬

tification of the large!' éléments is based only on

their general shape and articulation surfaces in

relation to other large bones (e,g. the articulât),

and tomparisuns with the general shapes of ihcse

éléments in other primitive gnachostomes (chon-

drichrhyans, other placoderms, primitive osreich-

chyans).

The largesr of the gill arch elementLS in

Campbellodus are a pair of inwardly curved, dis¬

tal ly broad éléments. No comparable shape ro

bones previously idenrified in rhe ptyctodoniid

viscéral skeleton by Watson (1934)» 0rvig

(1960), Gardiner (1984a) or Furey & Gardincr

(1986). These bones (Fig. 7) arc strongly curved

mcsially and have grooves for vascular or nerve

passages on the latéral surface near the disral

(smaller) end. The>' are roo curved mesially and

coo narrow dorsally to be meckeUan cartilages

524

GEODIVERSITAS • 1997 • 19(3)

Piyctodontid fishes from the Late Devonian Gogo Formation

Fig. 6. — Campbellodus decipiens Miles et Young, 1977. Attempted reconstruction ot dermal exoskeleton and viscéral arches, from

WAM 86.9.672. Stippled areas are hypothetically restored cartilage bones. ADL. anterior dorsolateral plate; AL. anterior latéral plate;

Art. articular; Aut, Autopalatine: BH, basihyal; Ce. central plate; CH. ceratohyal; HH, hypohyal, Hym. hyomandibular; IH, interhyal

element: IL, interolateral plate; l.tpi, lower tooth plate; M, marginal piate; MD. MD1, 2, 3. médian dorsal plate(s) or spines; Nu,

nuchal plate (posterior element); op.car, opercular cartilage; PNu, paranuchal plate; PRO. preorbital plate; PtO. postorbital plate;

Qd, quadrate; SM, submarginal plate; Sp. spinal plate; u.tpl, upper tooth plate.

supporting the toochplaccs. By comparison with regarded as a synapomorphy of higher osteich-

other gnathostome fishes they could be cerato- thyans (Gardiner 1984b) as the condition in

hyals, which are also large, fiat bones with mcsial acanthodians (Miles 1973) or primitive actino-

curvature in primitive ostcichthyans Uke ptcrygians (Gogo palaeoniscoids, Gardiner

Medoevia [l.ehcdcy 1995), Glyptolepis i] 2 vyik 1984b) is to hâve a slendcr rod-like ceratohyal of

1972) or primitive lungfishes (Miles 1977; siniilar form to the ceratobranchials.

Campbell & Barwick 1988). However it is noted What therefore is the évidence for calling the

that the presence of an expanded ceratohyal is elongate bone, bracing the articular in Ctenurella

GEODIVERSITAS • 1997

Long J. A.

Fig. 7. — Campbellodus deapiens Miles et Young, 1977, WAM

86.9.672. A'C. teft ceratohya); A, mesial view: B, dorsal view:

C. left latéral view, gr, groove.

gladbachensis, a “ceratohyal” {e.g. Forey &

Gardiner 1986)? The bone lies ventral to the

inferred position of the dorsal hyoidean bone,

which would priniitively lie next to the quadrate,

and is a large bone with a complex proximal

head. As rcstorcd by Forey & Gardiner 0986), It

would distally mcct wirh the restored hyomandi-

bular and forni part of a normal hyoidean arch

sj^tem, excepT for the faet rhat it braces ïhe jaw

joint rather than carries on vcntrally ro the basi-

hyal or hypohyal boncs. In rhis respect it would

be unique amongst vertebrates if regarded as a

ceratohyal. I propose an alternative explaivation:

the elongated bone wirh an expanded double

articulatory head,. which btaces the lower jaw, is a

specialised interhyaJ (or ‘'symplectic” in the ter-

minology ol Veran 1988, but not homologous

wirh the symplectic of higher actinopterygians).

Thus I regard the broad, expanded boues in

Campbellodus as true ctratohyals char hâve Inde-

pendently acquîred the derivcd condition of

being expanded for larger atiachment area of the

depressor mandibulae and interhyoideus muscle

groups. Such an adaptation would benefit a spe¬

cialised feeding n)echanism avS it occurs in ptycto-

dontids which were strong biters (in tlie

ecomorphological context of Liem 1993) and

thus required extreme modifications of the jaw

musculature .System to increaso biting pressure,

relative to the conservative muscle Systems

hypothetically rcstorcd in other placodcxms such

as arthrodires {e.g. Stensio 1963; Long 1995a).

The viscéral skeleton is virtually unknown in ail

otlicr placoderms, apart fiom a serial grinding

sériés by Stensio (1963i fig. 8) showing only the

ventral gill arch System in the arthrodire

Taptnostem. Thus the pre.sence or absence of an

intcrhyal in other placoderm groups is unknowm.

The function ofthis unusuol arrangement for the

expanded intcrhyal in prj^ctodontids can only be

suggested as an attachment brace for supporting

the large opercular covering over the branchial

lamina, possibly by attachment of additional dr-

tilaginou.s opercular éléments (as in the opercular

cartilages of chimaerids which emanated from

both thé epihya! and ceratohyal éléments; e.g.

Rhinochinioera and Callothynchus^ larvik 1980,

vol. 1, Figs 299, 303).

The next largest bones in the viscéral skeleton of

Citmpbellüdus are elongated paired bones with an

expanded head (Fig. 8), dircctiy comparable with

the éléments identified as ccratohyals by Forey &

Gardiner (1986), and found in rhe new Gogo

spccimcn described below, and also in articulated

position in Ctenurella gUjdbadn nsts (see below,

Fig. 25). These are not interpreted as epihyals

(= hyomandi bular) because of rhe présence of a

separaie epihyaJ in pasitiori on rhe new specimen

of Au^troptyctodiis (Fig. 29, Hyni). 1 regard these

as intcrhyal éléments which braced the lower jaw

joint (Fig. 6, ü I), the ventral most articular head

meeting the small articulation surface described

on the articular bone in ÂustroptyctodHS (Miles &

Young 1977> ‘"arthy”, fig. 2A). There is a well

defined foramen ai this articular head (for; Fig. 8)

which may hâve transmitted the hyomandibularis

nerve. The narrow distal end of the bone is com-

pressed laterally and ends in a slic-like articulation

surface (shown in Fig. 8E), presumably for

526

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

Fig. 8. — Campbellodus decipiens Miles et Young. 1977. WAM

86.9.672. A-0. left interhyal: A, dorsal view; B, left latéral view:

C, D, cross-sections crf the interhyal, respeclively in distal and

proximal sections; E, ventral view, for, foramen.

Fig. 9. — Campbellodus decipiens Miles et Young. 1977. WAM

86.9.672. A, B,, basihyal; A, verttral view; B, dorsal view. C-E.

hypohyal; C, mesial view; O. dorsal view; E, latéral view. art.

articulation facets; dep, dépréssion.

contacting the sirailai-sized aiticulation area on

the cerafohyal. Two sraall paired denienis having

threc articulation surfaces are here identified as

possible hypohyails (Fjg. 9C-E). 7*hey are

flask-shaped éléments with a small anterior (?)

articulation surface (art 1), and rwo niuch pre-

sumed Utrgen mesral (art 2) and dorsal (art 3) arti¬

culation facets. The presumed dorsally-facing

articulation surface is the largest of the rhree and

marches closely with ihe long ventral articulation

facet on the distal end of the ceratohyal. The

.second largest articulation Ls here assumed ro be

for mesial contact with the opposing hypohyal, as

in m;my modem selachians (e.g. Chtamydo-sela-

chiis, Smith 1937). They compare well to the

basic pattern of hypohyals scen in early osteich-

thyans (Gardiner 1984b; Lebedev 1995).

A small unpaired bone, presumably the médian

hyoid arch élément or basihyal (Fig. 9A, B), is an

almost circular bone with a single protruding

articulation facet, giving it the overall shape of a

circulât watcr-cantccn. This bone was identified

by Gardiner (1984a, fig. 3) and by Forey Ôc

Gardiner (1986) in Austroptyctadiis :3lS tbe uro-

hyal, yet this idendfication was based only on its

overall shape as it was fbund only in one spéci¬

men, and in which case the gill arch bones were

not in natural articulation. The aiichors identifi¬

cation of the élément as a basibranchial is based

on the lact rhat only one large médian element

of the ossified hyoid arch is présent in

Campbellodus^ and rhat bone is thcrcforc most

likely to be the basihyal. les rounded overall mor-

photogy )S similar to that of the osteolepiform

Medoevia (Lebedev 1995). The single articulat-

ory facet faced posteriorly and accommodated

the smaller anteriorly facing articulatory surfaces

on the hypobranchials, or allernatively, may hâve

met with a second smaller médial basibranchial

élément.

Dentition andjatu cartilages

The coothplates and jaw cartilages of Campbel-

lodiis hâve been well-described and figured by

Miles & Young (1977), and Long (19S8b) des-

cribed an isolated üpper jaw toothpiate of

Campbellodus ^p. from the slightly younger

Napier Range, ro the west of Ficzroy Crossing.

New materîal of Campbellodus showing the

GEODIVERSITAS • 1997 • 19 (3)

527

Long J. A.

Fig. 10. — Campbellodus dedpiens Miles ef Young, 1977, WAM

95.6.112. A. B, upper toothpiate. A, ventral view; B. mesial

view; C, D, lower toothpiate; C. mesial view: 0, dorsal view.

Whitened wïlh ammonium chloride.

upper and lower tooîhplates (WAM 95.6.112) is

shown here (Pig. 10), bue adds no furiher infor¬

mation to the publi.shed description. The rooih

plates had a crushing action wirh rhe posterior

end of eacK tooth plate being broadest and thick-

est, and incrcascd wear on rhe tooth plates resalt

in differing morphologies, especially for rhe

upper tooth plate, as noted by Miles ik Ybung

(1977: 150). A most peciiliar featurc of the den¬

tition is that the lower toothpiate extends ante-

riorly well torward of the anterior margin of che

upper toorh plate when ihey occlude, as sJiown

in the reconstruction (Pig. 6).

Left quadrarc. (Figs 1 K> 11 ) It is wcll-presen^ed

in WAM 86 9.672. It is a robust perichondral

ossified shell consisting of a main division wirh

an inner Hange, as desetibed for Austropiyctodus

gardineri (Miles ôc Young 1977* figs 24, 2^). The

main shaft is liai in cross-section with a broad

articular end. Latéral to ilie accicular surface

(art.md) is a break in the pcrichonchal bone sur-

rounded by a rhickening around It TTus process

(pr.dcc) is possibly a homologue with the “detent

process” on rhe postérolatéral région of the qua-

drate in arthrodircs (e.g. Goujetasteus pulchelliis^

Gardiner & Mlles 1990, fig. 20; Menamaraspis^

Long 1995b, fig. 16). l’his raises the question ol

whether ihe “detent process” on the quadrace of

ptyctodonrids is actually honiologous to rhat of

arthrodircs or corresponds to one of the several

palatobasal articulations with the cndocranium

seen on the quadratc or palatoquadrate of other

primitive placoderms (e.g. Romundina, Young

1986. fig. 12C). The function of the detent pro¬

cess in arthrodircs is to limit movement or lacerai

slip of rhe jaw joinr. This is clearly seen by phy.sic-

ally moving rhe lower jaws and fixed cheek iinits

againsc one another In well-prescrved Gogo

arthrodircs. In acandiothoracid.s and rhenanids,

the palatobasal and nearh\' articulatory lacets on

the palatoquadrate were for actiichment to the

endotranium. In Campbellodtis the quadrate is

situated a considérable distance ventral ro the

extent of the brainc3.se as dediiced from similar

positions of rhe endocranial ossifications and

jaws in Austroptyctodîis n.g., and thus the process

in pLvciodonlids is here seen lo be homologous

to the detent process in arthrodircs, a constraint

to latéral movement during opening and closing

of rhe jaw.s. The large wcll-defined cavity for the

po-sterior division of rhe adduttor rnandibulae

muscles (add.foss) is seen in me.sial view

(Fig. 1 IB). The ventral surface of the quadrate

(Fig. IIC) is relaiively fiat to weakJy concave. It

shows a roughened muscle or ligament aitach-

ment area (m.atr) immedlatcly anterior ro the

articulation area whlch may hâve been for the

mandihulohyoid ligament.

The articular is noi preserved in any of the

Campbellodus specimens, bue the autopalatine

ossification is known from the holotype, and has

been described and figured by Miles Ôc Young

(1977, fig. 11, pl. 2B).

Tru7fk shietd

The trunk shicld of Campbellodus (Figs 6, 12,

14) comprises large paired anterior latéral plates,

paired anterior dorsolaterals, three médian dorsal

éléments, the most distal of which is devclopcd

as a médian spine, a pair of large interolatcral

plates, paired small spinal plates, and a small

anterior médian ventral plate. The resiored trunk

shield (Figs 6, 14) is similar to rhat of

RhynchoHus tetrodon în having a very extensive

branchial lamina on the anterior latcrals and

interolaterals with large hooked stellace tubercies,

528

GEODIVERSITAS • 1997 • 19 (3)

Ptyctodontid fîshes from the Late Devonian Gogo Formation

but differs from ail other known ptycrodontids

in having three médian dorsal bones, and dis-

tinctly small spinal plates.

Médian dorsal plates. (MDl; Fig, IH) Situated

ventrally it straddles the anterior dorsolaterals

and is a thin bone lackmg a médian ventral keel,

as in Rhampbodopsisi Chelyophoms^ Ctenurella

and Austroptyctodus (e.gt Miles &: Ybung 1977,

fig. 29 D). It is the largest of the three dorsal

trunk bones and bas a strongly convex anterior

margin that slightly overhvmg the nuchal gap of

the head shield when the head was fitted onto

the articulated trunk armour. It has a small dor¬

sal overlap flange for the second médian dorsal

plate (MD2; Fig. IG), This plate is slightly more

elongated that the main médian dorsal, and also

has a short, narrow overlap shelf on irs po.stero-

dorsal margin for the médian dorsal spine. This

spine (MD3î Fig. IF) issimilar lo that figured by

Miles ôe Young (1977, fig. 13) for spccinicn

NHM P50907* It is a hollow bone with a groo-

ved posterior face and has only few scaitered

tubercles on its surface, unlike the strongly

developed dermal ornamentation in tlie spines of

Rhamphodopsis and Ptyctodopsis,

Anterior dorsolateral plate. (ADL; Figs 12-14)

It is of regular shape for ptycrodontids, not unlike

that of Ctenurella or Rhynchodus. It has a well-

art.md

pr.det

add.foss

5 mm

Fig. 11. — CampbelloduB decipiens Miles et Young, 1977,

WAM 86.9.672 A D. loft quadrate: A, latéral Vtew: B, mesial

view; C, posterior view; D, ventral view, add.foss, fossa for

adductor mandïbuiae muscles; art.md, mandiPular articulation;

m.att. attachmenî area for mandibulohyoïd ligament; mr. mesial

ridge of quadrate. Ifl, latéral flange of quadrate; pr.det. detent

process on quadrate.

GEODIVERSITAS « 1997 • 19(3)

529

Long J. A.

Fig. 12. — Campbellodus decipiens Miles ef Young, 1977, WAM

86.9.672. Partiatly articulated Irunk shield in left latéral view.

ADL, anterior dorsolateral plate; AL, anterior latéral plate; Sp.

spinal plate.

developed anterior ventral process ot ornamented

dermal bone that meecs the anterior latéral plate

(v.pr; Fig. 13), and the main lateral-line sensory

canal (11c) passes through a tube within the bone

and is not externally visible, nor is ic expressed as

a thickeued tube on the viscéral surface ot the

plate as occurs in ptyctodontid head shield boues.

The articular condylc (art.con) for the neck joint

is a broad fiat surhicc with a wcak médian ridge

which is hardly visible in latéral view (Figs 13,

14). Noticeablc difterence in the anterior dorsola¬

teral plate of Camphellodiis to those of other peyc-

todontids is thar it lacks the distinct angular

inflection seen in the anterior dorsolateral plate of

Rhynchodîis tetrodon (Gross 1933, pl. 10, figs 2-4)

or Chelyophorm verneuili (pers. obs.). It is broa-

dest about two-thirds down les heighc from irs

dorsal margin, uniike the dorsaliy broader plate in

Austroptyctodiis (Miles & Young i977> fig. 30),

and the externally exposed région is noticeably

broader in its ventral divi.sion than in either

Ctenurella or Rhamphodopsis. The overlap area for

the médian dorsal 1 plate (ov.MD) is much

smaller ihan the large ventral overlap surface for

the anterior lacerai plate (ov.AL).

Anterior lacerais. (AL; Figs 6, 12, 14) The.se are

the largesr boues of the dermal skeleton, as in ail

ptyctodonrids. The dorsal région of ihe plate is

very broad, being approximately thrcc tunes the

width of the narrow ventral division of the latcral

lamina. The dorsal région of the anterior margin

of the bone is strongly concave where the post-

branchial lamina (Fig. 14, b. lam) begin.s. It bas a

well-defined lacerai lamina with finely ornament¬

ed rugosc dermal bone, merging mesially into

the extensive flac posrbranchial lamina covered

with well-ordered rows of large,, triangular pecti-

nated tubercles. Each of chese tubercles ha.s a

spray of about five or six inwardiy pointed tips,

the central one being the largest, and the head of

the tubercles facing towards the centre of ossifi-

ov.MD

Fia. 13 — CampbeHodu$ rfec/pfens Miles et Young. 1977, WAM

86.9.672. A. B, anterior dorsolateral plate; A. nght latéral view;

B. rnesiai view, art.con, articular condyle or face on ADL plate;

Mc. main latéral line canal; ov.AL, overlap surfaces of anterior

latéral plate; ov.MD. overlap surfaces of médian dorsal plate;

v.pr, ventral process ot ornamented bone on anterior dorsolate¬

ral plate.

530

GEODIVERSITAS • 1997 • 19 (3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

cation of the bone, close ro its spinal margin.

Miles & Young (1977, figs I, 2F, pl. 4A) showed

part of this posrbranchial lamina on the type spé¬

cimen, and figured a scanning électron micro-

graph showing clearly the morphology of one of

ihese cubercles. The contact maigin for the spi¬

nal plate is a short, straight horizontally-directed

edge of bone above the embayed margin for the

pectoral fin.

Fig. 14-— Csmpbeitodus decipierisfAW&s ôfVoung, 1977. WAM

86.9.672. A, B. trunk shieW: A. anterior view; B. venlral view.

ADL, anterior dorsolateral plate: AL, anterior latéral plate; AMV,

anterior médian venlral plate, art-con, articular condyle or face

on AOL plate; b.lam. branchial lamina of trunk shield; IL, inlero-

latéral plaie; MOI. médian dors&i plate; pec.ln, pectoral fin inci¬

sion on trunk shield; Sp, spinal plate.

Unlike the condition in most other placoderms

whcre the spinal plate projects anteriorly to the

pectoral fin, ic is cicar that in Campbellodiis the

spinal plate is immediately dorsal to the main

embaymenr in the trunk shield latéral lamina.

The posirion of the scapulocoracoid in Aitstro-

ptyctndus^ ai.so showing the fin emerged below

the junction ol the anterior latéral and the intero-

laterah confirms that the pectoral fin did emerge

ventral ro the position of the .spinal in

Campbellodtis.

Spinal plate, (Sp; Figs 6, 12, 14) This small

bone, wifh a very short projection of the poste-

riorly-facing spinal process, contacts the anterior

latéral along almosr ail of its dorsal margin, but

bas only a very short anterior connection wirh

the inrcrolateral plate. In internai view, the .spinal

plate is hollow. li has been previously îdencified

and described for the NHM P50907 by Miles &

Young (1977, fig. 12).

Interolateral plates* (IL; Figs 6, 14) These

consist mosdy of the anteriorly lacing posrbran¬

chial lamina, with no cxtcrnal latéral lamina. T he

ventral laminae (Fig. 14B) are well-developed as

in ail ptyctodontids and meet tlie anterior

médian ventral bone mesially, not contactlng

each other as occurs in Rhynchodm tetrodofi

(Gross 1933). As noted for the spinal, they hâve

a well-defined pectoral incision for the pectoral

fin (pcc.in; Fig. 14A), and ventrally broaden ouc

mesially. The posrbranchial lamina has a sirongly

convex contact margin with the anterior latéral

plates, similar to the condition in boih

Rhynchodus and Austroptyctodus.

Anterior médian ventral plate. (AMV; Fig. 14

A, B) Unusually broad, it is more than twice as

broad as its length, although its externally expos-

ed surface in the articulatcd armour is ver)’ nar-

row. Most of its breadth is for the overlap

laminae fi>r the interolateral plates, and the.se sur¬

faces hâve a fluced bone texture. The anterior

margin of ihe plate is quiie suaight, unlike the

V-shaped anterior médian ventral place in

Chefyophorus.

Pelvk girdle mid endoskeleton

The pelvic girdles are well-preserved in the spéci¬

men showing iwo principal components, the

dermal pelvic bones and associated endogirdle,

531

GEODIVERSITAS • 1997 • 19(3)

Long J. A.

Fig. 15. — CampbeHoctusdecfpiensU\\fis e/Young, 1977, WAM

86.9.672. A, B. pr&pelvic tone and associaied encioskeletal pel-

vie girdie: A, dorsal view; B. ventral view art.s, articulation

scars for mesra) attachment: for. for 1, 2, foramen or identifîed

sériés of toramina: pei.g, groove between basai articulations on

pelvic endosKeleîal ossification; pr.pel, dermat process of pelvic

girdle; rad.art, 1, 2, 3. artfcular facets for fin radiais.

and a pair of asymmetric large, smooth basal

plates for the pelvic fin, similar to the élément

described in the female specimens of Rhampho-

dopsis threipLvidi (Miles 1967, figs 13, 15).

£xternal pelvic girdle. (Figs II, J, 15, 17) It bas

a large, narrow vencrolaceral lamina with external

ornament macching chat of the dcrmal bones and

scales. This part (pr.pel; Fig. 15) i.s probably

équivalent co the paired prepclvîc bones lying

anterior to the pelvic fins in Rhampbodopsis,

alchough the associaced endoskeictal girdle is not

known in chat form. In the new specimen the

perichondrally ossified cndogirdle shows chree

large, clongatcd articulation surface.s for the pel¬

vic fin radiais (rad.art 1~3; Fig. 15), with two

large foramina (forl, 2) berween rhe fin atrach*

ment surface and rhe oufer dermal bone, for the

passage of nerves, veins and arteries to the pelvic

fin. Musculature of che pelvic fin probably attach-

ed to che roughened area surrounding chese fora¬

mina and 10 the dermal componenc of che pelvic

girdle. These paired éléments met mesially by a

roughened connection area (art.s) with an mter-

digitating suture (Fig. 17). The smooth surface

surrounding this connective région was no doubt

covered with muscle or ligamentous connection

in lifè. When the rwo parts of the pelvic girdle

and endogirdie are reassembled in this way, the

dermal prepclvic bones arc not seen to bave any

mesiai contact, -xs seen in Rhamphodopsis, but are

widely separated, In re.storing the pelvic girdle

and endogirdies (Fig. 17), rhe bones were assem-

bled with plasticine holding the basal plates toge-

ther and then matched up with the posterior

width of the trunk .shield, so chat the estimated

width of the prepelvic boneÿ correlated with rhe

natural curvature of rhe body,

Fin basal plate.The large fin basal plate (Fig. 16)

is represented by both left and right éléments,

although, as prepared, it is not known which is

which. The élément has strong curvature in both

mesial-Jatctal direction and rostrocaudad, unlike

in Rhamphodopsis spécimens, iii which it seems

to bc a fiat, subtriangular bonc. Along its inner

ventral matgin Js a well-devclopcd ridge (ri;

Fig. 16A), presumably for insertion of the large

pelvic scales along a broad, smooth flangc (fl). A

roughened area (r.a) is seen next to the centrally

raised médian area, presumably for attachment

of ligaments and scales of rhe latéral flank of die

fish. The viscéral surface is smooth but has a

Fig. 16. — Campbellodus decipiens Miles et Young, 1977, WAM

86.9.672. A, B. right female pelvic basal plate; A, ventral view;

B. dorsal view (slightiy oblique, see figure 1 7 for possible orien¬

tation with respect to prepelvic bones and pelvic girdle). fl. flan-

ge; r.a, articulatory ridge on pelvic basal plate; ri, ridge for scale

overiap on pelvic basal plate.

532

GEODIVERSITAS • 1997 • 19(3}

Ptyctodontid fishes from the Late Devonian Gogo Formation

Fig. 17. — CampbeHodus decipiens Miles et Young, 1977.

Reconstruction ot pelvic région of a female showing possible

orientation ot prepelvic bones, pelvic girdie and pelvic basal

plates, ventral view; ant. anlerior direction; pel.bas. pelvic basal

bone (female basal ossification); pr.pei, dermal process of pel¬

vic girdie: rad.art, 1.2 articularfacets fortin radiais.

well-defined ridgc (ri; Fig. 16B) riinning along

its ventral lamina.

Scapulocoravoid?

A poorly preserved part of a perichondral ossifi¬

cation showing what appears to be a glenoid

facet is here shown în figure 18 (glen), although,

Fig. 18. — Campbellodus decipiens Miles et Young, 1977, WAM

86.9.672. Possible right scapulocoracoid ossification (incom¬

plète). glen, glenoid condyle of endocranium.

as nriost of the bone is mis.sing, its identification

is uncertain. It is possibly part of the scapulo-

corâcoid from the shoiilder girdie, or alternath^c-

ly may be à piece of the occipital ossification of

the endocranium, as described bclow in Austro-

ptyciodiis.

Axial skeleton

The vertébral column comprises the synarcual

(Fig. 19) and numerous paired perichondral clé¬

ments rhat srraddled the cartilaginous noto-

chord, as describcd for Rhamphodopsis (Miles

1976), Ctenurella gladbachensis (0rvig 1960),

and similar to tlie vertébral ossifications seen in

other placoderms (e.g. Coccosteusj Miles ÔC

Westoll 1968; Aiistrophyllolepiss Long 1984b:

Inchùscutum% Detmis-Bryan 6c Miles 1981;

EasttnanosteusA Dennis-Bryan 1987). Some of the

haemal arch clcmeius bave reasonably long ven¬

tral processes compared to those seen in

Ctenurdla or Rhatnphodopsis.

Synarcual. It is similar to that described lor

Ausiroptyctodus (Miles & Young 1977, fig- 32),

showing clearly the notochordal groove (not.gr;

Fig. 19) canal for che spinal cord (sp.c) and latéral

Fig. 19. — Campbellodus decipiens Miles et Young, 1977. WAM

86.9.672. A-O. synarcual; A. anterior view; B, oblique poslerior

view; C, laierai view, D, ventral view for, foramen or identified

sériés of foramina; not.gr, notochordal groove; sp.c, spinal cord

canal.

GEODIVERSITAS • 1997 • 19(3)

533

Long J. A.

Fig. 20. — Campbellodus dedpiens Miles et Young. 1977, WAM

86.9.672. A, dermal scale showing overall shape; B. detail of

externally ornamented area o! same scale. SEM photomicro-

graphs.

slit-like foramina (for) for the spinal ncrvc roots.

Large basal éléments for the médian fins are

found in the material and în general outline

match rhose described for Austroptyctodui

(Miles & Young 1^177, figs 33, 34). In addition

there is a posteriorly siuiated second médian dor^

sa! bonc thac beats a close resemblance co the

médian dorsal 1 of the rrunk shield. As for

CtenurelLi gladbachemis, this is presumed to be

the dorsal spine preceding the second dorsal fin.

Squamatîon

The specimen conrained many hundreds of

scales distributed thraughout the nodule, and

not concentrated specifically around the pelvic

girdle. ThUvS, as in ihc articulated specimen of

Austroptyaodus described below. in which order-

ed scale tows are seen ou the flank ol the irunk

région, the whole of the body posterior to the

trunk shield is assurned to hâve beeu covered by

large overlapping scales. Each scale has an orna-

mented cxternal région which is subrectangular

in form but quite variable as to précisé shape

(Figs 20, 2] ) attd a large, ventrally-facing .smooth

overlap surface, d'he scales are macromeric, trom

their large si?^ and the relative size of the neural

arch éléments ir is suggested thar there was a cor-

respondence of nne scale row per .somite, and

chat ihey were ordered in neat rows with large

overlapping ventral (langes.

Long (1995b: 110) gives an attempeed life resto-

ration of Campbellodus dedpiens based on the

new material described herein.

REVISION OF THE GENUS

Cte7îiirella 1960

Although the original description of Ctenurella

gladbachensis by 0rvig (I960) did not recognise

the présence of the submarginal bouc, this was

soon corrected along with further observations of

the material by Kim (1962). yVnothcr pectiliarity

of C. gladbachensis noted from Orvig's descrip¬

tion is the putporrcd absence of the anterior

médian ventral plate, présent in ail other piycto-

dontids where the armour is well-prcserved,

including C. gardineri (Miles & Young 1977,

fig. 31). His last reconstruciion of chc head of

C, gLidbachensis was modified to show hroader

anterior margins on the preorbical plates and was

subsequently adopted hy Stensio (1969,

fig. 40A) and used by 0rvig (1971) and Miles &

Young (1977, fig. 15). It incorporated a smaller

dermal bone anterior to the marginal plate (a

possible suborbical bonc).

DenLson (1978. fig. 3B) atiempred ro recommict

part.s of die viscéral skelcton of C. gladhachetisisy

adding the hyomandibuUr as an antertwenirally

directed bone, hracmg ihe jaw articulation and

meeting with an opercular cartilage. Forey &:

Gatdiner(1986) described a new specimen of rhe

G<îgo CtenurelLi' and figured newiy prepared

NMH spccimen.s of C. gladhachemis in which the

“ceraiohyal" was cicarly ideniified.

Original -speciniens in the MNHN, Paris, include

articulated individuals showing details of the

skull roof, jaws and viscéral skeleron (Fig. 22)

and one siipcrb specimen, both part and counter-

part (Figs 23, 24B, 25), meticulousiy prepared

bv Dr. D. Goujet, showing the dermal bones of

ibe skull and trunk shield, as wel! as jaws and

associated ossifications, the hyoid éléments, ros-

534

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

Fig. 21. — Campbellodus decipiens Miles e/Young, 1977, WAM

86.9.672. Dermal scales. A. basal view; B. C, coronal views.

tral cartilages and othcr viscéral arch éléments.

Four well'preserved specimens werc studied in

order to déterminé the nature of the hyoid arch

bones, the jaw cartilages and the reconstruction

of the head shield. Fhe new specimens examined

at the MNHN, Paris, corrohorate the orientation

of the interhyal bone, as observed by Forey &

Gardiner (1986, cailcd the “ceratohyal") in its

posteroventrally slanted position behind the arti¬

culât, as seen aJso in Austroptyctodus (Figs 28,

29). Gloser examinatioji reveals chat the expan-

ded head of the interhyal in C. gladhachensis only

makes contact with the posterior margin of the

articulât and does not meet with the posterior

edge of the quadraie (Fig. 25).

The skull roof is well-preserved in the NHM

specimens but differs in several respects from the

reconstructions gîven by 0rvig (1960, 1971),

Stensio (1969), Miles 67 Young (1977) and

Denison (1978). Jn all four of the NHM spéci¬

mens examined, the central plates meet each

other hehind the nuchal plate, uniike the condi¬

tion in boih the Gogo ptyctodontids, in which

the nuchal form.s ihc médian posterior margin ol

the head shield (Figs 23, 25B). The anferior mar¬

gin of the head shield is rclatively broad and

straight with the pineal bone tigbdy enclosed by

the antea>mesial corners of the preorbital plates,

The closure of the central plates to form the pos-

terior margin of ihe head vshield in Ctevnrella

gladhachensis is aiso hinted at in the onc skull

figured by 0rvig (1960, pl. 26, 1, 2) where the

left central plate protrudes behind the nuchal

plate, The pineal plate is aiways firmly enclosed

by the preorbital plates with only a short anterior

margin fbrming the anterior border of the head

shield, urdike the Gogo form which has a pinçai

plate significantly smaJlcr than the gap defined

for ir by the prcorbitals.

Thus, a new reconstruction of the skull roof of

Cteniirella gladhachensis is presented here

(Fig. 26B) which shows noticeable différences to

the Ciogo specimens.

It is noted that the sclerotlc ring, not previousiy

described for ptyctodontids, is well preserved in

one Bergisch-Gladbach specimen, and shown

clearly in ligure 22A (bottoni right corner above

the lower tooth plate). It comprises four sclerotlc

bones and matches closely with the supraorbital

vault defined by the preorbital and postorbitd

plates.

The lower toorh plates of Ctenurtdla gladbuchen-

sis bave a well-devcloped ventral process

(Figs 22A, 25). a featurc also seen in the Gogo

Aîistroptyctodus (Fig. 34; Miles & Young 1977.

pl. 5B). Further différences between Ctenurella

and Aîistroptyctodm ane seen in vhe médian dorsal

plates. In CtenureUu (Fig. 22A) it has weakly

convex latéral margins and tfie posterior margin

even has a taper to a posterior point. In

Ausîroptyctodus^ the rnedian dorsal plate has a

much broader anterior margin than its posterior

margin, weakly concave lacerai margins and a

more strongly devcloped posterior process

(Miles & Young 1977, fig. 29D).

535

GEODIVERSITAS • 1997 • 19(3)

.\~y^ i' jÊt

*f9B7vBp^ mSVv^7

IPI^W^^ i mmi^ff?Zj^^9v^^^ ^ T 1 * *r

7 JM

-v.v y -.riH^I

Long J. A.

AmENDED OFNF.RK: DIAGNOSIS RF.MARKS

A small pryctodontid with a nuchal completely The genus C.tcnurella is disringuishcd from

enclosed by the centrais and preorbitals; preorbi- Rhynchodus^ Rhamphodopsis-, Ptyctodopsis^ Tollodîis

tais meet in midiine and suture with rhe pineal; and Camphellodiis by its absence of a spinal place,

nuchal plate antcriorly pointed. M;irginal plates Chtlyophorus differs in havîng grooves developed

with well-deveJoped ventral process. Toothplates h)T the external sensory-line sysient, a shorier,

of the shearing type, lowcr tuoth plates having a broader nuchal plate and higher, shorter anterior

well'developed ventral process near the ariicular dorsolateral plate. Austroptyciodus n.g. is discin-

end. Trunk shield lacking a spinal place, médian guished by its skull-roof pattern, with nuchal

dorsal plate approximaiely a.s broad as long, lack- plate opencd, posteriorly, the different shape of

ing a dorsal spine* and with latéral margim gent- the médian dorsal plate and rhe presence of body

ly convex. Body lacking squamation. scale cover.

P PRO

Fig. 24. — Ctenurelia gladbachensis Orvig. 1960. Sketches of specimens showing head shield plates in articulated position.

A. MNHN ARD 233, B. MNHN ARD 230b: C MNHN ARD 232, Ce, central plate; MD, MOI, 2, 3. médian dorsal plate(s) or spines;

Nu, nuchal plate (posterior elemeni), P. pineal plate or space provided for it in the head shield; PNu, paranuchal plate; pp. posterior

sensory-line canal on head shield; PRO, preorbital plate; PTO, postorbital plate; soc, supraorbital sensory-line canal; suov, supra-

orbital vault.

538

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

1 cm

Fig. 25. — Ctenurella gladbachensis 0rvig, 1960. Sketch of specimen MNHN ARD 229 {as shown photographed in figure 22). Art,

articular; Aut, autopalatine: Ep, epibranchials, IH, interhyal element; l.tpi. tower tooth plate; M, marginal plate; nas.oss, nasal ossifi¬

cation of endocranium: orb.oss, orbital ossification of endocranium; PM, postmarginal plate; pr., dorsal process of the upper (ooih

plate; Qd, quadrate; ros.car, rostral cartilages (paired); SM. submarginal plate; u.tpi. upper tooth plate.

Aiistroptyctodus gardinieri

(Miles é'ï Young, 1977) n.g.

Aiistroptyctodus n.g.

Type species. — Austroptyctodus gardineri Miles et

Young, 1977.

Etymoi OGY. — From ihc continent Au-scralia and the

form genus Ptyclodus.

DiaGNOSIS. — A ptyctodontid placoderm having a

PiyctodusA'xkc crushing dentition* preorbital plates

separated from each other by a médian gap. Canal-

bearing nuchal pardcipacing in the posterior margin

of the skull roof* trunk shield lacking a spinal plate*

médian dorsal plate with much widcr antcrior margin

than posterior margin. The body vvas covered by large

overlapping seules.

REMARKîi. — Aiistroptyctodus n.g. is clearly dlstinguish-

ed from ail other welf-known ptyctodontids {i.e. those

known from most of the dermai armour) except

Ctenurella and Chelyophonis, in lacking a spinal plate.

It is distingujshed from Ctenurella by several features

noted above under “Remarks” for Ctenurella gladba¬

chensis.

Austroptyctodus gardineH

Miles et Young, 1977

Ctenurella gardineri Mües Young, 1977. — Denîson

1978: 29. - l.ong 1984a: fig. 17I-L. - Forey &

Gardiner 1986: fig. 2. — Long 1991: 366, fig. 201,

377 ^

Holotype. — WAM 70.4.253, previously described

and figured by Miles & Young (1977, pl. 2D, E,

pl. 3B, pl. 4B) wiih the provisional Natura! History

Muséum number Ibr the specimen (P.57637).

Other material. — NHM, London: P50906,

GEODIVERSITAS • t997 • 19(3)

539

Long J. A.

Fig. 26. — Comparison between lhe reconstructed head shields in dorsal view; A. Austropiyclodus gardineri (Miles ef Young, 1977)

n.g.; B, Ctenurella gladbachensis Orvig, I960: C. Rhynchodus tetrodon (after the Holotype); D, Campbellodus decîpiens Miles et

Young 1977- Ce^ central plate: Nu, nuchal plate (posterior element): P, pineal plate, or space provided for it in the head shiefd;

PNu, paranuchal plate; PRO. preorbital plate; PTO, postorbital plate.

P50908, P50909, P50910, P57654, P57655; WAM

86.9.662.

Description

The new Gogo specimen oi Austroptyctodus gur-

dineri (WAM 86.9.662, Figs 27-29) was collec-

ted by the author in Augusr 1986. It is an almosr

complété specimen presen'ed as Far posteriorly as

approximardy the niiddle ofthe main dorsal fin.

It has becn prepared by the resjn transfer method

for both part and counterpart. As Miles & Young

(1977) hâve aiready describcd in detail most of

the dermal .skeleton in this form, the following

description focuses only on new information,

and provides new reconstructions for the dermal

skull roof and viscéral skeleton, and external

armour in latéral view.

Skull roof and cheek

The skull roof was not reconstructed by Miles &

Young (I977i 157) as they stated that "several

problems were encountered in attempting to

reconstruct the skull-roof from the accuratcly

known shape of individual boues”, l he new

knowledge of the skull roof of Campbellodus pre-

sented aboYe shows thcrc is not a close fit bet¬

ween ail skull roof bones. Earlier, inaccurace

reconstructions of the skull roof of d. gardineri

540

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

Fig. 27. — Austroptyctodus gardineri (Miles ef Young, 1977) n.g. WAM 86.9.662, showing both sides of specimen embedded in

resin, whitened with ammonium chloride. Naturel size.

GEODIVERSITAS • 1997 • 19(3)

541

Long J. A.

Fig. 28. — Austroptyctodus gardineri {M\\es ef Young, 1977) n.g. WAM 86.9.662, showing details of internai ossifications of the head

and part of right side of trunk shield. Whitened with ammonium chloride. See figure 29 for scale.

542

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

Fig. 29. — Ausîroptycîodus gardineri n.g. (Miles et Young, 1977). WAM 86.9.662, sketch interprétation (see figure 27)- ADL. anterior

dorsolateral plate; AL, anterior latéral plate; AMV, anterior médian ventral plate; Art, articuler; Aut, autopalatine; Ep. epibranchials;

eth.oss, ethmoid ossification of endocraniurrt; Hym. hyomandtbular, IH, interhyal element; M, marginal plate: MD, MD1,2, 3, médian

dorsal platefs) or splnes; m.ros.cart., médian rosirai ossification; Nu. nuchal plate (postenor element), Occ.oss, occipital ossifica¬

tion of endocranium; op.car opercular cartilage; orb.oss, orbital ossification ot endocranîum; PNu, paranuchal plate; PRO, pre*

orbital plate; Qd, quadrate: sc. scales; SM, submarginal plate: u.tpi, uppertooth plate; vis, “viscéral skeleton éléments?”.

GEODIVERSITAS • 1997 • 19(3)

543

Long J. A.

were givcn by Long (1984a, 1991), made by fîi-

ting thèse bones together from sketches. Wien

the bones of one individual are accuraiely asseni-

bled {e.g. P57637, WAM 86.9.662), the skull

roof closcly resembles thar of Camphellodm in

having a médian gap between rhe preorbitals.

The pineal plate is actually snialler than the

notch as defined.for it by die assodated preorbi-

tal plates (Fig. 26A), as noted by Miles & Young

(1977). The viscéral surface of the skull roof

slîow's only weak development of the supraorbi-

tal vault, wiihout substancial development of an

inwardiy projecring lamina from chc orbital rim,

as seen in Campbeltodus.

The marginal and submarginal plates were well

described by Miles Ôe Young (1977). There is no

evidence of a smaller postmarginal boue, as sug-

gesced to be présent in Ctenurella gardineri by

0rvig (1970, aithougb this observation is not

confirmed by the présent study).

Viscéral skeleton

As discusscd above for Camphellodus^ the evidence

from specimens of Ctenurella giadhacbensü sug-

gests that the hyoid arch was well-ossified with

an expandcd interhya! elcmenr postcriorly exten-

ded to provide an extra attachment région for a

flexible opercular membrane. This cicment was

identified as the *'ceratohyal” by Forey bi

Gardiner (1986), and is here shown in varions

views (Fig. 30). It bas two articular lieads

proximally vvherc it meets the articular and the

hyomandibular dorsally (as in Ctenurella^

Fig. 25). 1 he broad, inwardly curved ceratoliyal

which is found in Camphellodus has not been

positively identified in the Âtislroptyciodiis maCc-

rial. It was probably not preserved in WAM

86.9.662 as the anterior région of the head is

missing, including the lower tooth place.s.

Opercular cartilage and hyomandibular.

(op.car; Fig. 29) It is found on the inside of the

head of the submarginal as in ail otlicr placo-

derms whcre it h preserved (sec Young 1986, for

a revaew of tlie distribution of this structure).

This structure was identified in Aiistroptyctodus

by Forey & Gardiner (1986, fig. IB) as the hyo¬

mandibular, and restored as having an enclosed,

tubular head. In Camphellodus-, tbe correspond-

ing ossification is broader, with an extensive

ventral lamina. There is no evidence thaï it was

an elongate élément, and a large cariïlage struc¬

ture that acted as the flexible gill-cover has been

restored (Fig. 6). WAA'l 86.9.662 gives further

support for interpreting this as an opercular car¬

tilage rather than as an epihyal, as the hyomandi-

bular is seen in r/7w, lying immediarely dorsal to

the quadrate (Hym; Figs 28, 29). The proximal

head of the hyomandibular is nor preserved but

ir renninates in close proximivy ventral to the

opercular cartilage, presumably meeting the

anterior postorbital process of ihc braincase (a

pcrichondral shell inside the marginal plate), just

forward of the centre of the orbital cavity, as it

docs in lirindiihellaspis (Young 1980).

Endocranium

Endûcranial ossifications in ptycrodondds were

first noted by Eichwald ( 1859, pl. 57, fig. î) in a

welJ-preserved spccimen of Chelyophoms iterneiii-

liy in which nvo pairs of rotighly circular ossifica¬

tions were found in tbe articulatcd head, below

the occipital région and underneath chc orbics.

