ISSCA

International Society for the Study

and Conservation of Amphibians

(International Society of Batrachology)

SEAT

Laboratoire des Reptiles et Amphibiens, Muséum national d'Histoire naturelle, 25 rue Cuvier, 75005

Paris, France. - Tel.: (33).01.40.79.34.87. — Fax: (33).01.40.79.34.88. - E-mail: dubois@mnhn.fr.

BOARD FOR 1997

President: W. Ronald HEyER (Washington, USA).

General Secretary: Alain Dugois (Paris, France).

Treasurer: Jean-Louis DENIAUD (Paris, France).

Deputy Secretari ritta GRILLITSCH (Wien, Austria); Stephen J. RICHARDS (Townsville, Australia).

Deputy Treasurers: Julio Mario Hoyos (Paris, France); Mark L. WyGoDaA (Lake Charles, USA).

Councillors: Janalee P. CALDWELL (Norman, USA); C. Kenneth Dopp, Jr. (Gainesville, USA); Marissa

FABREZI (Salta, Argentina); Frank GLAW (Bonn, Germany); Jon LOMAN (Lund, Sweden).

TARIFF FOR 1997

Individuals Institutions

Subscription to Alytes alone 280 FF /56$ (regular) 560 FF/112$

140 FF /28 $ (student)

Subscription to Alytes + ISSCA + Circalytes 300 FF / 60 $ (regular) 600 FF /120$

150 FF / 30 $ (student)

Back issues of Alytes: single issue 70FF/14$ 140 FF/28$

Back issues of A/ytes: one complete volume (4 issues) 225 FF/45$ 450 FF/90$

Back issues of A/ytes: complete set volumes 1 to 14 2520 FF/504$ 5040 FF / 1008 $

Five-year (1997-2001