This specimen bas now been acid prepared to

confirm the placement of rhese ossifications

(Dr. A. Ivanov, pers. comm. 1995). 0rvig (1962,

1971) obsen^ed perichondrally ossificd laminae

in the orbitals régions of the Bergisch-Gladbach

Ctenurella. specimens, and Miles (1967: 105a)

confirmed the presence of a sniall semi-circular

bone in the orbital région of Rhamphadopsis^ pre-

viously alluded to by Wat.son (1938).

Miles & Young (1977) gave the first detailed des¬

cription of the endocranial componenis of piyc-

lodontids based on the Gogo specimens of

Austroptyctodus. Fhey identified at Icast three

paies of pcrichondrally-ossificd bones which they

tetmed (1) chc occipital ossification, (2) the orbi¬

tal ossification, and (3) the ethmoid ossification.

Although varions foramina were described on

these ossifications, their oudincs were not com-

plctely clear and so they were only givcn approxi-

matc corrélations with the landmark foramina

known on the braincases of other placodcrrns.

They further stated that chc exact arrangement

and relationship of thèse endocranial ossifica¬

tions within the articulatcd head were not clear

at ail, The new specimen described hcre gives

more précisé information on the morphology,

544

GEODIVERSITAS • 1997 • 19(3)

Pryctodontid fishes from the Late Devonian Gogo Formation

F»g. 30. — Austroptyctodus gardineri {MWbs ef Young, 1977) n.g.

WAM 86.9.662. righl interhyal bone; A, C, latéral views; B. dor¬

sal view, art, articulation facets tor hyomandibutar: art.hym, arti¬

culation for hyomandibular; gr, groove.

1 cm

Fig. 31. — Chelyophorus verneuili Agass\z, 1844. Articulated

specimen, redawn after plate 57. fig. 1 of Eichwald (1859).

A, head shield in dorsal view; B, head in ventral view showing

orbital and orxiprtal ossifications of hraincase. C. head shield in

lett latéral view; D. poeturior view of head showing glenoid

condyles of brâiocfti^e and arttailar tiange ot paranuchal plates,

art.con, arlicular condylv or face un ADL piale, for.mag. fora¬

men magnum ot endocranium; gten, qlenoid condyle of endo-

cranlum: M, marginal pUia occ.oss, occpMal ossification of

endocranium; ofb.oes,. orbital ossificatiuri of endocranium:

P. pineai piato or spaca provldod tor it m tha h^aO shield;.

PNu, paranuchal plate; PrO. preorbital plate.

position and contact relationships of these élé¬

ments and can be corroborated by new observa¬

tions on the eiidocranial ossifications examined

in both Chelyophorus tferneuili and Ctemirella

gladbachemis. Retcntly prepared material of a

new genu:< of ptyctodontid ftom the Late

Devonian Gncudna Formation of Western

Australia also shows the occipital and orbital

ossifications perfectiy preserved in 3'dimen.sional

form, corroborating the toratnina and morpho-

logiçal Icatureç with chose preservçd in orher

ptyctodontids.

Thrcc paired ossifications of the endocranium of

Austi'optyciodus are preserved in WAM 86.9.662

(occ.oss. orb.oss, eth.oss; Figs 28. 29), ail in close

association and only displaccd sh'ghtly from arti¬

culated position, as supported by the close arti¬

culation ol the other ncighhouring dermal

bones. A fourth pair of bones lies dorsal to the

palatoquadratc which précédé rhe nasal capsules.

These bave been labelled as “metapcerygoids” In

previous descriptions. 'Lhcrc arc aUo pcrichon-

dral conical shells of bonc attachçd ro fhc inside

Wall ot the marginal plate thaï coiuacted the

orbital ossifications laterally. These arc herc assu-

med to bave houscd the posterior postorbital

process, as for other placoderms (Young 1979.

1980. 1986; Lchevre 1995).

The presumed position ol the posterior three o!

these paired endocranîal ossifications, with rela¬

tion to the dermal exocraniuni. was proposed by

Miles & Young (1977, fig. 22) w'ho correctiy

posirioned fhc occipital bones but restored the

orbitals as orienfed with their fiat lamina vertic-

ally. They did not attempt to place the ethmoid

ossification in relation to the skull root, but

nolcd that its large ancerior articulation lacet was

mosi likely an articulation to the autopalatine, as

also poinied out by Yourtg (1986). Evidence

from the new spccimcn (Fig. 28) shows an align-

ment of the occipital, orbital and ethmoid bones,

each part only slighrly displaccd from its anti-

mere. The aSvSumed fit of these bones is in line

forming the ventral wall of the endocranium, as

shown by Chelyophorus verneuili (Fig, 31,

redrawn from Eichwald 1859) and in several spé¬

cimens of Ctenimlla gladhachetuis in which rhe

paired orbital ossifications remain articulated

meslally, usually found in close proxîmity to the

GEODIVERSITAS * 1997 • 19(3)

545

Long J. A.

orbits (as it also occurs in the holotype of

Amtroptyclodmy WAM 70.4.253). Other spéci¬

mens of rhis specics show the ethnioid articula¬

tion in the anteroventral corner of rhe orbit,

closely associated with the aucopalatine and

metapterygoid, and with the head of rhe submar¬

ginal bone snuggled Inio a dépréssion immedia*

tely behind ils large articulatory facer. Thus,

from thèse varions specimens it is now possible

to rcdescribe and accurately reconsrruct rhe

cndocranium in Austroptyctodm^ and to discuss

the homolog}' of parts of its structure to that in

other placoderms.

Occipital ossification

The occipital ossification was well described by

Miles èc Young (1977-, Ftg. 20), although the

margins of their spccimen were nor well-

preserved enough to show its complète shape. Tn

Austroptyctodns (WAM 86.9.662), as well as in

Chelyophorus and in the new Gneudna ptycto-

dontid, the occipital ossifications are well-

preserved and show vheir complété outlines. The

matcrial largely supports the reconstructions of

Miles & Young (1977)» showing that rhe ventral

lamina of rhis bone possessed a large groove

(gr, dia; Fig, 32C) that prcsumably carried the

dorsolateral aorta, with each side cairying the

groove anrerolaterally away from the glenoid

condyles. In latéral view (Fig. 32A), there are

three large foramina visible and the outer dama-

ged part of rhe ascending occipital proce.ss

(pr.oc; Fig. 32 A) revcals that there was a hollow

tube in the outer wall of the ossification, proba-

bly opening in the position where Miles &:

Young (1977, fig. 20C) observed a slit in the

endocranial wall. The anterior two of chese large

foramina in the latéral wall of the occipital ossifi¬

cation (Fig. 32A, B, for 2, 3) were tenrarively

identified as for the vagus and glossopharnygeal

nerves by Miles Ôc Young. This interprétation

would seem correct by comparison with rhe fora¬

mina found in the .similar région of latéral endo¬

cranial wall occupied by other known

placoderms (e.g. Brindabcllaspis-, Young 1980;

Dicksonosteus^ Goujet 1984a; Macmpetalichthys^

as reinterpreted by Young 1986). There is also a

large ventral slit containinga foramen hteral to the

glenoid process (Fig. 32A, for), also recognlsed by

Miles & Young (1977, fig. 20, cl, si). As rhis

opening is posteriorly directed and not confluent

with rhe pathway for the dorsolateral aorta, it

may possibly represent the path of the occipital

Fig. 32- — A[jsUopl^cl')<Svt> gardineri (Mites er Voung. t977} o.g.

WAM B6.9.662, A. 0. right ocapilat ossificalion of braincase;

A. mesial view; B. latéral view. C, reconstruction ot postenor

view of bramcasÊ. for. for 1. 2. 3, foramen or identified senes of

foramina for.mag. foramen magnurn o» enaocranium: glen. gie-

noid condyle of endocranlum: gr.dla. groove for one dranen of

lhe dorsoiateral aorta: pr.oc. a.scp.nding occipital process of

braincase.

546

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

artery (also located in this position in

Brindiibellasph, Young 1980, figs 7, 8).

Orbital ossification

The orbital ossification figured by Miles &

Young (1977) was intcrpreted on the basis of its

presumcd orientation. They restored it as lying

vertically behind the orbital cavity based on one

specimen (P5Ü908), with the strucinre interpre-

ted as the attachmeni for an eyestaik located far

posterior of che eyeball. The foramina for trans-

micting vessels or nerves were thus seen passing

from within the braincase to the orbital cavity,

Spécimens of Ctcnurclla gbtdbachctms show that

the orbital ossifications are always joincd mesially

and lie within the orbit, implying chat they may

hâve bcen positioned horizontally in life, thus

fonning the ventral wall of the orbital cavity.

This interprétation is further supported by

Eichwald’s (1859) figured articulated specimen

of Chelyopbortis verncuiHy which shows in ventral

view the paired occipital o.ssifications tu situ

(Rg. 31), with one of the paired orbital ossifica¬

tions laying just anreriojr ro these. An excellent

specimen of an orbital ossification of

Chelyophorm vcrnmili 'm the MNIIN collections

bas been freed from the matrix and iÿ figured

hcre alongside chose of the Austroptyctodus spéci¬

mens (Fig. 33C> D) ro illustrate further the mor-

pholog)' of this bone. Addinonal évidence for che

horizontal position of ftie orbital ossification Ls

provided by che extensive mcsial lamiita of the

marginal place în boch Gogo ptycrodontids, in

which an extensive dorsal lamina is dcvcloped,

and which still bears its connection to the orbital

ossification in the liolor\'pe specimen of Austro¬

ptyctodus gardineri.

I bave resfored the orbital ossifications as being

oriented trans*\'ersely and longitudin-allv below tlie

orbit, in mcsial contact with cach other, cotmecced

by ciirtilagc to ebe dorsal, mesially directed shelf

above tlic perichondral conc. for rhe posterior

postorbital proccs.s ol the endocranium (Fig. 34).

This is based on sevcral pièces of évidence:

I. Their position in the ariiculated specimen

WAM 86.9.662 (orb.oss; Figs 28, 29) in which

the paired orbital ossifications lay vciy close to

each other, a short distance anrerior to ihc paired

occipital ossifications (seen in ventral view) and

in close proximity to the ethmoid ossification.

2. In the holorype of Austroptyctodus gardinert rhe

orbital ossification is articulated with the mesiai

perichondral process of the marginal plate, sug-

gesting horizontal aligmenr as the mesiai lamina

of che marginal is horizontal in life po-sition.

3. The l.ict that they are joined mesially in some

specirnens of Ctenurellu gladbachensis.

4- The (act that the articulated, unerushed speci¬

men ol Chelyophnrns verncuUi hhtyvis the horizon¬

tal position of fhe orbital ossifications in

continuity with the horizontal laminae of the

occipital ossificatinris (see Fig. 31).

The orbital ossifications are seen to lie in the

transverse plane forrning the central division of

the ventral endocranial wall, mosr of which

forms rhe extensive siibociilar shelf The dorsally

elevated process on rhe latéral margin of the

orbital ossification is niost likelv an eye.stalk

aitachmcnt, situated more to the antcromcsial

part of the orbit, as it is in other placodcrms (e.g.

BuchüHo.ucHS^ Brindabfilluspis.Yowa^ 1986).

A large robust articulation, lying to the antéro¬

latéral corner of the orbital ossification, can be

interpreted as a strong carfilaginous connection

to the perichondral, thickening on the viscéral

surface ol the marginal plate, thus bracing the

latéral wall ol the endocranium with tlie margi¬

nal plate. In this respect it is most possibly an

homologue of the posterior po.siorbital proccs.s of

other placoderms, which abuts the marginal

plate in archrodircs [Buchanostem, Young 1979).

It appears to be too posteriorly situated eiiher for

rhe opercular cartilage or lot hyomandibular arti¬

culation to the braincasc, which are located adja¬

cent CO ihc ethmoid ossification and can bc seen

by chc anterior position of the head of the sub¬

marginal plate with respect to the orbit on arti-

culatcd spécimens ol botb Ctenurella gladba-

chemis and Austroptyctodus gardineri.

The two loramina picicing the orbital os.sifica-

tion are small in comparison with tho.se for the

major nerves in placoderms. and do not pass

from the brain cavity, but from die ventral .sur¬

face of the endocranium inio the orbital région.

These foramina are clearly seen in the isolated

orbital ossification of Chelyophorm verneuik

(Fig. 3^C, D) but they are so small in chc Gogo

specimen that they tend to be obscured by the

GEODIVERSITAS • 1997 • 19(3)

547

Long J. A.

consolidating gluc and are seen as dépréssions

(Fig. 33). Thus, only one large canal is seen

penetrating the bone ncar che eycscalk aitach-

mcm in che Gogo specimen, and this is possibly

the canal for the orbital artery (orb.a; Fig. 33). A

larger canal more posteriorly situated on the

orbital ossification of Chelyophorus^ emcrging

from a wcll-defined pit on che dorsal surface

(orbital caviry), is most likely for the internai

carotid artery emerging from the ventral myo-

dome (i.car, v.my; Fig. 33C, D) which in

Divksonosîeus (Goujet 1984a) and Brindabellaspis

(Young 1980) runs up through the subocular

shelf and into the ventral myodome for the eye

muscles. Other smaller foramina which do not

seem to pcnetrate through the ossification may

bc vascular supply canals for che interperichon-

drium.

There are rwo well defined notches embayed into

the latéral margins of the orbital ossifications in

ar.Eth

1 mm

5 mm

Rg. 33. — Ausxropt^cioéus gardineri n.g. (Mifes t?r Young. 1977). WAM B6.9.662. orbital ossiHcattons ot brairwase. A. paired units

as preserved (see figures 27^ 28 for position with respect lo resi of speàmen): B, detail of iêft orbital ossification In ventral view. C,

D. Chelyophotus verneuiH Agassiz, 1844-, MNffN specimen, Agassiz type coftection (unnumbered. Collection of Verneuil. Laboratoire

de Paléontologie, MNHN): left orbital ossification. C. ventral view; D, dorsal view. ani. anterior direction; ar.Eth, articulation for eth-

moid ossification: ar.M. articulation for marginal piale; ar.Occ. articulation for occipital ossification es. eyestalK attachment: gr, groo-

ve; i.car, internai carotid foramen; n. notch: orb.a, ioramen for orbital artery; p.ppr, possible homologue of the posierior postorbital

process of endocranium; soc.sh, subocular shelf; v.my, ventral myodome.

548

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

both Gogoptyctodus and Chelyopborus (gr, n;

Fig. 33). Ah rbesc are con.siderably larger rban the

arterial foramina, rhc largest of thèse, situared

posterior to the eyestalk and internai carorid

foramen, Ls possibly for the pituitary vein.

Ethmoid ossification

The ethmoid ossification has been well-dcscribed

by Miles & Young (1977), but was not restored

in relation to the rest of the endocranium and

jaw suspensory mechanism. The new material

adds nothing new to the description of the erh-

moid ossification, as no isolaied ethmoid ossifi¬

cations hâve yer been recovered from the Russian

material or the new Gneudna specimens. Ji

should be noted that 0rvig (1962) restored the

ethmoid ossification in C gladhachmsls wiih a

large anteriorly facing articulatory facer for the

palatoquadrate, and bbeJled it as the “irieraptery-

goid”. It seems likely that the large anterior faceis

on the ethmoid faced anterolaierally, as suggested

by Miles & Young, to arttculate wich the articu¬

latory facets on the autopalatine, the midlines of

the ethmoid ossifications meeting medially held

by cartilage.

Nasal ossification

Observation of the Bergisch-Gladbacii material of

Ctenurella gladbachensis and of Âastroptyctodus

gardineri shows that the ethmoid ossification is

always preserved in a position ventral to rhe

“meiapterygoids” of the palatoquadrate. In the

holotype of Austroptyctodus (Miles & Young

1977; Fig. 23) the rigin *'mecaptcr>'goid" is sepa-

rated from the autopalatine and rests immediarely

dorsal to the ethmoid ossification, which clearly

séparâtes this ossification from the upper jaw ossi¬

fications. This leads me ro propose that the

“metapterygoid” has been misinterprefed and is

actually not part of the upper jaw apparatus but

could represent a paired nasal ossification partiy

enclosing rhe nasal capsules. These bones sit ante-

rior to the orbits direerly dorsal to rhe upper jaw

ossifications (nas.oss; Fig. 35), in a position

appropriate for the external nares by comparison

with other placoderms, The shape of the ossifica¬

tion as described lor Anstroptyciodtis by Miles &

Young (1977, fig. 26) shows that the latéral face Ls

concave and would hâve been able to support the

olfactor)^ bulb, in a way similar lo the preorbitai

rcces.s of antiarchs, immediarely anteriot ro the

orbit. The présence of paired nasal ossifications is

known in arthrodires as cribtosal bones, clearly

seen in many of rhe Gogo eubrachythoracids (e.g.

FMstmanosteus-, Dennis-Bryan 19tS7; Latocamurus^

Long 1988c; plourdosteids, see Gardiner & Miles

1990). There is a groove and a tidge developed

on the mesial side of ihe bone, noted by Miles

Young (1977: 176) as possibly being for attadt-

ment to the endocranium. The W'ell-dcfincd

groove which runs dorsally and anteriorly above

the cavity for the nasal capsule is possibly for a

terminalis nerve, which has been identified mesial

to the nasal capsules in the arihrodire

iMtùcamunis (Long l98Sc). d^he nasal ossifica¬

tions had well-developed posierodorsal processes

(Miles Young 1977, '‘prmpi’' fig. 26) which

may hâve mesially been joined by ligaments. The

funaion of this unusual process on the nasal ossi¬

fications could bave been as an artachmenc région

for the médian rosirai cartilage (m.ros.carc,

Fig. 281, an ossification présent in some

ptyctodonrids but absent in ail other placoderms.

Reconstruction ofthe endocranium

A reconstruction of the endocranium in ptycto-

dontids was glvcn by Miles & Young (1977,

fig. 22) based on the available specimens of

Austroptyctodus gardineri. In light of the new

material ;uid the cvidence from new' observations

on ihe aniculatcd position of braincasc ossifica¬

tions in both Chelyopborus and Ctenurella. it is

now possible to prmnde a new sketch reconstruc¬

tion of the ptyctodontid endocranium (Fig. 34)_

The position of the occipital ossifications is clear

as the glenoid processes are always aligned with

hori/onial long axes, as correcily restored by

Miles & Young (1977, fig. 22B, and shown here

Fig. 32C), as it also occurs in rhe arriculated spt-

cimen of Cbelyophorus (Fig. 31). That the paired

orbital ossifications lie in rhe borivontal plane

below the orbit bas been argued above from évi¬

dence seen iri unctushed articulaced .specimen of

Chelyopborus. plus observation.s on tbe Gogo and

Bergisch-Gladbach specimeas. Fhe relative size.s

oi the occipital, orbital, ethmoid and nasal ossifi¬

cations in relation to the skull root axe cleaily

seen from WAM 96.9.662, upon which the dor-

GEODIVERSITAS • 1997 • 19 (3)

549

Long J. A.

sal view ouiline reconstruction of the endo-

cranium was laigely bascd. The position of the

ethmoid ossifications immediately anterior to the

orbital ossifications and articulating with the

palatoquadrate is aiso based on obseivacions of

Ctenurella and of the WAM 86.9.662 spccimen

of Austroptyctodus. Finally» the position of the

paired nasal ossificarions, anterior to the ethmoid

ossifications and sirting above rhe palato¬

quadrate and behind the inferrcd position of the

nares, is a new interprétation based on observa¬

tions of several specimens of articulated

Ctenurella and Austroptyctodus.

The braincase of ptyciodonrids,, as restored

hcrein, is unique amongst placoderms in compris-

ing at least four paired perichondral components,

forming a solid floor to the endocranium but

lacking any dorsal ossification.. Furthermore it is

iinlikc any other pJacoderm in having a médian

suture running down îts midline where opposite

sides of the paired ossifications are joined by car¬

tilage. The rounded shape of the orbital ossifica¬

tions implies that a space exists anterior to the

mesial connection betwen these units and die

ethmoid ossifications immediately anterior to

them. This could be for a ventral hypophysial

Fig. 34. — Aîîempted reconstruction of the endocranium in dorsal view (shaded) of Austroptyctodus gardineri (Miles et Young, 1977)

n.g., based largely on WAM 86.9.662. Outline of skull roof bones shown as transparent, es, eyestalk attachment; eth.oss. ethmoid

ossification of endocranium: glen, glenoid condyle of endocranium: nas.cap, nasal capsule; nas.oss, nasal ossification of endocra¬

nium; occ.oss, occipital ossification of endocranium; or.oss, orbital ossification of endocranium.

550

GEODIVERSITAS • 1997 • 19(3)

Ptyctodontid fishes from the Late Devonian Gogo Formation

opening. There it, no parasphenoid ossification as ventral overlapped région. The external orna-

in arthrodires, phyllolepids and in the acantho- mentation is a very fine reticulate pattern,

thoracid Kosoraspis.

Figure 35 piovidcs a revjsed reconstruction for

the dermal exoskeicton and viscéral skeleton, as SUMMARY AND CONCLUSIONS

known for Austwptyctodus gardineri,

Dermal seules I. The genus Campbellodus deeipens Miles et

Thin scalcs covered the tail oî Austroptyctodus Young is redescribed from a complété new speci-

gardineri^ as preserved in WAM 86.9.662 (sc; men, showing it to hâve three médian dorsal

Figs 27-29). They closely resemblc those of plates, a dermal scalc cover and well-ossiPied

Campbelbdus in overall form, being boomerang- anterior gill arch sériés. The skull roof shows that

shaped, much higher than long in the articulated the preorbitals plates did not suture in the mid-

squamation, with a dorsal external lamina and a line, as it is now known to occur in some other

neur

Rg. 35. — Atlenipted reconstrucilop of the dermal exoskeleton and viscéral endoskellon of Austropt/ctodus gardineri n.g. (Miles et

Young, 1977), based largely on WAM 86.9.662 and on the holotype, WAM 70.4.263. ADL, antenor dorsolateral plate; AL. anterior

latéral plate; Art. articular, Aut, Auiopalatine, ba a. ba p. anterior and postehor basais plates: BH. basihyal; Ce ceoiral plate; CH,

ceratohyal; Ep. epibranchials; Hym. hyomandibuiar: IH, interhyal eiement; IL. interolatoral plate; l.tpt lower tooth plate; M. marginal

plate; MD, MOI, 2, 3, médian dorsal plate(s) or spines; nas.oss, nasal ossification of endocranium: neur. neurals arches;

Nu. nuchai plaie (posteriof element); orb. orbit; PNu. paranuchai plate, PRO, preorbltai plate, PTO, po$torbi|al plate; Qd, quadrate;

ros.car, rostral cartilages (paired); SM, submarginal plate; u.tpi, upper tooth plate.

GEODIVERSITAS • 1997

Long J. A.

ptyctodonrids (e.g. Austroptyctodtis n.g.,

Rijynchodm tehadon).

2. The large, posterovenlrally directed gill arch

bones that lie immediately bchind thc jaw articu¬

lation in ptyctodontids had previously been

interpretcd as “ccratohyals" in Ctenurellu and in

the Gogo tbrni Austroptyctodus, évidence

from Campbellodus and Austroptyctodus n.g. sug-

gests that rhese arc modified inrerhyal cléments

and rhat rhe ceratohyak arc large, deep bones, as

occur in Ciimpbrllodm.

3- Révision ot some Bergisch-Gladbach spéci¬

mens of Ctenurella gludbitchensis 0rvig, I960

shows that thc skull root had been incorrectly

restored, and rhat thc centrais do in fact meet

each other bchind the nuchal plate. A reviscd

diagnosis of the genus is given.

4. Ctenurella' gardhieri Miles et Young, 1977 is

shown to diflèr from Ctenurella gladbachensh in

the arrangement of skull roof bones and body

squamation, and is here relerred to a new genus,

Austroptyctodusganlinejî n.g.

5. The braincase in ptyctodontids is interpretcd

to comprise ac least four paired pcrichondral

ossifications, the occipital, orbital, ethmoid and

nasal unies. The latter was previously identified

as being the ‘^mctapierv'goid”. Pcrichondral unies

attached to the inside of the marginal plate may

hâve houscd the posterior postorbital process of

the endocranium, as in other placoderms.

Ptyctodontids apparencly lacked a parasphenoid.

Acknowledgments

The new spccirnens of Gogo ptyctodontids were

collccted in 1986 by the author whiJst under the

support of the National Géographie Society of

America (granr ^3364-86) T aiso thank

Prof. R Taquet and Dr. P. Janvier for ofîèring me

a visiting professer position for three months and

providing research facilities (Sepeember-

November 1993), and the Trustées of the

Western Australian Muséum for supporting this

research proposai. My colleagvies in France gave

freely of cheir rime and disciissed various aspects

of the Work, I am especially grateful to

Drs P. Janvier, D. Goujet, H. Lelièvre and

Z. Min. Thanks also to Dr P. Forey of the

Natural History Mu.seum, London, who gave

access to the collections and discussed aspects of

the work. I thank Dr. L. Grande for access to

collections in tlie Ficid Muséum, Chicago, in

April 1996, and to B. Hickerson, Augustana

College, Illinois, lor showing me his new finds of

ptyctodontids from the Spring Grove Member.

Drs D. Goujet and G. Young are thanked lor

dbeussing aspects ol thc work and reviewing the

manuscript. For somc of thc photographs of

Gogo spécimens. I thank Ms K. Brimmell, and

for somc of rhe Gogo spccimen drawings, I

thank Miss D. Hendricks.

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Hanken J. & Hall B. K. (eds), The Skuli Vol. 2.

Patterns of Structural and Systematic Dioersity.

University of Chicago Press.

Smith B. G. 1937. — The anatomy of the frilled

shark Chlamydoselacbus anguineus Garman.

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American Muséum of NaruraJ Hisrory, New York:

331-520.

Stahl B. J. 1967. — Morphology and rclarionships of

the Holocephali with spécial référence to the

\'enous sy^tem. Bulletin of the Muséum of

Comparative Anatomy Harvard 135: 141-213.

Scensl6 F.. A. 1959. - On ihe pccroraJ fin and shoul-

der girdic of the arthrodire.s. Kungliga Svenska

Vetemkap Ahiidamtens HandlingnrS: 1-229.

— 1963 — Anaromical studic.s nn the arthrodiran

head. P.trr 1. IVeface, geological and gcographical

distribution, the organisarion of rhe arrnrodires, the

anatomy of the ncad in the Dolichothoraci,

Coccosteomorphi and Pachyosteomorphi.

Taxonomie appendix. Kungliga Svenska Vercmkap-

Akadtnniem HandlingarA (9) 2: 1-419.

— 1969. — Elasmobranchiomorphi Placodermata

Arthrodires; 71-692, in Piveteau J. P. (ed). Traité

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de Paléontologie. Masson, Paris.

Veran M. 1988. — Les éléments accessoires de l’arc

hyoïdien des poissons téléostomes (Acanthodiens et

Osteichthyens fossiles et actuels). Mémoires du

Muséum national d'Histoire naturelle, série C 54 ;

13-98.

Watson D. M. S. 1934. — The interprétation of

arthrodires. Proceedings of the Zoological Society of

London 3: 437-464.

— 1938. — On Rhamphodopsis, a ptyctodont from

the Middle Old Red sandstone of Scotland.

Transactions of the Royal Society of Edinburgh 59:

397-410.

Woodward A. S. 1891. — Catalogue of the fossil fishes

in the British Muséum (Natural History). Volume 2.

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— 1941. — The head shield of a new macropetalich-

thyid (Notopetalichthys hillsi gen. et sp. nov.) from

the Middle Devonian of Australia. Annals and

Magazine of Natural History 8; 91 -96.

Young G. C. 1979. — New information on the struc¬

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Society 66: 309-352.

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10-76.

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PalaeontoloQ* 27: 625-661.

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Submitted for publication on 14 June 1996;

accepted on 5 Novemher 1996.

GEODIVERSITAS • 1997 • 19(3)

555

Evolution of the premaxMlary

in the primitive fossil actinopterygians

Cécile POPLIN

Laboratoire de Paléontologie - LIRA 12 du CNRS, Muséum national d’Histoire naturelle,

8 rue de Buffon, F-75231 Paris cedex 05 (France)

Richard LUND

Department of Environmental Studies, Adelphi University,

Garden City, NY 11530 (USA)

Poplin C. & Lund R. 1997. — Evolution of the premaxillary in the primitive fossil actinoptery¬

gians. Geodiversitas (3) : 557-565.

KEYWORDS

Vertebrata,

Actinopcerygii,

comparative anatomy,

evolutionary ircna,

premaxillary,

dcrmal snout.

ABSTRACT

The different conditions of' the premaxillary in primitive aainopicrygians are

individualized, or fused lo adjacent boncs. Thcir dental field can aiso bc divi-

ded and fused to neighbouring bones, the premaxiilaries may be separated

across the midline, or, finally, they hâve disappeared. This séparation and

absence can resuit in a rostral notch observed in rhadinichthyids, and presu-

med in other groups such as the redfieldiiformcs. It can be sug-

gested that the plesiomorphous gnathosiomc dermal skcletal condition is

micromeric, that the primitive actinopterygian larval snout condition derivcd

from that condition was mcsomeric, and that heierochronic changes during

early actinopterygian évolution gave rise during development (1) of mesomc'

rie adult primitive actinopterygians through neoreny, (2) of macromeric

adult primitive actinopterygians through fusions of bones, (3) to the condi¬

tion of actinopterygians lacking a premaxillary through its loss. The neopte-

rygian condition may hâve arisen through paedomorphosis from either

mesomeric primitive fossil actinopterygians, or directly by heterochrony

from the larval primitive condition.

GEODIVERSITAS • 1997 • 19(3)

557

Poplin C. & Lund R.

MOTS CLÉS

Vcrtebraiâ,

Actinopterygü,

anatomie comparée,

tendance évolutive,

préniaxillaire,

museau dermique.

RÉSUMÉ

Les difterenies dispositions du prémaxillaire chez les actinoptérygiens primi¬

tifs sont : différencié ou fusionné à des os adjacents, le territoire dentaire peut

erre divisé et fusionné à des os voisins, les deux prétnuxillaire.s être séparés

sans contact l’un avec l’autre, enfin le préniaxillaire peut avoir disparu. Certe

séparation ou celte absence sc traduisent le plus souvent par une lacune

osseuse roseraie observée chez des rhadinichthyidés et supposée dans plusieurs

autres groupes dont les redftelduformes. Il est suggéré que la disposition plé-

siomorphe du squelette dermique de.s gnathostomes est micromérique, que la

disposition larvaire du museau des acrinoptérygiens dérivée dé cette disposi¬

tion piésiomorplie était mésomériquc et que les changements hétéroch to¬

niques au début de l’évolution dcvS actinoptéiygiens ont donné pendant le

développement. (1) par néoténie, des acrinoptérygiens primitifs adultes

mésomériques, (2) par des fusions osseuses, des actinoptérygiens primitifs

adultes macromériques, (3) par disparition, des formes dépourvues de pré-

maxillaire. Les néoptérygiens seraient issus par pédomorphose, soit des acti-

noptérygiens primitifs fossiles mésomériques, soit directement, par

hétérochronie de la disposition primitive larvaire.

INTRODUCTION

The snout in teleostome fishes is a région of the

dermal skull concentrating éléments sensitive to

adaptations and évolution, as it bears teeth,

narial openings and che anreriormost part of the

latéral sensory sysrem. The variations of irs ana-

tomy hâve been often dealt w'ith in the past

(Westoll 1937; Pehrson 1947i 1958; Gardiner

1963; Wenz 1967: Pearson &c Westoll 1972:

Patterson 1975; Pearson 1982; Schaeffer 1984;

Long 1988). More recently che evolutionary

implications of some of its bony units in lower

actinopterygians wcrc discussed (Poplin & Lund

1995). In the présent work, analysis is focussed

on the area of the prcrjiaxillary among the der¬

mal bones of ihe snout which underwent the

most numerous modifications of any area of

skull bones. Therefore, it is potendally one of the

most significant complexes of bones and latéral

line canals for phylogenetic purposes in lower

actinopterygians. Because of difficulties in obser¬

vation and préservation in fossil fishes, accurate

descriptions and reconstructions of the snout are

rather rare so chat wê refer here to the besi

known taxa, even if reappraisials of them should

bc eventually désirable.

THE DIFFERENT STATES OF THE PRE-

MAXILLARY IN LOWER ACTINOPTERY¬

GIANS

In order ro avoid confusion owing to che many

bnne nomenclatures used by authors, which

somehow darkened the understandlng of the der¬

mal snout évolution in the past, the “premaxilla-

ry” is defined herc as the most anterior paired

upper anamestic toothbearing bone of the rim of

the niouth. When it is fused to oeber bony terri-

tories. compound names are used (Poplin &

Lund 1995). As a whole, the five following States

of the premaxillary hâve been observed among

primitive actinopterygians.

1. Individualized typical premaxillac arc rather

rare in lower fossil actinopter)^gians: for instance,

in Lower Carboniferous, fishes from Bear Gulch

(Montana, USA), the Tri.assic Pteronisculiis

(Nielsen 1942), Perleidus (Fig. lA; Lehman

1952). According to Hutchinson (1978). it is

aiso présent in monophylecic lineages such as the

Triassic Brookvaliidae and Schizurichihyidae. In

récent forms* separace prcjnaxiüaries are présent

in iarval Polypterus (Fig. IB; Pehrson 1947,

1958) and in ail the neopterygians, wfiere they

558

GEODIVERSITAS • 1997 • 19(3}

Evolution of the premaxillary in actinopterygians

may even be larger than the maxillae (Fig. IC). resulting in compound bony units such as “ros-

tro-premaxillo-anrorbitals”, “rostro-premaxilla-

2. More often, in lower fossil actinopterygians, ries" and “antorbico-premaxillaries” (Fig. ID, E;

the premaxillary is fused with adjacent bones Poplin &C Lund 1995). In adult Polypterus the

Fig. 1. — Dermal snouts: A-G. lett latéral view; H, front view. A. Periôidus piv&teaui (after Lehman 1952, fig. 86). B, Polypterus,

9.6 mm larva (afler Pehrson 1958, tig, 8); C, Pomatomus saltatrijt (after Gregory 1933, fig. 177); D, Birgeria groenlandica (after

Nielsen 1949. fig. 69), E. Moythomasia nitida (after Jessen 1968, fig. 1): F. Polypterus adult (after Daget 1958, fig. 1791); G,

Watsonichthys pecUnatus (after Gardiner 1963, fig. 1); H. Howqualepis rostridens (afler Long 1988, fig. 14B). APx. antorbtlo-pre-

maxillary; AoPxR, antorblto-premaxillo-rostral; IMx. infraorbito-maxillary; Mx. maxîHary; Na, nasal: Px, premaxillary; Pr. postrosiral;

RAo, rostro-antorbital; RPx. rostro-premaxillary; RPrPx, rostro-postrostro-premaxillary.

GEODIVERSITAS • 1997 • 19(3)

559

Poplin C. & Lund R.

premaxiliary \s fiised ta rhe lacerai roscral and to

the antorbital (Fig. IF» Pehrson 1947, 1958;

Lehman 1958:2092).

3. The terrirory of thc premaxillary dental field

may aiso he divided into nvo unies chat are fused

to neighbouring boncs (Moy-l'homus 1934; Ten

Cate 1985). This is thc case foi instance in

Watsonichthys pectirunns (Fig. iG) whicli shows

an anrorbito-prcmaxillary together with a rostro-

premaxillary. The Dcvanian Mo)fshofU 4 sia durga-

ringa and Howqualepjs rostride7U {çf. Gardincr

1984; Long 1988) are more complex and ques-

tionable cases (Fig. I f I); their anterior marginal

teeth are borne by three bones: paired antorbico-

premaxillaries (= Gardiners and Longs “pre-

maxillaries’') and a rnedian rostro-postrostro-

premaxillary (= “dentigerous rostro-postrostml").

According to our interprétation, thc territories of

the right and left premaxillaries (or their dental

fields) are divided inro four units; tlie médian

ones arc Rised to the single rostro-postrostral and

the latéral oncs arc fused to the paired antorbitals

(Poplin & Lund 1995).

4. In some cases, such as in some Bear Guich

taxa, bofh premaxillaries are so weak and so loose

that they are not in contact with each other. This

situation results in a small médian rostral notch

quite like that described below.

5. The last state of the premaxillary is encounte-

red in a number of primitive fossil actinoptery-

gians: its disappearance revc;ilcd by the complété

absence of the characteristic learurcs ot its terri-

tory, Le. anamestic and presence of anrerior mar¬

ginal teeth (Poplin & Lund 1995).

Such a lack has hecn somerimes observed, or sus-

pected, in the past. We.stolJ (1937) and latcr

Heyler (1969) noticed that the AeduelUdac hâve

no premaxillaries. The Redfieldüformcs gave risc

to a small disagreemenr on this respect berween

Hutchinson (1973, 1978) and Schaeffer (1967,

1984): the former thinks that the lack of a pre¬

maxillary characterizes only the Family

Redfieldiidac, and ihe lauer daims that it i.s a

feature of the whole order. More recently the

absence of this bone has been directly observed

in Lower Carboniferous paleoniscoids from Bear

Guich (Montana, USA; Poplin & Lund 1995).

The absence of tlic premaxillary results eltber in

the anterior development of the maxillaries

which rhen meer cadi other above the mouth

(e.g. At'dîifllctj Fig. 2C), or in thc snout skeleton

having a médian notch above the mandibular

symphysis. Such a notch is observ'ed in Lower

Carboniferous rhadinichthyids (Fig. 2A, B) like

thuse Irom Monvana (Poplin & Lund 1995) and

Scodand (Moy-Thomas &r Dyne 1938). We sus¬

pect the presence of thi.s notch in m.my other

pâleoniscoid forms which lack the characicristic

features of the premaxillary and show, in side

view, a typically protruding snoui above lhe

aperture of the mouth: for instance PaLaeoniscus

(Fig 2D; Aldinger 1937), Cycloptyvhim, Hlonich-

tbys (Moy-Thonias & Dyne 1938), Boreostn7ius

(Nielsen 1942; Lehman 1952), Dicellopyge

(Brough 1931).

Schaeffer’s description suggesis that the

Redfieldiidae (Fig. 2E) probably aIso had this

anterior notch (1967: 307, 308): “As ihc man-

dibles are about the same Icngth as the infraorbi-

tal ramus of the maxilla, thc toothlike dentides

along the ventral margin of thc rostral and the

antorbital could not have functioned in scizing

prey. Furrhermorc, it has not been possible to

reconstruct [...J the snout [..*] in a way that

would permit rhe roscral teeth to mcct the man-

dihular ones, even if rhe lower jaws were actually

longer. Part of rhe space between antorbitals

must have been occupied by rhe mandible when

thc mouth wxs compleiely dosed, but we have

been unabic to climinatc the resulting space bet¬

ween rhe ventral margin of thc rostral and the

mandibular symphysis.” The presence of an ante¬

rior notch is confîrmed, according to us, by the

characteristic protruding snout in side view, as

explained above.

In this peculiar redfieldiid snout, covered with a

quantify of small dermal ruberdes, whar could

be thc function of an anterior notch? First it

could cause a smaller aperture of the mouth and,

rhus, increase rhe inhaJing strength during

expansion of the mouth: this would facilîtate

560

GEODIVERSITAS • 1997 • 19(3)

Evolution of the premaxillary in actinopterygians

Fig. 2. — Dermal snouts: A, ventral view; B-E, left latéral view. A, B, Rhadinichthyid from Bear Guich (after Lund & Poplin in prep.):

C. Aeduella {after Heyler 1969, fig. 92); D, Palaeoniscus freieslebeni (after Aldinger 1937. fig. 250); E, Cionichthys greeni (after

Schaeffer 1967, fig. 7). Ao. anlorbiial; Mx. maxillary: md. mandible; n. noich; Ro, rosirai; RPr, rostro-postrostral.

suction in a bentliic feeding mode (Lund et ai

1985). Indeed, this combination of an armored

projecting snout and the notch would permit

these fishes to root aroutid (like hogs), using the

denticles to stir up the sédiment and the notch

to facilitate suction upon those prey items that

were scared out of their hiding places. Moreover,

Schaeffer and Hutchinson emphasize that these

fishes could hâve had a thick fleshy lip supported

by these denticles and overhanging the mouth:

this lip helped them to fecd at the sediment-

water interface, somewhat like the protrusive

mouth of recenc teleosts. In thi.s hypothesis could

an anterior notch hâve been linked to a very

short appendage like a tiny irunk? Like the pro¬

trusive premaxillae in recent teleosteans, this

would increase the buccal volume during abduc¬

tion of the lower jaw, as well as just after the food

was engulfed and the mouth was closed again

(Alexander 1967).

The existence of this anterior notch raises the

question of the anatomy of the underlying endo-

cranial and viscéral régions: cthmoidal endoske-

leton and vomers, as well as oral valves, if there

were any in these fishes. In the total absence of

data it is difficult to answer.

DISCUSSION ABOUT THE PRIMITIVE

STATE AND FURTHER EVOLUTIONARY

TRENDS OF THE ACTINOPTERYGIAN

PREMAXILLARY

The anatomical variety of the premaxillary in

primitive fossil actinopterygians, briefly descri-

bed above, leads to two fundamental questions:

— Wliat was the condition of the premaxillary, in

the ancestral morphotype of actinopterygians?

- What does this variety indicarc about the rela-

tionships of the main actinopterygian lineages?

GEODIVERSITAS • 1997 • 19(3)

561

Poplin C. & Lund R.

In the past the rhree following hypothèses

(absent, ftised To other bunes, présent) hâve been

proposed concerning the ancestral condition of

the premaxillary la actlnoprerygians.

Hypothesis 1

Absence of the premaxillary: Westoll (1937) was

among the first to speculate about the fate of the

premaxillary. He noticed rhat the holostean and

teleostean premaxillary was quice complex and

different ffom whac was known of paleoniscoids

at his time. Therefore he thought that the very

first actinopterygians had no premaxillary and he

proposed four schemes lo explain the existence

of a premaxillary in the upper actinopterygians;

(1) it is a neoformation; (2) it results fiom a frag¬

mentation of rhe paleoniscoid rostraJ; (3) the pri¬

mitive maxiliary has been split into maxillary and

premaxillary; (4) or the lineages which gave rise

to the upper actinopterygians hâve been separa-

ted very early From the paleoniscoid ones, which

implies thac prcmaxillaries developed indepett-

dantly in boch groups. Westoll considered ihis

last hypothesis as improbable. The first of

WestoU’s suggestions can now be discarded since

ail other osteichthyan groups share rhe plesio-

morphous occurrence of a premaxillary Westolls

other schemes are early previews of the subsé¬

quent hypothèses srated below (premaxillary pro-

duced by fragmentation of compound bones,

very early séparation of the lineages leading to

paleoniscoids and neopterygians, parallelism of

eventual structures).

Hytwhrsi.s 2

Presence of the premaxillary as a compound

bone, macromeric snout: many authors, such as

Pehrson (1947t 1958), Gardiner (1963, 1984)

and Jessen (1968) suggested tbat a premaxillary

was présent in the first actinopterygians bue as a

rostro-premaxillo-antorbita). This view, based on

the observation that this compound bone is pré¬

sent in rhe most primitive Devonian forms and

in the Recent Polypterus^ is part of rhe more

generalized hypothesis ofa macromeric primitive

pattern of the dermal snout (Gardiner 1963;

Patterson 1975). Lacer in accinopterygian history,

different and successive splittings of the rostro-

premaxillo-antorbital would hâve led to the

various dispositions observed in paleoniscoids

and to the mcsomeric snout anatomy of neopte¬

rygians (Fig. 3).

H\tothesis 3

Presence of an individualized premaxillary: meso-

meric snout evolving by fragmentations. The

ancestral accinopterygian morphorype has Indeed

indépendant prcmaxillaries in a mesomeric snout

(Tearson 1982; Schaeffer 1984; Long 1988;

Gardiner üsC Schaeffer 1989). This is more

consistent vvith the rne.soixieric snout disposition

of sarcopterygians and of the larval Polypterus

than with Westolfs first rhree schemes or with

that of a macromeric primitive pattern We note

that this hypothesis fits better with the more

recent data about rhe pattern of occurrence of

separate prcmaxillaries among the paleoniscoids.

Primitive hypothetic disposition

Primitive actinopterygians

Neopterygians

MACROMERIC

[pn+lNil

+ I RPxAo

fragmentations

ŒlI

RPxAo

RPx

RAo

[Xol

[Px]

MESOMERIC

[Nâ]

[Px]

rÂôi

[RÔ]

Adults

Fig. 3. — Hypothesis about the évolution of the dermal snout after Pehrson (1947,1958), Gardiner (1963,1984), Jessen (1968). and

others (see text). Ao, antorbital; APx, antorbito-premaxillary; Na. nasal; Px, premaxillary; Pr. postrostral; RAo. rostro-antorbital; Ro,

rostral; RPx, rostro-premaxillary; RPxAo, rostro-premaxlllo-antorbital; RPr, rostro-posîrostral.

562

GEODIVERSITAS • 1997 • 19(3)

Evolution of the premaxillary in actinopterygians

The lack of premaxillar)^ is better cxplaincd as a

mere lack of its rerricoiy in the embryo rarher

than as an involurion during later development

(Poplin & Lund 1995). In order to specify this

third hypothesis, Schaeffer (1984: 5) adds that

the pattern in the 24 mm Polypterus repre-

sents the primitive actinopterygian lançai condi¬

tion, whereas that in the mature Polypterus [...]

may be regarded as the primitive adiilt condi¬

tion.”

Therefore, based on ihis view, the third hypothe¬

sis is completcd as follows when we add the

recent data (Fig. 4). The primitive larval pattern

of the snoüt in actinopterygians was mesomeric

wich separacé postrostrals, rostrals, nasals, pre-

maxillarie.s and antorbitals. Different processes

during development and maturation led to the

varions di.spositions observed in the primitive

fossil adult actinopterygians: (1) fusion.s leading

to the variery of macfomeric snouts observed in

primitive fossil actinopterygians; (2) precocious

disappearances during development of its cerrito-

ry resulting in the absence of premaxillary; and

(3) neoieny maintaining the larval pattern in

adults (Jollie 1969). The neopterygian adult pat¬

tern (aiso characterized by rhe absence or fusion

of a postrostral) sprung after paedomorphosis

either from aiready known lineages of mesomeric

primitive actinopterygians, or directly from the

primitive hypothetic larval pattern.

CONCLUSION

We propose the following hypothesis about the

mechanisms which gave rise to the main patterns

of die derinal snout in actinopterygians: the pri¬

mitive mesomeric snout cvolved and diversifîed

either ihrough heierochronous processes, such as

neoceny and paedomorphosis, either through

fusions or disappearances. This hypothesis leads

to the following considérations.

— The ancestral larval morphotype of the acti-

Primttive hypothetic disposition

Primitive actinopterygians

Neopterygians

MESOMERIC

ŒD+[Hi]

[Na] +[^+rPx1

Adults

Fig. 4. — Hypothesis proposée! in this paper about the évolution of the dermal snout, based on those of Pearson, Schaeffer, Long,

Gardiner & Schaeffer (see text). Ao, antorbital; APx, anlorbito-premaxillary; Na, nasal; Px, premaxillary; Pr, postrostral; Ro, rostral;

RPx, rostro-premaxillary; RPxAo, rostro-premaxillo-antorbital; RPr, rostro-postrostral.

GEODIVERSITAS • 1997 • 19(3)

563

Poplin C. & Lund R.

noptetygians is likely to hâve bcen providcd with

a separate p^cmaxl]la^)^

- It is more piirsimonious, from a phylogenetic

point of view, to think that the lincages with a

mesomeiic disposition and possessing a pre-

maxillary are more closely rclated to neoptery-

gians than the other lineages (macromeric and/or

lacking premaxillaries).

— The multiple States of ihe premaxillary (parti-

cularly its loss) and tlieir systematic distribution

indicate that, ai least some of chem could hâve

appeared more than once, l'hese data and new

informations on the actinopterygian relation-

ships of Pidypterm can be interpreted as suppor-

ting the hypothesis that the lower actino-

pterygian.s conveniently called “paleoniscoids”

may not be a natural group.

Finally, rhis review of the problems concerning

the primitive pattern of tho premaxillary, and of

its subséquent evoludonary trends, is a démons¬

tration of the parallel évolution of knowledge

and ideas. It is rather amusing to notice that

WestoHs first ihree schemes are invalidated by

rccent data, and that his lasr schemc, that he

considered as the less likely, turned to be the one

favoured herein. In sixty years from now, whar

will remain of the analysis exposed in this paper?

Acknowledgments

We are thankful to Richard Cloutier and John

Long who revised the manuscript and to Henri

Lavina who computerized the drawings and

tables.

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Hutchinson P. 1973. — A révision of the

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GEODIVERSITAS • 1997 • 19(3)

Evolution of the premaxillary in actinopterygians

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Submittedfor publication on 8 January 1996;

accepted on 28 May 1996.

GEODIVERSITAS • 1997 • 19(3)

565

Late Triassic cynodonts from

Saint-Nicolas-de-Port

(north-eastern France)

Pascal GODEFROIT

Département de Paléontologie, Institut royal des Sciences naturelles de Belgique,

29 rue Vautier, B-1000 Bruxelles (Belgique)

Bernard BATTAIL

Laboratoire de Paléontologie, Muséum national d’Histoire naturelle,

8 rue de Buffon, F-75231 Paris cedex 05 (France)

Godefroit P. & Battail B. 1997. — Late Triassic cynodonts from Saint-Nicolas-de-Port

(north-eastern France). Geodiversitas ^9 (3) : 567-631.

KEYWORDS

Cynodontia,

Late Triassic,

Saint-Nicolas-de-Port,

dental morphology.

ABSTRACT

Numerous isolatcd cynodont teeth hâve been collected from the Late Triassic

of Saint-Nicolas-de-Port (north-eastern France). The material is very diversi-

fied and the following taxa are recognixed: Pseudoti-konodon wildi Hahn,

Lepage É’rWouters, 1984; Tncuspes tuebingensisY.. v. Huene, 1933; Tricuspes

sigogneauae Hahn, Hahn Godefroit, 1994; Tricuspes tapeinodon n.sp.;

Meurthodon gallicus Sigogneau-Russell et Hahn, 1994; Hahnia oblii^ua n.g..

n.sp.; Gaumia longiradicata Hahn, Wild Woucers, 1987; Lepagia gaumen-

i/j, Hahn, Wild Wouters, 1987; Maubeugia lotharingica n.g., n.sp.;

Rosieria delsatei n.g., n.sp. and aff. Microscalenodon. This cynodont fauna

mainly includes small insectivorous forms, more particularly represented by

Dromatheriidae; tiny herbivorous are represented by rare dwarf

Traversodontidae. The study of the palaeogeographical and stratigraphie dis¬

tribution of the Late Triassic to Early Jurassic cynodonts indicates that the

fauna discovered in Saint-Nicolas-de-Port is characteristic of the Late

Norian-Rhaetian period and is actually the most représentative of this period

for Western Europe. Granulométrie analysis of the bone-bed reveals that

they accumulated in a nearshore shallow marine environment.

GEODIVERSITAS • 1997 • 19(3)

567

Godefroit P. & Battail B.

MOTS CLÉS

Cynodontia,

Trias supérieur,

Saint-Nicolas-ae-Porc,

morphologie dentaire.

RÉSUMÉ

De nombreuses dents isolées de cynodontes ont été découvertes dans le Trias

supérieur de Sa.int'N!Colas-de'PorT (nord-est de la France). Le matériel étudié

esc très diversifié et les taxa suivants sont représentés : Psmdotrkonodon wiUii

Hahn, Lepage et Wouters. 1984 ; Tricuspes tuebingensis E. v. Muene, 1933 ;

Tricuspes sigvgftcaïuie Hahn, Hahn et Godefroit, 1994 ; Tnatspcs tdpeinodon

n.sp. ; Mexirthofhn galliais Sigtigneau-Russell et Hahn,. 1994 î Hahnia obli¬

qua n.g., n.sp. -, Gamnia longiradicata Hahn, Wild et Wourers, 1987 ;

Lepagia gaumemh, Hahn, Wild et Wouters, 1987 : Maubeugia lotharîngica

n.g., n.sp. ; Rosiêria delsatei n.g., n..sp. et aff. Mit'roscalenodon, La fiiune de

cynodontes est surtout composée de petits insectivores, représentés notam¬

ment par les Dromatheriidae vde iTiinuscuies herbivores, frirmes naines de la

famille des Travcrsodontidac, sont egalement présents. L’etude de la réparti¬

tion paléogéographique et stratigraphique des cynodontes du Trias supérieur

et du Jura.ssique inférieur montre que la faune de Saint-Nicolas-de-Porr est

caractéristique de la période Norien supérieur-Rhétien ; c'est incontestable¬

ment la faune la plus représentative de cette période pour l’Europe de

l’Ouest. L’analyse granulométrique du sédiment du hone-bed a révélé qu’il

s’était accumulé dans un environnement marin proche du rivage.

INTRODUCTION

In 1851, Levallois recorded fossil bones from the

'^gres infra-Uasique'^ in the vicinity of Saint-

Nicolas-de-Porc (Meurthe-et-Moselle, north-

eastern France; Fig. 1). In 1862, lie mentioned

the presence of a layer rich in fish and saurian

remains to the south of this cown. In 1928.

Corroy mentioned Saint-Nicolas-de-Port among

the most important upper Keuper localities of

Lorraine.

In 1971. Laugier gave the .stratigraphie log in a

sand quarry opened in 1922, 2.5 km south-east

of Saint-NicoIas-de-Port. Ttus quart)'' falls pardy

within the boundary of the adjacent village

Rosières-aux-Salines. He also documented the

diversity and abundance of the fauna discovered

there. The stratigraphy and the sedimentology of

rhis section was studied in detail by Al Kharib

(1976).

The first mammal-like tooth was discovered in

1975 by G. Woutejs, a Belgian collector. This

tooth was subsequently described by

Russell et ai (1976). Since then, several tons of

sédiments hâve been washed and screened by

G. Wouters, teams from the Muséum national

d’Histoire naturelle (Paris) and from the Institut

royal des Sciences naturelles de Belgique and

several amateur collectors. Attention was particu-

larly paid to mammal teeth discovered in this

quarry: the.se hâve been described in a sériés of

papers by a team Icad by D. Sigogneau-Russcll

(Sigogneau-RusscU 1978, 1983a, 1983b, 1983c,

1989, 1990; Franlt et al. 1984, 1986: Sigogneau-

Russell étal. 1986; Flahn et al. 1989. 1991).

Amphibian and reptile material has been descri¬

bed by BufFeiaut & Wouters (1986), Cuny &

Ramboer (1991) and Cuny (1993). Fish rcmains

hâve been studied by Sigogncau-Russcll et al.

(1979), Martin étal. (1981) and Duffin (1993).

Synthetic faunal lists are given by Cuny (1993)

and Duffin (1993).

Until now> little work has been completed about

the cymodont teeth discovered in Saini-Nicolas-

de-Port, in spite of their abundance and iheir

scientific interest. The double-rooted

mammal-like tooth described by Russell et al.

(1976) was subsequently named Meurthodon gai-

lient Sigogneaü-Russcll et Hahn, 1994 and refer-

red to the Family “Therioherpetidae”

(Sigogneaij-Russell ôc Hahn 1994). Hahn et al.

(1994) described teeth of Tricuspes sigogtieattae

Hahn, Hahn et Godefroit, 1994 and revtcwcd

the systematic position of the Family Droma-

568

GEODIVERSITAS • 1997 • 19 (3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Motorways

Main roads

Secondary roads

Fig. 1 . — Locality sketch map for Saint-Nicolas-de-Port.

theriidae. fhe purpose of the présent paper is to

describe the cynodonc remains discovered in

Saint-Nicolas-de-Port, on the basis of the whole

currently available inaterial. The collections are

housed in the Institut royal des Sciences natu¬

relles de Belgique (Brussels: IRSNB) and in the

Muséum national d^Histoire naturelle (Paris:

MNHP). The foss'ils were collected by

G. Wouters, D. Sigogneau-Russell, J.-C. Lepage,

D. Delsate and P. Godefroit.

GEOLOGICAL SETTING

Laugier (1971, fig. 19) described the geological

section exposed in the quarry of Saint-Nicolas-

de-Port. The base of the section is formed by

schistose maris of the Keuper. It is ovcrlain by

four sedimentary cycles. Bone-beds can be ob.ser-

ved at the base of each cycle, followed by sands

and sandstones, fmally by clays. The bonc-beds

decrease in thickness through the sequence. Lhe

basal conglomerate, above the Keuper maris,

reaches a thickness of 1.05 m.

LJnfortunately, the quarry is now being used as a

city dump and the section described by Laugier

cannor be observed any longer. Recent excavations

and new sections demonstrate that rhe geological

structure of the quarry is mucK more complex

than described by Laugier. Mosr of the deposits

are lenticular and show, therefore, important laté¬

ral variations. Furthermore, corrélations betweeu

close sections are very difFicult to establish.

Most of the vertebratc material discovered since

1975 at Saint-Nicolas-de-Porr has beeti found in

only one bonc-bed. Figure 2 illustrate.s chc geolo¬

gical section observed in ihis part ol the quarry.

The bone-bed is an intra-lormational conglome-

ratc which varies in thickness from 0.2 to 1 m. It

is formed by coarse sands and smaJl pebble.s. It

lays upon more than 7 m of alrernating marly

clays and sands. The bone-bed is capped by near-

ly 3 m of compact sandstones. Rccenr excava¬

tions exploited other bone-beds in other parts of

GEODIVERSITAS • 1997 • 19(3)

569

Godefroit P. & Battail B.

the quarry. The sampled sédiments hâve still to ved in any of the recent sections of the quarry.

be screened and sorted. It is interesting to notice The âge of the Saint-Nicolas-de-Porc quarry has

that, nowadays, Keuper maris cannot be obser- been much disputed. Lack of international agree-

29. Silt

28. Brown grits

27. Silty, brown and compact grits

26. Ferruginous grits

25. Yetlow sands and pobbles

24. BONE-BED: brown sands, green clay and pebbles

23. Green clay. ferruginous grits and brown sands

22. Green clay

21. Ferruginous grits

20. Green clay

19. Ferruginous grits

18. Green clay

17. Ferruginous grits

16. Green clay

15. Ferruginous grits

14. Green clay

13. Ferruginous grits

12. Green clay

11. White grits

10. Ferruginous grits

9. White sands

8. White sands with green clay

7. Green clay

6. White grits with green clay

5. Ferruginous grits with green clay

4. White grits

3. Ferruginous grits

2. White sands

1. Green stratified clay

Fig. 2. — Stratigraphie log of the Upper Triassic section at Saint-Nicolas-de-Port.

570

GEODIVERSITAS - 1997 • 19(3)

Late Triassic cynodonts from Saint-NIcolas-de-Port

ment on thc status of the Rhaetian Stage Umits

the discussion. Moreover, palynological sam-

plings in the quarry are. at the présent time,

unprofitable. From a Üihological point of view,

the sédiments are regaided as Lower Rhaetian in

âge (Laugier 1971; Al Khatih 197h; Sigogneau-

Russell 1983a). BufFetaut (1985), Buffetaut &C

Wouters (I9S6), Cuny & Ramboer (1991),

Duffin (1993) and Cuny (1993) argue for a

slighcly older âge; the vercebrate fauna from

Saint-Nico!as-de-Port shows close similarities to

that of the Knollenmcrgcl at Halbcrstadt in cen¬

tral Germany (Upper Norian).

Granulométrie analysis of the sédiments

(Al Khatib 1976) reveals that they accumulated

in a nearshore shallow marine environment. The

sands hâve some characters of river or beach

deposits.

SYSTEMATIC PALAEONTOLOGY

The sysiematics of the Cynodontia adopted by

Battail (1991) is followcd in the présent paper.

Concerning thc family Dromatheriidae, the clas¬

sification proposcd by Hahn et al, (1994) is fol*

lowed. As thc taxa treated in the présent paper

are defined excliisively on dental characters, it Is

usually difficult to sectie wjth certainty the pola-

rity of thèse traits. For that reason, it has beeti

decided to include borh apomorphic and plesio-

morphic characters in the diagnoses of

Cynodontia incertae scelis ta^ca; tlierefore, thevse do

not follow strictly the cladistic principlcs.

OrderTHERAPSIDA Broom, 1905

Infraorder CYNODONTIA Owen, 1861

CYNODONTS WITH SECTORIAL POST¬

CANINE TEETH

Orientation of the teeth

The orientation of isolatcd reech In cynodonts

with sectorial teeth Ls discussed by Peyer (1956),

Russell et al. (1976) and Hahn et al. (1984,

1987, 1994). The most convexside is convention-

ally and somewhat arbitrarily regarded as the

labial side, on both the upper and lower post¬

canines, The distal inclination of the cusps,

when présent, déterminés the rnesial and distal

sides of the teeth. The accessor)' cusps are usually

more numerous or better developed on the distal

haif of the crown than on the mesial half. When

wear i.s developed, it impossible to distingtiish the

upper teeth from thc lower ones: wear develops

on the lingual sidc of the former and on the

labial side of the latters. When wear is not deve-

lopcd or when the lingual and labial sides of the

crown are symmetrical, it is thus impossible to

scttle whether the specimen belongs to the upper

or to the lower tooth row.

Family Dromatheriidae GUI, 1872

Remark

The cladogram of the Dromatheriidae proposed

by Hahn et al. (1994) shows that this group is

clearly paraphyJetic, as the ancestry of the mam-

mals lies within it.

Genus Psetidotriconodon

Hahn, Lepage er Wouters, 1984

Pseudotriconodon Hahn, Lepage er Wouters, 1984:

358.

TyI'E SPECIES. — Pseudotriconodon wildi Hahn,

Lepage et Wouters, 1984.

Otmf.R REFFRRED SPECIFS. — Pseudotriconodon chat-

terjeei Lucas et Oakes, 1988. Identification of this

taxon as a cynodont has bcen qucsiioncd by Sucs

Olscn (1990), but without aigumentaiion,

DiAGNOSIS. — Crown of postcanine teeth tricuspid to

penracuspid and veiy narrow (2.4 < ratio “length/

widrh” of the crown < 4.2); labial and lingual sides of

the crown ncarly paralleJ. Cuiring edge pcrfecily

straight. Base of tnc crown not con.9tnctcd. Root

semiclliptical in outline, about 1.5 times as high as the

crown; tip of the root sometimes divided by a short

furrow; pulpal canal small, ellipticdl in shape and

sometimes double.

Pseudotriconodon wildi

Hahn, Lepage er Wouters, 1984

(Figs 3, 4)

Pseudotriconodon wildi Hahn, Lepage et Wouters,

1984: 358, pl. l, figs l, 2; pl. 2, figs 2-6; pl. 3, figs 1-

6. — Clemens 1986: 238. — Hahn et at. 1987: 17,

GEODIVERSITAS « 1997 « 19(3)

571

Godefroit P. & Battail B.

pl. 5, fig. 2. — Lucas & Oakes 1 988: 447. — Batrail

1991: 88. - Hahn et ai 1994: 142, fig. 2a. -

Sigogneau-Russell Ôd Hahn 1994: 206, fig. 10. lOd.

HolotypF.. — MNHL ‘‘R.M. I”, in rhe Muséum

national d'Hiscoire naturelle de Luxembourg.

Locus TYPrcus. — ‘^Rinckebierg” (Medernach,

Great'Duchy of Luxembourg).

Sl'RATUM TYPICUM. — Bone-bed included within the

Steinmergel'Gruppe (Norian, Upper Triassic).

New hypoittes. — From Saint-NicoIa-s-de-Port:

IRSNB R156. IRSNB Rl57> IRvSNB 28114/68.

IRSNB 28114/lÜÔ, IRSNB 28114/638. IRSNB

28114/737, IRSNB 281l4/739> TRSNB 28114/752,

IRSNB 28114/811, fRSNB 28114/859, IR.SNB

28114/870, IRSNB 28114/905, IRSNB 28114/906,

IRSNB 28114/994, MNHP SNP25. MNHP SNP54.

MNHP SNP115L. MNHP SNP61W, MNHP

SNP63, MNHP SNP68W, MNHP SNP75W,

? MNHP SNP83W. MNHP SNP198W, MNHP

SNP288W, MNHP SNP295W, MNHP SNP300W,

MNHP SNP306W, ?MNHP SNP337W. MNHP

SNP351W, MNHP SNP423W, MNHP SNP425W.

Diagnosis. — 0.9 mm < length of rhe crown of post-

canine teeth <3.1 mm; 0.35 mm < width or the

crown of postcanine teeth < 0.95 mm.

Description

Classification

Hahn et al. (1984) base their classification of the

postcaninc teeth in Psticdotriconodon luildi on the

number and the arrangement of the accessory

cusps. Six categories can be distinguished.

Group 1:

1 anterior and I posterior accessory cusps.

Group IL

1 anterior and 2 posterior accessory cusps.

Group III:

1 anterior and 3 posterior accessory cusps.

Group IV:

2 anterior and 2 posterior accessory cusps.

Group V:

2 anterior and 3 posterior accessory cusps.

Group VI:

? anterior and 2 posterior accessory cusps.

Measuremefits

The measurements taken on the postcanine teeth

of Pseudotrkonodon wildi are shown in table 1.

The orientation of the teeth and the measure¬

ments are illusirated by Hahn étal (1984, fig. 1).

Crown

In occlusal view, the crown appears elongated

antero-posteriorly and quite narrow labio-

lingually: in the specimens discovered in Saint-

Nicolas-de-Port, the ratio “length/width” of the

crown varies between 2.45 and 4.45. Both the

lingual and the labial sides of the crown are

Fig. 3. — Postcanine teeth of Pseudotriœnodon wildi, from the Late Triassic of Saint-Nicolas-de-Port. A-C, IRSNB R156: A. latéral

view; B, occlusal view; C, posterior view. D-F, IRSNB R157; D, latéral view; E, occlusal view; F, posterior view. Scale bar: 1 mm.

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodoncs from Saint-Nicolas-de-Port

nearly straight, slightiy convex at the level of the

main central cusp. Ail the cusps are in line with

the anrero'posterior axis of the crown. The cut-

ting edge is very sharp and perfectly straighr.

In anterior and posterior views, ail the cusps are

nearly perfectly straighc, without marked curve

towards the lingual side of the crown.

In latéral view, the main cusp occupies a médian

pOsSition. It has the outline of an isosceles tri¬

angle; its anterior and posterior edges arc straight

or slighrly convex- It is flanked by one to

two anterior and one to three posterior accessory

cusps of decreasing heighrs AU are triangular,

sharp and clearly separated from each other.

Their vertical axes usually diverge slightly from

the main cusp; they can be curved towards the

.A .ciî A Ô

P A ,û

Fig. 4. — Outline of postcanine teeth of Pseudotrlconodon wildi, from the Laie Triassic oî Salnt*Nicolas-de-Poit A. IRSNB R157;

B. IRSNB R156; C. IRSNB 28114/859, D. IRSNB 28114/739, E, IRSNB 28114/906; F. MNHP SNP300W; G, IRSNB 28114/737;

H. MNHP SNP306W: I. MNHP SNP63Wi J. IRSNB 28114/68; K, IRSNB 28114/905; L. IRSNB 28114/752; M, IRSNB 28114/870;

N, IRSNB 28114/627; O, IRSNB 28114/766; P. IRSNB 28114/100; Q, MHNP SNP115L; R. MNHP SNP425W; S. MHNP SNP68W:

T. MNHP SNP75W; U. MNHP SNP351W; V. IRSNB 28114/811; W. IRSNB 28114/994; X. MNHP SNP423W, Y, MNHP SNP295W:

Z, MNHP SNP288W. Scaie Dar: i mm.

GEODIVERSITAS ■ 1997 • 19(3)

573

Godefroit P. & Battail B.

médian axis of rhe crown.

The wear ou the cusps is apical but very erratic:

it does noi forni clearly defîned facets. It is there-

fore usually impossible to distingitish upper and

lower posrcanmes. The crown has no basal cin-

gulum and no basal groove separating rhe crown

from the root.

Root

The root is about 1.5 times as high as the crown.

Its outline is semielliptical in latéral view. Its

médian portion is slightly dcpresscd in compari-

son with the anterior and the posterior borders.

The pulpal foramen, when it can be observed, is

elliptical and elongated antero-posteriorly.

Ncither bipartition of the root nor undoubling

of the pulpal canal can be observed in the teeth

discovered in Saint-Nicolas-de-Port. In anterior

view, the root is very compressed labio-lingually,

like the crown.

Table 1. — Measurements (in mm) ot the postcanine teeth of

Pseudotriconoàon wHdi, from the Late Triassic of Saint-Nicolas

de-Port. Le. length of the crown; Wc. widlh of the crown; Hc,

height of the crown. For the signification of the groups, see text.

Group

Number

L/W

IRSNB 28114/737

195

0.55

3.55

IRSNB 28114'68

1.65

0.6

115

2.75

IRSNB 28114/628

2.1

0.55

1.4

3.82

IRSNB 28114/752

0.5

>165

IRSNB 20114/8111

1.7

0.7

243

RSNB 28114/100

1.65

0.55

MNHP SNP54

1.5

0.37

4.05

MNHP SNP 115L

1.65

0.5

115

3.3

MNHPSMP61W

2.37

0.9

2.63

MNHNP SNP68W

1.35

0.55

2.45

MNHNP SNP288W

1.1

0.25

0.9

4.4

MNHP SNP306W

1.9

0.45

115

4.22

II?

IRSNB 28114/994

?1.8

0.65

72.77

IRSNB Rl56

2.45

0.75

185

3.27

IRSNB 28114/739

2.85

0.95

2.25

MNHP SNP75W

142

0.55

2.58

MNHP SNP300W

2.18

0.55

145

3.96

IRSNB 28114/859

2.25

0.7

3,21

IRSNB 28114/905

2.25

0.6

>16

3.75

IRSNB 28114/970

0.7

1.45

72.86

IRSNB 28114/906

2.55

0.85

MNHP SNP63W

0.45

4.44

MNHP SNP295W

1.35

0.45

105

MNHP SNP351W

115

0.4

2.88

MNHP SNP423W

1.75

0.6

2.92

MNHP SNP425W

1.7

0.55

3.09

IRSNB R157

3.1

0.75

2.1

4.13

Discussion

Small teeth with fundamcncally tncuspid crowns

and undivjded roots are also known, in

Triassic rimes, in Tanystropheus, Macracnemus

(Prolacertilia) and Eudimorphodon (Pterosauria).

Haho et aL (1984) list the features distinguj.shing

the teeth t>f these animais. Différences can parti-

cularly be observed in the structure of the root,

bur also in the ornamentanon of the enamel or in

the proportions of che crown. During the Late

Triassic, Pseudotricotiodon and Eudimorphodon

lived together in Sainr-Nicolas-de-l\)rt (Godefroit

& Cuny, in prep.), as in Medernach (Great-

Duchy of Luxeraburg, Hahn et ai 1984) and in

the Chinle Formation of New Mexico, USA

(Mtirry 1986; Lucav'v m Oakes 1988).

In contemporary Morganucodontidae (rtal

mammals), the root in premolars and molars is

complerely dividcd; moreoven the crown is sur-

rounded by well devcloped cingula.

Ornithischian dinosaurs from Lare Tria.ssic

assemblages of Nortb America dso possess multi-

cuspid rriangular teeth (Huni 6c Lucas 1994), In

rhese animais rhe crowns are more massive and

usually recurved (at leasi in the premaxÜlary

teeth), The cusps are more numerous and much

les.s distinct, The root is higher and separated

from the crown by a well dcvelopcd neck.

The genus Pseudorriconodon is now urianimously

relerred to the Family Dromarheriidae (Carroll

1988; Lucas & Oakes 1988; Battail 1991;

Hahn et ai 1994; Sigogneau-Russell & Hahn

1994): this attribution is based on the partial

bipartition of the root observed in some spéci¬

mens, on the triconodont organization of the

crown and on the combinaced absence of cingula

and constriction berween the crown and the root.

The teçth from Saint-Nicolas-dc-Port difter from

Pseudotriconodon chaiterjeeiy from the Chinle

Formation ot New Mexico, by the absence of

distinct striations on the enamel and by their lar-

ger si/.c. Thcy are both morphologically and

morphometrically doser to Pseudotriconodon

wildi, from Medernach.

Figure 5 shows the relative évolution of rhe length

(x axis, in Ln) and of the width (y axis, in Ln) of

the dental crowns Ln Pseudotriconodon wildi. The

allometric parameters hâve been estimated, using

GEODIVERSITAS • 1997 • 19 (3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Fig. 5. — Dispersion diagram of the postcanine teeth in Pseudotriconodon.

Teissiers (1948) formulas (both the length and

the widch of the crown are here tegarded as

dépendent variables), separatcly for the popula¬

tions from Mcdernach and Sainc-Nicolas-de-

Porc. The allomeüy coefficient is similar in both

population: b = 0.90 and 0.92, respectively in

the populations from Saint-Nicolas-de-Port and

Medernach. The isometry between the variables

can therefore reasonably be conduded. On the

other hand, the characteristic ratio difters in the

rwo populations: a - 0.31 and 0.40, respectively

in the populations from Saint-Nicolas-de-Port

and Medernach. In average, the teeth discovered

in Saint-Nicolas-de-Port seem natrower than

those from Medernach. This différence cannot

be considered as statiscically significant because

Pearson’s corrélation coefficients between the

variables are not suffîciently high, r = 0.80 for

the teeth from Saint-Nicolas-de-Pon and 0.73

for the teeth from Medernach. Nevertheless, this

observation is quite interesting because ic reflccts

a more general morphometrical trendr Tessier

(1936) and Chevais (1937) hâve actually compi-

led cxamples in which local races of a same spe-

cies do not differ in “^b” value, but can be

distinguished in ‘a” value. The proportions of

the studied organ differ in these populations, but

the différences are preserved without change

during the life of the animal (at least, in mature

speciniens). Therefore, the scudy of dental allo-

metry in heudotricorwdm wildi shows that the

morphometrical différences ohserved between

the teeth discovered in Saint-Nicolas-de-Port and

Medernacli cân be incerpreeed as normal varia¬

tions between two local (geographicaliy and/or

sttatigrapbically) fâunas of a same species. There

is no morphological or morphometrical evidence

now available to support a systematic distinction

between these populations.

Genus Tricuspes E. von Huene, 1933

Trkuspes E. von Huene, 1933: 82.

Type species. — Trkuspes tuebingensis E. von Huene,

1933.

O'I'HER REFERRED SPECIES. — Trkuspes sigogneauae

Halin, Hahn etGodefroit, 1994; Tricuspes tapeinodon

n..sp.

DiagnosiS. — Accessory ensps sometimes dcvelopccE

on tlie anicrior (TJe) or on ilic posterior (D/d) border

of the molar crown. Cusps not perfçctiy aligned but

arranged in a V-like mannei*: the anterior and posteri(»c

cusps arc set in a riightly more lingual posinon than the

more central cusps ajid the crown has an arched aspect

in occlusal view. Axis of the crown pertecily vertical.

GEODIVERSITAS • 1997 - 19(3)

575

Godefroit P. & Battail B.

Crown separatcd from the root by a marked constric-

tion. Rooi subdividcd in its full lengih, but both por¬

tions remain in close contaa wirh onc anocher*

Tricuspes tuebingeiisis E. von Huene, 1933

(Fig. 6A-C)

Tricuspes tühingensis E. von Hucnc, 1933: 82, pl. 1,

fig. 7a, b. — Kunn 1965: 85.

Tricuspes tuhingensis — Hopson & Kitching 1972:

82. - Clcmens et al 1979: 10. - Clemens 1980: 66,

pl. 10, figs 1, 2a-c. — Battail 1991: 89. - Hahn et al.

1994: 148, fig. 3.

? Schncidezann S. — H. von Huene 1933: 84, pl. 1,

fig. 9a-d.

HOLOTTtTE.. — An isolatcd righc molariform preserved

in the GeoIogisch'Palâonrologischen Institut der

Universitàc 3’übingen (Germany) and figured, among

others, by Clemens (1980, pl. 10, figs 1,2a'c).

Locus rypICüS. — Gaisbrunnen, north of Tübingen

(Württembcrg, Germany).

Stratum TYPICUM. — “Rbâtbonebed”, included in

Rhaetian sandscones. Upper Triassic.

New HYPOTYPÊS. — From Sainr-Nicolas-de-Port;

IRSNB RI 58 (upper molariform).

DlAGNOSlS. — Molariform teeth wich a ciny accessory

cusp m in postero-lingual position; crown rather high:

ratio ^‘lengrh/heiglit” of the crown = 1.53 in IRSNB

RI 58 and < 1.5 in the holotype. Accessory cusps D/d

and E/e, when présent, incorporated in the cutting

edge of the crown.

Descri pnoN

Measuremmis

Lengch of the crown = 2.75 mm; width of the

crown = 1.06 mm; height of the crown =1.8 mm.

Croîvn

The nameneJature of the cusps in Tricuspes is

illustrated by Hahn et al. (1994, fig. 5). The

enamel is petfectly Smooth. In occlusaJ view, the

crown is râther elongaced. the ratio

“length/width” of the crown = 2.59. The labial

side is very convex antero-posteriorly and the lin¬

gual sidcj slightiy concave. The crown is formed

by five very distinct cusps. Contrary to

Pseudotriconodon. these are not perfectly aligned,

but they are arranged in a V-Iike rnanner:

cusps B and C are set in a more lingual position

than cusp A; in the saine way, accessory cusps D

and E are set in a slighdy more lingual position

than cusps C and B. The cutting edge is not as

developed as in Pseudotriconodon. The base of the

crown is clearly constricied.

In lingual view, the crown is not very high (ratio

“length/height” of the crown = 1.55) and domi-

Fig. 6. — A-C, IRSNB RI 58, upper postcanine tooth of Tricuspes tuebingensis, from the Late Triassic of Saint-Nicolas-de-Port;

lingual view; B, occlusal view; C, posterior view. D*F. IRSNB R159. upper posîcanine tooth of Tricuspes sigogneauae. from the Late

Triassic of Saint-Nicolas-de-Port; D, lingual view; E, occlusal view; F, anterior view. Scale bar: 1 mm.

576

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

naicd by the médian cusp A. The anrerior and

posrerior edges of thh cusp arc clearly convex and

separated from cusps B and C by distinct

notches. Its vertical axis slopes slightly backwards.

Antcrior cusp B is lower than posterior cusp C.

The latcer slopes more backwards than cusp A;

cusp B slopes somewhat forwards. Cusp B is flan-

ked anteriorly by a low> bulbous accessory cusp E;

cusp C is posteriorly flanked by a very eroded

accessory cusp D, These accessory cusps are

incorporated in the cutting edge of the Crown. A

tiny, very eroded accessory cusp m is visible on

the lingual side of the crown, just below cusp C.

Wear facets affect the lingual side of the apex of

the cusps. This loodi is thus an upper molari-

form. On cusp A, the wear facer is triangular and

very concave. Cusp B is more affected by wear

than cusp C. Accessory cusp D, as mentioned

above, is very eroded.

Rooi:

The root is not preserved in IRSNB RI 58.

Discussion

Triciispes îtiehingensis is known by one lower

(holotypc) and one upper (IRSNB RI58) mola-

riform teeth. These reeth differ from chose of

Tricuspes sigogneaii^ (see below) in cite presence of

a tiny accessory cusp m on the posrero-lingual

portion of cusp c. Accessory cusps d and e,

althoLigh eroded, are also better dcveloped in

IRSNB R158 than in Tricuspes sigogneauae (see

Halm et al. 1994, figs 5-9) and are clearly loca-

ted on the cutting edge of the crown. IRSNB

RI 58 dift'ers from the holotype by its crown pro-

portionally lower and longer. This character, cor-

related to the development of accessory cusps d

and e, probably reflects a more distal position in

the tooch row of the former. Hahn et al. (1994)

did not observe significant différences in the pro¬

portions of lower and upper molariform teeth in

Incîispes sigogfieaiuie.

Tricuspes sîgogtieauae

Hahn, Hahn et Godefroit, 1994

(Fig. 6D-F)

Tricuspes sigogneauae Hahn, Hahn Godefroit, 1994:

149. Egs 5-13-

Triempes cf. tubingensis Clemens, 1980: 71, pl. 10,

fig. 5a-c.

Holotype. — MNHP SNP49LW, a lower molari-

form figured by Hahn étal. (1994, fig. 5).

Paratypf.S. — 6 upper molars, 7 lower molars and

4 premolars preserved in the MNHP and the IRSNB

(see Hahn et al 1994, tabs 2-4, for catalogue num-

bers).

Locus TYPICUS. — Quarry at Rosières-aux-Salines,

région of Saint-Nicolas-de-Port (Meurthe-et-Moselle,

France).

Stratum TYI^ICUM. — “Rhaetian” sandstones. Upper

Triassic.

New HYPOTYPES. — From Saint-Nicolas-de-Port:

IRSNB R159, IRSNB 28114/193, MNHNP SNP55,

MNHP SNP24W, ? MNHP SNP98W, MNHP

SNP289W, MNHP SNP343W, MNHP SNP345W.

DiACNû.SÏS. — Molaritomi teeth without accessory

cusp m in posiero-lingual position; crown high: ratio

“length/hcight" of the crown < 1.3. Accessory

cusps D/d and E/c, when présent, not incorporated in

the cutting edge of the crown, but located on its ante-

rior and posterior wall.

Table 2. — Measurements (in mm) of the new molariform teeth of Tricuspes sigogneauae, from the Late Triassic of Saint-Nicolas-

de-Port. Le, length of the crown; Wc, width of the crown; Hc. height of the crown; LL. lower left; LR, lower right; UL, upper left;

UR, upper right.

Number

Position

Le/Wc

Root

Cusps

IRSNB 28114/193

2.92

1.16

2.8

2.52

MNHP SNP289W

1.86

0.77

1.75

2.42

3(?)

MNHP SNP24W

2.56

1.1

1.95

2.33

+ 3 +

MNHPSNP55

1.67

0.68

1.36

2.46

IRSNB RI 59

2.17

0.8

1.75

2.71

+ 3 +

MNHPSNP343W

1.13

0.5

2.26

(?)3

MNHPSNP345W

0.87

+3(?)

GEODIVERSITAS • 1997 • 19(3)

577

Godefroit P. & Battail B.

Description

The molariform reerh of this species were very

accurately described by Hahn et aL (1994). The

new material discovered in Sainr-Nicolas-de-Porr

does noc give new morphological informarions.

Table 2 gives a summary of the main morpholo-

gical and morphometrical informations collecled

from the new molariforms of Trictispes sigo-

gneaiiae. The classification of the teeth, following

the development of the accessory cusps, was crea-

ted by Halin et ai (1994) and Ls cxplained below

(description of Triempes tapeinodon).

Discussion

Hahn et al. (1994, figs 13, 14) attribute four pre-

molariform teeth to Tricuspes sigogneauae. These

are regarded, in the présent paper, as belonging

to Cynodontia incertae sedis.

Tncttspes tapeinodon n.sp.

(Figs 7, 8)

Tricîispes sp. indet. — Hahn et ai 1994: 154, partim^

fig. 16 .

Holottpe. — IRSNB R161, an upper right molari-

form.

Paratypes. — IRSNB R160, IRSNB 281 14/35,

IRSNB 28114/80, IRSNB 281 14/106, IRSNB

28114/107, IRSNB 28114/108, IRSNB 28114/109,

IRSNB 28114/827, IRSNB 28114/988. MNHP

SNP]60\C^.

Locus TYPICUS. — Quarry at Rosières-aux-Salines,

région of Saint-NicoIas-de-Porr (Mcurlhc-ct-Moselle,

France).

DerIV^ATIO NOMINIS. — tapeinos (Greek) = low, and

odous (Greek) = tooth.

S tratum TYPICUM. — “Rhaetian” sandstones. Upper

Triassic.

DiAGNOSIS. — Crown of ihc molariform teeth very

low: nicio “length/hcight" of the crown 1.55.

Médian cusp A/a not muth higher than cusps B/b and

C/c. No accessory cu.sp m in postero-lingual position.

Accessory cusp.s d and c, when présent, incorporated

in the cutting edge of the crown.

Description

Classification

As proposed by Hahn et al. (1994) in Tricuspes

sigogneauae. 3: both accessory cusps D/d and E/e

absent; +3: E/e présent, D/d absent; 3+: E/e

absent. D/d présent; +3 +: both D/d and E/e pré¬

sent.

Measurements

The measurements taken on the molariform teeth

of Triempes tapeinodon are shown in table 3.

Fig. 7. — Molariform teeth ot Tricuspes tapeinodon, from the Late Triassic of SaInt-Nicolas-de-Port. A-C, IRSNB R161, upper post-

canine; A, lingual view; B, occlusal view; C, antehor view, D-F. IRSNB R160, ? lower postcanine: D, lingual view; E, posîerior view;

F, occlusal view. Scale bar: 1 mm.

578

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Crown

The enamel is aiways perfectly smooth. The

Crown is composecl of three main cusps. The

highest (A/a) is set in a submedian position and

flanked by an anterior cusp (B/b) and a postcrior

cusp (C/c). Two accessory cusps are sometimes

developed on thc anterior and posterior portion

of the Crown (respectively E/e and D/d). In

occlusal view, the crown is proportionally long

and narrow: thc ratio “length/width” of the

crown varies between 2.25 and 3-8, on che reeth

currendy studied. The crown lias a pronounccd

arched aspect; its labial side Js very convex antero-

posteriorly and its lingual side. slighdy concave;

at the level of the central cusp, the lingual side ol

the crown is neverlheless somewhat convex. As

usual in Triaispes, the cusps are not perfectly ali-

gned, but set in a V-Iike mariner. The cutting

edge joining the cusps together is less developed

than in Tricuspes tiiehingensis or Trlcuspes sigO'

gneauae. The anterior and posterior ends of the

crown are tapering.

In lingual view, the crown is very low; the ratio

"length/hcight" of die crown varies between 1.55

and 2.25 m thc material referred to this species.

The main cusp A/a is not much higher than

cusps B/b and C/t. Cusps B/b and C/c are usual-

ly subequal in size and it is thcrcforc more diffî-

cult to distinguish the anterior and the posterior

ends of the crown than in Trienspes tnebingensis

or in Tricuspes sigogneattae. They are more roiin-

ded and stocky than cusp A/a and their vertical

axis can be somewhat divergent. The cusps are

well separated from each other by deep notches.

F G

The accessory cusps D/d and E/e, when présent,

are incorporated in the cutting edge, as in

Tricuspes tuehwgensis, and not rejected on the

anterior and posterior walls of the crown, as in

Triciapes sigogneduae.

There is no trace of clngulum or accessory

cusp m, as in Tricuspes Uiebingensis. The crown

was apparently separated from the root by a

constriction.

Wear facets arc not always as well marked as in

Tricuspes sigogfieauae and it is therefore some¬

times difficult to distinguish the lower from the

upper molariform reeth. Wear erodes the upper

teeth on their lingual and the lower teeth on

their labial side.

In IRSNB Rt60 (lower molariform), the apices

of cusps A, B and C are truncated by wear and

hâve thus a bevel-edged aspect. Cusp A beats a

second elliprical wear facet, from the apical facet

to its base.

In IRSNB 28114/108 (upper molariform), rhe

apices of cusps A. B and C arc slightly blunt by

small circulât wear facets. The lingual side of the

crown bearSj below cusp b, a wide facet reminis-

ceni ot a contact lacet with the contiguous tooth

in the dental row.

The lingual side of IRSNB 28114/109 (upper

molariform) has a very extensive, mat and slight¬

ly concave wear facet, extending from the ante¬

rior edge of cusp B to the anterior edge of

cusp c and from rhe base of the crown to the

apices of rhe cusps. A second wear facet, at the

base of the posterior side of cusp C, can be inter-

H I

Fig. 8. — Outline of molariform teeth of Tricuspes tapeinodon, from the Late Triassic of Saint-Nicolas-de-Port. A, IRSNB R161;

B. IRSNB 28114/80; C, IRSNB 28114/108; D, MNHP SNP160W: E. IRSNB 28114/109; F, IRSNB 28114/106; G, IRSNB R160:

H. IRSNB 28114/107; IRSNB 28114/35. Scale bar: 1 mm.

GEODIVERSIT4S • 1997 • 19(3)

579

Godefroit P. & Battail B.

Table 3. — Measurements (in mm) of the molariform teeth of Tricuspes tapeinodon, from the Late Triassic of Saint-Nicolas-de-Port.

Le, length of the crown; Wc. widih ot the crown; Hc. height of the crown; LL, (ower left; LR, lower right; UL, upper left; UR, upper

right.

Number

Position

Lc/Wc Root

Cusps

IRSNB 281 U/35

?LL

1,15

0.4

0.74

2.87

IRSNB 28114/107

?LL

2.28

0.6

1.02

3.8

+ 3

IRSNB 28114/106

2.87

0.85

1.5

3.38

3 +

IRSNB R160

?LR

2.27

0.7

1.33

3.24

+ 3 +

IRSNB 28114/80

2.62

0.82

1.46

3.19

3 +

IRSNB 28114/827

0.98

1.5

+ 3(?)

MNHPSNP160W

>2-3

0.72

>3.26

+ 3(?)

IRSNB R161

2.83

0.9

1.62

3.14

+ 3 +

IRSNB 28114/108

2.15

0.95

1.27

2.26

3 +

IRSNB 28114/109

1.65

0.67

0.75

2.46

preted as a contact facet with the contiguous Root

posterior tooth in the dental row. It seems, there- The root is not preserved in the molariform

fore, thar the teeth of the same row were aligned, tooth referred to Tricuspes tapeinodon.

which permits one-to-one occlusion between

teeth of the opposite rows. DISCUSSION

The labial side oflRSNB 28114/106 (lower mola- Figure 9 compares the distribution of the length

riform) beats three wear facets. The first one (x axis, in Ln) and of the width (y axis, in Ln) of

erodes the posterior edge of cusp b and the ante- the molariform teeth in the three species recogni-

rior edge of cusp a. The second one is conrinuous zed in the genus Tricuspes. le appears that

on the posterior edge of cusp a and on the anterior T tapeinodon has, in average, proporiionally nar-

edge of cusp c. The third facet aftccts the posterior rower dental crowns than T. sigogneauae, This

edge of cusp c and the anterior edge of cusp d. resuit can be considered as significant because

0.60

Fig. 9. — Dispersion diagram of the molariform teeth in Tricuspes.

580

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts ftom Saint-Nicolas-de-Port

Pearsons corrélation coeffîclcnts are sufficiently

high: r = 0.91 and 0.84, respecrively in 77 sigo^

gfieauae and X tapeinodim, The al!ometr>' coefti-

cient, estimared by Teissiers (194S) formula

differs betwecn rhese species (b = l 16 in T sigo-

gneauae and 0.9 in T. tapeinodon)y whlch

confirms their taxonomie distinction. There is

no evidence, at our présent State of knowledge,

to support a generic distinction of Tricuspes

tapeinodon.

Genus Meurthodon

Sigogneau-Russell Hahn, 1994

Meurthodon Sigogneau-Russell er Hahn, 1994: 212.

Type species. — Meurthodon galltcus Sigogneau-

Russell et Hahn, 1994.

DiagNOSIS. — As for the only currendy recognized

species Meurthodon gallicus Sigoaneau-Russcll et

Hahn, 1994.

Meurthodon gallicus

Sigogneau-Russell e? Hahn, 1994

(Figs 10, 11)

Meurthodon gallicus et Hahn, 1994:

212, figs 10.11. — Hahn étal. 1994: 142. fig. 2f

Tricuspes sp. indet. - Hahn et al. 1994: parüm 154,

fig. 15.

^'‘Dent d'aspect mammalien" (Russell et ai 1976: 377,

pl. 1, fies 1-3).

probabiy représentative of a cynodont reptile...”

(Qcmens 1979; 11).

“Advanced mammal-like reptile” (Clemens 1980: 62).

“French mammal (?)” (Gow 1980: 480, fig. 10).

Holotype. — MNHP SNPl W.

Locus TYPICUS. — Quarry at Rosières-aux-Salines,

région of Saint-Nicolas-de-Port (Meurthe-et-Moselle,

France).

Stratum TYPICUM. — “Rhaetian” sandstones. Upper

Triassic.

New hypotype.s. — From .Saint-Nicolas-de-Port:

MNHP SNPIW, IRSNB R162, IR.SNB RI63.

IRSNB 281141/5. IRSNB 28114/17, IRSNB

281 14/40, IRSNB 28114/45, IRSNB 28114/56,

IRSNB 28114/746'. IRSNB 281 14/754, IRSNB

28114/814, IRSNB 28114/902, IRSNB 28114/993.

MNHP SNP51DD. MNHP SNP64W. MNHP

SNPl I5W. MNHP SNP200W, MNHP SNP210W,

MNHPSNP514W.

DiagNÜSIS. — Crown of postcanine teeth asymmetri¬

cal and tetracuspid, The second cusp is always the lar-

gest and the firsi cusp is usually the smallest. The

three posterior cusps are clearly inclined backwards.

Small erratic cingular éléments on some teeth. Crown

Fig. 10. — Postcanine teeth of Meurthodon gallicus, from the Late Triassic of Saint-Nicolas-de-Port. A-C, IRSNB R162. lower post¬

canine: A. latéral view; B, occlusal view; C posterior view. D-F, IRSNB RI 63, upper postcalne; D, latéral view; E, occlusal view; F,

posterior view. Scale bar: 1 mm.

581 I

GEODIVERSITAS • 1997 • 19(3)

Godefroit P. & Battail B.

clearly separared from the roor by a sulcus. Roots

completely subdividcd and fully separated on the dis¬

tal tnree quartcrs of their length.

Diisc:RipriON

Preliminnry remark

Until now, the hülot)''pe (MNHP SNPIW) was

the only known specirnen of Meurtbodan gullicus.

d'he original description of this cooth

(Russell et al. 1976) is parcicularly detailcd.

Therefore, the following description points only

to differenrial characters observed in new mate-

rial referred to this species.

Measurements

The measurements taken on the postcanine teeth

of Meurthodon galllcus are shown in table 4.

General characters of the crown

The Crown is letracuspid and the cusps are very

compressed labio-lingually. The second cusp is

always the highesr. 1rs is flanked by a small ante-

rior cusp and by cwo posrerior cusps of decrea-

sing sizes. 'l’hc thrcc posterior cusps slopc

backwards. *I'he crowns of somc teeth (IRSNB

28114/005, IRSNB 28114/902) arc proportion-

ally less long, but higher than in MNHP

SNPIW. This feature can rcflect the relative

position of the tooth in the jaw: the most slender

teeth hâve a pronouneed premolariform aspect.

First cusp

The firsr cu.sp is always quite small. Its axis is near-

ly perfeerly vertical, but can somerimes slope

backwards (IRSNB 281 i4/40). It is asually adja¬

cent to the second cusp, but can be separated Irom

it by a more or less deep groove. Ir is sometimes

slightly displaced towards the lingual sidc ol the

crown (IRSNB 28114/5, IRSNB R163, IRSNB

28114/814, MNIIN SNP115W'). The firsi cu-sp

of MNHP SNPIW, IRSNB 28114/40. IRSNB

28114/056, IRSNB RL62, MNHP SNP64W and

MNHP SNPZIOW bears, on its anierior lingual

side, a well marked liât triangular lacet. This sug-

gests a coniaa beween contiguous teeth and thus,

a mesio-discal overlapping of the teeth (Russell

et ai 1976). In IRSNB Rl62, a riny accessory

cusp, at die base of ihe labial sidc of rhe firsc cusp,

is prolonged backwards by a brief ridge.

Second cusp

The second cusp is always by far the highest. Its

labial sidc is more convex than its lingual side. Its

apex is rounded. It slopes backwards: its vertical

axis forms an angle of 60" to 70" with the hori¬

zontal axis of the crown, 1rs posterior matgln is

always less oblique than its anterior margin. Both

are made thinner, cuteing, usually pinched ai the

base and more rounded at the top. fhe cusp can

be slightly curved towards the lingual side of the

crown (IRSNB 28114/5, IRSNB 28114/17,

IRSNB Rl63). At the level of the junction with

the third cusp, both the labial and rhe lingual

sides of the crown bear a concave dimple. The

labial one is always better marked.

Third aisp

The third cusp is ncarly identical to the second.

It is usually still more melined backwards

(MNHP SNPIW, IRSNB R163. IRSNB

28114/40, IRSNB 28114/56. IRSNB

28114/902). It is always smaller rhan rhe second

cusp and higher than rhe first and the fourth. Its

anterior and posterior margins are cutting, too,

particularly at their ba.se. Its labial and lingual

sides aiso bear small facets, at the levcl of the

junction wiih rhe fourth cusp.

Fourth cusp

The fourth cusp is usually higher than the frrst

one (MNHP SNPIW, IRSNB 28114/5, IRSNB

28114/17, IRSNB R163, IRSNB 28114/45,

IRSNB 28114/56, MNHP SNP64W, MNHNP

SNP2Î0W), but can sometimes be somewhat

smaller (IRSNB 28114/902, IRSNB 28] 14/993,

MNHP SNP200W). It is always less indined

backwards than che third: its slope is approxima-

tely the same than rhat of rhe second cusp. Its

apex is usually more sharp-pointed than that of

the second and the thîrd cusps. Its anterior mar¬

gin is sharper than its posterior margin, winch

participâtes in the posterior border ol che crown.

The posterior border of the fourth cusp bears, in

IRSNB 28114/5 and IRSNB R163, a well mar¬

ked iriangular mat facet, probably corresponding

10 rhe overlapping area with the contiguous pos-

lerior tooth in the dental sériés. In IRSNB

28114/040, a posterior swelling forms a tiny

posterior accessory cusp.

582

GEODIVERSITAS - 1997 • 19(3)

LateTriassic cynodoncs from Saint-Nicolas-de-Port

Base of the croxvn

The base of the crown is distincrly constricted by

a sulcus scparating it from the root. Undcr the

cusps, the labial sidc of the crown is usually

convex antero-postcriorly; the lingual side is flat

to slightly concave. The labial side somctimes

présents a concavity beeween the second and the

third cusp (MNHP SNP IW, IRSNB 28114/5,

IRSNB 28114/56). Between these cusps, the

base of the lingual side of the crown bears a

dimple in continulty wiih the séparation line of

the roots.

The labial side of IRSNB Rl62 bears, under ihe

junction between the third and the fourth cusp,

a small swclling which can be inrerpreted as the

rough shape of a cingulum. ff rhe orientation

proposed above is correct, the présence of cingu-

lar cléments on the labial sidc should indicare, by

analogy with the Morganucodontidac. that this

tooth is an upper postcanine. The presence of

wear faects on rhe labial side of the cusps concra-

dicts this inrerpretacion (see below). Siich a swel-

ling can be observed on ihe lingual side of

IRSNB 28114/17, under the junction between

Fig. 11. — Outline of postcanine teeth of Meurthodon gaUicus, from the Late Triassic of Saint-Nicolas-de-Port. A. MNHP SNPIW:

B, IRSNB R162 {lower postcanine); C, IRSNB 28114/902; D. IRSNB 28114/40; E. MNHP SNP210W; F, MNHP SNP64W; G. IRSNB

28114/993: H, IRSNB R163 {upper postcanine); I. IRSNB 28114/746; J. IRSNB 28114/17 (lower postcanine); K, MNHP SNP514W;

L, IRSNB 28114/56 (lower postcanine); M, IRSNB 28114/45 (lower postcanine); N, MNHP SNP51DD: O, MNHP SNP20W. Scale

bar: 1 mm.

583 I

GEODIVERSITAS • 1997 • 19(3)

Godefroit P. & Battail B.

the second and rhe third cusp. With rhe lingual

dimplc betw^een fhe second and the third cusp,

this swelllng delimits a small lingual basin. A

riny accessory cusp can bc ubserved on rhe lin¬

gual side of IRSNB 28114/5, under the junction

berween the second and ihc third cusp. These

last vwo teeth, which présent cingular cléments

only on cheir lingual side, are rherefore probably

lower postcanines.

Wear facets

Russell et aL (1976) did not observe clearly defi-

ned wear (acets in MNHP SNPlW. The flat

anterior facct on the first cusp is neveriheless

interpreted, as mentioned above, as a contact

area wirh the coniiguous cooth. The flatter upper

half of the fourth cusp is .similarly regarded as a

contact area with the poscerior tooth. These

facets indicatG rhat the teeth of the sanie row

were aligned, which is an important prerequisite

to one-to-one occlusion (Crompton àc Luo

1993; Luo 1994). However, sc-veral other teeth

présent clearly dcfincd wear facets.

Two elongatcd. scmielhptical and concave facets

are présent on the labial side of rhe second and

third cusps, in IRSNB 28114/5. The facet

extends nearly as far as the base of the second

cusp. If rhe orientation proposed is correct, this

tooth is cherefore a lower postcanine.

In IRSNB 2S114/56, wear facets are aiso located

on the lingual side of the second and third cusps.

The first facet truncates the top of the second

cusp. The second facct is long and oblique for-

wards: it reaches the base of the third cusp. This

tooth is rherefore probably a lower postcanine.

In IRSNB 28114/17. the labial side of the apex

is truncared by un elhprical wear facet, which

confirms iis attribution to rhe lower dental sériés.

In IRSNB RI62, a wear facet extends on rhe ante¬

rior side of the apex of the seetmd cusp, replacing

its natural cutting edge by a narrow, fiat and elon-

gated facet, and, on the its labial sîdc, forming a

small triangular area. The interpretation ol this

tooth is dLfficultr both the cingular éléments and

the wear facct arc présent on the same side and the

cusps are not cun^d. If the orientation of this

tooth is correct, it is thus a lower postcanine with

tiny external cingular éléments.

MNHP SNP 115W has been identified by

Hahn et al. (1994, fig. 15) as Trkuspes s'p. In fact,

it présents ail the diagnostic characters of

Meunhodon gallicus. Tht labial side of its last

ihree cusps possesscs wcll marked wear facets.

Thus, it is probably a lower postcanine.

MNHP SNP 200W aIso possesses a wcll marked

elongatcd wear facet on the labial side of its

second cusp, which permits its attribution to the

lower dental sériés.

Two wear facets can be obscived on chc lingual

side of IRSNB RI63. The First, triangular in

shape. is located at the apex of the second cusp;

the second facet is elongatcd on the third cusp.

This is therefore probably an upper postcanine.

Roots

The roots can only be observed on the holotype

and hâve been descrîbed in detail by Russell et ai

(1976).

DiSCUvSSION

Russell et al (1976) discuss in detail the affinities

of the holorype MNHP SNPlW and emphasize

the close resemblance of this tooth with those of

the Late Triassic cynodont Therioherpeton cargni-

ni Bonaparte et Cabrera, 1975 and with those of

Sinoconodon rig^ieyi Patterson ef Oison, 1961.

The latter genus is now clearly recognized as a

true mammal, forming the sister-group of a

monophyletic taxon rhat includes ali the other

Table 4. — Measurements (in mm) of the postcanine teeth of

Meurthodon gaîlicus, from the Late Tflassic of Saml-Nicolas-de-

Porf. Le, length of lhe crown; Wc. width of the crown; Hc, heighl

of the crown.

Number

Lc/Wc

MNHPSNPlW

4.25

1.32

3.05

3.22

IRSNB 28114,005

2 17

0.8

2.71

IRSNB 28114/017

2.32

0.8

2.23

2.9

IRSNB 0163

225

0,72

2.12

3.12

IRSNB 2S114/040

1.1

>2.1

3.54

IRSNB 28114/045

2.42

0.9

2.69

IRSNB 28114/056

2.6

0.87

>1.85

2.99

IRSNB R162

4.25

1.35

2.9

3.15

IRSNB 28114/746

3.95

1.07

2.4

1.65

IRSNB 281147754

2.98

0.9

3.31

IRSNB 20114^902

0.88

2.37

2.27

IRSNB 28114/993

2.48

2.1

MNHP SNP64W

3.53

0.97

2.25

3.64

MNHP SNP200W

1.85

0.8

1.43

2.31

MNHP SNPPtOW

3.02

1.01

2.7

2.99

MNHP SNP514W

267

0.89

2.17

584

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Pon

mammals (Crompion & Luo 1993; Wible &

Hopson 1993; Lucas & Luo 1993; Luo 1994).

Sigogneau-Russell & Hahn (1994) group

Therioherpeton and Meurthodon within rhe Fami¬

ly Theriohcfpctidae. Thjs family is thoughi to

form che sister-group of thc Dromatheriidaf.

Hahn et al. (1994) gaiher both généra within che

Family Dromatherüdae.

The new specimens discovered in Saint-Nicolas-

de-Port perniii a better underscanding of rhe

déniai variability in Meurthodon. The postcanine

teedi of Meurthodon are compared in detail wirh

chose of Therioherpeton and Sifioconodon^ in

order to clarify the affinities of the genus;

1. The présence of wcar facets on the labial side

or on the lingual side of the crowns auests that

the niaterial referred to Meurthodoti includes

upper and lower postcanines morphologically

identical. This seems to bc a usual character in

the Dromatheriidae. 3*he upper and lowcr post¬

canines seem also very similar in Sinoconodon. In

TherioherpetOTK the upper aiid rhe lower postca¬

nines seem to bc constructed following the same

plan» but rhe poor preservadon of the material

prevents more précisé comparisons.

2. In ShiocoHodony postcaninc leeth lack différen¬

ciation inro prcmolanform and molariform cceth

(Crompton Sun 1985). In adule dental formu¬

la, ihe single canine is separated from rhe firsr

postcanine by a long diastema (Patterson 6c

Oison 1961). The anterior postcanines are lost

without replacement, resulting in an incrcasingly

large postcanine diastema during ontogeny. Ac

least two postcanines are added to thc posterior

end of the tooth row and at Icast one posccanine

was replaced in older specimens (Crompton

Luo 1993). In Thenoherfeton, the crowns of die

anterior posreanines are not preserved, but rhe

size of their alvcolae are smaller than in die pos-

rerior molariform tccth. 1 heir postcaninc denti¬

tion was thus probably subdividcd into

premolariforni and molariform tecth.

Bonaparte & Barbcrena (1975) observed an

alternate tooth replacement in rhis genus. In

Meurthodon, only isolarcd teeth hâve been disco¬

vered; rhis prevents thc identification of premo-

lariform teeth in this genus (sce below).

Nevertheless, some teeth hâve a more slender

aspect than others: rhis can reflecc their relative

position in the dental sériés. The tooth replace¬

ment pattern is unknown in Mewthodon.

3. ïn Meurthodon, rhe roots of molariform teeth

are iully separated on rliree quarrers of their

leïigth, but fused proximally below the cTown. In

Thenoherptton, lhey are separated on the whole

length, but connected by a rhin sheet of dentine.

In Sinoconodon, like in Meurthodon^ rhe post-

canine roots are divided only along their distal

parts (Luo 1994. fig- 6.6).

4. In Meurthodon, the presence ofsmaJl lacets on

the anterior and posterior parts of the crown

reveals thc contact between contiguous postca-

nines. In Therioherpeton, the discal postcanines

bave an oblique implantation, like in tbe

Trithcledontidae: thc anterior margin of the dis¬

tal postcanine is placed antero-iingually to the

postêrior margin of die mesial tooth. The adja¬

cent postcanines of Sinoconodoit do not interlock

with one aiiuther (Crompton & Luo 1993).

5- rhe postcanines of Meurthodon show wcar

facets. They do not .seem constant, like in thc

MorgaiiuCüdontidae or later mammals, indica-

ting that the relations between lower and upper

postcanines were not yet clearly defined. A stron-

ger wear seems to affect the cusps of

lherioherpeton (sce Bonaparte & Barbcrena

1975). In Sinoconodon, ihe postcanine crowns

lack wear facets, which is probably correlated to

the absence of one-io-one alignnient of ihe cor-

responding upper and lowcr molariforms

(Crompton & Luo 1993: Luo 1994).

6. Tiny and very inconstant cingular éléments can

bê observed un Meurthodon postcanines.

Therioherpeton lucks cingulum or cingular accesso-

ly cusps. Sonic of thc best preserved postcanines

of SinocoTJodon possess a faim labial cingulum on

the uppers and a more distinct one on the poste-

roiingual surface of the lowers (Crompton & Sun

1985: Crompton ôc Luo 1993).

7. In tliese three généra, rhe crown is larerally

compressed and fundamcnially retracuspid: the

second cusp is the highe.st and the decreasing -size

of the distal cusps is regular. The cusps are pro-

portionally higher and better defined in

Meunhodan than in Therioherpeton, but this niay

be a resuir of a stronger wear in the latrer genus

(Sigogneau-Russell & Hahn 1994). The cusps do

GEODIVERSITAS • 1997 « 19(3)

585

Godefroit P. & Battail B.

not présent baclcwards slope in Therioherpeton.

The First cusp is îndcpendam from the second

and the la5t two cusps are doser side by side than

in Metirthodon (Russell et ai 1976). A fifth ante-

rior accessory cusp can be observed on some

postcanines in Sinoconodon (see Patterson &

Oison 1961; Crompton & Sun 1985). The first

cusp is usually better separated from the second

than in Meurthodon. The last three cusps are also

usually less inclined.

Comparisons with the advanced cynodont

Therioherpeton and the primitive mammal

Sinoconodon^ whose dentition is most similar,

reveal that the postcanine teeth of Meurthodon

présent a mosaic of plcsioiîiorphic (low develop¬

ment of cingular éléments) and apomorphic (bet¬

ter separated roots, wear facets, ? contacts

between adjacent postcanines) characters. As this

taxon is currcntly Icnovvn only by its postcaninc

teeth, il is not possible to décidé whether

Metirthodon is a very advanced cynodont or a true

early mammal. Waiting for fimher evidence, ihis

genus is provisionally and questionably classificd

whithin the Dromatheriidae» as suggested by

Hahn et ai (1994). This scems the mpse conser¬

vative course, in the présent State of knowledge.

Morphometrically, the dispersion diagram of the

postcanine teeth in Meurthodon gallicus shows a

négative allomeiry between the width and the

lengîh of the ctowns (Fig. 12): the allomerry

coefficient b, calculated according Tessier’s

(1948) formula, is 0.63. Pearsons corrélation

coefficient is high (r = 0.89) and ihis resulc can

therefore be regarded a.s correct. This négative

allometry refleers rhe cutting function of the

postcanine teeth in Meurthodon. The corrélation

beiwcen the length and the height ot the postca¬

nine crowns is too low (r = 0.63) to permit a cor¬

rect estimation of the allometry coefficient

between these variables.

CVNODONTIA INCERTAE SEDIS

Genus Hahnia n.g.

Type species. — Hahnia obliqua n.sp.

DerivaTIO NOMINIS. — Dedicaced to Prof.

Dr. G. Hahn, for his contribution to the knowledge

of Late Triassic cynodonts and early mammals from

Lorraine.

DiaGNüSIS. — As for the only currently recognized

species Hahnia obliqua n.sp.

Discussion

See under Hahnia obliqua n.sp.

Fig. 12. — Dispersion diagram of the postcanine teeth in Meurthodon.

586

GEODIVERSITAS * 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Hafmm obliqua n.sp.

(Fig. 13)

Holotype. — [RSNB R164, a left uppcr postcanine,

with its root nearly completely preserved.

PaR/\tytf.s. — MNHP SNP50DD, a complété lower

right postcanine; IRSNB 28114/102, MNHP SNP23

and MNHP SNP57. crowns without roots of upper

postcanines.

Derivatio NOMINIS. — oblîquîis, -a, -um

(lat.) - oblique. Refers to the vertical axis of the

Crown, inclincd backwards.

Locus TYPICUS. — Quarry at Rosières-aux-Salines,

région of Saiiit-NicoIas-de-Port (Meurthe-et-Moselle,

France).

Stratum taticum. — “Rhaetian” sandsrones. Upper

Triassic.

Diagnosis. — Ratio “lengrh/width” of rhe

Crown > 3. Vertical axis of the crown inclincd back¬

wards. Main cusp slightly curved towards the lingual

side. Labial side of the crown clearly more convex

than the lingual side. Elongated wear facets along the

anterior and posterior cutting edges, on the upper

postcantnes. Base of the crown not constricted. Root

semielliptical in outline, 1.5 co 2 times as high as the

crown. PulpaJ canal narrow and elliptical in outline.

Description

Measurements

Table 5 shows che measurements taken on the

postcattine teetli of Hahnia obliqua from Saint-

Nicolas-de-Port.

Crown

The crown is tricuspid and the enamel, perfectly

smooth. In occlusal view, the crown is very com-

pressed labio-lingually: 3 < ratio “length/widch”

of the crown < 3.65. The labial side is convex

antero-posrcriorly, while chc lingual side is slight¬

ly concave. As in Pseudotriconodony the thrcc

cusps are perfectly aligned on chc mesio-distal

axis of che crown. Nevertheless, the edge is not as

sharp as in rhe latter genus. On cite upper post-

canines, the edge is parricularly blunt berween

the main caasp and the mesial cusp. The apex of

rhe main cusp is rejccced to the lingual side.

In anterior view, rhe main cusp is not perfectly

straighc, as in PseudotriconodoHy but curved

towards che lingual side, parricularly in its upper

portion.

In lingual view, the vertical axis of che crown is

inclined backwards, forming an angle of approxi-

mately 15*^ with the vertical axis of rhe root. The

Fig. 13. — Postcanine leeth of Hahnia obliqua, from the Late Triassic of Saint-Nicolas-de-Port. A-C, IRSNB R164, upper postcanine;

A, latéral view; B, occlusal view; C, anterior view. D-F, MNHP SNP50DD, lower postcanine; D, latéral view; E, occlusal view; F, pos-

terior view. Scale bar: 1 mm.

GEODIVERSITAS • 1997 • 19(3}

587

Godefroic P. & Battail B.

Table 5. — Measurements (in mm) of the postcanine teeth of

Hahnia obliqua, from the Late Triassic of Saint-Nicolas-de-Port.

Le, length of the crown; Wc, width of the crown: Hc, height of

the crown; Hr, height of the root

Number

IRSNB R164

1.6

0.45

1.15

2.1

IRSNB 28114/102

1.25

0.4

> 1.2

MNHP SNP50DD

1.82

0.5

1.25

1.9

MNHP SNP23

2.3

0.75

main cusp has a triangular ouiline; its anterior

and posterior etlges are srraight, but its apex is

always somewhar blunt. It is flanked by a pair ol

very blunt rriangular accessory cusps. Tliese are

not well separated from the main cusp. Becaiise

üf rhe baclwards slopc of the crown, the distal

accessory cusp seems lowcr chan the inesial cusp.

In the upper postcanines, a well marked wear

facet runs along the posterior edge, on the lin¬

gual sidc of the main cusp. This looks like an

elongated, very narrow and mat surface. In

IRSNB 28114/102 and MNHP SNP23, a

second wear lacet is présent on the anterior edge

ol rhe main cusp; it is less marked attd less long

(stopping below the apex ol the main cusp) than

rhe first one. This facet is absent from IRSNB

R] 64. but ihe anterior edge of the main cusp is

very blunt. A third small facet is présent on the

lingual side of rhe apex of the main cusp. In

MNHP SNP50DD. identîfied as a lower postca¬

nine, a small wear facet is présent on rhe labial

side of the main cusp, in the middlc of chc ante¬

rior edge.

There is no constriction between the crown and

the root.

Root

The root is nearl}' complété in IRSNB RI64 and

complète in MNHP SNP50DD. In IRSNB

RI64, the root is nearly 2 timcvS a.s high as the

crown; in MNHN SNP50DD, the ratio ^height

of the root/height of ihe crown” = l.S. In basal

view, it is very compressed labio'linguâlly. Its

labial sidc is slightJy convex antero-posveriorly;

the upper portion of its lingual side is fiai and

the lower portion is slightly concave. The pulpal

foramen is small and ellîptical in outline. k does

not show any évidence ol bipartition.

In latéral view, the root has a scmi-elliptical out¬

line. It gradually and symmetrically gets narrow

towards the cîp.

Discussion

By ihcir general morphology, these teeth are remi-

nisceiu of the small carnivorous cynodonts from

the Upper Triassic: the crown is tricuspid, smooth,

very narrow labio-lingually, wirh a cutting edge

and withoui cingulum; the root is high and

semielliptical in shape (Hahn et ai 1984). The

affinities wiih the different familles of Triassic car¬

nivorous cynodonts are neverthele.ss dilïicult to

establish. The main characters of the postcanine

teeth in these familles are reviewcd helow and

compared wirh rhose of Hahnia obliqua.

Thrinoxodontidae

(Lare Permian of South Africa and Russia, Early

Triassic of South Africa)

In conrrast with Hahnia obliqua, the postcanine

teeth oi the Thrinaxodontidae are not strictly

sectorial, but possess an internai cingulum with

small cusps (Hopson ÔC Kitching 1972; Battail

1991). rhe lingual side of the upper postcanines

does not beat marked wear fiicets.

Galescinridat

(Tare Permian and Early Triassic of South Africa)

Like in Huhrtiay the postcanine teeth of the

Gale.sauridae arc dêVoid of cingulum. Never-

rheless. in Cynotaurus Schmidt, 1927. they are

less compressed labio-lingually and the anterior

accessory cusp is less detachêd. In Galesaurus

Oweu, 1860. the postcanines arc very compres-

sed labio-lingually, but, in conctast with Hahma,

the main cusp is Very curved backwards and

there Is nci anterior accessory cUsp (Battail 1991).

The teeth do not bear marked wear facets

(Crompton 1972).

Cynognathidae

(Early Triassic and Early Middle Triassic of

South Africa and South America)

The Cynognathidae form a monogcneric family

(Battail 1991). The postcanine teeth of

Cymgtathui Scelcy, 1895 are similar ro rhose of

Hahnia-, the crown is very compressed labio-

lingually, devoid of cingulum and formed by a

588

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

high central cusp flanked by several accessory

cusps perfecrly alignée! antero-posteriorly, for-

ming a cutting edge. The vertical axis of the

Crown slopes bacicwards. The lingual slde of the

upper postcanines and rhe labial side of the lower

postcanines bear marked wear facets (Crompton

1972). The root is undivided, but can be slightiy

depressed by a longitudinal furrow. Nexxrtlieless,

différences can bc observed: in Cyno^iathus^ rlic

main cusp i.s curved backvvards and somewhat

serrated, especially in younger spccimens.

Chiniquodontidae

(Lower Triassic of South Africa and Argcnrina,

Middle Triassic of Tanzania, Argentina and

Brazil, Upper Triassic of Argentina and Brazil)

In the Chiniquodontidae, the root of the postca-

nine teeth is never suhdivided and can he separa-

ted from the crown by a well marked

constriction. The prcscnce of wear lacets atlcSTs

constant contacts between upper and lower po.st-

canines> like in llahnid. The crowns of postca¬

nine teeth are strictly sectorial, following the

complété disparition of dic cingulum, in Probelc'

sodon lewisi Romer, 1969 and Probaînognathui

jenseni Romer, 1970 (Battail 1989). The crowns

of the postcanincs, in Probainognathns, although

very worn, are quite different from those of

Hahnia: the main cusp, Jow and weakly develo-

ped, is flanlvcd by un anterior and a posterior

cusp poorly developed. The edge formed by

rhese cusps is slnuous and devoid of .sharp

points. Only the mosc posterior postcanînes are

iricuspid in Probeksodon: the anterior accessory

cusp is always very low and poorly separated

from the main cusp. The lattcr is very curved

backwards.

Tritheledontidae

(Late Triassic of Argentina, Early Jurassic of

South Africa and the USA)

In the 'Irithelcdontidae, rhe crowns of the post¬

canine teeth are always less compressed labio-

lingually chan in Hahnia and usually bear a cin¬

gulum (see Gow' 1980).

Dromatheriidne

(Middle Iriassic of Argentina, Late Triassic of

Europe and the USA)

The postcanînes of Hahnia are very similar to

rhosc oi Pseudoti-iconodon: the crown is triciispid,

strictly sectorial without cingulum and very com-

pres.sed labio-lingually; the cusps are perlectly ali-

gned following the antero-posterior axis of the

crown, forming a cutting edge; iherc is no

constriction between the crown and the root; rhe

root is semielliptical in outlinc and very com¬

pressed; the pulpal foramen is small and elliptical

in outline. Marked wear lacets arc absent from

Pmidotriconodon postcanines, but are observed in

Tricuspes. The backwards slope of the crown is an

uncommon fcaturc in specics currently relcrred

to the Dromatheriidae. The only tnie dîagnosti-

cal character of the Family Dromatheriidae is the

subdivision of the root în posterior postcanines.

This fcaturc is not présent in the rwo complété

teeth currently discovered in Hahnia.

Neverthcless, rhe subdivision of the base of the

root is very rare in the primitive Dromatheriidae

Pseudotricomtdon.

Small carnivoroUi cynodonts inccriac sedis

(Late Triassic of l'Europe)

In Lepagia Hahn, Wild et Wouters, 1987 and

Gaarnia Daim, Wild f*tWüutcrs, 1987, the post-

canine teeth are fundamentally tricuspid and

strictly sectorial, withcjut cingulum, like in

Hahnia. The roor is always undivided. Conuary

to Hahnia, the crown i.s never inclincd back¬

wards, the main cusp is not curved to che lingual

side and does not bear marked wear facers, in

boih gcncra. Morcover. the crown is wcll separa¬

ted from the root by a marked constriction.

In che current staïc of knowledge, the phylogene-

tical position of Hahnia within the infraorder

Cynodontia seems difficuU to establish. The

structure of the postcanine teeth is similar to

those of Cynognathidae, but che artribution to

rhis Family is very dubious, for want of true dia-

gnostical characters in the posreanines’ rhe

Cynognathm Zone in South Africa (Sparhian ro

Anisiun, see Shishjtin et ni 199S) and the Upper

Tria.ssic in Saint-Nicola.s-dc-Port are aciually

separated by a spacc ol time oJ about 25 Ma.

The postcanines of Hahnia re.semble those of che

Dromatheriidae, too, but rhere Is no trace of

biparliiion ol ilie roor in the material currently

GEODIVERSITAS • 1997 • 19 (3)

589

Godefroit P. & Battail B.

discovered. Waiting for further évidences.

Hahnia is dius referred to Cynodontia incertae

sedis.

Genus Gaumia Hahn, Wild et Wbuters, 1987

Gaitmia Hahn, Wild et Wouters, 1987: 11.

Type SPECIES. — Gaumia longiradkata Hahn, Wild et

Wouters, 1987.

Other referred .spectes. — Gaumia ? incisa Hahn,

Wild er Wouters, 1987.

Diagnosi.S. — Crown of the postcanine tceth “irico-

nodont”, more or Icss narrow, with the labial and lin¬

gual sides nearly symmetrical. Axis of the crown per-

fectly vertical. Cusps not curvcd and more or less sym-

metrically arranged, the central cusp bcing the

highest: cuaing cd^ pcrfectlv straight. No cingulum.

Base of the crown cunstrictcd. Root trianguUr in out-

line and very high, at Icast 1.5 timcs as high as the

crown. Tip of the tout undivîdcd; pulpal canal .small

and rounded to elliptical in outline.

Gaumia lon^radicata Hahn,

Wild er Wouters, 1987

(Pigs 14, 15)

Gaumia longiradicaUi Hahn. Wild et Wouters, 1987:

12, pl. 4, fig. 1, pl. 5, fig. I. - Battail 1991: 89. -

Sigogneau-Russell & Hahn 1994: 206, fig. 10.10b.

Holotype. — IRSHR “R.M.35”.

Fig. 14. — Postcanine teeth of Gaumia longiradicata, from the Late Triassic of Saint-Nicolas-de-Port. A, B, IRSNB R165; A, latéral

view; B, occlusal view. C-E, IRSNB RI66; C, latéral view; D occlusal view; E, ? anterior view. Scale bar: 1 mm.

590

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodoncs from Saint-Nicolas-de-Port

Paratype. — IR5NB “R.M.36”.

Locus TVPicus. — Side of ihc speedway E25-E411,

at Habay-Ia-Vicillc (Belgian Lorraine).

Stratum typicum. — Bone-bed “HLV-2”, Grès de

Mortinsarr (Rhaerian, üpper Tna.ssic).

New HYPOTYPES. — From SainL-Nicolas-de-Pori;

ÏRSNB R165. IRSNB R166. IRSNB 28114/047,

IRSNB 281 14/055. IRSNB 281 14/088, IRSNB

28114/090, IRSNB 28114/093, IRSNB 28114/646,

IRSNB 28114/982. ^ IRSNB 281 14/771. MNHP

SNP131L, MNHP SNP430W.

DiaGNOSTS. — Crown of postcanine teeth tri- ro pcn-

tacuspid and relatively thick: 2.1 < ratio

*‘Iength/widih^’ of the ctown < 2.75. First pair of

accessory cusps (or médian accessory cusps) not clearly

individualizcd; second pair (latéral accessory cusp)

more clearly separated. Smooth enamel on ail cusps.

Description

Classification

The postcanine teeth of Gaumia longiradicata

discovered in Saint-Nicolas-de-Port are classified

according to rhe number and the position of ihe

accessory cusps, as in Pseudotriconodon wildi (see

above). The estimate of the number of accessory

cusps is not aiways easy because these are usually

weakly differenciated.

Measîirements

The measurements taken on the postcanine teeth

of Gaumia longiradicata discovered in Saint-

Nicolas-dc-Port are shown in table 6.

Crown

In Gaumia longiradicata, the postcanine crowns

are perfectly smooth. In occlusal view, the cruwn

is thicker than in Pseudotriconodon ivildi or in

Gaumia ? incisa: 2.1 < rario “length/width” ol the

Crown < 2.75. Both the labial and the lingual

sides of the crown arc convex at the level ol the

main cusp. The width of the crown progressively

decreases towards the anterior and posterior

ends. The cusps are perfectly aligned on ihe

antero-posierior axis of the crown. Their edge,

perfectly médian and straight, is not as sharp as

in Pseudotriconodon wildi or in Gaumia ? incisa.

In anterior view, the main cusp is perfectly

Fig. 15. — Outline of postcanine teeth of Gaumia fongiradicata, from the Late Triassic of Saint-Nicolas-de-Port. A. IRSNB R165: B,

IRSNB 28114/47: C, IRSNB R166: D. IRSNB 28114/982; E. IRSNB 28114/90; F, IRSNB 28114/93; G. IRSNB 28114/55; H, IRSNB

28114/88;!, IRSNB 28114/646; J, MNHPSNP131L Scale bar: 1 mm.

GEODIVERSITAS • 1997 • 19(3)

591

Godefroit P. & Battail B.

Table 6. — Measurements (in mm) of the postcanine teeth of Gaumia longiradicata, from the Late Triassic of Saint-Nicolas-de-Port.

Le, lengîh of the Crown; Wc, width ot the crown; Hc, height of the crown; Hr. height of the root. For the signification of the groups,

see text.

Group

Number

LcAVc

Hr/Hc

IRSNB 28114/047

1.95

0.75

1.4

2.75

2.6

1.96

IRSNB 28114/088

1.2

0.5

0.85

2.4

IRSNB 28114/090

1.5

0.65

1.2

2.31

IRSNB 28114/093

1.7

0.8

1.3

2.12

IRSNB 28114/646

1.9

0.7

1.1

>1.6

2.71

>1.5

MNHP SNP131L

1.67

0.61

? 1.18

2.73

MNHP SNP430W

1.32

0.53

2.49

IRSNB R165

1.6

0.71

3.3

2.26

1.65

IRSNB 28114/055

1.9

0.75

1.8

2.53

IRSNB 28114/982

1.95

0.75

1.5

>1.9

2.6

>1.27

IV ?

IRSNB R166

2.3

0.9

1.8

2.65

2.56

1.47

straighc, noc curved to the lingual side of the IRvSNB R165), or can be presented as a vague

crown. undulation ot the edges of the main cusp

In latéral view, the main cusp has a triangular (IRSNB 28114/047, IRSNB 28 1J 4/646). When

outline and is specially broad: its base occupics the latéral acces.sory cusps arc présent, they are

nearly the full length of the crown. Its borders set at ilie base of the crown, quite anteriorly

are straight to slighily concave. Its apex is less and/or posteriori)'. These latéral accessory cusps

sharp than in Pseudotricoriodon tvildi. The are very small (less than one tcnch of the height

médian pair of accessory cusps is set along the of the main cusp), narrow, but better differencia-

lower third of the main cusp. These are not very ted than the médian accessory cusps.

developed and always very blunr: they can be Wear is apical and very erratic, as in

separated from the main cusp by an indentation Pseudotricoriodon wildi, It does not form clearly

which is not very deep (IRSNB 28114/093, marked wear facets. The crown and the root are

Ln {length of the crown)

Fig. 16. — Dispersion diagram of the postcanine teeth in Gaumia longiradicata.

592

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-NicoIas-de-Port

clearly separated by a constriction.

Root

The root is prcserved in IRSNB 28114/047,

IRSNB 281 14/646, IRSNB R165. IRSNB

281 14/982. IRSNB R166 and MNHP

SNPI31 Lm In anrerior view, rhe root is less nar-

row and rhus, more robust ihan in Pseudotri-

conodon wildi. This explains ihe highcr

proportion of preserved roots in Gaurnia longira-

dicata. The root is mucli higher than the crown:

rhc ratio ‘'hetght of rhe roor/heighr of che crown”

varies bcnveen 1.47 {IRSNB R166) and 1.96

(IRSNB 28114/047). Ir has, in latéral view, a

subtriangular outline: irs length lessens quickly

and symmetrically rowards che rlp. Its anterior

and posterior bordées are srraighr (IRSNB

28114/913) ro slightly convex (IRSNB

28114/047, IRSNB R165, IRSNB 28114/982).

The tip of the root is rtmnded and pierced by a

small rounded to elliptical pulpal loramen: this

pulpal canal is never double, as in Iheudotricono-

don ivitdi.

In IRSNB RI 66, rhe anterior (?) border of the

root is naturally truncated at the level of its lower

third. A small lunulate foramen is visible at the

level of the iruncature. As this feature can be

observed in only one specimen, it is not possible

to know whether this represents a second pulpal

foramen or more simpiy an isolated anomaly of

the root.

Discussion

Gaurnia resembles Pseudotriconodon in the gene¬

ral aspect ol the crown of its postcanines.

However, the base of the crown is constricted

and the root is higher and subtriangular in out¬

line. riic absence ol bipartition of the root sug-

gests that Gaurnia is not a membet ol che lamily

Dromatheriidae. l'hc présence of a second pulpal

loramen in IRSNB RI 66 needs to be confîrnted

by future discovery ol addirional specimens sho-

wing this Icaturç. The absence ol truc apomoi-

phics in the postcanine dentition of Gaurnia

leads to consider this genus as a Cynodontia

incertae sedh (see Hahn et al. 1987î Battail

1991).

The postcanine teeth discovered in Saint-

Nicolas-de-Port can be referred to the species

Gaurnia longiradicata Hahn, Wild et Wouters,

1987: their crown is relatively thick and the

enamel is perfectly smooth on ail cusps. These

teeth cannot l»e morpliomeirically distinguished

from the type material discovered in Habay-la-

Vieillc (Fig. 16). In this species, the length and

the width of the crown are isometrical (b = 0.99;

r = 0.94). The dental crowns relerred ta Gaurnia

? incha Hahn, Wild et Wouters, 1987 are signifi-

cantly narrower and enamel ridges arc présent on

the lingual side of the main cusp. Peyer (1956,

pi- 9, Bgs 18, 27, 34, 44 and 47) describes seve-

ral teeth from ihe Upper 'friassic of Hallau

(Switzcrland) iliat can be referred to the genus

Gaurnia. They are characterîzed by lew indistinct

enamel ridges on both the lingual and the labial

sides ol the main cusp: they probably belong to a

new undescribed species (Sigogneau-Russell &

Hahn 1994).

Genus Lepagia Hahn, Wild ef Wouters, 1987

Lepagia Hahn etal.^ 1987: 5.

'rvPH SPECIES. — Lepagia gaumensis Hahn, Wild et

Wouters, 1987.

DlAGNOSlS. — As for the only currently recognized

species, Lepagia gaumensis Hahn, Wild et Wouters,

1987.

Lepagia gaumensis

Hahn, Wild et Wouters, 1987

(Figs 17, 18)

Lepagia gaumensis Hahn étal., 1987: 7, llg. 2, pl. 1,

fig. 1, pl. 2, figs 1,2.- Banail 1991: 89. - Sigogneau-

Russell & Hahn 1994: 2Ü6, fig. 10. lOa.

^Zâhne von wahrscheinlicb synapsiden Reptilien,

Grappe tP (Peyer 1956; 56, partim, pl. 5, fig. 66,

pl. 10, fig. 68).

**Zahn eines syruipsiden Reptiles* (Kindlimann 1984: 3,

fig. 4).

Hoi-OTYPE. — IRSNB "R-M.28”.

Paratypes. — IRSNB "R.M.29” and IRSNB

“R.M.30”.

Locus TYPICUS. — Side of the speedway E25-E411,

at Habay-la-Vieille (Belgian Lorraine).

GEODIVERSITAS • 1997 • 19(3)

593

Godefroit P. & Battail B.

Stratum typicum. — Bone-bed “HLV-2”, Grès de

Mortinsart (Rhaetian, Upper Triassic).

New HYPOTYPES. — From Sainr-Nicolas-de-Port:

IRSNB R167, IRSNB 281 H/051, ? IRSNB

28114/104.

DiagnosiS, — Crown ot' tlie postcauinc teeth long,

narrow (2.5 < ratio “length/widtli” of the

Crown” < 3J) and tricuspid to pcniacuspid; labial and

lingual sides of rbe crown dightly^ convex and ncarly

parallel; cutting edge of the cusps perfeerly straight.

Crown asy'mmerrical in latéral view. Axis of the crown

perfectiy vertical. No cingulum. Base of rhe crown

very constricted. The root, ncarly rectangul.ir in larcraJ

view and subcqual in height to the crown, doe.s not

taper distally. Pulpal canal rcstrictcd to a long and

narrow slit. Horizontal ramus of the inandiblc very

low. Splenial very thin, extending halfway up on the

lingual sidc of the dentary.

DESCRiraON

Orientation

As in Pseudotriconodon wildi (see above).

Measurements

Measurcments taken on the postcanine teeth of

Lepagia gaiimensis discovered in Sainr-Nicolas-

de-Port are shown in table 7.

Crown

l'he crown is perfectiy smooth in IRSNB

28114/051 and IRSNB R167: some indistinct

enamel ridges are présent on the labial side of the

apex of the main cusp, in IRSNB 28114/104. In

occlusal view, rhe crown is rather long and nar-

row: the ratio “length/width*^ of the crown varies

between 2.5 and 3.5 in the teeth discovered in

Saint'Nicolas-de-Port. The labial and lingual

borders are nearly parallcl: rhe labial side is

somewhat more convex chan rhe lingual one.

The cusps are perfectiy aligned followmg the

aniero-posterior axis of the crown; ihey form a

sharp cutting edge.

In ancerior view, the main cusp is perfectiy

straight and not curved towards the lingual side.

Fig. 17. — IRSNB RI 67, postcanine tooth of Lepagia gaumensis, from the Late Triassic of Saint-Nicolas-de-Port. A, latéral view; B,

occlusal view; C, ? anterior view. Scale bar: 1 mm.

594

GEODIVERSITAS • 1997 • 19 (3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Table 7. — Measurements {in mm) of the postcanine teeth of Lepagia gaumensis. from the Late Triassic of Saint-Nicolas-de-Port.

Le, length of the crown; Wc. width of the crown: Hc, height of the crown; H, height of the root. For the signification of the types, see

text.

Group

Number

Lc/Wc

Hr/Hc

?ll

IRSNB 28114/051

1.25

0.5

7 0.95

2.5

1.05

IRSNB R167

3.65

1.05

2.7

1.7

3.47

0.63

IRSNB 28114/104

2.65

0.85

1.8

3.12

In latéral view, the crown is more irregular, less

symmetrical ihan in Pseudotriconodon or

Gaumia. The main cusp, rriangular in shape, is

proportionally less high and iis apex is less sharp

than in the laiter gênera. Il is llankcd by one or

two anterior, and by one or two posterior acces-

sory cusps. In IR.SNB 281 14/104 and IRSNB

Rl67, which possess two pairs of accessory

cusps, the anterior accessory cusps are sec higher

on the edge of the main cusp than the posterior

accessory cusps. Tlte firsi pair of accessory cusps

(médian accessory cusps) is rather large^ bue not

very sharp; on the other hand, the second pair

(latéral accessory cusps) is smaller, but sharper.

The crown of IRSNB 28114/051 is very eroded.

Its main cusp seems slighrly inclined backwards;

the anterior accessory cusp is small but very

sharp, whereas the posterior one appears as a

vague ondulation of the posterior edge of the

main cusp..

As in Pseiidotriconodon and Gamma, wear îs erra-

cic on the apex of the cusps and docs not form

clearly defined facecs. There is no trace of cingu-

lum. The crown and the root are separated by a

well marked constriction.

Root

The root is undivided and never clearly higher

than the crown: the ratio “height of rhe

root/height of the crown” is about 1.05 in

IRSNB 28114/051 and 0.63 in IRSNB RI67. In

anterior view, ic is always very narrow. In latéral

view> the root of IRSNB R167 has an irregulat

trape7.oidaJ ourline. Its Icngth is greater than irs

height. Its anterior border is straight and oblique

backwards and iis posterior border is clcarl}^

convex. The roor of IRSNB 28114/051 is pro-

partionally highcri its anterior and posterior bor-

ders arc slightly convex and nearly parallel.

The tip of the root is well preserved în IRSNB

R167. Il is long and nearly straight. The pulpal

foramen is restricted to a long, very narrow and

undivided slit.

Discussion

IRSNB 28114/051 and IRSNB R167 are similar

to the postcanine teeth of Lepagia gaumensis

Hahn, Wild er Wouters, 1987 from the Rhaecian

of Habay-la-Vieille (Belgian Lorraine) and

Hallau (Switzerland): the crown is asymmetrical

and irregular, there is a well marked constriction

Fig. 18. — Outline of postcanine teeth of Lepagia gaumensis, from the Late Triassic of Saint-Nicolas-de-Port. A, IRSNB RI 67;

B, IRSNB 28114/104; C. IRSNB 28114/51. Scale bar: 1 mm.

GEODIVERSITAS • 1997 • 19(3}

595

Godefroit P. & Battail B.

between the crown and rhe roor, the roor is pro-

portionally low and subrrapezoidal, the pulpal

canal is a long and narrow slit.

The identification of IRSNB 28114/104 is more

problematical because of ics broken root. The

shape of the crown resembles that of Lepagia

gaumensis, but erratic enaniel ridges can be

observed on the labial side of the apex of the

main cusp. Nevertheless, this character is too

poorly expressed to justily the création of a new

species. WaJting lot Inrther evidence, this tooth

is tentatively identified as Lepagia gaumensis.

Hahn et al. (1987) compare the mandible of

Lepagia gaumensis with that of Probainognathus. in

both taxa, the splenial is very narrow and extends

haliway up on rhe lingual side of the dentary As a

resuit of this comparison, Lepagia is grouped

within the famÜy Chiniquodontidae. Battail

(1989) observed a comparable réduction of the

splenial in ail the other lamilies of advanced cyno-

donts, correlatively to the development ol the

dentary. Moreover, the horizontal ramus of the

mandibule is much lower in Lepa^i than in the

Chiniquodontidae and is racher rcminisccnt of the

mandible of the Dromatheriidae. Nevertheless,

rhe root of the posreanine recrh is not subdivided

in Lepa^ay as in the Dromatheriidae. Thus, in the

current State of our knowledge, it is not possible

to State precisely the systematic position of

Lepa^agaumensis within the Cynodontia.

Table 8. — Measurements (in mm) of lhe cynodont premolariform teeîh, from the Late Triassic of Saint-Nicolas-de-Port. Le, length of

the crown; Wc, width of the crown; Hc, height of the crown. For the signification of the forms, see text.

Form

Number

Lc/Wc

Lc/Hc

IRSNB 28114/029

1.4

0.65

2.15

IRSNB 28114/032

1.45

0.58

1.9

2.5

0.76

IRSNB 28114/039

1.13

0.68

1.43

1.66

0.79

IRSNB 28114/114

1.25

0.55

2.27

IRSNB 28114/116

1.4

0.65

2.15

IRSNB 28114/118

1.05

0.6

1.2

1.75

0.87

IRSNB 28114/119

1.25

0.7

1.47

1.79

0.85

IRSNB 28114/120

1.65

0.88

2.3

1.87

0.71

IRSNB R168

2.4

1.2

3.95

0.61

IRSNB 28114/755

1.9

0.85

2.24

IRSNB 28114/765

1.87

2.48

1.87

0.75

IRSNB 28114/904

2.15

1.25

2.82

1.72

0.76

IRSNB 28114/911

1.12

0.57

>1.58

1.96

>0.7

IRSNB 28114/973

1.5

0.98

1.83

1.53

0.82

IRSNB 28114/000

2.13

1.25

1.7

IRSNB 18114/925

1.68

MNHP SNPâSDD

2.37

1.15

3.27

2.06

0.72

MNHP SNP58W

1.52

2.17

MNHPSNP136W

0.95

0.53

1.05

1.79

0.9

MNHPSNP159W

1.32

0.5

1.5

2.64

0.88

MNHPSNP214W

1.73

0.98

1.76

MNHP SNP215W

1.28

0.64

1.57

0.82

MNHP SNP282W

0.73

0.35

1.05

2.09

0.7

MNHP SNP328W

0.7

0.32

0.77

2.18

0.91

MNHP SNP342W

0.88

0.48

1.83

MNHP SNP395W

2.04

1.1

3.11

1.85

0.66

MNHP SNP402W

2.21

3.24

0.68

MNHP SNP404W

1.57

0.77

2.04

MNHP SNP443W

0.58

0.33

0.68

1.76

0.85

MNHP SNP451W

1.3

0.51

2.55

MNHP SNP468W

2.15

1.16

3.28

1.85

0.66

IRSNB R169

1.5

0.65

2.3

MNHPSNP95L

1.07

0.35

3.05

MNHPSNP12W

2.19

1.19

1.84

MNHPSNP85W

1.39

0.68

1.49

2.04

0.93

IRSNB R170

2.15

3.8

2.15

0.57

IRSNB RI71

2.25

1.05

1.9

2.14

1.18

IRSNB 28114/877

0.75

0.18

4.17

MNHPSNP484W

1.8

0.47

1.42

3.83

1.27

596

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

PrEMOI^RIPORM TEHTU INCLRTAi. SRDIS

Teeth with a slender crown composée! by a high

anterior cusp and by a smail posterior accessory

cusp are described and discussed in the présent

chapter. Biomcrrical data observed on these teeth

are shown in table 8. Six categories can be distin-

guished, on the basis of the general morpho-logy

of their crown.

Form 1

(Figsl9A. B, 20)

MaIERIAL EXAMINED. — Specimens discovered in

Saint-Nicolas-de-Port: IRSNB R168, IRSNB

28114/000, IRSNB 281I4/029> IRSNB 28114/032.

IRSNB 28114/039. IRSNB 281 14/114. IRSNB

28114/116, IRSNB 28114/118, IRSNB 28114/119,

IRSNB 28114/120. IRSNB 281 14/755. IRSNB

28114/765, IRSNB 28114/904. IRSNB 28114/911,

Fig. 19. — Cynodont premolariform teeth, from the Late Triassic of Saint-Nicolas-de-Port. A, B, IRSNB R168, form 1; C, D, IRSNB

R169. form 2; E, F, IRSNB R170. form 3; G, H, MNHP SNP484W, form 6; I, J, IRSNB R171. form 4. A, C, E, G, I. latéral views; B, H,

J, apical views; D, F, posterior views. Scale bars: 1 mm.

GEODIVERSITAS • 1997 • 19(3)

597

Godefroit P. & Battail B.

IRSNB 281 14/925, IRSNB 28114/973, MNHP

SNP72DD, MNHP SNPS3DD, MNHP SNP5HW,

MNHP SNP136W, MNHP SNP159W, MNHP

SNP214W. MNHP SNP2J5W. MNHP SNP282W,

MNHP SNP328W, MNHP SNP342W. MNHP

SNP395W, MNHP SNP402\V. MNHP SNP404W,

MNHP SNP443W. MNHP SNP451W, MNHP

SNP468W.

Description

Premolariform teeth of form 1 are, by far, rhe

most numerous. The crown is rather siender

(0.61 < ratio “length/height” of the crown <

0.93), but their base is relatively robust (1.53 <

ratio “length/width” of the crown < 2.55).

The main cusp is high and has a triangular outline

in latéral view. It is curved baclcwards and slightly

towards die lingual sidc. Ils apex is rather sharp on

the highcst crowns, but more rounded on the

smallcst teeth. Nevertheless, it miist be noxcd that

the apex of the cusp can be parnally eroded. Its

anterior border is very convex: its base is usually

thinner rhan ics apical portion which can form a

flatten edge. Its posrerior edge is less convex, but

very sharp along its wholc height. 1rs labial sîde is

convex anrero-posteriorly. Its lingual side fbrms a

central convex ridge, flanked by an anterior and a

posrerior concave third. The posterior concaviry is

usually better marked than the anterior one.

Fig. 20. — Outline of cynodont premolaritorm teeth {form 1), from the Late Triasslc of Salnt-Nicolas-de-Porl. A, IRSNB R168

B, MNHP SNP395Wi C. MNHP SNP468W; D. MNHP SNP492W; E. MNHP SNP58W; F, MNHP SNP83DD; G. IRSNB 28114/765

H, IRSNB 28114/904: I. IRSNB 28114/32; J. IRSNB 28114/29: K, IRSNB 28114/973; L. IRSNB 28114/648; M, MNHP SNP214W

N, IRSNB 28114/39; O, IRSNB 28114/119; P. MNHP SNP342W; Q, MNHP SNP382W; R, MNHP SNP136W, S, MNHP SNP443W

T. MNHP SNP78. Scale t>ar: 1 mm.

598

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Pon

The posterior accessorV cusp is always vcry redu-

ced and triangular in latéral view, les maximum

height can reach the third of che height of che

main cusp. Its apex is nor vcry sharp. Its vertical

axis usually .slopes baclcwards.

Wear can affect the apex of rhe cusps, but does

not form cicarly defincd facets. The crown is dis-

tinctly separated from che root by a constriction,

particularly well marked on the anterior and the

posterior sides of the teeih (MNHP SNP342W,

MNHP SNP443W, MNHP SNP451W). Thc

root is not preserved in the premolariform teeth

discovered in Saint-Nicolas-de-Port.

Discussion

Premolariform teeth of form 1 appear, at first

sight, morphometrically heterogeneous: the small

crowns sccn> proportionally mucli lowcr than the

taller ones. Figure 22 shows the relative growth

of the length (in Ln) and the height (in I n) of

the Crown in the premolaritorm teeth discovered

in Saint-Nicolas-de-Port. The coefficient of cor¬

rélation calculated for the teeth of form 1 is asto-

nishingly high: r - 0.985, The allometry

coefficient b, calculated according to Teissiers

(1948) formula, is 1,21. The apparent morpho-

merrical heterogeneit)' of these teeth can chere-

fore be easily explained by the positive allometry

between the length and the height of the crown:

the height grows more quickly than the length.

Figure 23 shows that the length and che width of

the crown, in the premolariform teeth of form 1,

can be regarded as isomecncal: b = 1.05; r = 0.94.

In conclusion, it can be assumed that the mor-

phomerrical vanabiliry observed in these teeth

reflccts ontogenetical différences and/or rhe posi¬

tion in the jaw, instead of taxonomie heteroge-

neity.

Form 2

(Figs 19C, D, 21A-C)

Material EXAMINED. — Spccimens discovered in

Saint-Nicolas-de-Port: IRSNB R169. MNHP SNP

95L, MNHP SNP12W. MNHP SNP85W.

Description

The premolariform teeth grouped in form 2 dif-

fer from che othet forms by a second small acces-

sory cusp, posteriorly. le is very reduced and

reaches only the quarter of rhe height of rhe first

accessory cusp. The proportions of the crown are

similar to chose observed în the premolariform

teeth of form 1 (see Table 8, Figs 22, 23). The

asymmetry between the lingual and the labial

sides of the main cusp is less marked than in the

premolariform teeth of form 1, In anterior view,

the main cusp is slightiy curved towards the lin¬

gual side of the tooth. Hahn et al. (1994) descri-

be a well defined wear facet on the labial side of

MNHP SNP12W: this is therefore a lower pre¬

molariform tooth, The base of the anterior

Fig. 21. — Outline of cynodont premolariform teeth, from the Late Triassic of Saint-Nicolas-de-Porl. A, MNHP SNP85W (form 2);

B, IRSNB R169 (form 2); C, MNHP SNP95L (form 2); D, IRSNB R1471 (form 4); E. MNHP SNP484W (form 6); F, IRSNB 28114/877

(form 5): G, IRSNB R170 (form 3). Scale bar: 1 mm.

GEODIVERSITAS • 1997 • 19(3)

599

Godefroit P. Ôc Battail B.

border of the main cusp is very sharp in IRSNB

R169. In MNHP SNP85W, a small swelling on

the base of the anterior cdge of the main cusp

can tentatively be interpreted as the rough shape

of an anterior accessory cusp. The base of the

Crown is clearly scparated from the root by a

constriction, as in the premolariform teeth of

form 1. The root is not preserved in the known

material.

Discussion

Hahn et al. (1994) refer SNP I2W to Tricuspes

sigogtieatiue. I his identification is mainly based

on the position of the second accessory cusp, on

the postcrior wall of the crown. Nevertheless it

seems that, in the présent case, this charactcr

mainly reflects the low development of this cusp.

Thus, because of the important divcrsify of the

cynodont fauna from Saint-Nicolas-dc-Port, this

identification is doubtful, in the absence of jaw

fragments associating both premolariform and

molariform teeth (see below).

The morphological différences observed between

the premolariform teeth of fornt I and form 2

can perhaps bc interpreted as différences of posi¬

tion in the tooth row: premolariform teeth of

form 1 shouid be set în a more anterior position

than premolariform teeth of form 2.

Form 3

(Figs 19E, F, 21G)

M/VTERIAL EXAMiNED. — Specimen discovered in

8aint'Nicolas-de-Port: IRSNB R170.

Description

IRSNB R170 is characterized by its very high,

slender and canmiform crown: the ratio “Jength/

height” of the crown is 0.57 (see Fig. 22). On the

other hand, the ratio "length/width” of the

crown, which is 2.15, has a usual value, as in the

premolariform teeth of form 1 or 2. Borh the

labial and the lingual sides of the main cusp are

nearly symmetrically convex. The main cusp has,

in latéral view, a triangular oucline and is curved

backwards. Its apex is slightiy blunt. 1rs posrerior

edge is very sharjî. Its anterior border forms a

flattcned edge, on ks whole height. Along the

anterior border of its lingual side, it l>ears a long,

elliptical and flaiten wear facet. If the orientation

proposed for this toolh is correct, it is thus an

upper premolariform. The posterior accessory

cusp is tiny: it is only represented by a small

swelling at the base of the posterior border of the

main cusp. The root is not preserved.

Discussion

The very slender aspect of the crown (see

Fig. 22. — Dispersion diagram (length/height) of the cynodont premolariform teeth.

600

GEODIVERSITAS • 1997 • 19 (3)

Late Triassic cynodonts from Saint-Nicolas-de-Poit

Fig. 22) and the tiny posterior accesüory cusp

discinguish IRSNB RI 70 from the other premo-

lariform tecch discoverêd in Saint-Nicolas-de-

Port. These différences could reflect a more

anterior position of chis spccimen in che tooth

row ot the animal. Ncverthcicss the présence of a

well marked wcar facct. not observed in the pre-

molariform tecth of forms 1 and 2, indicates that

this tooth probably belongs to another taxon.

Form 4

(Figsl9I>J,21D)

Material exAMINED. — Specimen discovered in

Saint-Nicoias-de-Port: IRSNB R171.

Description

Contrary to IRSNB RI70, this tooth is very

sfoclcy: the ratio “lengrh/heighr" of the crown is

1.18. The ratio "length/width’* of the crown,

which is 1 14, iç usual, as in the other forms of

premolariform teeth previousiy described. The

labial and lingual sides of the crown are quite

asymmetrical: the labial sidc is very convex ante-

ro-posrcriorly and che lingual one, straJght. The

main cusp is low, stocky and triangular in out-

line. Its apex is rounded and beats a small ellipti-

cal wear facet, showing the dentine, on its labial

side. If the orientation proposed for this tooth is

correct, IRSNB R171 is chus a lower premolari¬

form. Boch thé anterior and posterior edges of

rhe main cusp arc not very sharp. The posterior

accessory cusp, weakly developed and very roum

ded, rcaches che quarter of che height of che

main cusp. At che junction between rhe two

cusps, the labial side of the crown bears a smaJl

dimple. The root is noi preserved.

Discussion

Figure 22 shows that this tooth is morphometri-

cally different from rhe other premolariform

teeth discovered in Saint-Nicolas-dc-Pori (excepe

MNHP SNP484W) becausc of its low and sco^

cky crown. l'he very rounded apex of the cusps is

an unusual feature, too.

Form 5

(Fig. 21F)

Material EXAMINED. — Specimen discovered in

Saint-Nicolas-de-Port: IRSNB 28114/877.

Description

This fragmentary dental crown is very small and

extremely thin: the ratio “length/width" of the

crown is 4.17. The main cusp has, in latéral

- 0.6

0.4

0.2

-0.4 -0.2 0 0.2

- 0.2 4 -

-k-

0.4

-0.4

-1

- 1.2

-1.4

-1.8 -L

Ln (length of the crown)

0.6

■

^ -1

0.8 1

■ Form 1

4 Form 2

• Form 3

♦ Form 4

X Form 5

A Form 6

Fig. 23. — Dispersion diagram (length/width) of the cynodont premolariform teeth.

GEODIVERSITAS • 1997 • 19(3)

601

Godefroit P. & Battail B.

view, a rriangular ourline and is tather elongated

amero'posteriorly. Its apex is very sbarp and both

its anterior and posterior edges are extremely

sharp, too. The anterior edge is sJighcly longer

than the posterior one and, therefore, the main

cusp slopes ^lightly backwatds. The posieiior

accessory cusp is rriangular and very sbarp, too.

It reaches the half of the hcight of the main cusp.

The base of the crown Is broken, but seems par-

ticularly high.

Discussion

IRSNB 28114/877 differs from the other pre-

molariform tecth discovered in Saint-Nicolas-de-

Port becausc of its extremely narrow crown (see

Fig. 23) and its very sharp edges.

Form 6

(Figs 19G, H,21E)

MaTERIAL EXAMINED. — Specimen discovered in

Saint-NicoIas-de-Porr: MNHP SNP484W

Description

MNHP SNP484W is characrerized by its pro-

portionally long, low and narrow crown: the

ratio “length/widrh” of the crown is 3-83 and the

ratio “length/heighr** of the crown, T27. Both

the labial and the lingual sides of the crown are

symmerrically antero-posteriorly convex. The

edge is sharp on the whole length of the crown.

The main cusp is short, not very high and rrian¬

gular in outline. Both its anterior and posterior

cutting edges are slightly convex. Its apex is

rather rounded. The posterior accessory cusp is

quite low and rounded, but very elongated ante¬

ro-posteriorly. Ar rhe base of the anterior edge of

the crown, an elliptical flattened surface, sho-

wing the dentine, probably represents a contact

facet with the anterior adjacent crown in the

tooth row. The base of the crown seems constric-

ted.

Discussion

MNHP SNP484W is clearly different from the

other premolariform teeth discovered in Saint-

Nicolas-de-Port: the proportions of the crowns

are unusual (see Figs 22, 23), the main cusp is

very short and low, the accessory cusp is propor-

rionally very long and the contact area, ar the

base of the crown, is not présent in the other spé¬

cimens. Consequently, it probably belongs to

another taxon.

AePINITIES of PREMOLARII-Om TEETH

FROM Saint-Nicolas-uf-Por'e

Premolariform teeth similar to rhose discovered

in Sainr-Nicolas-de-Port hâve been described in

primitive pccrosaurs, Triassic cynodonts and early

mammals.

Pterosaurs

Teeth similar to premolariforms discovered in

Saint-Nicolas-de-Port are described in the ptero-

saur Eiidimorphodon mnzii (WÜd 1978) These

are formed by a main cusp slightly curved back-

wards, with a sharp-pointed apex and a very

sharp edge, and by a small posterior accessory

cusp. Ncvertheless, the enamel bears numerous

longitudinal ridges and the crown is Icss com-

pressed labio-lingually. “Premolariform” teeth of

Eudimorphodon are preserved in the Upper

Triassic of Sainr-Nicolas-de-Port, too (Godefroit

& Cuny, in prep.).

Cynodonts

The general pattern of premolariform reeth dis¬

covered in Saint-Nicolas-de-Port can be obser\'ed

in scveral groups of Triassic cynodonts.

Thrinaxodontidae. In Thrinaxodon liorhinus

Sceley, 1895, from the Early Triassic of

South Africa, the most anterior upper postcanines

are compressed labio-lingually and bi-

cuspid, with an anterior main cusp and a posterior

accessory cusp. Ncvertheless, these always bear a

wcll dcvelopcd lingual cingulum (Battail 1991).

Galesauridae. In Galesaurus Owen. 1860, from

the Early Triassic of South Africa, both the upper

and the lower posreanines are compressed labio-

lingually, bicuspid, without distinct anterior

accessor)'^ cusp and without cusped cingulum

(Battail 1991). Neveriheless, they differ from the

premolariform teeth from Sainr-Nicolas-dc-Port

in their main cusps very curved backwards and

in their posterior accessory cusp proporrionally

higher.

Cynognathidae. In Cynognathus crateronotus

602

GEODIVERSITAS • 1997 * 19 (3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Seeley» 1895» from the Early Triassic and Early

Middle Triassic of South Africa, the postcanine

teeth are always Gomprcsscd labio-lingüally, ver)'

sharp and devoid of cingulum. In the largest spé¬

cimens, the most anterîor po.sttanLnes are very

similar fo rhe premoiariturm leeth from Saint-

Nicolas-de-Port, with a high main cusp slightly

curved backwards and a small posterior accessory

cusp. Ncvcrthdess thcse teeth are clearly larger in

Cypiognathus, The juvénile specimens hâve a

more complex postcanine structure (Battail

1991).

Chiniquodontldae. Scctorial and bicuspid post¬

canine teeth can be observed in Probelesodon

lewisi Romer, 1969 and Probaïnognathus jemeni

Romer, 1970, from the Middle Triassic of

Argentina. In Probaimgpmthm. the main cusp is

very low and noi very deveJopcd and, morcover,

the edge of the crown is sinuous, wirhout well

defined accessory cusp. The postcanine teeth of

I^obeksodon are cypically bicuspid: only rhe most

posterior postcanines possess an antenor accès-

sory cusp. NeVerchelcss, the main cusp is aiways

more curved backwards than in rhe premolari-

form teeth from Sainc-Nicolas-de-Port.

Trîtheledontidae. If bicuspid dental crowns are

présent in Pacbygelenm Waeson, 1913.

Tritheledon riconoi Broom, 1912 and

Diartbrognathus broorni Crompton, 1958, from

rhe Late Triassic of South Africa, these teeth are

never as scrictly sectorial as in the premolariform

teeth from Sainr-NicoUs-de-Port.

Dromathenidae. The postcanine teeth of rhe

Dromatheriidae are aiways strictly sectorial,

without developed cingulum and with a cutting

edge. In DromiHherhm .ylvestiv F.rnmonSj 1857,

from the Late Triassic of the United States, some

postcanincs seem typically bicuspid: the posterior

accessory cusp is cither smaller chan the main

cusp or almosr ol rhe sarrie si^e. The root is

always double and, contrary to the premolari¬

form teeth discovered in Saint-Nicolas-dc-Port

(at least in the forms T 2 and 6), there is no

consrriction betw'cen the crown and che root. It

is interesting to observe thar, in Dpvmathermm,

these “premolariform*' teeth arc set more poste-

riorly than the tricuspid teeth. Premolariforms

are not recorded in other .species, only known by

very fragmentary material or by îsolated teeth. As

explained above, the premolariform teeth attri-

buced to Tricuspes sigogneauae by Hahn et al.

(1994) are hcre more cautiously referred to

Cynodontia indet,

Early ntammals

Morganucodontidae. (Rhaerian and Early

Liassic of \X^estem Europe» Groenland, China

and South Africa). Morganucodonridae are

l'cprcscnted in Saint-Nicolas-de-Port by isolated

molars of Brachyzostrodon coupatezi Sigogneau-

Russcll, 1983 and Brachyzostrod^m maior Hahn,

Sigogneau-Russcll et Godefroit, 1991. Other taxa

are also présent but hâve not been described yet.

In the Morganucodonridae, rhe premolariform

teeth présent a similar structure as those discove¬

red m Saint-Nicolas-de-Port.

In Morganucodon Kuhne. 1949 the prcmolars are

formed by two cusps» as in the premolariforms

discovered in Saint-Nicolas-de-Porr. Neverthe-

less, the crown is less narrow labio-hngually and

rhe anterîor side is rounded and somefimes e%'en

bulbous, The main cusp is more elongated

antero-posteriorly. A wcak cingulum seems

always présent. The naot is double (Mills 1971 î

Kermack et ai 1973; pers. ob.s.).

In Megiizostrodoti ruduerae Crompton er Jenkins,

1968, pm2 and PM4 are bicuspid and they scem

devoid of cingulum. Neverthele.s.s, they clearly

differ from premolariform teeth discovered in

Saint-Nicolas-de-Port by rheir more stocky and

bulbous appearance (see Crompton 1974,

figs 4-6).

In Erythrotherium parringtoni Crompton, 1964,

pm2 and pm3 rescmble the premolariform teeth

from Saint-Nicolas-de-Port in being bicuspid

and apparently devoid of cingulum.

Ne\'ertheless, as in the other Morganucodonri¬

dae. these teeth look less sectorial and more bul¬

bous.

Kuehneotherndac. (Rhaetian and Early liassic

of Western Europe, Groenland and India).

Theria are represented, in Sainr-Nicolas-de-Port,

by the Woutersiidae Woutersla Sigogneau-

RusselJ, 1983 and by orlier undescribed

Kuehneotheriidae. Premolars are known in rhe

Kuehneotheriidae Kuehneotheriutn praecursoris

Kemiack, Kermack et Mussett, 1968. They differ

from the premolariform teeth discovered in

GEODIVERSITAS • 1997 • 19(3)

603

Godefroit P. &C Battail B.

Saint-Nicolas-de-Porr by their more elongated

and more curved main cusp and also by the fre¬

quent présence of a small anterior accessory cusp

and of cingular éléments.

CONCI.USÏONS

From the preceding compari.sons, it appears that

the premoiariform tecth discovered in Saint-

Nicolas-de-Port hâve évident afîinities with the

cynodonts. In rhe other groups of reptiles, only

the pterosaur Eiuiimorphorlon has dentaJ crowns

with a similar structure, but with numerous and

well marked enamel ridges. In the early mam-

mals Morganucodontidac and Kuehneotheriidae,

the crowns of the prcmolars are more bulbous

and usLiaJly possess cingular eJements.

The premoiariform teeth from Saini-Nicolas-de-

Port do not show clear diagnostical characters allo-

wing their strict identification at the Family levcl.

The attribution of scv^eral prcmohinform teeth to

the species Triruspn sigogneauaCr proposed by

Hahn et ai (1^194)^ is here regarded as doubrful..

The absence of preserved root is particularly déter¬

minant. The morphologicai and morphomecrical

variabilicy of the crown permits die distinction of

six “forms"\ This heterogeneicy probably reflects

the presence of several taxa in this material. If dro-

marheriids had alternating (and continuons) repla¬

cements like in Therioherpeton, it can not be

excluded that premoiariform teeth represent, in

face, replaced dcciduous teeth, which must be

numerous In the fossil sample.

GOMPHODONT CYNODONTS

Family Traversodontidae von Huene, 1936

Preliminaky remarks

Hopson (1984, 1985) thinks that the

Traversodontidae represent a paraphylctic group:

he believes that the ancestry of rhe family

Tritylodontidae lies wlthin it. Therefore, the

Traversodontidae are not strlcdy monophylctic,

but rather represent a grade group. On rhe ocher

hand, Batrail (1991) recogniees the Traverso¬

dontidae as a monophyletie group: rhe Tritylo¬

dontidae should form the sister-group of the

Traversodontidae.

It is interesting to note that the Traversodonti¬

dae, known by complété skull marcriaJ, arc rclati-

vely small forms in the late Early Triassic

{Pasctialgiutthus, Andescymodorh.r), medium-sized

forms in the early Middle Triassic [Saücnodon,

M/tîsttngtitithu^...) and large to very large forms tn

the late Middle Triassic and in the early Late

Triassic (Exaeretodony Jschîgnathusy Scaleno-

dantoides...). It is therefore rather surprising to

fmd, in deposits dated from the very end of the

Triassic. tiny teeth which, on the basis of their

structure, seem to bc attributable to travers'odon-

cids. It cannot bc excluded, however, chat the

taxonomie position of these forms might be ree-

valuated. should more complété material rcveal

major anatomica! différences with the typical,

well known Traversodontidae.

Genus Maubetigia n.g.

Type species. — Mauheugia lotharingica n.sp.

Df^RIVAHO NOMïMS. — Dcdicaccd to Dr. P.-L.

Maubeuge, for his concriburiori co the knowledge of

the geoiogy and palaeontology of the Lorraine area

and for his active participation in the exploration of

the quarry of Saint-Nicolas-de-Port.

DiaGNOSIS. — As for the only currently recognized

species Maubetigia lotharingica n.sp.

Discussion

Sec below.

Maubeugia lotharingica n.sp.

(Figs 24. 25)

Holotype. — IRSNB R172, a left upper postcanine,

with its root nearly complerely preserved.

DerivaTIO NOMINIS. — lotbaringicus, -a, ~um

(lat.) - from Lorraine (north-eastern France).

Locus TYPICUS. — Quarry at Rosières-aux-Salincs,

région of Saint-Nicolas-de-Port (Meurthe-et-Moselle,

France).

S'I RAI UM TYPICUM. — “Rhaetian” sandstones. Upper

Triassic.

L)I^GN0SIS, — Traversodontidae known by only one

upper postcanine tooth, with the following characters:

crown very small (width = 0.80 mm) with an ovoid

604

GEODIVERSITAS • 1997 • 19(3)

Late Triassic q^nodonts from Saint-Nicolas-de-Pon

outlinc in occluial view (ratio “Jcngth/width” of thc

Crown = 0,80); lablaJ NÎdc iorigci. bur Icss convcx rlian

the lingual sidc. Main labiaf cusp somrwbat higher

ihan rhe lingual onc. l'ransverse ridge set behind the

middle of rhc crown, but nor tnerged wiih thc posrc-

rior cingulum; anrerior baiin œn.scqucnily larger chan

rhe poüterior haNtri. Wdl dcvclopcJ centril cusp on

the transverse ndge, dose to the labial main cusp and

separared from thc lingual cusp by an embayment.

Large antcro-labial accessory cusp connecced to the

main labial cusp by a prominent ridge. Both anterior

and posterior "cingula” very low and very poorly

expressed.

Description

Orientation

The orientation of IRSNB RI 72 proposed here is

mainly based on comparisons with the upper

postcanincs of ScaUnodon charigi Cronipcon.

1972 and Boreogomphodon jeffersoni Sucs f/ Olsen,

1990 , which closely rcsemble rhis tooth. Jn lhe

Traversodontidae, the upper postcanincs arc clear-

ly wider (labio-Ungually) than long (mesio-

distally). As in advaneed Traversodontidae, the

transverse ridge of IRSNB RI 72 is set behind the

middle of rhe roofh and the anterior basin is

therefore bettci developed than the posterior one.

rhe buccal sidc is longer and less convcx than the

lingual side. A tall accessory cu.sp is set on the

anrero-labial margin of the crown. Thus, IRSNB

RI 72 is a left upper postcanine.

Measnrements

Length of the crown (= maximum mesio-distal

diarneter) = 0.65 mm; width of the crown

(= maximum labio-lingu;d diarneter) = 0.80 mm.

Crown

In occlusal view, the crown is subovoid in out-

line, wider than long (the ratio “length/widch'^ ûf

the crown = 0.81). The labial border is longer,

but less convex than tJic lingual one; the anterior

border is more convex than the posterior one.

Three cusps are arranged to form a rransverse

row. The lingual cusp seems the widest and the

centra! cusp is by far the smallest. The central

cusp is doser to the labial cusp. The three main

cusps are connccted together by a transverse

ridge. This ridge is set in a posterior position,

behind the middle of the crown. A very large

accessory cusp, nearly as wide as the labial cusp,

is set on thc antero-labial margin of the crown.

*rhc edges of both rhe main and îhe accessory

labial cusps form a conrinuous ridge, parallel to

thc labial side of the crown. Very low ridges, res-

pcctively parallel to the anterior and the poste-

rior margins of the Crown, connect, on one hand,

rhe accessory labial to rhe lingual cusps and, on

the other hand, the main labial to the lingual

cusps. A wide anterior basin is surrounded by rhe

lingual side of thc accessory labial cusp, by the

antero-lingual sidc of the main labial cusp, by

the anterior side of rhe central cusp and by the

antero-labial sidc of rhc lingual cusp. A smaller

and less well defmed posterior basin occupies a

corresponding position behind the transverse

ridge: it is Surrounded by the postcro-lingual side

of the main labial cusp. by rhe posterior side of

rhe central cusp and by the postero-labial .side of

the lingual cusp.

In labial view, the main and the accessory labial

cusps are separated from cach other by a shallow

indentation. The accessory cusp is somewhat

lower than the main onc. Thelr apices arc very

rounded. At rhe level of their junction, the anie-

rior side of rhc crown forms a very small basin.

The crown is separated from the root by a well

marked con.striction.

In lingual view, the lingual cusp seems lower

than the main labial cusp, and its apex seems less

rounded. kt the base of the crown, a small, cllip-

tical and deep dépréssion can be observed. This

is probably duc to post-mortem distortion of the

specimen.

In anterior view, the crown bas a bell-moulhed

outline. Both labial and lingual sides are convex

dorso-ventrally: the lingual wall is somewhat

more convex than the labial onc. l he main labial

cusp is the highest. It is connected to die central

cu.sp by a prominent ridge wkh anterior wall

nearly vertical. The central cusp is separated

from the lingual cusp by a rather deep indenta¬

tion. The rransverse ridge passes on the labial

side of the lingual cusp. l’he crest connecting the

accessory labial cusp to the lingual cusp (“ante¬

rior cingulum") is quite low and forms tiny

undulations. The constriciion between the

crown and clic root is very clearly marked.

In posterior view, thc posterior wall of the por¬

tion of the transverse ridge connecting the labial

GEODIVERSITAS • 1997 • 19(3)

605

Godefroit P. & Battail B.

and the central cusps is less vertical than the

anterior wall. The ridge connecting the main

labial and the lingual cusps (‘'posterior cingu-

lum”) is very low and not very devcloped.

Root

The tip of tlie root is broken. Complété, the root

was probably much higher than the crown. In

lingual view, it is subrectangular in shape: its

anterior and posterior sides are straight and ncar-

ly parallel. In anterior view, the root is genriy

tapering to the tip. The posterior border is more

oblique than the anterior one.

Discussion

The morphology of the upper postcanines is very

variable in the Traversodontidae: therefore, they

are very useful to establish the phylogenetical

relationships of the different généra within this

famiiy (Battail 1989). Thm, ir is interesting to

compare IRSNB RI 72 wiih the upper post¬

canines in currently known traversodonts.

Pascualgnathm Bonaparte, 1966

Andescytiodon Bonaparte, 1969

RuscoTiiodon Bonaparte, 1970

(Lower Triassic of Ai^entina)

The upper postcanines of fhese small and primi¬

tive Traversodontidae share several plesiomorphic

characters (Battail 1989). Contrary to IRSNB

RI 72, the transverse ridge connecting the labial

and the lingual cusps is set anieriorly, in rhe

anterior part of die crown. The posterior basin is

consequently larger than the anterior one. d’here

is no trace of central cusp. An accessory cusp is

présent, posreriorly to the main labial cusp. Both

the anterior and the posterior cingula are well

developed.

Fig. 24. — IRSNB R172, left upper postcanine of Maubeugia lotharingica, from the Late Triassic of Saint-Nicolas-de-Port. A, stereo-

photographs; B, occlusal view; C, labial view; D, lingual view; E, anterior view; F, posterior view. Scale bar: 1 mm.

GEODIVERSITAS * 1997 • 19(3)

Lace Triassic cynodonts from Saint-Nicolas-de-Port

Scalenodon Crompton, 1955

(Middie Triassic of Tanzania, Zambia and ?

Russia)

The different species in the genus Scalenodon

{sensu Batrail 1991) differ mainly from each

other in the structure of their postcanine teeth.

The différences observed in the Tanzanian spe¬

cies are summarized by Crompton (1972,

table 1). The transverse ridge is always set poste-

riorly, behind the middie of the crown, like in

IRSNB RI72. The ancenor basin is thcrefore

much larger ihan the posterior basin. In several

spccies, the transverse ridge, quitc posteriorly set,

merges with the posterior cingulum and the pos¬

terior basin is consequently lost. Except in

Scalenodon charigi Crompton, 1972, rhe trans-

verse ridge supports a well developed central

cusp. The anterior and posterior cingula are

more or less developed in the different species of

Scalenodon, Antero-labial and/or antero-lingual

accessory cusps are occasionally présent. The

upper postcanines of Scalenodon differ from

ÎRSNB RI72 in several details, The crown,

much larger, is always proportionally wider. The

labial side is usually more convex than the lin¬

gual one. The central cusp is set more lingually:

it ïs connected to the lingual cusp by a promi¬

nent ridge and separated from the labial cusp by

a deep embayment.

Massetopiathus 1967

(Middie Triassic of Argentina)

In Massetogfiathus, the transverse ridge is set quite

posteriorly and merges with the posterior cingu¬

lum; it supports a central cusp, close to the lin¬

gual cusp. The posterior basin is consequently

Fig. 25. — IRSNB R172, left upper postcanine of Maubeugia lotharingica, from the Late Triassic of Saint-Nicolas-de-Port. A, occlusal

view; B, labial view; C, lingual view; D, anterior view; E, posterior view, ab, anterior basin; al, antero-labial cusp; c, central cusp;

L. lingual cusp; ml, main labial cusp; pb, posterior basin; tr, transverse ridge. Scale bar; 1 mm.

GEODIVERSITAS • 1997 • 19(3)

607

Godefroit P. &: Bartail B.

lost, but chc ancerior basin is ênlarged. A large

accessory cusp is set anceriorly and slightly lin-

gually to rhe labial main cusp. The lingual wall of

rhe Crown looks tberefore oblique- The labial side

of rhe Crown is ver)' convex antero'posteriorly.

Traversodon von Huene, 1936

(Upper TViassic of Bruzil)

In this large Traver.sodontidae, the upper postca¬

nines are proportionally much wider than in

IRSNB 28114/113. The iransverse ridge connec¬

ting the labial and the lingual cusps is set behind

the middle of the crown and the anterior basin is

somewhat larger than the postetior one.

Contrary to IRSNB 28114/113> the lingual cusp

is much higher than the labial one and clierc is

neither central cusp nor accessory cusp.

Gomphodontosuchus von Huene, 1928

(Upper Triassic of Brazil)

In this genus> the transversc ridge connecting the

lingual and rhe labial main cusps forms the pos-

terior wall of the crown and is devoid of central

cusp. A labial and a lingual accessory cusps are

set on the anterior margin of the crown and

connected to the corresponding main cusp by a

low ridge. The labial cusps are clcarly set more

anteriorly than the lingual ones. The anterior

basin surrounded by these four cusps is particu-

larly enlarged, but not very deep.

Exaeretodon Cabrera, 1943

(Upper Triassic of Argentina, Brazil and India)

Ischignathiis Bonaparte, 1963

(Upper Triassic of Argentina)

The upper postcanincs of these large Traverso-

dontidac are formed by two main cusps connec¬

ted by a low posrerior transverse ridge, concave

posteriorly and oblique. The main labial cusp is

set much more anteriorly than the main lingual

cusp. An accessory lingual cusp is set in iront of

the main lingual cusp. An accessory labiiil cusp

forms an anterior lobe accommodaied in the

posterior concavity of the anterior adjacent

tooth. Theretore, the crown of the upper postca¬

nines bas, in ocdusal view, a characteristic geni-

culate outline. An accessory posterior cusp can

occasionally be dcvelopcd. The central cusp is

apparently absent. The anterior basin is more or

less enlarged in the different species.

Arctotniversodon Sues, Hopson et Shubin, 1992

(Upper Triassic of Canada)

The upper posreanines of this large Traverso-

dontidae arc very large and very compressed

mesiü-distally. The transverse iidge connecting

the labial and the lingual cusps forms the poste¬

rior wall of the crown and supports a prominent

central cusp. Ir is close to the lingual cusp and

sepaxated froni the labial cusp by a deep embay-

ment. There is no anterior accessory cusp. The

anterior cingulum is well developed.

Microscalenodon Hahn, Lepage Wouters, 1988

(Upper Triassic of Belgium)

The upper postcaaines of Micmcalenodon are. as

IRSNB R172, very small. rhe crown is vety

compressed mesio-di.stally mà its morphology is

quite simple; a large lingual cusp and a small

labial cusp are connected by a transversc ridge

forming the posterior wall of the crown, without

central cusp, accessory cusp and anterior cingu¬

lum.

Boreogomphodon Sues erOlsen, 1990

(Upper Triassic of the USA)

The upper postcanincs of this genus closely

resemhie IRSNB RI 72 They are very small, less

than 5 mm wide. The labial side is longer and

less convex than the lingual one. The transverse

ridge, set behind rhe middle of rhe crown, sup¬

ports a well developed central cusp. A large

antero-labial accessory cusp is connected to the

main labial cusp by a prominent ridge. The ante¬

rior ridge ("anterior cingulum") connecting the

accessory labial cusp to the lingual cusp is very

low and poorly developed. Neverthelcss, they

difïer in severaJ details. The crown is proportio¬

nally wider in Boreogomphodtm, The transverse

ridge is set more posteriorly and the po.sterior

basin is consequently lost. The central cusp is

close CO the lingual cusp and separaicd from the

labial cusp by a deep embayment.

brom these dctailed comparisons with the upper

postcanines in the different généra of

Traversodontidac, it appears that IRSNB RI 72

shows an original set of morphological characters

608

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

justifying its attribution to a separate new genus:

— The Crown is ovoid in occlusal view and not

very compresscd mesio-distally.

— The tranüverse ridge is set behind the middie of

the Crown, but does not participate in the poste-

rior Wall of the crown. The anterior basin is lar-

ger than the posterior basin.

— The transverse ridge supports a wcll developed

central cusp» close to the labial cusp and separa-

ted froni the lingual cusp by a deep embayment.

— The antero-labial accessory cusp is parcicularly

well developed and connected to the main labial

cusp by a prominent ridge.

— The tooth is very small.

In the structure of its upper postcanines, Mau-

beugia more closely resembles Scalenodon and

Eoreogomphodon than any other taxon. Figure 26

illustrâtes the possible phylogenetic relationships

between the different généra of Traversodonti-

dae. Although discovered in Late Triassic out-

crops, Maubetigia looks, in the structure of its

upper postcanines, rather “primitive”. This cia-

dogram, modified from Bartail (1989, fig. 128),

only reflects the modifications in the structure of

the upper postcanines and is, therefore, very res¬

trictive. A more definitive assessment oi the phy-

logeny of the Traversodontidae must await an

analysis of the whole skeleton in these gompho-

dont cynodonts.

Genus Roseria n.g.

Type SPECIES. — Rosieria debatei n.sp.

DerivaTIÜ NOMINIS. — From the type locality

Rosières-a ux-Salines.

DiagnoSIS. — As for the only currently recognized

species Rosieria debatei n.sp.

Discussion

See under Rosieria debatei n.sp.

Microscalenodon

Fig 26. — Possible phylogeny of ihe Traversodoniidae. foUowing lhe modifications of the structure of their upper postcanines (after

Battail 1989. modified). 1. upper postcanines mainly tormed by orie main lingual cusp and one main labial cusp. connected togelher

by a transverse ridge; presence of cingula in front of and behind lhe fransverse ridge; presence of one postero-labial accessory

cusp. 2. disparition of the postero-labiat accessory cusp. fransverse ridge set behind the middie of lhe crown. 3. formation of a basin

in front of the fransverse ridge; apparilion of one anlero-labial accessory cusp. 4. central cusp connected to the main labial cusp.

5. central cusp connected to the lingual cusp. 6. transverse ridge merging with the posterior cingulum. 7, antero-labiaf accessory

cusp dispiaced medially. 8, upper postpgnines very compressed mesio-disially 9. development of a central basin; apparition of one

antero-lingual accessory cusp. 10, transverse ridge concave backwards; geniculate outline of the upper postcanines.

GEODIVERSITAS - 1997 • 19(3)

609

Godefroit P. & Battaîl B.

Rosieria dekatei n.sp,

(Figs 27, 28)

Holotyi'E. — IRSNB RI 73, an upper lefr post¬

canine, root not preserved.

DerivatIO NOMINIS. — Dedicaccd in honour to

Dr. D. Dcisatc, for his active palaeontological

field-work in Lorraine and adjacent areas.

Locus 'HTICUS. — Quarry at Rosières-aux-Salines,

région of Sainc-Nicolas-de-Port (Meurthc-et-Moselle,

France).

Stratum TVPICUM. — “Rhaetian” sandstones. Upper

Triassic.

Diagnosis. — Traversodontidac known by onc upper

postcanine tooth, with the following characters:

Crown very small (width * L22 mm) with a subrec-

tangular outlinc, in occlusal view (ratio

“Icngth/width” of the crown = 2.2); labial side straight

and lingual sidc convex. Main lingual cusp much

higher tnan the labial one. Lransverse ridge set behind

the middie of the truwn: it ducs noi participaie in the

pcisterior wall of the crown; anterior b;tsin conse-

qucntly inuch larger ihan rhe posterior basin. No cen¬

tral cu.sp on the rransverse ridge. Smail anteto-labial

accessory cusp conncctcd to the main labial cusp by a

prc»mincnt ridge. Both anterior and posterior cingula

not dcveloped.

Description

Orientation

The orientation of IRSNB R173 proposed here

is mainly based on the presence of an accessory

cusp, assumed to be set in antcro-labial position,

as in rhe advaneed Traversodontidac (see Battail

1989, fig. 123). If this orientation i.s correct, the

lingual side of the crown is more convex than the

labial one, as in most Traversodonridae, and the

lingual cusp is clearly higher than the labial one,

as iiî Traversodon von Huene, 1936, Scalenodon

angustifrons (Farrington, 1946), or Micro-

scalenodon Hahn, Lepage et Wouters, 1988.

Fig. 27. — IRSNB RI 73, left upper postcanine of Rosieria delsatei, from the Late Triassic of Saint-Nicolas-de-Port. A, stereophoto-

graphs, occlusal view: B, labial view; C, anterior view; D, posterior view; E, lingual view. Scale bar: 1 mm.

610

GEODIVERSITAS • 1997 • 19 (3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

Moreover, the transverse ridge is set behind the

middle parc of the crown, as in ail advanced

Traversodontidae. Thus, IRSNB R173 is a left

upper postcaninc.

Measurements

Length of the crown = 0.55 mm; width of the

crown = 1.22 mm.

Crown

The crown of IRSNB R173 is very small. In

occlusal view, it is elongaced (ratio

“length/widch” of the crown = 0-45) and subrec-

tangular in outline. The labial border is nearly

straight, whereas the lingual border is very

convex. Both the anterior and posterior borders

are slighrly concave and nearly parallel. The

crown is formed by two main cusps connected

by a cutting transverse ridge. The main lingual

cusp is much larger rhan the labial one. The

transverse ridge is set behind the middle of the

crown and does not support any central cusp.

This ridge delimics a large anterior basin and a

small posterior basin. A small anccro-labiaJ cusp

is connected to the main labial cusp.

In labial view, the main and the accessory labial

cusps are connected by a high ridge: their limit is

not clear. The main labial cusp is clearly highcr

than the accessory one. Their apex is very roun-

ded.

In lingual view, the lingual cusp has a piriform

outline. Its base is very broad and both its ante¬

rior and posterior borders are sigmoid. Its apex is

rounded.

In anterior view, both the labial and lingual bor¬

ders ot the crown are very convex. The lingual

cusp is much wider and higher than the main

labial cusp. The transverse ridge connecting thèse

cusps is very high and its anterior wall is not as

vertical as the posterior one- The anterior basin is

not limited by an anterior cingulum.

In posterior view, the posterior wall of the trans-

Fig. 28. — IRSNB R173, left upper postcanine of Rosieria delsatei, from the Late Triassic of Saint-Nicolas-de-Port. A, occlusal view;

B, labial view; C. lingual view; D, anterior view; E. posterior view, ab, anterior basin; al, antero-labiai cusp; L, lingual cusp; ml, main

labial cusp: pb. posterior basin: tr, transverse ridge. Scale bar: 1 mm.

611 I

GEODIVERSITAS • 1997 • 19(3}

Godefroit P. & Battail B.

verse ridge connecting the lingual and che main

labial cusps is ncarly vertical. The posterlor

basin, very poorly developed, forms a small

dépréssion at the level of the junccion benveen

the lingual and the labial cusps; it is not limited

posteriorly by a posterior cingulum. A constne-

tion delimits the crown and the root.

Root

The root is not preserved in IRSNB R173.

Discussion

IRSNB RI73 differs from IRSNB R172, referred

to the new spccies Maubeugia totharingica, in its

propordonally wïder outline, in its lingual cusp

much higher than its main labial cusp and in lack-

ing a central cusp. Moreover, the antero-labial

accessory cusp is clearly less developed than in

the larter; however, the development of tliis cusp

is highly variable in the tooth row of the

Traversodontidae (see Crompton 1972).

Ir resembles IRSNB R406, discovered in rhe

Rhaetian of Habay-la-Vicille and referred to

Mtcroscalmodon nanm Hahn, Lepage r’r Wouters,

1988, in its small she, in its propordonally wide

Crown, in its lingual cusp much higher than its

labial cusp and in lacking a central cusp, It dif-

fers from the latter in retaîning a small posterior

basin and an antero-labial accessory cusp.

IRSNB RI73 resembles rhe upper postcanine

teerh o{ Scalenodon angustifrorn (Farrington,

1946), from the Middle Triassic of Tanzania, in

the elongated oudine of its crown, in its lingual

cusp clearly higher than its labial one, in the pré¬

sence of an antero-labial accessory cusp, in its

transverse ridge set posteriorly, behind the mid¬

dle of the crown, and in retainmg a small poste¬

rior basin. It diflers, however, from die latter in

its smaller .size and in lacking a central cusp as

well as a dngulum.

The new tooth from Saint-Nicolas-de-Port

resembles rhe upper postcanines of Traxtersodon

von Huene, 1936 m its lingual cusp much higher

than its labial cusp, in the absence of accessory

cusp and in the presence of a posterior basin dis-

tinedy smaller than the anterior one. It differs in

its smaller size and in the presence of a well deve¬

loped antero-labial accessory cusp, absent in

Traversodon. Moreover, the transverse ridge seems

set more posteriorly in IRSNB R173-

Contrary to the upper postcanine reeth of

Massetogtmthus Romer, 1967, Gomphodonto-

suchusvoïi Huene, 1928, Isdngnathus Bonaparte,

1963, Exaeretodon Cabrera, 1943, Boreogompho'

don Sues er Olscn, 1990 and An totraversodon

Sues, Hopson ef Shubin, 1992, the transverse

ridge of IRSNB RI73 does not form chc poste¬

rior wall of the crown and the anterior basin is

conscquently less cniarged than in the former

genem.

In conclasion, the crown of IRSNB R173 pré¬

sents an original set of characters justifying its

attribution to a new genus of Traversodontidae;

Rosieria, Figure 26 shows ihat the upper postca-

nines oi Roseria can easily be derived from those

of Traversodon by simple addition of an antero-

labial accessory cusp and by slight backwards

movemenr of lhe transvcr.se ridge. In the .sarne

way, the postcanine teeih of Scalenodon and

Muubeu^a can bc derived from chose of Rosterla,

by doubling of the lingual or the labial cusp, res-

pectively.

Genus aff. Roseria

(Figs 29, 30)

MatERIAL EXAMINED. — Specimen discovered in

Saint-Nicolas-de-Port: IRSNB R174, a left upper

postcanine.

Description

Orientation

As in IRSNB R173.

Measurements

Lengch of che crown = 0.65 mm; width of the

crown = 1.05 mm.

Crown

In occlusal view, the crown is very elongated

lahio-lingually (ratio “Icngth/width” of the

cTow = 0.62) and subelliptical in outline. The

lingual border is more convex than the labial one

and lhe anterior border, much more convex than

the posterior one: lhe latter is nearly pcrfectly

straight. The crown is formed by iwo cusps

612

GEODlVERSITAS * 1997 • 19 (3)

Late Triassic cynodoncs from Saint-Nicolas-de-Pon

connected together by a rransverse ridge. The

lingual cusp is much larger rhan thc labial one.

The tranüverse ridge is rclativcly low, in the

middle of che crown. It is sec bchind thc middle

of the crown and does not support any central

cusp. This transverse ridge delimirs a small posre-

rior basin and a larger anterior basin. The poste-

rior basin is limitcd posteriorly by a low, poorly

developed and straight posterior cingulum. The

anterior cingulum limiting the anterior basin is

very poorly expressed, too, but very convex.

There is no evidence of an accessory cusp.

In lingual view, the lingual cusp bas a pinform

outline: its base is broad and its apex rounded.

Its anterior border is slightly concave, but its pos¬

terior border is nearly straight. There is no clear

constriction between thc crown and che root.

In labial view, the labial cusp has a triangular

outline: borh its anterior and posterior borders

are nearly srraighe Its posterior border is more

oblique than its anterior border. Its apex is rather

rounded.

In anterior view, the lingual cusp is much wider

and somewhat higher than the labial one. The

Fig. 29. — IRSNB R174, left upper postcanine of aff. Rosieria, from the Late Triassic of Saint-Nicolas-de-Port. A, occlusal view; B,

labial view; C, lingual view; D. anterior view; E, posterior view. Scale bar: 1 mm.

GEODIVERSITAS • 1997 • 19(3)

613

Godefroit P. & Battail B.

transverse ridge lorms a deep notch, ar thc level DISCUSSION

of the junction bccween these cusps. ~1 he slope of [RSNB R174 is reminiscent of IRSNB RI 73,

the anterîor wall of the transverse ridge is not refeired to the newly defmcd spccies Rosieria del-

very marked. The antei ior cingulum is very low. satei^ in its small and elongated crown, in its lin-

In posterior view, the posterior basin looks very gual cusp larger and higher than its labial one, in

small. The posterior wall of the transverse ridge its transveise ridge set behind the middie of the

is more vertical than the anterior one. The poste- crnwn, without central cusp, and in the rétention

rior cingulum is very short and very low. of a small posterior basin. It differs mainly in the

absence ol a small antcro-labial accessor)' cusp. In

Root this character, it rather resembles Tntversodon.

The root of IRSNB RI 74 is robust, but very ero- However, the absence of this accessory cusp on an

ded. It was at least 1.5 times as high as the isolatcd tooth is, in advanced Traversodonridae, a

Crown. In lingual view, it has a semielliptical ouc- négative character without acrual phylogenecical

line. Its vertical axis is oblique, set at an angle of significance. In Scalenodan, for cxample, the deve-

abour 30® with the vertical axis of the crown. Its lopmenr of the anterior accessory cusps and of

anterior side is more convex than its posterior the cingula is variable wîthin the dental row of a

one. In anterior view, the root has a triangular same animal (see Crompton 1972). For this rca-

outline. Both its labial and lingual sides are son, it cannot be excluded thaï IRSNB R174

slightiy convex. T he lingual side is longer than bclongs to the same spccies or, at least, to che

the labial one. 1 he dp of the root is very roun- same genus as IRSNB RI73. That is the reason

ded and set at the level of the junction berween why the former postcanine is provisionally refer-

the cusps of the crown. red to alF. Rosiena^ waîting for further evidence.

Fig. 30. — IRSNB R174, left upper postcanine of aff. Rosieria, from the Late Triassic of Saint-Nicolas*de-Port. A, occlusal view; B,

labial view; C, lingual view; 0, anterior view; E, posterior view, ab, anterior basin; L, lingual cusp; I, labial cusp; pb. posterior basin;

tr, transverse ridge. Scale bar: 1 mm.

I 614

GEODIVERSITAS • 1997 • 19(3}

Late Triassic cynodoncs from Saint-Nicolas-de-Port

Gcnus aff. Microscalenodon

(Figs 31, 32)

MaTERIAL EXAMINED, — Specimen discovered in

Saint-Nicolas-de-Porr: IRSNB R175, a left upper

postcanine.

Description

Orientation

See Hahn, Lepage & Wouters 1988.

Measurements

Length of the crown: 0.58 mm; width of the

Crown: 1.15 mm.

Crown

In occlusal view, the crown is proportlonally very

wide (ratio “lengrh/width” of the crown = 0.5)

and subrectangular in outline. The labial border

is shorrer and more convex than the lingual one,

which is an unusual character in the

Traversodontidae. The posterior border is perfect-

ly straight and the anterior border, somewhat

convex. The morphology of the crown is quite

simple: two cusps connected together by very

poorly devcloped anterior and posterior ridges

(“cingula*'). ‘ITie lingual cusp is by far the largest;

the labial cusp is very short antero-posteriorly,

but rather elongated labio-lîngually. The ridges

delimit a large central basin. Therc is no évi¬

dence of a trnnsversc ridge: it is merged probably

with the posterior ridge, forming the posterior

wall of the crown. Therc is neither central nor

accessory cusps.

In lingual view, the lingual cusp is not very high

and has a piriform outline: its base is large

antero-posterioly and its apex Ls very rounded.

In labial view, the labial cusp is very low and tri-

angular in outline. It clearly slopes towards the

anterior side. 1rs apex is rounded, too.

In anterior view, the lingual cusp is distinctly

higher than the labial cusp. The anterior ridge is

nearly non-existent. The central basin gently

slopes Irom the posterior wall to the anterior

base ot the crown.

In posterior view, the posterior ridge is clearly

higher than the anterior one and forms the pos¬

terior wall of the crown.

Fig. 31. — IRSNB RI 75. left upper postcanine of aff. Microscalenodon. from the Late Triassic of Saint-Nicolas-de-Port. A, occlusal

view; B, labial view; C. lingual view; D, anterior view; E. posterior view. Scale bar: 1 mm.

GEODIVERSITAS - 1997 • 19(3)

615

Godefroit P. & Battail B.

Fig. 32. — IRSNB R175, left upper postcanine of aff. Microscalenodon, from the Late Triassic of Saint-Nicolas*de-Port. A, occlusal

view: B, labial view; C, lingual view; D. anterior view; E, posterior view. cb. central basin; L, lingual cusp; I. labial cusp. Scale bar:

1 mm.

Root

The root is not preserved in this specimen.

Discussion

IRSNB RI75 resembles Microscalenodon nanus

Hahn, Lepage et Wouters, 1988 in the quite

simple structure of its crown, wichout transverse

ridge, central and accessory cusps. Moreover. the

anterior and the posterior sides of the crown are

nearly parallel, the lingual cusp is very rounded

and the central basin genily slopes froni the pos¬

terior wall to the anterior base of the crown. It

differs from IRSNB R406. che holotype and only

upper postcanine currcntly referred to

Microscalenodon nanus, in irs crown proportion-

ally lower, in its labial cusp less developed and in

lacking an extended wear facer on its occlusal

side. In the current State of our knowledge, for

wanr of material, we cannot form a correct esti-

mare of the dental variation wirhin the species

Microscalenodon nanus. That is the reason why

IRSNB R175 is tentatively referred to aff. Micro¬

scalenodon.

Family TraversODONTIDAE, gen. and sp. indet.

(Figs 33, 34)

Material examined. — Specimen discovered in

Saint-Nicolas-de-Pori: IRSNB R176, a left lower

postcanine.

Description

Orientation

In the Traversodontidae, the lower postcanines

are formed by a transverse ridge supporting two

main cusps on the anterior half of the crown and

by a low basin on the posterior half of the crown.

The labial main cusp is usually higher than the

lingual one.

Measurements

Lcngth of the crown = 1.32 mm; width of the

crown =1.13 mm.

Crown

In occlusal view, the crown has a subtrapezoidal

outline. It is proportionally longer than wide: the

616

GEODiVERSiTAS » 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

ratio "Icrigth/width’’ of the crown = 1.17. The

posterior half of the labial border and the poste-

rior border are very convex. The lingual border is

nearly perfeccly straight. The ancerior border is

slightly concave and very oblique. The ancerior

half of the crown is formed by two large cusps

connected together by an ancerior transverse

ridge. The labial cusp Is much longer (mesîo-

distally), but somewhat less wide (labio-lingually)

than the lingual cusp, In front of the transverse

ridge, the labial cusp beats a poorly developed

swelling. A tiny ancerior dépréssion is limited by

the ancerior wall of the transverse ridge and by

the lingual side of the ancerior swelling of the

labial cusp. The posterior half of the crown

forms a talon, noi very large and dlstincdy narro-

wer than the ancerior part of the crown. The pos¬

terior talon forms a central valley elongated

ancero-poscerîorly and surrounded by a ridge

which bears a broad lingual acccssory cusp,

adjoining che main lingual cusp.

In ancerior view, the crown has a bell-shaped

oücline. The labial cusp is distmcrly higher than

the lingual cusp. The cransverse ridge connecting

rhese cusps is not very high. The ancerior déprés¬

sion has a triangular outline. The crown and the

root are separared by a well marked constriction.

In posterior view, the central valley of the poste-

Fig. 33. — IRSNB R176. left lower postcanine of Traversodontidae indet., from the Late Triassic of Saint-Nicolas-de-Port. A, stereo-

photographs, occlusal view; B, labial view; C, lingual view; D, anterior view; E, posterior view. Scate bar: 1 mm.

617 I

GEODIVERSITAS • 1997 • 19(3)

Godefroit P. & Battail B.

rior talon gently slopes from the transverse ridge

to the posrerior wall oi the crown. The posterior

portion of the ridge surrounding the valley is

particularly low.

In labial view, the large labial cusp bas a triangu-

lar outline. It is broader than high. Its anterior

border is convex; its posterior border is shorter

and straight. Therefore, this cusp somewhat

slopes bacicwards. Its apex is vcry eroded. The

lingual part of the talon looks proportionally

very short. The crown is separated trom the root

by a well marked constriction, as in anterior

view.

In lingual view, the main and the accessory lin¬

gual cusps are so closely united and their apex are

so eroded that they form a quasi-continuous and

straight ridge which slopes obliquely downwards

from the main to the accessory cusp. The anterior

swelling of the labial cusp lies in front of the level

of the anterior border of the main lingual cusp.

Root

The tip of the root is broken. At the level of the

fracture, the root has, in basal view, an ovoid

outline. Its anterior border is shorter, but more

convex than its posterior border; its lingual bor¬

der is more convex than its labial border. The

pulpal canal is very small and rounded.

Discussion

IRSNB R176 has the rypical traversodont pat¬

tern of a transverse ridge supporting two main

cusps on ihe anterior half of the crown and a

narrower talon on its posterior half. If the upper

postcanines are very variable and, thus, phylo-

genctically useful in the Traversodontidae, rhe

lower postcanines are much more constant and

less diagnostical.

The lower postcanines of the primitive

Traversodontidae Pascualgnathus Bonaparte,

1966 Andescynodon^ Bonaparte, 1969 differ

Fig. 34. — IRSNB R176, left lower postcanine of Traversodontidae ind., from the Laie Triassic of Saint>Nicolas-de-Port. A, occlusal

view; B, labial view; C, lingual view; D, anterior view; E, posterior view, ad, anterior dépréssion; aL, accessory lingual cusp; I, labial

cusp; mL, main lingual cusp; ta, talonid; tr, transverse ridge. Scale bar: 1 mm.

I 618

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

froxn IRSNB R176 in rhe présence of a posrero-

labial accessory cusp, connectée! to che main

labial cusp by a low ndge, and in the lack of a

postero-lingual accessory cusp on the talon of

their crown. Moreover, the posterior basin îs

more enlaiged ihan in the lancr. There is no

trace of anicrlor .welling on the ancerior side of

the main labial cusp.

In the lower postcanincs of Scalenodon

Crompton, 195^, a small accessory cusp» équiva¬

lent to the anrerior swelling of the labial cusp

übserved in IRSNB RI76, is developed on the

antero-labial side of the crown. However, a pos¬

terior accessory cusp is présent on the labial side

of the talon, rather than on the lingual side. as in

IRSNB R176, Moreover, the posterior basin is

more enlarged than in the larter.

In Massetognathus Romer, 1967, the posterior

talon is lowcr and its basin is more enlarged than

In IRSNB R176. Both the labial and lingual

ridges of ihc talon are crenulated, but there is

neither well developed posterior accessory cusp

nor anterior swelling of rhe labial cusp.

The lower postcanincs of Gomphodontosuchus

von Huene, 1928, Exaaetodon Cabrera, 1943,

Ischîgnathus Bonaparte, 1963 and Scalenodon^

toides Crompton et Ellenberger, 1957 dlffer from

IRSNB R176 in possessing the following derived

characters;

— The lingual cusp is distinctly inclined oblique-

ly backwards.

— The labial cusp is broader than the lingual

cusp.

— Excepr in hchigtiathusy the labial cusp is set

anteriorly with respect to the lingual cusp.

— There are two accessory cusps: a postero-

lingual one and a postero-labial one.

The lower postcanine referred to Microscalenodon

nantis Hahn, Lepage Wouters, 1988 resembles

IRSNB RI76 in its very small s\it and in the

proportion.^ of its main cusps. Nevertheless, an

accessory cusp is developed on the postero-labial

side of the crown, the talon and the posterior

basin are distinctly more developed and the labial

cusp does noc beat any anterior swelling.

From these comparisons with the lower post-

canines in the different généra of Traversodonti-

dae, it can be concKided that IRSNB R176 shows

an original set of morphological characters:

— The antero-labial cusp is longer (mesio-distal-

ly) but less wide (labio-lingually) than the antero-

lingual cusp.

— The antero-labial cusp supports an anterior

swelling.

— There is a broad postero-lingual accessory cusp.

— The talon is noc very enlarged: it forms a cen¬

tral valle}’^ elongated antero-posteriorly.

— The tooth is very small.

In che absence of more complété material, corres-

pondences with che généra Maubeugia and

Rosieriay defincd on isolated upper postcanines

from che same locality, are impos.sible to esra-

blish. That is the reason why IRSNB R176 is

referred to Traversodontidae indet.

Family aff. TRAVERSODONTIDAE,

gen. and sp. indec.

(Figs 35, 36)

Material examined. — Specimen discovered in

Saiiit-Nicolas-de-Port: IRSNB RI77-

Description

Orientation

IRSNB R177 shows morphological affinities

with the upper postcanines of the Traverso¬

dontidae (see discussion). The marked slope of

the main cusps permits to distinguish the ante¬

rior and posterior sides of the crown. If the inter¬

prétation proposed here is correct, the small

accessory cusp would be set on the antero-labial

border of the crown, as in advanced

Traversodontidae. Therefbrc, it is identified as a

righr upper postcanine.

Measurements

Length of the crown = 1.39 mm; width of the

crown = 1.5 mm.

Crown

In occlusal view, the crown of IRSNB RI 77 is

subtrapezoidal and very elongated antero-poste¬

riorly: the ratio “length/width” of the crown is

0.93. The lingual border is long and very convex;

GEODIVERSITAS • 1997 • 19(3)

619

Godefroic P. & Battail B.

the labial one is sborter and slighrly concave. Borh

the antcrior and postcrior bordcrs are nearly

straight and oblique: the postcrior border is longer

than the anterior one. The crown is divided lato

rwo parts by an antero-posteriot furrow. The lin¬

gual part is the widest and Js fully covered by a

very large lingual cusp. The labial side of the

crown is tormed by two labial cusps. TWe postcrior

labial cusp is the largest: it is connected to the

apex of the labial cusp by a rransversc ridgC:. set

behind the rniddlc of the crown. The antero-labial

accessory cusp is connected to the main labial

cusp by a small ndge and connected to the lingual

one by a poorly devcloped anterior dngulum. The

transverse ridge, connecting the lingual and the

main labial cusps, delimics an anterior and a pos-

terior valley. The anterior valley is surrounded by

the antero-labiaJ side ol rhe lingual cusp, the

anterior Wall of the Transverse ridge, the antero-

lingual side of the main labial cusp. the lingual

side of the accessory labial cusp and the postcrior

Wall of the anterior cingulum. The postcrior val¬

ley is disrinerly smailcr than the anterior one: ir is

limited by the postero-labial side of the lingual

cusp, the postcrior wall of the transverse ridge and

the postero'lingual side of rhe main labial cusp.

Therc is no évidence of a postcrior cingulum.

In anterior view, rhe lingual cusp is by far the

highest: the main labial cusp reaches the half of

its heighf and the accessory labial cusp, the îhird

of the main labial cusp. Borh the lingual and che

main labial cusps are somtfwhar inclincd Tuwards

the labial side of the crown. The transverse ridge

is deepiy notched b)' the antero-posrerinr furrow.

The anterior cingulum is very low and is al.so not¬

ched by the antero-posterior furrow. d’he posccro-

lingual side of the main labial cusp is less vertical

than the antero-labial side of the lingual cusp.

In postcrior view, the postero-labial side of the

main cusp is nearly perfecily verncal; che poste-

ro-lingual side of che main labial cusp is more

oblique. The postcrior valley is opened posterior-

ly: it is noi limited by a poscerior cingulum. The

poscerior ridge of the lingual cosp is well inarked.

In lingual view, rhe lingual cusp ns subrriangular

in outlinc and clearly inclined baclcwards. The

anterior border is oblique, forming an angle of

about 45‘’ with the base of the crown, and

somewhat convex. The postcrior border is shor-

ler, more vertical and very slightly concave. The

apex of the cusp is very rounded.

In labial view, the main labial cusp has almost

Fig. 35. — IRSNB R177, right upper postcanine of ? Traversodontidae indet., from the Late Triassic of Saint-Nicolas-de-Port. A,

occlusal view; B, labial view; C, lingual view; D, anterior view; E, posterior view. Scaie bar: 1 mm.

620

GEODIVERSITAS • 1997 • 19(3}

Late Triassic cynodonts from Saint-Nicolas-de-Port

the same ourline as che lingual cusp. le is inclined

backwards and iis apex is rounded too. The

acceSvSory labial cusp, very low, is placed against

it: rhe ridge connecting the two labial cusps is

low and poorly dcveloped.

Root.

The root is not preserved in IRSNB RI77.

Discussion

IRSNB R177 is undoubtedly reminiscent of the

upper postcanine teeth of rhe advanced

Traversodontidae in rhe general organisation of

its Crown. A large lingual cusp is connecied to

the main accessory cusp by a transverse ridge set

behind the middle of the crown and delimiting

an anterior and a smaller posterior valley. An

accessory cusp is set in front of ihe main labial

cusp and the anterior valley is closcd by an ante¬

rior cingulum. The organisation of chc cusps Is

similar to IRSNB R174, referred to ihe newly

defined genus Ro:^ieria. Ncvertheless, it differs

from the upper postcanines of ail currently

known Traversodontidae in being longer (mesio-

distally) than wide (labio-lingually).

In its proportions, IRSNB RI77 more closely

resembles the lower postcanines of the

Traversodontidae. Nevertheless, its morphologi-

cal organization is quitc different. The lower

postcanincs of the Traversodontidae arc rather

constant indeed (sec Battail 1989): a high trans¬

verse ridge supports two cusps on the anterior

half of the crown and a low basin forms the pos¬

terior half. An accessory cusp is usually présent

on the posiero-labial portion of the crown.

In certain respeas, IRSNB R177 is reminiscent

of the postcanine of the Har-imiyidac. This

group, oiily known by isolated teeth» is very

abundant in Saint-Nicolas-de-Porc (Sigogneau-

Russcll 1989, 1990). The Haramiyidae are centa-

rively idencified as primitive allotherian

mammals (see Buder & Macintyre 1994 for an

extended discussion of Haramiyidae affinities).

As in IRSNB Rl77, the dental crowns of the

Haramiyidae are elongated antero-posteriorly

and they are divided into two rows of cusps by a

deep ancero-posterior furrow. However, the

“accessory cusps” are more numerous on the

anterior part of the lower postcanines and on the

posterior parc of the upper ones. Moreover» the

posterior slope of the dominacing cusps is never

as marked as in IRSNB R177.

Fig. 36. — IRSNB RI 77. right upper postcanine of ? Traversodontidae indet., from the Late Triassic of Saint-Nicolas-de-Port.

A, occlusal view; B, labial view; C, lingual view; D, anterior view; E, posterior view, ab, anterior basin; al, antero-labial cusp; L, lin¬

gual cusp; ml, main labial cusp; pb, posterior basin; tr, transverse ridge. Scale bar; 1 mm.

GEODIVERSITAS • 1997 • 19(3)

621

Godefroit P. & Battail B.

It can be concluded that ÏRSNB R177 mosf cio-

sely resemble.s the upper postcanines of rhe

Traversodonüdae: the general organiz;iriün of the

cusps is similar to the new dcPined gcnus

Rosieria. Becau.se of îts very unusual proportions,

it is caurioiisly referred to familîn aff. Travcrso-

dontidae, waiting for rhe discovery of more com¬

plété material.

PALAEOBIOGEOGRAPHY OF LATE TRIAS-

SIC AND EARLY JURASSIC CYNODONTS

FoSSn. LOCAIJTIES AND HORIZONS

Table 9 givcs a synihetic corrélation, niodified

from Lucas & Hunt (1994)^ of Lace Triassic and

Earlyjurassic formations discussed in ihe text.

Ischigualasto Formation

(San Juan Province, Argentina)

Age. Latc Carnian (Hunt 1991; Hunt & Lucas

1991). Eaxiy to Lace Carnian (Battail 1993).

Taxa discovered. Traversodoniidac: Exaeretodon

frenguelli Cabrera, 1943; Exaeretodon vincei

(Bonaparte, 1963); hchignathus sudamerkanus

(Bonaparte, 1963).

Chiniquodontidae: Chiniquodon theotonicus

von Huene. 1936.

Upper part of the Los Colorados Formation

(La Rioja Province, Argentina)

Age. Late Norian (Bonaparte 1972; Lucas &

Hunt 1994),

Taxa discovered, Tritheledontidae: Chaliminia

Bonaparte, 1978,

Remark. Bf»naparte (1972) îdentified postcranial

bones as cf. Tritylodon, Lucas & Hunt (1994)

suspect tliat theypçrcain to Chaliminia.

Upper Santa Maria Formation

(Rio Grande do Sul, Brazil)

Age. Latc Carnian (Hunt 1991; Hunt & Lucas

1991). Early Carnian (Battail 1993).

Taxa discovered. Traversodontidae; Traversodon

stahleckeri yon HuenC;, 1936; Gomphodontosuchns

hrasiliensis von Huene, 1928; Exaeretodon fren-

Cabrera, 1943.

Dromacheriidae: Therioherpeton cargnini

Bonaparte et Barbcrena, 1975.

Chiniquodontidae: Chiniquodon theotonicus

von Huene, 1936; Belesodon magnificus

von Huene, 1936.

Loiver Elliot Formation

(Morobong Hill, Lesotho)

Age. Late Carnian or Early Norian (Hopson

1984).

Taxon discovered. Traversodontidae: ScalenO'

dontoides macrodontes Crompton et Ellenberger,

1957.

Upper Elliot and Clarens Formations

(South Africa and Lesotho)

Age. Hectangian to Sinemurian (Olsen & Galton

1984).

Taxa discovered. Tritheledontidae; Pachygenelus

montis Watson, 1913: Diarthrognathus hroomi

Crompton, 1958; Tritheledon riconoi Broom,

1912.

Tritylodontidae: Tritylodon longaevus Owen,

1884 (rcmwSues )986h).

Remark. Pattsta likhoelensis Lees et Mills, 1983,

from Lesotho, is certainly a Tritheledontidae,

possibly a synonyni of Pachygenelus monus

(Lucas & Hunt 1994).

Maleri Fortnatinn

(Andhra Pradesh, India)

Age. Late Carnian (Hopson 1984; Battail 1991).

Taxon discovered. Traversodontidae: Exaere-

todon staffsticae Chauerjecy 1982.

Remark. Battail (1991) considers that Exaere¬

todon statisticae might be a junior synonym of

Exaeretodon frenguelli.

Bull Canyon Formation

(Eastetn Nevv Mexico, USA)

Age. Early to Middic Norian (Lucas & Hunt

1994, fig. 20.5).

Taxon discovered. Dromatheriidae; Pseudotri-

conodon chatteijeei Lucas «tOakes, 1988.

Remark. The identification of ihis taxon as a

cynodont has been questioned by Sues & Olsen

(1990), but without justification.

Kayt»tta Formation

(Nortb-eastern Arizona, USA)

Age. Late Sinemurian - Early Pliensbachian

622

GEODIVERSITAS • 1997 • 19 (3)

GEODIVERSITAS - 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-l

Godefroit P. & Banaü B.

(Peterson & Pipiringos 1979; Clark & Fastovsky

1986; Sues 1986b).

Taxa dîscovered. Tritylodontidae; Kayentathe-

ritim wtllesi Kêrrnack* 1982; Qligokyphtts sp.;

Dinnebu<fdon amarûli Sues, 1986; Nearctylodon

broomi Lewis, 1986.

La Boca Formation

(Tamaulipas, north-eastern Mexico)

Age. ? Early Jurassic (Clark et ai 1991, 1994).

New radiomctric datas indicate rhat rhis forma¬

tion would be Middie Jurassic in âge (Luo,

pers. comm.).

Taxon dîscovered. Tritylodontidae: Bocatherium

mexicanum Clark et I lopson, 1985.

Navajo Satidstones

(Arizona, USA)

Age. Pliensbachian (Marzolf 1990).

Taxon dîscovered. Tritylodontidae: Tritylo-

dontid indet. (Winklcr er æ/. 1991).

Turkey Brançh Formation

(Richmond Basin>Virginia, U.S.A.)

Age, Early ro Middie Carnian (Sues & Olsen

1990; Sues 1994),

Taxa dîscovered. Traversodontidae: Boreogom-

phodon jejfersoni Sues et Olsen, 1990,

Dromatheriidae; Microconodon tenuirostris

Osborn, 1886.

Cîimnock Formation

(Sanford Basin, Norrh Carolina, USA)

Age. Late Carnian (Sucs et ai 1994; Lucas &

Hunt 1994).

Taxa dîscovered. Dromatheriidae: Dromathe-

riurn sylvestre Emmoiis, 1857; Microconodon

r^'m//7Tc;rrr/.r Osborn, 1886.

Wolfuille Formation of the Fundy Group

(Minas Basin, Nova Scotia, Canada)

Age. Late Carnian or Carno-Norian (Hopson

1984).

Taxon di.scovered. Traversodontidae: ArctO'

traversodon plemmyridon (Hopson, 1984).

Mc Coy Brook Formation ofthe Fundy Group

(Novia Scotia, Canada)

Age. Early Jurassic (Sliubin et al. 1991):

? Hetiangian (Lucas Hunt 1994).

Taxon dîscovered. Tritheledontîdae: Pachyge-

nelus cl. monus.

Remark. ? Pachygenelus milleri Chatterjee, 1983,

(rom the Dockuin Formation (Upper Iriassic) of

Near Post (Western Texas, USA) is regarded by

Shubin et ai (1991) as doubtfiil because it lacks

diagnostic cynodont characters: teeth are fused to

the jaw and cherc are no cingula on the post¬

canine teeth.

Pant 4 Quârry ofSt Bridées island

(Glamorgan, U.K.)

Age. Hcctangian to Early Sinemurian (Evans &

Kermack 1994).

Taxon dîscovered. Tritylodontidae: Oligokyphus

cf major.

Windsor Hill Fissure

(Somerset, UK)

Age. Pliensbachian (Kühne 1956).

Taxon dîscovered. Tritylodontidae: Oligokyphus

Kühne, 1956.

Remarks. Kuhne (1956) described originally

cwo spccies, O. major and O. minor^ which are

probably sexual dimorphs (Sucs 1985).

A tritylodontid incertae sedls is présent at the

nearby Holwell Quarry (Savage 1971).

Saint-Nicolas-de- Port

(Meurthe-et-Moselle, France)

Age. Late Norian (Buffetaut & Wouters 1986;

Cuny ôf Ramhoer 1991; Cuny 1993) or Early

Rhaetian (Sigogneau-Rtisscll 19S3a).

Taxa dîscovered. Dromarherüdae; Pseudotri-

conodon wildi Hahn, Lepage et Wouters, 1984;

Tricuspes tuehingensis E. von Huene, 1933;

Trictiîpes sigog7ieituae Flahn, Hahn et Godefroit,

1994; Tricuspes tapeinodon n.sp.; Meurthodon

Sigogneau-Russcll et Flahn, 1994.

Traversodontidae: Maubeugia lotharingica n.g.,

n.sp.; Rosieria dehatei n.g., n.sp.; genus

aff. Mtcroicalenodon.

Cynodontia incertae sedis: Hahnia obliqua n.g.,

n.sp.; Gaumia longiradicata Hahn, WÜd et

Wouters, 1987; Lepagia gaumensis Hahn, Wild et

Wouters, 1987.

Remark. Godefroit (1997) describes a Late

Triassic fauaa in the nearby and contempora-

624

GEODIVERSJTAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

neous locality of Varangéville. This fauna

includes teeth of indeterminate advanced cyno¬

donts.

Medemach

(G.-D. Luxemburg)

Age. ^ Middie Norian (Hary & Muller 1967;

QunycPaL 1995).

Taxa discovcred, Drorriatheriidae: Pseudoîrico-

nodon wildi Wahn, Lepage et Wouters, 1984;

“cf. Triciispes tueèfmgerjs/s” (= Triciispes alT. sigo-

gneauaé).

Cynodontia incertae sedis\ Gaumia cf. incisa.

Habay-Lz- Vieille

(Gaume, Belgium)

Age. Early Rhaetian (Bock 1987).

Taxa discovercd. Dromatheriidae; Pseudotrico-

7iodûn ? sp.

Traversodoniidae: Microscalenodon nantis Hahn,

Lepage Wouters, 1988.

Cynodontia incertae sedis: Gaumia longiradicata

Hahn> Wild et Wouters, 1987; ? Gaumia incisa

Hahn, Wild Wouters, 1987; Lepagia gaumensis

Hahn, Wild Wouters, 1987.

Hallau Bone-bed

(Kanton Schalïhauscn, Switzcrland)

Age. For Clemcns (1980), the Hallau Bone-bed

postdates rlie Upper Norian (Knolenmergel), but

is no younger than the Lower, but not

Lowermost, Hcrtangian (the bonc-bcd is overlain

by a mari conlaining the ammonite Psiloceras

johnstoni), Therefore, the Hallau local fauna is

probably of Rhaetian âge.

Taxa discovercd. Dromatheriidae: Triciispes sigo-

gneaiiae HaJin, Hahn Wouters, 1994.

Cynodontia incertae sedis'. Gaumia .sp.; Lepagia

gaumensis Hahn, Wild er Wouters, 1987.

Rhütsandstein bone-beds ofWürtîemberg

(Germany)

Age. Probably not older than Upper Norian and

not younger than Lower Hettangian (Clemens

1980).

Taxa discovercd. Dromatheriidae: Tricuspes tue-

bingensis E. von Huene, 1933.

Tritylodontidac: OUgokyphus triserialis Hennig,

1922 {sensu Sues 1985); Trttyl’odon fraasi

Lydekker, 1887; Chalepotherium plieningeri

(Ameghino, 1903).

Lower Lufeng Pormation

(Western Yunnan, China)

Age. Hettangian co Pliensbachian (Chen et al.

1982; Luo& Wu 1995).

Taxa discovercd, (according to Luo bc Wu

1994). Ttitylodontldae; Bienothenurn yunnanense

Youag, 1940; Bienotheritim Young, 1947;

Bienotijeriurn magnton Chow, 1962, OUgokyphus

lufengensis Luo et Sun, 1993; Lufengia delicata

Chow et Hu, 1959; Yunnanodon brevirostre (Cui,

1976); Dianzhongia longistrata Cui, 1981.

PALAEOGEOGRAPHICAL SKETCH OF

ADVANCED CYNODONTS AND AFFINl-

TIES OF THE SAINT-NICOLAS-DE-PORT

CYNODONT FAUNA

Threê .successive stages can be distinguished in

the Late Triassic and Early Jurassic cynodont

assemblages worldwide: the Late Cariiian/Early

Nori-an assemblages, the Lace Norian/Rhaecian

assemblages and the Liassic assemblages. Tbç,

Late Carnian/Early Norian assemblages are parti-

cularly well represented in South America

(Argentina and Brazil), but éléments have also

been di.scovered in Southern Africa, India and

eastern Norrh America, l’hese assemblages are

dominated by Traversodontidac. With the excep¬

tion of Boreogomphodon, ail are large or giant

herbivorous cynodonts. The Chiniquodontidae

appareiitly disappeared ac the end of the

Carnian. The Dromatheriidae appeared during

the Carnian. Thcy are very small cynodonts with

perfectly secroria! postcanine teeth. This Late

Carnian/Early Norian cynodont assemblages can

be included wirhin the B-type assemblages, defi-

ned by Romer (1966),

The Late Norian/Rhaetian cynodont assemblages

are well represented in Western Europe, on the

western margin of the Ccrmanic Rcalm. The

fauna discovercd in Saint-Nicolas-de-Porc is the

most représentative of this type of cynodont

assemblages. These are dominated by smail car-

GEODIVERSITAS • 1997 • 19(3)

625

Godefroit P. & Battaîl B.

nivorous or însectivorous cvnodonts with secto-

rial posccanine teech (Dfomachcrüdae or

Cynodonüa hicenae sedis). The Traversodoncidae

are very rare and only represented by dwarf

forms. The cynodonc fauna from Saint-Nicolas-

de-Port appears very slmilar with thosc from

Medernach (three généra tn common), Habay-la-

Vicille (three or four généra in common) and

Hallau (three généra in common).

From a palaeoecological point of view, it is inter-

esting to observe that, in Saint-NicoIas-de-Porc,

small herbivorous Traversodontidae co-exisr with

two groups of herbivorous allorherian maramals;

the Haramiyidae and che Theroteinidae. Ail

these small herbivorous groups probably had dif¬

ferent dictary spécialisations, allowing their sym-

pathy. For Sigogneau-Russell & Hahn (1994),

the haraniiyid teeth, which are rarely strongly

worn, may be indicative of a dier bascd on soft

plant matrer; the low cusps and délicate mors of

the theroteinid molars perhaps suggest a diei

based on rather softer vcgctables. ‘l'he stout root

and the high cusps of the dwarf traversodontid

postcanine teeth suggest a diet based on haidcr

vegetablcs, The wcar pattern of the postcanine

teeth is unfortunaiely insufficiently known, in

this group, to confirm this hypothesis. In the

same way, the Dromatheriidae co-cxLst with mor-

ganucodontid mammals in Saint-Nicolas-dc-

Port, as in Hallau (Peyer 1956) and Medernach

(Cuny étal. 1995). Both groups axe characterized

by triconodont cutting teeth and probably occu-

pied similar ecological niches. Sigogneau-

Russell àc Hahn (1994) suggest tfiat the

Dromatheriidae (“chiniquodontoids”) were pro¬

bably too small to be carnivorous: perhaps they

fed on insects with hard elytrae. In Saint-

NicoIas-de-Port, the most frequent morganuco-

dontid, Brachyzostrodtnu is characterized by its

relatively large and very stocky molars, îndicating

that ir fed on larger preys: it was probably a small

carnivorous.

The cynodont fauna discovered in the

Rhatsandstein bone-bed.s from Germany bas a

intermediate composition betvveen the typical

Late Norian-Rhactian assernblages and the

Liassic ones. Tricuspes is the only dromatheriid

discovered in this area, whereas at least three

généra of triylodontids hâve bcen discovered.

These are the oldest Trîtylodontidae currcntly

recognized.

Outside Western Europe, the Late Norian

Los Colorados Formation of Argentina has yicl-

ded the oldest known Trirheledonridae:

Cbalbnima. The presence of Pseudotriconodon in

the Norian Bull Canyon Formation of New

Mexico is doubtfui (Sues & OIsen 1990).

Traversodontids and dromaiheriids are absent

from the Liassic cynodont assemblages. T hese are

characterized by the presence of Tritylodontidae

and/or Trithelcdontidae. f.iassic rricylodontids

hâve a pangean palaeogeographical distribution:

th^ are known from Europe, Norrh America,

China and South Africa. This reflects the appa¬

rent cosmopolitanism of tetrapod faunas at that

period, as already noted by Sbubin et ai (1981),

OIsen èc Galton (1984) and Lucas &c Hunt

(1994). Nevertheless, at the gcneric level, the

Liassic tritylodontids appear more endemic. Out

of ren tritylodontid généra recognized in the

Early Jurassic (the Rhatsandstein botie-beds from

Germany are provisionally regarded as Late

Triassic in âge), eighr hâve currcntly only been

discovered în a limited palaeogeographical area.

Dhuiebttodofh from the Kayenta Formation

(USA), and yitfinanodon, from the Lower Lufeng

Formation, are vet)^ similar and probably repre-

sent sister-taxa by dental aponiorphies (Luo pets,

comm.). If this taxonomie similarity is taken into

consideration, rhe endemism of tritylodonts

would be lower. However, as the stratigraphie

position of each ft>rniation is noc clcarly establi-

shed, definitive palaeogeographical conclusions

arc very hazardous for that period. The genus

OUgokyphus has a wide palaeogeographical distri¬

bution: reinains bave been discovered in

Germany, che United Kingdom* China and

North America. Straügraphically, it probably

ranges from ihe Rhaetian lo the Pliensbachian.

The Upper Ellioi and Lower Clarcns Formations

of Southern Africa hâve yicided three tritheledon-

tid generâ. Outside Southern Africa, a jaw frag¬

ment of the trithclcdontid Pachygeknus cf. morrus

has been discovered in the ^ Hettangian Mc Coy

Brook formation of Nova Scotia.

626

GEODIVERSITAS • 1997 • 19(3)

Late Triassic cynodonts from Saint-Nicolas-de-Port

CONCLUSIONS

The Late Triassic cynodonc fauna discovered in

Saint-Nicolas-de-Pon is unique in rerms of the

diversiry of the fauna. The following taxa are

rcpresenred: Fseadatriconodon wildi Hahn,

Lepage Wouiers. 1984; Triempes tuebingensis

E. von Huene, 1933: Tricuspes sigo^eattae

Hahn et Godefroit, 1994; Tricuspes tapei^

nodon n.sp.; Meiirthodon gnllicus Sigogneau-

Russell et Hahn, 1994; Hahnia obliqua n.g.,

n.sp.; Gatimiü longiradicata Hahn, Wild et

Wourers, 19B7; Lepagia gaurnensisy Hahn,

Wild er Woucers, 1987; Maubeugia lotharin-

gica n.g., n.sp.; Rosieria dehaiei n.g., n.sp, and

aff. Microscalenodon. Small carnivorous or insec-

rivorous cynodonts are panicularly numerous

and diversified (eight species). They are represeni-

ed by the Family Dromatheriidae and by

Cynodontia incenae sedis. h has been previously

shown that Dromatheriidae probably represenc

the sister-taxon ol Mammalia (Tlahn et ai

1994). Herbivorous cynodonts are rare and pro¬

bably represented by dwarf fotms of the Family

Traversodontidae. AlthougK very advanced, these

rraversodonts are characterized by a primitive

dental morphology. The study of the palaeo-

geographical and stratigraphie distribution of

Lare Triassic to Early Jurassic advanced cyno¬

donts indicares that the fauna discovered in

Saint-Nicolas-de-Port i.s characterisiic of the Late

Norian-Rhaetian period.

Acknowledgmen ts

The authors are grateful to D. Sigogneau-Russell

for having allowed and facilitated access to the

collection in her care as v/ell as for the loan of

specimens, Z. Luo and G. Hahn very kindly

reviewed the manuscript and made helpful sug¬

gestions to improve this paper. SEM photo-

graphs by J. Cillis. P. Godefroit s work is flinded

by a FRFC-IM gtanr.

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Submittedfor publication on 21 June 1996;

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GEODIVERSITAS • 1997 • 19(3)

631

Les hipparions du gisement miocène supérieur

d’Aubignas (Ardèche, France)

Samir ZOUHRI

Département de Géologie, Faculté des Sciences d’Aïn Chock.

B. P. 5366 Maârif - Casablanca (Maroc)

Léonard GINSBURG

Laboratoire de Paléontologie, Muséum national d’Histoire naturelle,

8 rue de Buffon, F-75231 Paris cedex 05 (France)

Zouhri S. & Ginsburg L. 1997. — Les hipparions du gisement miocène supérieur

d’Aubignas {Ardèche, France). Geodiversitas 19 (3) : 633-640.

MOTS CLÉS

Miocène supérieur,

Aubignas,

hipparion,

Perissoûactyla,

Mammalia.

RÉSUMÉ

Dans le gisement d'Aubignas l, découvert au siècle dernier, coexistent deux

espèces d’hipparions ; une forme trapue et de taille moyenne, Hipparion

depereti Sondaar, 1974, bien connue à Montredon (Hérault, France) et une

autre espèce de petite taille, Hipparion sp., qui rappelle par sa taille

Hipparion nuicedonicum Koufos, 1984. Récemment, un nouveau pointement

fossilifère, Aubignas 2, très proche du précédent mais légèrement plus haut

dans la stratigraphie, a livré une faune assez voisine. Contrairement à

Aubignas I, une seule CvSpcce d^hipparion de grande taille et aux dents bra-

chyodontes existe à Aubignas 2. Elle est apparentée à Hipparion truyolsi

Sondaar, 1961, signalée aussi aux Mistrals (Vaucluse) et à la Montagne

d^Andance (Ardèche). D’après les caractères morphologiques des hipparions,

un âge Vallésien supérieur-Turolicn inférieur (Miocène supérieur, MNll)

est suggéré pour Aubignas 1 et un âge légèrement plus récent, Turolien

moyen (MN12), pour Aubignas 2. Le changement de faune entre les deux

gisements indique un net changement de paléoenvironnement.

GEODIVERSITAS « 1997 • 19(3)

633

Zouhri S. & Ginsburg L.

KEYWORDS

Late Miocène.

Aubignas,

hipparion,

Perissociactyla.

Mammalia.

ABSTRACT

l'he vertebrate Fauna oF Aubignub 1 discovered during the last century

contains n\'o co-existing hipparion species: a medium-sized and robust form,

Hipparion depercti Sondaar» 1974> wcll known from Montredon (Hérault,

France), and another small species, Hipparion sp., which is oF similar size to

Hipparion niacedonicum Koutos, 1984, Recently, a new FossiliFerous site,

Aubignas 2. close to the preceding one, but slightly of higher stratigraphie

age^ has yielded a simiJai Fiuna, Conirar)' to Aubignas lonly one largc-sized

species of hipparion with brachyodont teeih lived in Aubignas 2. h is related

to Hipparion tntyolsi Sondaar, reported (rom the Mistrales (Vaucluse)

and the Montagne d’Andance (Ardèche). According to ihc morphological

characters of the hipparions, it is vsuggested thac Aubignas I is dated to Upper

Vallcsian-Lower Turolian âge, whilc a slightly younger age, Middlc Turolian,

is proposed For Aubignas 2.

INTRODUCTION

Le gisement d'Aubignas, découvert en 1882 par

Torcapel, se trouve à 3 km au nord du village du

même nom, dans le département de FArdèche. Les

fossiles alors exhumés dans ce niveau (Aubignas 1)

ont été étudiés par Gaudiy qui constate de fortes

affinités avec les faunes du Monr lubéron

(Vaucluse^ Fiance) er de Pikermi (Grèce). Bout

(1966) puis Guérin & Mein (1971) reprennent la

liste faunique de Gaudry en la transformant l^è-

rcment. Les hipparions ont été signalés sous la

dénomination classique à"Hipparion gracile.

Depuis, Sondaar (1974) a rapproché les équidés

d’Aubignas I (ïHipparion depereti.

Réccmment> un nouveau pointement fossilifère

(Aubignas 2), très proche du précédent mais

situé légèrement plus haut dans la stratigraphie, a

livré une faune avsser voisine de celle du niveau

inférieur (Azanza et al. 1993). Les hipparions des

deux niveaux d'Aubignas appartiennent à des

espèces différentes.

MATÉRIEL, MÉTHODES

ET ABRÉVIATIONS

Le matériel d’Aubignas 1 préservé au laboratoire

de Paléontologie du Muséum national d’Histoire

naturelle comprend un fragment d'hémimandi-

bule avec p2-m2, une vingtaine de dents isolées

(surtout des dents jugales supérieures), une extré¬

mité distale de métacarpien principal (Mc III) et

deux secondes phalanges,

À Aubignas 2, les hipparions sont représentés par

un matériel aussi réduit que celui d’Aubignas 1 :

une douzaine de dents isolées, un astragale, un

métatarsien principal (Mt III) tronque au niveau

de l'épiphyse distale, trois secondes phalanges et

un fragment de scaphoïde.

Les observations et mensurations ont été faites en

suivant les recommandations de la Conférence

Internationale sur les équidés (Eisenmann et al.

1988). Les comparaisons sont faites à l’aide de

diagrammes de dispersion pour les dents. L’in¬

dice d'hypsodontie de Gromova (1952) rapporte

la hauteur maximale du parasryle de dents vierges

ou peu usées à la longueur mesurée à 1 cm des

racines. L’indice de développement de la quille

distale des métapodes centraux a été calculé tel

quil a été défini par Gromova (1952).

AUBIGNAS 1

CoMBiFN d’hivfarions À Aubignas 1 ?

L’unique Mc III incomplet et les deux phalanges

intermédiaires ont des dimensions générales et

des proportions qui indiquent un hipparion de

taille moyenne et d’allure trapue.

Malgré la petitesse de l’échantillon — une douzaine

de dents en tout, réparties entre les différentes

catégories et appartenant à des stades d’usure dif¬

férents - les dents jugales supérieures ne sem-

634

GEODIVERSITAS « 1997 • 19(3)

Hipparions du gisement miocène supérieur d’Aubignas

Fig. 1. — Hipparion depereti, Aubignas 1. A-A^, fragment d’hémimandibule droite n° Aub.1 ; A, vue occlusale (p2-m2) ; A^, vue ves-

tibulaire. B-B^, extrémité distale du Mc III n° Aub 42 ; B, vue antérieure ; B^, vue postérieure. C-Ci, Aubignas 1. phalanges intermé¬

diaires principales (Ph II) ; C, Ph II n° Aub 40 ; C^, Ph II n° Aub 39.

GEODIVERSITAS • 1997 • 19(3)

635

Zouhri S. ÔC Ginsburg L.

blent pas constituer un dchantillon homogène.

Uexamen des dimensions (Fig. 2), du degré de

plissement de Fémail dentaire et d’hypsodontie,

de la forme du protocône, etc, permet de faire les

constatatioas suivantes.

1. Une P2 (n" 27) et trois Ml ou M2 (n° 18, 37,

38) se distinguent respectivement des dents de

leur catégorie à la fois par des dimensions (lon¬

gueur et largeur à 1 cm des racines) plus grandes

et par un plas fort degré de plissement de fémail

dentaire ■ vingt-cinq plis pour la P2 de grandes

dimensions contre vingt-et-un seulement pour

une autre (n° 28) plus petite mais du meme stade

d’usure qu’elle et vingt-sept à vingt-neuf plis

pour deux Ml ou M2 (n® 37, 38), contre seule¬

ment vingt pour une P3 ou P4 (ti® 25) à peu près

de même stade d’asure (en tenant compte, bien

sûr, du fait que J’cmail dentaire des molaires est

un peu plus pUssc que celui des prémolaires

d’une même série dentaire).

2. Une différence d’hypsodontie est évidente entre

d’un côté une Ml ou M2 (n° 18) non usée [l’indi¬

ce d’hvpsodontie (TH) de Gromova (1952) est voi¬

sin de 25], classée dans le loi des dents de grandes

dimensions, et de l’auirc côté deux Ml ou M2

(n° 24, 32) égalemenr non usée.s (IH = 230 et

220), ainsi qu'une P3 ou P4 (n” 22) à peine enta¬

mée par l’usure (IH = 190),. classées dans le lot des

dents à petites dimensions (Tableau 1).

Les dents jugales inférieures sont peu nom¬

breuses et ne permccienc pas de relever des diffé¬

rences de dimensions. La double boucle y est

typiquement hipparionienne. Un protostylide

peut être observé sur toutes les dents mais aucune

ne possède d'ectostylidc. L’indice d’hypsodontie

ne peut-être estime avec une bonne précision que

sur une Ml ou M2 (n" 11). La hauteur de la

couronne étant de 48 mm et la longueur à 1 cm

des racines, de 22 mm, cet indice devrait être

voisin de 220 (Tableau 1).

Sans doute exisraii-il deux espèces d’hipparions à

AubignavS 1, si l’on en juge d’après les dents

Fig. 2. — Diagrammes de dispersion. A, variations des lon¬

gueurs et des largeurs à 1 cm des racines des deuxièmes pré¬

molaires supérieures (P2) criet des riipparions ;.B, variations

des longueurs et des largeurs à 1 cm des racines des troi¬

sièmes et quatrièmes prémolaires supéneures (P3 et P4} chez

des hipparions. C. variations des longueurs et des largeurs à

1 cm des racines des premières et deuxièmes molaires supé¬

rieures (Ml et M2) chez des hipparions.

22 f

20 l

[13 W-pnm/geniüiTjd Eppelsheim

SonOaari974

O H. deperedOe Monlredon

Eisenmann i988

1 Aübmnas i * AuDignas 2

,L1 : Longueur à 1 cm (mm)

20 21 22 23 24

636

GEODIVERSITAS • 1997 • 19(3)

Hipparions du gisement miocène supérieur d'Aubignas

jugales supérieures. Les quelques os des membres

appartiennent à une seule et même forme trapue^

ainsi que les dents de plus grandes dimensions, à

fort degré de plissement de Témail dentaire, à

hypsodontie miiyenne, à protocône ovale et à pli

caballin multiple. I.^autre espèce possède des

dents plus petites, relativement brachyodontes

avec un plissemeni modéré de l'émail dentaire et

une constriction de Thypocône.

Quels hipparjonsà Aubignas 1 ?

Le matériel d’Aubignas 1 a été rapporte par

Sondaar (1974) à Hipparion depereti, nouvelle

espèce qu’il avait alors créée à Monrredoii

(Hérault, France). Eîsenmann (1988) ensuite,

s'appuyant sur un matériel un peu plus abon¬

dant, a démontré la présence dans ce gisement,

en plus lŸHipparion depereti, d’un petit hippa¬

rion dont la taille évoque Hipparion macedoni-

cum du Vallésien supérieur du ravin de la Pluie

en Grèce (Koufos 1986). Eisenmann (1988 : 85,

91) a souligné en particulier la ressemblance des

dimensions générales du Mc III incomplet

d'Aubignas 1 avec ceux ^Hipparion depereti et la

concordance des dimensions de certaines dents

d'Aubignas 1 avec celles des petites dents de

Montredon rapportées par elle à Hipparion sp.

En effet, il n y a pas de doute que les quelques os

des membres et les dents à fort degré de plisse¬

ment de Témail, et à hypsodontie moyenne,

appartiennent à Hipparion dtperrti Sondaar,

1974. Le deuxième hipparion d'Aubignas 1 a

effectivement des dents jugales semblables à

celles de la petite forme de Montredon, mais ni

les informations, trop disparates sur ce dernier, ni

celles apportées par le matériel d’Aubignas 1 ne

permettent d’apparenter ou d’éloigner ces deux

hipparions,

Fig. 3. — . A Di, Hippanon depareli. Aubignas i ■ dénis jugales

supérieures. A A,, P2 droite n® Aub 27 ; A, vue occlusale ;

A^, vue vesîibulaire. B'B,, M1 ou M2 droite n’ Aub 37 ] B, vue

occlusale : 6^, vue vestibufaire. C-C^, M1 ou M2 droite

Aub 38 : C, vue occlusale . C,, vue vestibulaire. D-D.,, M1 ou

M2 : gauche n"* Aub 13 ; D. vue ooclusate : D,. vue vestibulaire,

E-Ji, Hipparion sp. Aubignas 1, dents jugales supérieures.

P2 gauche n- Aub 28 ; E, vue occlusale : E,. vue vestibulaire.

F-F^, P3 Ou P4 gauche n** Aub 25 ; F. vue occlusale , F^, vue

vestibulaire. G-G,. Ml ou M2 droite n' Aub 2A : G. vue occlu¬

sale ; G,, vue vestibulaire. H-H,. Ml ou M2 gauche Aub 32 :

H, vue occlusale - vue vesubulaire. II,. M1 ou M2 gauche

Auo 22 ; I. vue occlusale : vue vestibulaire J J-j. M3

gauche n° Aub 23 : J, vue occlusale : vue vestibulaire.

GEODIVERSITAS • 1997 • 19(3)

637

Zouhri S. & Ginsburg L.

AUBIGNAS 2

Combien o’hipparion.s à Aubignas 2 ?

Les quelques os des membres énumérés précé¬

demment forment un matériel homogène. Ils

sont de grandes dimensions, voisines de celles

A'HipparioH primigenium et plus grandes que

celles ÿH'îpparion depereit. Bien qu’incomplet, le

Mt III semble appartenir à un hipparion assez

robuste : la largeur de la diapbysc au milieu est

de 27 mm, qui est aussi la valeur de son diamètre

antéro-postérieur au même niveau (respective¬

ment, mesures 3 et 4 d'Eisenmann et ai 1988).

Sur la surface articulaire proximale existe une

petite facette articulaire pour le petit cunéiforme.

Les dents jugales sont peu nombreuses, mais

contrairement à celles d Aubignas 1, elles consti¬

tuent un échantillon homogène.

Les dents jugales supérieures sont au nombre de

six spécimens ; trois B2-, une P3 ou P4 et deux

M! ou M2. l.euTS dimensions sont grandes

(Fig. 2) et s'inscrivent à l'intérieur des limites de

variation A' flipparion primigenium d’Eppelsheim

(Sondaar 1974). Le degré de plissement de

Fémail dent.aire est Cependant plus faible que

chez rhipparion vallésien d’Eppeisheim : vingt

ou vingt-et-un plis sut les F2. vingt-cinq plis sur

une P3 ou P4 moyennement usée. Les dents sont

brachyodontes ; l'indice d'hypsodontic estimé

sur une MI ou M2 à petne entamée par l’usure

est de 190. La forme du protocône est ovale sur

toutes les dents à partir d’un certain stade

d’usure. Le pli caballin est simple ou double.

Les dents jugales jnférieiires sont au nombre de

sept spécimens : deux p3 ou p4, deux ml ou m2

et trois m3. La double boucle y esc typiquement

hipparionienne. Le sillon vcstibulaire est un peu

profond sur les dents peu usées, très profond,

entrant même en contact avec le pédoncule de la

double boucle sur les dents très usées. Un proto-

srylide est obserx'é sur la pluparr des dents enta¬

mées par l'usure. Sur une m3 non usée, le

protostylide aireinr seulement un centimètre

environ de haurcur. Aucune dent jugale infé¬

rieure définirive ne possède d cctostylide.

Quel hipparion à Aubignas 2 ?

L’hipparion d'Aubignas 2 diffère de ceux

d’Aubignas 1 par sa grande taille et par les carac-

TA 61 .EAU 1. — Indice d'hypsodontie des hipparions d'Aubignas 1

et 2 IH = indice d'hypsodontie, H = hauteur de la couronne.

L1 = longueur de la aent à 1 cm des racines. 11 « largeur de la

dent à 1 cm des racmes.

catégorie

de dent

IH=:

H/L X 100

L1 xM

(mm)

Hipparions

Aub18

M1-2

250

21,5 X 21

H. depereti

Aub 11

ml *2

220

22 x ?

Aub 24

Ml-2

203

19,6x20

Aub 32

MV2

220

21 x19,6

Hipparion sp.

Aub 22

P3*4

190

21 x21

Aub 212

Ml-2

190

24,5 X 23

H. truyolsi

tères morphologiques de scs dents. Les dents

jugales supérieures sont plus grandes, à émail

dentaire moins plissé et surtout beaucoup plus

brachyodontes que celles rapportées à Hipparion

depereti d’Aubignas L Celles AUipparion sp. sont

encore beaucoup plus petires. l’hipparion

d'Aubignas 2 a eflfcctivement des dimensions voi¬

sines de celles des Hipparion prunigeniunt mais se

distingue nettement de ces derniers par un

moindre degré de plissement de I email dentaire

de.s jugales supérieures, et par la forme du proto-

cône. plus arrondie chez V Hipparion

d’Aubigna.s 2. Par .ses grandes dimensions, ses

dents brachyodontes, la forme de son protocône

et le degré de plisseinent de son émail dentaire,

rhipparion d'Aubignas 2 se rapproche énornié-

menr A^Hipparion truyoUi Sondaar. 1961 et

qu’Alberdi (1974) décrit sous la dénomination

.subspécifique A'Hippation primigenium truyolsi.

UÂGE DES GISEMENTS D’AUBIGNAS

La présence de deux hipparions dans le gisement

d’Aubignas 1 pourrait plaider pour un âge turo-

lien puisque la tradition voulait qu'une seule

espèce d'hippanon .soit présente dans les gise¬

ments vallésicns et au moins deux dans le

Turolien, Cependant, la coexistence de deux hip¬

parions dès le Vallésien supérieur semble cire

aujourd’hui bien établie (Koufos 1986 ;

Eisenmann 1988). Toutefois, Page géologique

d’Aubignas I et 2 peut être estimé à partir des

caractères morphologiques des hipparions.

Le Mc III incomplet et les secondes phalanges

d’Aubignas 1 ont des dimensions générales et des

638

GEODIVERSITAS • 1997 • 19 (3)

Hipparions du gisement miocène supérieur d'Aubignas

proportions qui les rapprochent de certains hip¬

parions vallésiens, en particulier à!Hipparion

depereti de Monrredon pour lequel Eisenmann

(1988) a suggéré un âge Vallésien supérieur-

Turolien inferieur. Les dents Isolées d’Aubignas 1

posent problème dans la mesure ou elles ont été

réparties encre deux espèces d’après les diffé¬

rences de leurs dimensions, mais aussi d’après les

différences de leurs caractères morphologiques. Si

le fort plissement de l'émail dentaire et fhypso-

dontie moyenne (biozone 2 de.s hipparions

d’après Sen et aL 1978) des dents attribuées à

Hipparion depereti et la brachyodontie de celles

à'Hipparion sp. placent Aubignas 1 parmi les

Fig. 4. — Hipparion truyolsi, Aubignas 2. A-A,, Mt III droit (n° Aub 203) ; A, vue de la surface articulaire proximale : A^, vue anté¬

rieure. B-B,, astragale droit (n® Aub 202) ; B, vue antérieure : B^, vue postérieure. C-C.,, trois secondes phalanges principales

(n® Aub 204, 205, 206) ; C, vue de la surface articulaire antérieure ; Ci, vue antérieure.

GEODIVERSITAS • 1997 • 19(3)

Zouhri S. & Ginsburg L.

gisements vallésiens supérieurs, le plissement

modéré de Téniail dentaire ÿHipparion sp. ainsi

que le développement relativement progressif de

la quille divStale de runique Mc III [indice de

Gromova {19‘>2) de 91] suggèrent plutôt un âge

Turolien inférieur (MN 11 ) pour Aubignas 1.

La morphologie crânienne d'Hlpparion truyolsi

est méconnue. Cette espèce a été définie par

Sondaar (1961) d’après las caractères dentaires et

sur la base d’un matériel asse?. réduit. La mor¬

phologie dentaire d'Hipparion truyolsi ne semble

pas être très répandue non plus, fin dehors

d’El Arquillo en Espagne, localité-rype, cette

espèce n a été décrite par la suite que dans le gise¬

ment turolien des Mistrals (Vaucluse, Trance) où

elle est une forme rare à côté d'Hipparion prosty-

lum, Tespèce la plus commune (Sondaar et ai

1977) et dans la Montagne d’Andance en

Ardèche (Demarq et al. 1988). Un âge Turolien

et plus vraisemblablement Turolien moyen

(MN12) peut être suggéré pour le gisement

d’Aubignas 2. Ce dernier serait par conséquent

légèrement plus récent que le niveau

d’Aubignas 1. Ces résultats stratigraphiques

conPirment ceux précédemment avancés par

Azanxa et al. (1993) et établis principalement sur

Tétude dçs artiodactyles.

Remerciements

Les auteurs remercient pour leurs critiques

constructives G. Koufos, ainsi que le second rap¬

porteur qui a souhaité conserver l’anonymat.

RÉFÉRENCES

Alberdi M. T. 1974. — El genero Hipparion en

Espana. Nuovas formas de Câstilla y Andaloucia,

révision e bistorica evoluciva. Trahajos sobre

Neogeno-CiuJternario, L Madrid, l46p.

Azanza B., de Broin F., Galoycr A., Ginsburg L. &

Zouhri S. 1993. — Un nouveau site â Mammifères

dans le Miocène supérieur d’Aubignas (Ardèche).

Comptes rendus de PAcadémie des ScienceSs Paris,

tome 317, série 11 : 1129-1134.

Bout P. 1966. — Flistoire géologique et morphoge¬

nèse du système .SE Boutonières-Coiron. Revue

Géogrtsphie Physique et Géologie Dynamique (2), 8

(3) : 225-252.'

Demarq G., Meit> P,, Baüesio R. Ôc Romaggi J.-P.

1988. — Le gisement d’Andance (Coiron,

.Ardèche, France) dans le Miocène .siipéricur de la

vallée du Rhône ; un essai de cotrélaiion marîu-

coniinemal. Bullain de la Société géolosrique de

France, série 8, 5 (4) : 797-806.

Eisenmann V. 1988. — Les Peri.ssodactyIe.s, Equidae,

in Ginsburg L. (cd.). Contribution à Fétude du

gt.semeiu miocène .supérieur de Monrredon

(Hérault). Les grands Mammifères. Palaeoverte-

braia. Mémoire Extraordinaire ; 65-96.

Eisenmann V., Alberdi M.-T., de GluÜ C. &

Staesche U. 1988. — In Woodburne iM. &

Sondaar P. (ed.s), Studying fosstls horses. CoHecttd

papers afier the New York International HippUrion

Conférence, 1981, Volume 1: Mcrliodolog)'. Brill,

Leiden, 71 p^

Guérin & Mein P. 1971. — Les principaux gise¬

ments de mammifèrc.s miocènes et pliocènes du

domaine rhodanien. Documents du Laboratoire de

Géologie de PUniversité de Lyon. H. S. ; 131-170.

Gromova V. 1. 1952. — Le genre Hïpparton. Bureau

de recherches géologiques et minières C.E.D.P. 12 :

1-288.

Koufos G. D. 1984. — A new Hipparinn (Mamm.,

Perissodactyla) from the Vallesian (Lare Miocene)

rii Greece. Patamiiologische Zeitsclmft 307-317-

— 1986. — Srudy of vallesian Hipparion.s of the

Lower Axios Valley (Maccdonia, Grcccc). Geobios

19:61-69.

Sen S., Sondaar P. Y. ôc Staesche U. 1978. — The

biostratigraphical applications of the genus

Hlpparion with speciàl référencés ro rbe Furkish

représentatives. Konnklijke Nederlandse Akademie

van Wetenschappm Proceedings SI (3): 370-385.

Sondaar P. Y. 196L -— Les Hipparions de FAragon

méridional. Estudios Geologicos 17: 209-305.

— 1974. — l he Hipparions of the Rhône Valley.

GVt7/;/o5 7 (4): 289-306.

Sondaar P. Y., Mctn P.. Truc G. èê Demarq G.

1977. -— Lc.s Hipparions (Mamm. Perissodacq^la)

du gisement Turolien des Misti*ales près de Vairéas

(Vaucluse* France). Géohkn 10 fl) : 117-121.

Torcapel M, 1382. — Le plateau des Coiroivs (Ardè¬

che) esr des alluvions soas-basaltiques. Bulletin de

la Société géologique de France 3 {10) : 406-421.

Soumis pour publication le 18 juillet 1995 ;

accepté le 26juillet 1996.

640

GEODIVERSITAS • 1997 • 19(3)

Equus stenonis irom the middie Villafranchian

locality of Volax (Macedonia, Greece)

George D. KOUFOS & Théodore VLACHOU

Laboratory of Geology and Palaeontology, Aristotle University of Thessaloniki,

54006 Thessaloniki (Greece)

Koufos G. D. & Vlachou T. 1997. — Equus Stenonis from the middie Villafranchian locality

of Volax (Macedonia, Greece). Geodiversitas 19 (3) : 641-657.

KEYWORDS

mammalia,

Equidae,

middie Villafranchian,

Macedonia,

Greece.

ABSTRACT

The locality of Volax is situated in eastern Macedonia, Greece, in a small

karstic-tectonic basin, ’l'he Volax horse is a large-sized horse with moderately

plicated enamel in the upper teeth, short prococone with fiat lingual border,

hypsodont teeth, sÜghtly plicated flexids in rhe lower teeth, as well as short

and robiist metapodials. The dental and postcranial characcers of the Volax

horse indicatc thaï it is a stenonoid horse with grcatest similarities to rhe

hor.se from Dafncro (Cireece) and La Puebla (Spain). Ir is aiso close to

E. s. vireti front J>ainc-Vallier, as wcll as to rhe hor.se from Oiivola and

Matassino (Italy). The study of the Volax equid adds to our knowledge

about the Villafranchian horses and their relationsliips. The age of the Volax

locality is also discussed and a middie Villafranchian age (MN17) is propo-

sed.

MOTS CLÉS

mammifere.s,

équidifs,

Villafranchien moyen,

Macédoine,

Grèce.

RÉSUMÉ

Le gisement fossilifère de Volax se situe en Grèce, dans la Macédoine orien¬

tale. Le matériel d’cquidc trouve dans ce gisemenr fait Tobjer de ce travail. Il

s’agit d’un équidé de grand taille, à l’émail de la denture supérieure modéré¬

ment plissé, doté d’un court protocône et d'une face linguale place, d’une

hyp.sodontie assez forte. Les flexides de la denture inférieure sont légèrement

plissés, les métapodiaux courts et robustes. Ces caractéristiques montrent de

fortc.s similitudes avec £. s. tnreti des giscmcnt.s de Dafncro (Grèce) et de

La Puebla (Espagne). I .’équidé de Volax ressemble aussi à E. nenonîs de

Saint-Vallicr, et à l’équidé d’Olivola et de Matassino (Italie). L’étude des

équidés de Volax parfait notre connaissance des chevaux du Villafranchien et

de leurs relations de parenté. La datation du gisement est également discu¬

tée ; un âge Villafranchien moyen (M N17) peut être propose.

GEODIVERSITAS • 1997 • 19(3)

641 I

Koufos G. D. & Vlachou T.

INTRODUCI’ION

The locality of Volax has been discovered in

1961 by Prof. H. J. Martini (University of

Hannover)^ who investigated the area studying

the manganium deposits and informed

Prof. O. Sickenberg, ol the .saine University,

about rhe new locality. With the permission ot

Prof. M. Mir/opoulos (University of Arhens) and

Prof G. Marinos (University of Tliessaloniki),

Sickenberg excavaced and collected abundant

material which was carried to Hannovcr

(Sickenberg 1968a). Part of rhe material, indu-

ding the carnivores and rhe gI^affids^ was scudied

by Sickenberg and then sent back ro rhe

University of Athens (Sickenberg 1967, 1968b).

The rest material remaincd in Hannover iill

1992. At chat rime one of us (G. Koufos) askcd

from the University of Hannover lo send back

the material. The dirccror of the laboratory in

Hannover, Prof Becker-Piatten, sent back imme-

diately to our laboratory the material in his dis¬

posai. This material was prepared and registered

again. The artiodactyls (bovids and cervids) were

given by G. Koufos to D. Kostopoulos and hâve

been studied by him as a part of his thesis

(Kostopoulos 1996). The rest material, including

the equids, is studied in this article.

The locality is situaied near the village of Volax

about 11 km north-wesi of Drama (Fig. 1) in a

small karstic-ieaonic bxsin. The basin is filled by

clastic sédiments belonging to two alluvial fans.

The depo.siis consist of ahetnacing heds of

conglomérâtes and calcareous sandstonc-s with

lemicular intercalations of very hard calciric-

arenaccous clays including the fossils. Two fossi-

liferous sites hâve been found, referred as Lager 1

and Lager 2 (Sickenberg 1968a). Bofh .sites are

situaied in l^eprokaria ravine; Lager 2 is* locaied

at the eastern wall of the ravine and Lager 1 at

the western wall, abour 3-5 m above Lager 2

(Kostopoulos 1996). The matrix is very hard and

the préparation of the fossils quite difFicuIt. The

material from both sites was mixed by

Sickenberg and for this rea.son it will be referred

as a single sample under the locality indication

"Volax" (VOL).

The Volax material includes quite well preserv^ed

specimens of equids which allow a good descrip-

tion and comparison with the known

Fig. 1 . — Sketch map indicating the various referred Villafranchian localities of Macedonia. Greece.

642

GEODIVERSITAS • 1997 • 19(3)

Equus stenonis from middle Villafranchian of Macedonia

Vilkfranchiaii fiorses oi Grcece and Europe. Some

years ago the VUlafranchian ccjuids of Greecc were

more or less unknown. Recently a ricli sample

trom the varîous localiries ot Mygdonia basin

(Macedonia, Greecc) lias been described (Koufos

1992; Koufos êt al. in prep.). Some material of

Villafranchian horscs wxs also desaibed from wes¬

tern Macedonia, Greece (Sceensma 1988;

Koufos & Kostopoulos 1993). Moreover some

equids are also reported from the Villafranchian

localiry of Seskion (ThcssaJy, Grcece) by

Symeonidis (1991-1992). The study of chc Volax

equids will add to our knowledge about the

Villafranchian horses and thetr relationshjps, as

well as to the biostradgraphy ofVillafraachian.

The descriptions and ineasurements of the mate¬

rial are given according to the System proposed

by Eisenmann étal. (1988).

PALAEONTOLOGY

Order PERJSSODACTYLA Owen, 1848

Family EQUIDAE Gray, 1821

Genus Linneaus, 1758

Species Equtts stenonis Cocchi. 1867

Equus stenonis cf vireti

Locality. — “Volax”, VOL (= Lager 1 and 2 of

Sickenberg 1968a)» Macedonia, Greece.

Age. — Middle Villafrandijan (laïc Pliocène).

Material. — Maxilla wiih P2-M3 dex and P2-M2

sin, VOL-203; P2 dex, VOL-209; P3,4 sin, VOL-

207; M3 sin, VÜL-208; mandible. VOL-202; right

mandibular ramus wiih dp2-dp4, VOL-204; 5 distal

parts ofhumcrus„VOL-172. 173. 174, J75, 177;

radius, VOL'170; proximal part of radius, VOL-169;

2 distal parts ol radius, VOL-167. 168: 2 Mc III,

VOL-i52, 155: proximal parc of Mc 111, VOL-157;

2 distal pans ofMc IJL VOL-15.3, 156; tibia,. VOL-

162; 2 proximal parts of tibia, VOL-l 63, 165; 4 discal

parts oF tibia, VOL-l6(), 16], 164. 166; os cuboid.

VOL-198; 2 astragali» VOL-167. 169; 2 Mt lU.

VOL-145, 149; 3 pioximal parts of Mc lU, VOL-144,

146, 147; 5 distal parts ol Mt III, VOL-148, 150,

154, 158, 159; fitst anterior phalanx, VOL-183; first

posterior phalanx. VOL-181; proximal part of first

phalanx, VOL'184; 2 distal parts of first phalanx,

VOL-1S2, 185; 2 second phalanges. VOL-186, 187;

4 third phalanges, VOL-188, 189, 190, 191.

DhSCRlPllON

Maxilla and mandible

A maxilla (Fig. 2) is only known with both

coochrows and .a more or less complété mandible

(Fig. 3) wirhout the ascending ramus. The palate

is relatively elongated. narrow and deep. The dis¬

tance anccrior border of P2-choanae is 148 mm,

while the palatal breadth is 73.4 mm in front of

P2 and 75.5 mm between the posterior borders

of P4. The choanae arc broad and their anterior

border is situated at the middle of M2. l'hc facial

crest is strong and its anterior border is situaied

above Ml. The toothrow length Is 185 mm and

the length of the premolar and molar rows is

102 mm and 83.6 mm rcspectively. The index

Molar length X 100/Prcinolar length is 83-6 ps

88.6 for E. s. cf. vireti (Dafnero, western

Macedonia, Greece), 84.2 for E. s. mygdoniensis

(Gerakarou, Mygdonia basin, Macedonia,

Greece), 84.1 for E. s. cf. vireti (La Puebla»

Spain), 82.7 for/:', s, vireti (Saint-VaJlier, France),

80 for E. s. senezensis (Seneze, France) and

76.9-86.2 for E. s. stenonis from U. Valdarno;

data from Prat (1968), Eisenmann (1980), Privât

Defaus (1986), Koufos (1992), and Koufos &

KostopouJos (1993). The Volax horse in this

characcer is similar to chc stenonoid horscs. In

front ot P2 thcrc is chc trace of a small single-

rooted dPl.

The mandible is large and elongated with relaci-

vely shallow horizontal ramus. The snout is rela¬

tively long and narrow; however at the inçisors

area it is wide. The symphysis is elongated.

Thcre is not any trace of dpi, The toothrow

length is 188.5 mm. while lhat of the premokars

and molars is 92.2-98.3 mm and 91.5 mm res-

peccively. The index Molar length X 100/

Premolar length is 93.6 vs 92.6 for E. s. cf vireti

(Dafnero, western Macedonia, Greece). 95.6 for

E. s. mygdonicnsh (Gerakârou. Mygdonia basim

Macedonia, Greece), 92.3 for E, s. senezensis

(Senèze, France) and 90.3-96.6 for E. s. stenonis

from U. Valdarno; data from Prat (1968), Privât

Defaus (1986), Koufos (1992) and Koufos &

Kostopoulüs (1993).

Permanent dentition

The upper teech are small relatively to the skull

with strong mesostyle.

643 I

GEODIVERSITAS • 1997 • 19(3)

Koufos G. D. & Vlachou T.

The fossettes are alvvays closed and isolated. The

enamel tn cheir borders Ls slighdy plicated. In the

very worn ceeth (VOL-209) dic enamel is simple

and che fossettes arc buccolingiially narrow. The

plication immber is as an average Five plis in the

premolars and six plis în the molars. The proto-

cone is assymetrical and relatively short wkh fiat

lingual border. In the premolars it is triangular,

while in the molars it is more elongated and

elliptical. In the extremely worn P2 (VOL-2()9)

the protoconc is rounded. The short protocone

characterizes E. stenonE (Azzaroli 1965; De Giuli

1972). The pli cabalin is simple and small or

rudimentary. The hypocone is elliptical with

rounded distolabial border. The distal hypoconal

groove is narrow and shallow, while a shght lin¬

gual groove is présent only in rhe premolars- In

M3 ihcre is one isolated hypoconal islet. There

are no unworn or little worn teeth ro mcasure

ihe hypsodoniy but from the available material

ihe teeth seein to be hypsodonc.

The lower incisons are medmm-sized with cllipti-

cal-rounded crowns and well devcloped cusps.

The paraconid is moderately dcveloped in p2.

llie parosty^id is moderately devcloped; its lingual

border does not exceed the middle of the meta-

conid. It is also closed from ail sides, suggesting a

“stenonine” ty'^pe horse (Eisenmann 1981, fig. 3).

Fig. 2. — Equus stenonis cf. vireti, Volax, Macedonia, Greece. A, maxilla with P2-M3 dex and P2-M2 sin, VOL-203: B, right toothrow

of the maxilla VOL-203: C, left toothrow of the maxilla VOL-203.

I 644

GEODIVERSITAS • 1997 • 19(3)

Equus stenonis from middle Villafranchian of Macedonia

The metaconid is roundcd, the metastylid ellipti-

cal-rounded and the entoconid squarish in the

premolars and elliptical in the molars. The lingual

Wall of both metaconid and metastyUd is convex.

The linguaflexid is V-shaped and deep, like in the

“stenonine” type horses (Aizaroli 1965; De Giuli

1972; Eiseiimann 1981). The linguaflexid is shal-

lower in the premolars than in rhe molars; in rhe

latter it sometimes touches the eaollexid. The lat-

ter is V-shaped, open and shallow in the premolars

but deeper and narrower in the molars. There is a

simple and very small rudimentary pli caballinid

which tends to disappear in the more worn tecth

(ml of VOL-208). The enamel at the preflexid’

borders' is simple, while the postflexid has plicated

or crenulated enamel in its buccal border.

Milk dentition

A unique complète lower milk tooth row with

slightiy worn teeth is availablc. The paraconid in

dp2 is moderatcly developed. The parasrylid in

dp3v4 is well developed and closed, The enamel

at the flcxid's borders is simple, wirhout plica-

tions. The linguaflexid has open-V shape, while

Fig. 3. — Equus stenonis cf. vireti, Volax, Macedonia, Greece. A, mandible with both toothrows, VOL-202; B, left toothrow of the

mandible VOL-202: C, right mandibular ramus with dp2-dp4, VOL-204; D, right milk toothrow of the mandible VOL-204.

GEODIVERSITAS • 1997 • 19 (3)

645

Equus stenonis from middie ViUafranchian of Macedonia

index (= distal articular breadth X 100/height) is

20.1, indicating a relaiively robust metapodial.

The kcel index (= distal articular breadth

X 100/max DAP of the kecl) is 129.9, indicatinga

moderatel)' dcvelopcd kecl. In the availablc nieta-

carpals therc Ls no fusion oftlie lareral metapodials

with the central one, the proximal part is flatiencd

and the anteroposreriot dlamcter of the proximal

articular facec is short, 'fhe suprarticular fossae are

sharp in the anterior lace of the distal part with

various deprh, whÜe in rhe postenor face the kecl

is not ver\' high. AN these features of the metacar-

pals are characreristic for rhe stenonoid horses

(Gromova 1949; DcGiuli 1972).

Metatarsals. Thèse arc short and robust; the

sienderness index is I7> indicating a robust meta-

tarsal. Morphologically, Ln rhe posterior surface

of the discal part, there are rwo fossae separated

by a slighc crest indicating a stenonoid horse

(De Giuli 1972). In the stenonoid horses ihe

metararsals relative to the metacarpals are shorter

A PROTOCONE INDEX

B POSTFLEXID INDEX

Fig 5. — Comparative diagram nt Protocone index (A) and

Poslflexid index (B) lor the leelh of various stenonoid horses. -,

E s. Cf, vkeU, Volax, VOL; E s cf, viretù Dafnero. Gieece

(Koufos & Kosiopoulos 1993): . E s cf. vireti. La Puebfa,

Spain (Eisenmann 1980. l9B1)r ♦. £ s vtrefK Satnt-Vallter.

France (Etsenmann 1980. 1981): ▲, E. s. senezensis, Senèze,

France (Eisehmenn 1980. I98iy, #. E. s. mygdoniensis,

Gerakarou, Greece (Koufos 1992).

(De Giuli 1972). The index heighr Mc III

X lüO/hcight Mt lu ]s 87.6, t/s 84.2 for DPN,

86.5 for La Puebla, 87.8 for Saint*Vallier, 86.5

lor Olivola and 87.5-89 for Gerakaroii horse.

According to ihis character the Volax equid

helongs to the stenonoid horses, as this index for

E. caba/lus ïs 82 (De Giuli 1972).

Astiagalî. rhe rwo availahle a.stragali from Volax

hâve higher than 100 index heighr of the latéral

condylc X 100/niax breadth; rhis index is at

mcan 105 for the Volax equid, whilc in the

caballoid populations ic is 96.3 (De Giuli 1972).

The crest distinguishing the facer.s for navicular

and cuboid is very sharp and the facet for cuboid

is very oblique. These two morphological fea¬

tures suggesr a stenonoid horse (Gromova 1949;

De Giuli 1972).

First phalange.s. These are relatively short and

robust; ibe anteriot first phalanx is slenderer than

ihe posterior one. The rrigonum phalangis is

rclatively short: the index max length of trigo-

nuni phalangis X 100/heighr is 56. l vs 70-74 for

the caballoid honses (De Giuli 1972). Thus, in

this feature, clic Volax horse is similar to the .ste*

nonoid horses. The second phalanges are short,

robust and anteroposteriorly llancned.

DISCUSSION

As referred in the description, the Volax equid

has dental and postcranial morphology and pro¬

portions similar to chose of E. stemnE. However

there are scveral subspecies of E. stetioms descri-

bed from various European localitics. l'wo well

known subspecies are known from Macedonia:

E. s. cf. uireii Irom the locality of “Dafnero”

(DFN), western Macedonia. Greece (Koufos &

Kostopoulos 1993), and E. s. mygdoniemE Irom

the localic)^ of “Gera-karou-l” (GER), Mygdonia

basin, Macedonia, Greece (Koufos 1992). A .ste¬

nonoid horse referred as £. stennnis is known

from Thessaly (Symeonidis 1991-1992). A

small-sized stenonoid horse similar to thac from

Gerakarou is aiso referred from rhe Grevena

basin as E. s. cf. scTiczensis (Steensma 1988).

Besides these Greek sub-Species there arc scveral

others known from the ViUafranchian of Italy,

France and Spain. The Volax equid will be com-

GEODIVERSITAS • 1997 • 19(3}

647

Koufos G. D. & Vlachou T.

pared with these in ordcr to fmd its relatîonships

with them.

The Dafnero horse is a stenonoid onc which bas

great similariries with that fiom Volax. It is a

large-sized horse with niodcratcly plicated

enamel in thc upper teçrh (an average of six plis

in the premolars and 6.4 plis in the molars).

short protocone with flat lingual border, hypso-

dont teeth, sJightly plicated flexids in the lower

teeth, short and robiist metapodials (Koufos &

Kostoponlos 1993). The protocone index

(Fig. 5A) ol Volax and Dafnero horse is more or

less similrir, while the postflexid index (Fig. 5B)

of the Dafnero horse is high, suggcsring longer

posrflexicl. As the postflexid length dépends

upon the attririon, and as the spécimens from

Volax are few ( l'2), this diftcrcnce is possibly not

valid. The Volax metapodials arc very similar to

rhose of Dafnero (Fig. 6A). In the dlagrams of

figure 6 their Unes are parallel to those of

Dafnero horse, suggesting similar sue and pro¬

portions. Moreover vheir general proportions arc

similar to those of the large stenonoid horses

confirming rheir dcterminarion to E. stejionis.

Similar results are also taken fcom the compari-

son of thc first phalanges (Fig. 7). Thus the horse

from Volax Ls similar to that from the middie

Villafranchian locaiity of DFN and both can

bclong to rhe sanie subspecies.

Another stenonoid horse is known from the loca¬

iity of Sesklon (Thessaly. Greecc). le has large

dimensions; the length of thc lower toothrow is

191 mm (Symeonid.is 1991, 1992). The size of

the First phalanges and astragalus are very close to

tho.se of the VOL equid. Unfortnnarejy therc arc

no measuremencs frojn the metapodials for a

comparison with lhe studied ones; the material

of Sesklon is still on study. However from the

few avai labié data thc Sesklon horse seems to be

very close to those of Volax and Dafnero.

The horse of Là Puebla (Spain), referred as

E. s. cf. virttL is a large-sized stenonoid horse,

similar to die studied one. The upper toothrow

length is 191 mm (Eisenmann 19S0) vs 185 mm

for the Volax equid The protocone index of the

Volax equid is similar to that of the La Puebla

horse; only the protocone index of Pd and M3

from Volax is smallcr chan chat of La Puebla

(Fig. 5A). The postflexid index of thc Volax

horse is smaller in p4 and ml,2 than that of

La Puebla (Fig. 5B). But as thc Volax material is

very scaniy comparadvely to that of La Puebla,

this différence is not sufficiently proved. The

metapodials and first phalanges of the Volax

horse fit vêry wcll with chose of La Puebla; their

size and proportions are rhe same (Fig. 6).

Moreover thc varions indices calculated for die

metapodials of the Volax horse are similar to

chose for the La Puebla one (sec description),

"làking in account ail the above data, thc Volax

and l.a Puebla equids are similar and can be

determincd to the same subspecies.

The subspecies E, s. vireti is known from the

locaiity of Sainc-Vallier (France). Ir is larger than

THIRD METACARPAL

THIRD METATARSAL

F.g. 6. — Logarithmic ratio diagram comparing the metapodials

of lhe Volax equid wilh lhûf*e of E stùnonis from vanous locali-

tios Standard E. t^envonue orwger (ElîSenmann & Beckouche

1986).-, B. s. et. Vfreti, Volax, VOL; -, E s, et. vir&ti. Datnero.

fKûulos & Kostopoulos 1993); . B. s. Of. vireti,

La Puebla. Spam (Eiafthmauf' 1979); i, B. s vireti, Saint-

Vallier. Kiance (Eieenmann 19?9). •, E s. mygdoniensis,

Geiâkarou, Grftece (Koufos 1992); ■. E. s, stenonis. Oüvola,

lla:y (DeOtuli 1972).

648

GEODIVERSITAS • 1997 • 19(3)

Equus stenonis from middle Villafranchian of Macedonia

the Volax horse wirh relatively higher pmtocone

and posrflexld indices except rhose of P2 and p2

(Fig. 5). The toothrow length is 182-196 mm

(mean 197.5 mm) for the upper and

176-199 mm (mean 190 mm) for the lowcr jaw

(Prat 1968). The toothrow length of the Volax

horse is inco the ranges of variation for E. s,

but its mean values are slightly sraaller than

thosc of Saint-Vallicr. However che metapodials

of E. s. vircti hâve similar height with rhose from

Volax but their proportions are larger, îadicating

slightly more robust metapodials than those of

Volax (Fig. 6). This différence is clearer in the

^ FIRST ANTERIOR PHALANX

0.18

0.16

0.14

0.12

0.1

0.08

0.06

0.04

0.02

- 0.02

r 3 4 5 6 7 9

B FIRST POSTERIOR PHALANX

0.16

0.14

0.12

0.1

0.08

0.06

0.04

0.02

r 3 4 5 6 7

Fig. 7. — Logarithmic- ratio diagram comparing lhe first pha¬

langes of the Volax equid with those of F. stenonfs from vanous

localilies. Standard E hemiûnu$ onager (EIsenmann & De Gtuli

1974: Dive & Eisenmann 1991). -, E s. cl. v/reti, Volax, VOL:-.

E s. cf. vlreti. Datnero, Qreece (Koutos & Kostopoulos 1993);

E S- cf. vireti. La Puebla, Spain (Eisenmann 1979),

E s. vireti, Saint-Vallier. France (Eisenmann 1979).

metatarsals. The fîrst phalanx of E. s, vireti is al.so

larger than that of Volax (Fig. 7). Considering ail

these characters the Volax equid has great simlla-

rlries with the type material of E, r. vireti but it is

slightly smaller with slightly slendener metapo¬

dials.

The rypical subspecies E. s. stenonis is known

from the area of Tuscany, Italy (Valdarno»

Olivola, Matasslno). A good description of this

subspecies is given for the material of Olivola and

Matassino by De Giuli (1972). The rooth-row

length IS 187-189 mm for rhe upper and

194-195 mm for che lower jaw; chese values are

close CO those of the Volax sample. The metapo¬

dials from Olivola hâve slightly larger dimensions

than those of Volax, Dafncro and La Puebla,

situated beeween rhem and E s. vireti from

Saint-Vallier (Fig. 6). The maximal diameter of

the anicular facec for the os magnum in Mc III is

significandy longer in the Olivola sample than in

the others (measureraenc 7 Ln Fig. 6A), The dJa-

physis is wider in the Olivola metatarsals than in

the other horses (measiirement 3 in Fig. 6B).

E. s, stenonis is noi very different from E, s, vireth

their skull size îs sîmilar but E. s. stenonis has lon¬

ger metapodials (Az/^roli 1990), The comparison

of the metapodials (Fig. 6) suggests that their

general proportions arc very similar.

AU the Eiiropean siibspecies of E. stenonis are

based on différences in the si/e and proportions

represenring geographical and/or chronological

varieties. Someiimes the few availabic or frag-

mentary material cannot allow a good statistical

analysis evidencing some différences. Three pos-

sibilities can be proposed for these large horses of

the end of Pliocène: (a) to represeru a single sub¬

species of if. stenonis with local varieties; (b) to

represent rwo subspecies, E, s. vireti (La Puebla,

Dafnero, Volax) and E. s. stenonis (Valdarno.

Olivola, Matassino); and (c) to include Dafnero,

Volax and La Puebla to a new subspecies. The

first hypothe^is seems to be the most probable

but since I bave not seen ail this material I can¬

not support it at the moment; a munography

revising ail European stenonoid horses is necessa-

ry in order to clarify their relationships and to

define the valuable spedes and subspecies.

From the Villafranchian localides of Mygdonia

basin (Macedonia, Greece), a stenonoid horse has

GEODIVERSITAS • 1997 • 19(3)

649

Koufos G. D. & Vlachou T.

been dcscribed as E. s. myg€loniemb\ ihe bcuer

sample is that of tlie locaÜty oP ^‘Gerakarou 1”,

GER (Koutos 1992). E. s. myge/onteyisb is smallcr,

with relativeJy slendercr merapodials rhan the

Volax horse. The toorhrow length is 173.5 mm

for the upper and 1 Pï 7.8 mm Idf the lowcr jaw i^s

185 mm and 188.5 mm for the Volax horse res-

pectively. The slcnderness index lu 18.6 for Mc lîl

and 15.9 for Mt III, while in the Volax horse it is

respectivcly 20.1 and 17. The metapodials of die

Gerakarou hor.se have more or less similar heiglu

but their relative proportions arc quite smaller

than those of the studied equid (Ftg. 6). The

horse found in the localicy of Livakos (Grevena

basin) and described a.s E. J. cf. stnezetisis

(Steensma 1988) is smaller than thaï of Volax and

doser to f. s. wygdoniemrs {Kauios 1992).

Concerning ail the above nientîoned descriptive

and comparative data, the Volax horse belongs to

E. stenorm and has' grcaresc similarities with the

forms from Dafnero and La Puebla. It is also

close CO E. s. vbrn from Saint-Valüer. It has as

well some similarities to E. s. stenonis from

Olivola and Matassino. Thus, the Volax horse is

referred as E. s. cf. vireti.

BIOCHRONOLOGY

The Volax horse belongs to the large-sized steno-

noid horses which appeared at the end of

Pliocène. The oldest représentative of Eqtius in

Europe is E. Iwerïzovensis while the first appea-

rence of the genus in Eurasia has been dated at

about 2.5 Ma (Lindsay et al. 1980;

Bonadonna Ôc Alberdi 1987). E. stemnis includ-

ing the late Pliocene-early Plei.stocene horse.s

with sevcral forms, allowed the subdivision of

that time span (Bonadonna & Alberdi 1987;

Azzaroli 1990). The Volax horse has some simila¬

rities with E. s. vireti from Saint-Vallier. The

Saint-Val lier localicy has been dated to late

Pliocène, MN17 (Mpin 1990). According ro

Torre et al. (1992) the Saint-Vallier locality

belongs ta the Saint-Vallier Faunal Unit corres-

ponding to the end of rtiiddle VÜlafranchian.

The horse of Volax is very similar to that of

Dafnero (Greccc) and La Puebia (Spain). The

Dafnero locality has been dated to middle

FAUNA

VOL

DFN

PUE

STV

OLI

Macaca cf fforenPna

sp.

Paradolichopithecus

arvemensts

Anapcus arvemensis

Archfdishodon menodionalis

ElApbantiUiae Indot.

Nycieroulos rnegafffSstoides

Vulpûs alopecûideS'

prapcorsi^c

Can/e*cf, falconer

Canis otrascus

Ursîus, i>fTu/;cus

BottdSQioe fêlinos

Pltahyatma pernen

Plloh/anna bwvirostris

cf.

Chasmaporthetos tunensis

Moijanlareon magantereon

Lynr isshdorensis

Aanonyx pardimmcis

Pànîdvrs ((ChautH

cf.

Pantdera gombasiongensis

Molasi thoréill

Enhydriala nrdaa

Homotfwn'um satmeili

Homothonum cmrtafidens

Equus .^tanonis s/irati

cf.

Equu 9 sianonla ^lanonis

Diccrorh/nus t*tnjscu$

Rhinocorottdae rdot

Sus »lroz/i(

MiiHarfoftitfnum nfatpnii

Euaadocùros senccensis

Euc(adoinafo& ôicramos

“Carvuÿ'' phitisi

CrouPtacoTos ramosus

Laptohofi êtanomatopon

Loprodos atruscüs

Loptobos:

cf.

GafatioapifS toaàxtfpis

cf.

Gdlfogorat menegfvnii

cf.

Ga^olla tjouvraini asp.

sp.

Oaj0llà ùo.^onica

Procamptoceras bnvatense

?sp

Antilopinae indet.

■f

Fig 8. — Faunal list: VO. Volax (Sickenberg 1967. 1968a. b;

Kostüpoulos 1996); DFN. Dafnero (Koufos 1993; Koufos &

Kostopoulos 1993. 1997; Kostopoulos 1996); PUE. La Puebia

(Aguirre & Morales 1990), STV, Saint-Vallier (Heintz ef a/.

1974), OU. Olivola.

Villafranchian (zone MN178 of Mein 1990; or

MNQI7 of Guérin 1990), (Koufos et ai 1991;

Koufos 1993; Koufos & Kostopoulos 1993;

Kostopoulos & Koufos 1994, Kostopoulos

1996). The locality of La Puebia is also dated to

middle Villaffauchian, MN17 and is considered

siighily yuunger rhan that of Saint-Vallier (Mein

1990). Taking into accouiu the above mentioned

similarities of the Volax horse with those from

650

GEODIVERSITAS • 1997 • 19(3)

Equus stenonis from middle Villafranchian of Macedonia

Simpson’s Index VOL

DFN

PUE

STV

OLI

VOL 100 100

75 62

77 63

DFN

100 100

91 69

PUE

100 100

STV

100

OLI

100

Pickford’s Index

VOL

DFN

PUE

STV

OLI

VOL

8 23

DFN

4 18

PUE

0 0

STV

Fig. 9. — Faunal similarities indices of Simpson and Pickford, calculated for the localities of figure 8. The left number is at generic

level and the right number at spécifie level.

the orher localiries, a similar âge can be proposed

for the localicy of Volax.

The material collected from Volax has been

determined by Sickenberg (1967, 1968a, b) and

the following ^pecies are referred: Megantereon

megantereon megantereon, Nyctereutes megamas-

toides megarruistoidesy Vulpes praeconacy Bosdaglus

felinusy Felts {Lynx) issiodorensis^., Macedonithe-

riurn martinii, Leptohos sp., Nemorhedut sp-,

Guzetla sp., Gazelloapira sp., Oidernpjk^eros spo

E(juus {Allohippîis) sp. and Prnhosc'tdea inder.,

whilc an earliest Pleistocene âge has been propo¬

sed. However lhe presence of Nyctereutes in the

Volax fauna suggests an older âge; the genus has

been replaced by Canis ar the beginning of latc

Villafranchian (lorre et al. 1992). Thus the

Volax fauna must be older than Early Pleis¬

tocene. The recent srudy of the bovids and cer-

vids from VoUix (Fig. 8) and their comparison

with rhose of rhe other Greek and Kuropean

localities suggest also a middle Villafranchian

(MNl7a) age (Kostopoulos & Koutos 1994;

Kostopoulos 1996). This age confirms the above

mennoned age proposed for the studied equid.

As ic was referred beforc, the Volax equid is simi¬

lar or has similarities with that from Dafnero,

La Puebla, Saint-Vallier and Olivola. A compari¬

son of the whole fauna from Volax with those of

the above mencioned localities is necessary ro

establish the.se similarities.The faunal composi¬

tion of Volax is similar to that of Dafnero,

La Puebla and Saint-Vallier (Fig. 8). The simila-

rity index of Simpson is high, both in generic

and spécifie level, wbile the distance index of

Pickford is small (Fig. 9), indicating strong fau¬

nal similarities. The différences in the faunal

composition are referred in the absence of sonie

small carnivores (Fig. 8), whlch are difflcult to be

pre&erved pre- and posr-mortem. Taxonomical

problcms cause ai.so somc différences in the com^

position of rhe fauna. The ursid Basdagius is

known only from Volax and po.ssibly represents a

form of tire genus Lksus.

However rhe Olivola fauna differs more from the

orhers and seems to be younger. The Simpson

index is small and the Pickford index is high

both In generic and spécifie level indicacing the

differcndaiion of ihe Olivola fauna from the

ochers (Fig. 9). The presence of Canis etrnscus,

Pliohyaena brevirostris and Panthera gombaszoe-

gensis indicates a younger age for the Olivola

fauna. As menrioned before, Canis etruscus cor¬

responds to the beginning of early Pleistocene

(Toitc et al 1992). The large-sized Pliohyaena

brevirostris appeared in Europe at early

Pleistocene in Olivola fauna (Torre et al. 1992).

However, in Greece, this species has appeared

earlier in the Gerakarou fauna, where ic was

found together with IHiahyaena penieri. The

Genikarou fauna has been dared ar the rransitioii

berween Pliocene/Pleisracene (Koufos 1992:

Kostopoulos 1996). Panthera gombaszoegensis aiso

characterizes ihe beginning of lare Villafranchian

(Azzaroli et al 1988) and its presence in the

GEODIVERSITAS • 1997 • 19(3)

651

Koufos G. D. & Vlachou T.

Olivola fauna indicatcs a j^ungcr agc tlian that

of Volax. Da/nero, La Puebla and Saint-Vallier.

In the lasc rwo localities the more primitive

Panthera schaubi is présent. The Volax fauna pré¬

servés more primitive characters and corresponds

CO Saint-Vallier Faunal Unit of Torre et al.

(1992). These faun;il similarities of the Volax

material with rhe other localities rcflcct aiso âge

similarities and a middle VÜIafranchian âge is

proposed for ihe local ity of Volax.

Acknowledgments

We thank very much Prof. A. Azzaroli and

Dr V. Eisenmann for their useful comments on

the manuscripts.

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— 1990. —The geiuis Eeims in Europe: 321-356, in

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di.stinctifs des premières phalanges anrdrieuivs et

posicrieures chez certain équidés actuc!.s et fossiles.

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Centre d Etudes et de Documentation, PaUontologie

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Européen Neogene Mamnial Chronofogy, Plénum

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Bureau de Recherches Géologiques et Adinières, Paris

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KostopoulovS D. S. 1996. — The Plio^Pleistocenc artio-

dactyls of Alacedonia, Greece. Systematics,

PaLïcoecology, biocbronology, biostraügraplty: 1 -532.

Ph. D. Thesis. IJniversity of J'hessalonîfd.

Kostopoulos D. S. & Koufos G. D. 1994. — J'he

Plio-Plcistocenc artiodactyls of Maccdonia

(Northern Greece) and iheir bitJsrrarigraphic signi-

Picance; prcliminary report. Compte Rendus de

VActidémie des Sciences, Paris 318 : 1267-1272.

Koufos G. D. 1992. — Early Pleiscoccne equids from

Mygdonia basin (Maccdonia, Grccce). Paleonto-

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(3/4): 357-376.

Koufos G. D. 3c Kostopoulos D. S. 1993. — A sreno-

noid horse (Equidae. Mammalia) from the

Villafranchian of Western Maccdonia (Greccc).

Bulletin Geolagicat Society of Grcece 28: 131-143.

— 1997. — Somc carnivores from die Villafranchian

of Maccdonia. Grccce with the description ofa riew

cajïid. Münchenet Geowi^ensebaften 33-63.

Kouhis G- D., Ko.stopoulos D. 5. de Koliadimou K. K.

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le Villafrandiien de ^4acédoI^e occidentale (Grèce).

Comptes Rendus de l'Académie des Sciences, Paris,

série IL 313:831-836.

Lindsay C. H., C^pdykc N. D. & Johnson N. M.

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laie cenozoic mammalian dispersai events. Nature

287: 135-138.

Mein P. 1990. — Updaung of MN Zones: 73-90, in

652

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Lindsay E. H., Fahlbusch V. & Mein P. (eds),

European Neogene Mammal Chronology. Plénum

Press.

Prat F. 1968. — Recherches sur les équidés pleistocènes

en France. Thèse de Doctorat d’Etat, Université de

Bordeaux : 1-325.

Sickenberg O. 1967. — Die unterpleistozane Fauna

von Wolaks (Griech. Mazedonien). 1. Eine neue

giraffe {Macedonitherium martinii nov. gen. nov.

spec.) aus dem unteren Pleistozân von Griechen-

land. Annales de Géologie des Pays Helléniaues 18 :

314-330.

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Volax (Griech. Mazedonien). Geologische Jahrbuch

85: 33-54.

— 1968b.— Die unterpleistozane fauna von Wolaks

(Griech. Mazedonien). II. Die Carnivoren. Annales

de Géologie des Pays Helléniques 19 : 621-646.

Steensma J. J. 1988. — Plio~Pleistozane Grossàugetiere

(Mammalia) aus dem Becken von Kastoria-Grevena,

südlich von Neapolis-NW Griechenland\ 1-315.

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early Pleistocene (Villafranchian) âge from the

basin of Sesklon (Volos). Annales de Géologie des

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Pleistocene of Western Europe. Courier Forschung

Institut Senckenberg 153: 51-58.

Submitted for publication on 13 May 1996;

accepted on 28 August 1996.

GEODIVERSITAS • 1997 • 19(3)

653

Koufos G. D. & Vlachou T.

APPENDIX

MEASUREMENTS AND STATISTICS

Mandible

VOL-202

VOL-204*

-156

95.2

91.5

188.5

110.5

110

57.7

79.5

63.7

37.2

{24}

140

Tablé 1 . — Equus stenonis cf. vireti. Volax, Macedonia. Greece.

Mandible. *. VOL-204 is a hemimandible wilh milk teeth. 2,

muzzie langth. middie of the line connecting the anterior borders

of p2 to a point situated between the iwo h: 3. premoiar length

(alveolar); 4, molar length (aiveolar); 5. toothrow length (alveo-

lar): 7, muzzie breadth: breadth at the posterior borders of i3;

10, height of the jaw behind m3; 11, idem between p4 and m1 ;

12, idem in front of p2:13, symphysis length; 14, minimal breadth

of the symphysis: 16. length of diastema p2-i3.

VOL-203 VOL-209

dex sin

41.8

39.6

41.3

27.8

28.0

28.2

6.8

6.3

6.4

5.7

5.4

5.8

16.3

15.9

15.5

30.4

30.8

27.3

28.7

7.7

7.6

6.0

5.4

25.3

24.7

29.5

29.8

29.5

9.4

5.2

31.5

26.4

29.0

29.2

8.4

•

5.0

29.0

26.9

{30.4}

27.4

9.6

4.4

35.7

31-4

23.3

10.0

3.3

31.8

Table 2. — Equus stenonis cf. vireti, Volax. Macedonia, Greece.

Upper permanent cheek teeth. Lo, occlusal length; Bo, occlusal

breadth: Lp. protocone length; Bp, protocone breadth; PI, proto-

cone index.

654

GEODIVERSITAS • 1997 • 19(3)

Equus stenonis from middle Villafranchian of Macedonia

dex

VOL-202

sin

37.5

36.5

Bo ant.

14.2

13.1

Bo post.

16.7

17.0

Lprfl

9.0

Lptfl

15.0

13.5

40.0

37.0

31.2

Bo ant.

17.7

18.4

Bo post.

17.4

19.0

Lprfl

9.4

9.8

Lptfl

12.4

13.4

39.7

42.9

30.5

29.6

Bo ant.

17.0

17.8

Bo post.

17.4

19.0

Lprfl

9.4

9.2

Lptfl

12.2

12.6

40.0

42.6

28.0

27.7

Bo ant.

17.4

17.0

Bo post.

16.8

18.2

Lprfl

7.6

7.8

Lptfl

9.0

9.8

32.1

35.4

30.0

Bo ant.

16.2

Bo post.

Lprfl

7.8

Lptfl

10.1

33.7

33.3

Bo ant.

15.8

Bo post.

13.6

Lprfl

7.4

Lptfl

9.4

28.2

Table 3. — Equus stenoni cf. vireti, Volax, Macedonia, Greece.

Lower permanent cheek teeth. Lo, occlusal iength; Bo ant.,

anterior occlusal breadth: Bo post., posterior occlusal breadth;

Lprfi, prefiexid Iength; Lptfl, postflexid Iength; IF, postflexid

index.

Humérus n x min max s v

37.05

36.5

37.6

0.78

2.10

45.60

44.9

46.3

0.99

2.17

82.50

81.0

84.0

2.12

2.57

87.53

85.2

89.6

2.35

2.69

50.17

47.2

52.7

2.78

5.53

40.00

44.73

43.1

46.5

1.70

3.81

Table 4. — Equus stenonis cf. vireti. Volax. Macedonia. Greece.

Humérus. 3, minimal breadth (oblique); 4, diameter perpendicu-

lar to and at the level of 3; 7. maximal breadth of the trochiea:

8, distal maximal depth; 9. maximal trochlear height (médial);

10, minimal trochlear height (in the middle); 11. trochlear height

at the sagittal crest (near the condyle).

GEODIVERSITAS • 1997 • 19(3)

655

Koufos G. D. & Vlachou T.

Radius n x min max s v

362.80

343.00

44.10

43.9

44.4

0.26

0.60

30.50

28.5

33.0

2.29

7.51

75.70

[36]

80.90

65.95

65.4

66.5

0.78

1.18

39.30

78.65

78.1

79.2

•

25.50

25.0

26.0

16.90

Table 5. — Equus stenoni cl vireti, Volax, Macedonia, Greece.

Radius. 1- length: 2. médial length: 3. minimal breadth

of diaphysls; 4, DAP oï the diaphysts at the level of 3; 5. proxi¬

mal articuiar breadih; 6, proximal adicuiar DAP. 7, proximal

maximal breadth: 6, distal articuiar breadth: 9, distal articuler

DAP: 10. distal maximal breadth: 11. diameter ot the articuiar

facet for navicular. 12. /dem fonriqueirum

Mc Ml n X min max s v

241.45

236.4

246.5

241.70

241.7

35.85

35.5

36.2

28.70

28.3

29.1

52.00

33.80

44.00

17.00

7.50

48.93

47.4

50.0

1.12

2.27

48.55

47.4

49.7

1.10

2.27

35.80

33.9

37.2

1.39

3.90

27.53

27.0

27.9

0.38

1.40

30.18

29.1

31.5

0.91

3.03

8.00

7.5

8.5

•

Table 6. — Equus stenonisci. vireti, Volax, Macedonia, Greece.

Third metacarpal. 1, maximal length; 2. internai length; 3, bread¬

th of ihe diaphysis (in the middie); 4, DAP* idem ai lhe level of 3;

5. proximal articuiar breadth: 6, proximal articuiar DAP; 7. maxi¬

mal diameter oi the articuiar face! (or os magnum: 8. diameter of

the ar^terior facei for hamatum: 9, diameter of lhe articuiar facet

for Mc M; 10, distal maximal supra-articular breadth: 11. distal

maximal articuiar tyeadth; 12, distal maximal DAP of the Keel;

13. distal minimal DAP of the latéral oondyle. 14, distal maximal

DAP of the médial condyle; 16. diameter for lhe articuiar lacet

for Mc III.

Tibia

min

max

46.80

45.4

47.7

1.00

2.14

32.63

31.3

33.5

0.96

2.93

74.1

61.1

71.23

68.5

75.9

3.32

4.66

47.00

44.3

49.2

2.03

4.32

17.0

Astragalus

VOL-196

VOL-197

65.8

[63.2]

30.6

28.8

64.7

51.3

[55.5]

34.5

48.5

Table 7. — Equus stenonis cf. vireti, Volax, Macedonia, Greece.

Tibia. 3. minimal breadth ot the diaphysis; 4, DAP of the diaphy¬

sis ât the level of 3; 5, proximal maximal breadth: 6. proximal

maximal depth; 7. maximal distal breadth; 8, maximal distal

DAP; 9, length of the fossa digitalis.

Table 8. — Equus stenonis cf. vireti, Volax, Macedonia, Greece.

Astragalus. 1, maximal length (height) articulation surface for

navicular-top of the internai condyle; 2, meximaJ diameter ot the

internai condyle; 3, irochlear breadth: mIddIe of the Internal-

middle of the external condyles; 4. maxtmal breadth (in projec¬

tion). 5. distal articuiar breadth; 6. distal articuiar DAP;

7, maximal DAP ol lhe inlernal condyle.

656

GEODIVERSITAS - 1997 • 19 (3)

Equus stenonis from middle Villafranchian of Macedonia

Mt III

min

max

275.50

270.0

281

35.60

33.7

37.3

1.31

3.68

32.94

31.4

34.6

1.14

3.46

49.80

47.0

2.55

5.13

38.25

38.0

38.5

47.50

47.4

47.6

11.50

10.7

11.9

0.47

4.12

6.4

40.70

47.3

1.11

2.29

47.65

46.2

49.5

1.31

2.75

36.44

34.5

37.9

1.16

3.2

26.72

25.4

27.5

0.82

3.08

30.94

29.3

31.7

0.97

3.12

Phalanx 1 VOL-181

VOL-182

VOL-183

VOL-184

VOL-185

78.4

84.6

81.8

71.4

74.9

32.5

33.5

34.2

55,7

54.2

44.7

54.6

37.0

37.4

29.3

44.1

43.0

46.2

47.1

42.1

45.0

46.4

23.7

24.4

25.2

42.0

•

50.1

45.5

Phalanx II

VOL-186

VOL-187

48.6

46.7

34.3

33.2

45.4

45.2

53.8

52.2

33.6

32.7

49.5

48.1

Phalanx III

VOL-188

VOL-189

VOL-190

VOL-191

57.3

47.8

55.7

47.8

50.5

49.8

67.3

37.1

41.4

38.8

40.8

Table 9. — Equus stenonis cf. vireti, Volax, Macedonia, Greece.

Third motatarsai. 1. maximal lengih: 3. breadlh o1 diaphysis

(In the middte) 4, DAK idem at tho fovel ot 3; 5. proxtmal articu

lar breadiin, 6. proximal anicular DAP; 7, maximal dlamatar of

the articular lacet for the cuneiforni; 6. diameter o! the anicular

tacet #or cuboid: 9. idem for cunoiform II: 10, distal maxirpai

supra-dificular hreadih, 11. maximal aniCülar breaclth;

12. distal maximal DAP o( lhe keel; 13. dietal minimal DAP

the latéral condylo; 14, distal maximal DAP of lhe medial con

dyle.

Table 10. — Equus stenonis ci. vireti, Volax, Macedonia,

Greece. First phalanx of lhe third digil, 1, maximal length:

2, anterior length: middle of lhe proximal articular facst-middle of

the distal facet, 3. minimal breadth of the diaphysis: 4, proximal

breadth: 5. proximal DAP; 6. distal breadth at the tuberosilies;

7. distal articular breadth; Ô, distal articular DAP; 9. minimal

length of the trigonum phalangis.

Table 11. — Equus stenonis cf. vireti, Volax, Macedonia,

Greece. Second phalanx of the third digit. I, maximal length,

2, anterior length (as in the firsl phalanx): 3, minimal breadth of

the diaphysis; 4, maximal proximal breadth; 5. proximal DAP;

6, distal articular maximal breadth.

Table 12. — Equus stenonis cf. vireti. Volax, Macedonia,

Greece. Third phalanx of the third digit. 1, length from the poste-

rior edge of the articular surface to the tip of the phalanx;

2, anterior length; 3, maximal breadth; 6, maximal height.

GEODIVERSITAS • 1997 • 19(3)

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R^érences bibliographiques

Denison R. H. 1978. — Placodermi, in Schultzc

H. P. (ed.), Handhook of Paleoichthyology,

Volume 2. Custav Fischer, Stuttgart, 128 p.

Marshall C, R. 1987. — Lungfish: phylogeny and

parsimony, in Remis W. E., Burggien W. W.

& Kemp N, E. (eds), The Biology and

Evolution of Lungfishe.s, Journal of Morphology

1 : 151 - 162 .

Schultze H. P. & Arsenault M. 1985. — The pan-

derichthyid fish Elpistostege: a close relative to

tetrapods? Paleontology 28; 293-.509-

Schultze H. P. 1977a — The origin of the tetra-

pod limb within the rhipidisrian fishes:

541-544, in Hecht M. K., Goody P. C. &

Hecht B. C. (cds), Major Patterns in Vertebrate

Evolution. Plénum Press, New York and

I^ndon.

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3 cm and ail p^es numbered. The original figures

should bc sent wûh the revised manuscript, as well

as a 3.5” disquette Apple Macintosh ur IBM-com-

patiblc (Word, Word Pcrfect...) format, which will

also contain tables and possibly figures (Adobe

lUustrator, Photoshop; Dcneba Canvas).

Format

Papers are to be written in simple and concise

French or English. They should be organized as fol-

lows:

— a bràef litle:

— a suggested running head;

— namc(s) of author(s), followcd by their full pro-

fessional addres.s(es) and, if po.ssible, Fax number

and e-mail;

— abstracts (in English and French) not exceeding

800 signs each, with key words and ‘*mots clés”;

— text with italicized words for Latin (taxa of gene-

ric and spécifie tanks, errf/.,...);

— référencés to authors in main text should be pre-

sented, in lower case, as follows: Smith (2001),

Smith (2001, 2002), (Smith 2001), (Smith 2001;

Cary 2002), Smith (2001; l), Smith (2001, fig. 2);

— référencés to îllusuations and tables should be

indicated as follows: (Fig. 1), (Fig. 2A, D), (Figs 3,

6), (Figs 3-5), (Table 1);

— keep acknowlcdgemcnrs short and place them at

the end of the text before références; picasc do not

660

GEODIVERSITAS • 1997 • 19(3)

Instructions aux auteurs

forget che revisers;

- give captions to illustrations on a separate sheet.

Illustrations

The éditorial board will pay spécial attention to the

quality and pertinence of illustration.

Line drawings must be in Indian ink or high quali¬

ty laser printouts; high contrast phorographs, pla-

ced on white or black backgrounds, arc required.

These can be grouped into figures and identified

by letters A, B, C ... Plates are not placed at the

end of the article: they will be considcred as figures

and numbered as such. Arrange figures to fit one or

two columns (70 x 190 mm or 144 x 190 mm).

Associate interprétation of photograph with line

drawing. No diagram or table is to exceed one

page. Letters, numbers, etc., for each figure, are to

be indicated on an accompanying overlay, not on

the original figure (line eut or half-tone). A scale

bar is needed for each figure.

Référencés

Denison R. H. 1978. — Placodermi, in Schultze

H. P. (ed.), Handbook of Paleoichthyology.,

Volume 2. Gustav Fischer, Stuttgart, 128 p.

Marshall C. R. 1987. — Lungfish: phylogeny and

parsimony, in Remis W. E., Burggren W. W.

& Kemp N. E. (cds), The Biology and

Evolution of Lungfishes, Journal of Morphobgy

1: 151-162.

Schultze H. P. & Arsenault M. 1985. — The pan-

derichthyid fish Elpistostege: a close relative to

tetrapods? Paleontology 28: 293-309.

Schultze H. P. 1977a. — The origin of the tetra-

pod limb wirhin the rhipidistian fishes:

541-544, in Hecht M. K., Goody P. C. &

Hecht B. C. (eds), Major Patterns in Vertebrate

Evolution. Plénum Press, New York and London.

Proofs and reprints

Proofs will be sent to the first author for correction

and must be returned within eight days by express

mail. Authors will receive twenty-five offprints free

of charge; further offprints can be ordered on a

form supplied with the proofs.

The submission of a manuscript to Geodiversitas

implies that the paper, or a similar one, is not being

offered for publication elsewhere. Copyright of

published paper, including the illustrations,

becomes the property of the journal. Requests to

reproduce material from Geodiversitas should be

addressed to the editor.

GEODIVERSITAS • 1997 • 19(3)

661

Mise en page

Noémie de la Selle

Packaging Editorial

Achevé d’imprimer

sur les presses de l’Imprimerie Durand

28600 Luisant (France)

Dépôt légal n° 64880

Printed on acid-free paper

Imprimé sur papier non acide

Date de distribution le 30 septembre 1997

Couverture : Poteriocrinus (Carbonifère, Louisiane)

geodiversitas

1997 * 19 ( 3 )

505

515 •

^ Gagnier P.-Y. & Goujet D.

Nouveaux poissons acanthodiens du Dévonien du Spitsberg

Long j. A.

Ptyctodontid fishes (Vertebrata, Placodermi) from the Late Devonian Gogo Formation, Western

Australia, with a révision of the European genus Ctenurella 0rvig, 1960

557

567

^ Poplin C. U Lund R.

Evolution of the premaxillary in the primitive fossil actinopterygians

, Godefroit P. & Battail B.

Late Triassic cynodonts from Saint-Nicolas-de-Port (north-eastern France)

653 •

641

Zouhri S. & Ginsburg L.

Les hipparions du gisement miocène supérieur d'Aubignas (Ardèche, France)

^ Koufos G. D. & Vlachou T.

Equus stenonis from the middie Villafranchian locality of Volax (Macedonia, Greece)

Vente en France

Muséum national d'Histoire naturelle

Diffusion Delphine Henry

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Conception Graphique : Isabel Gautray

ISSN : 1280-9659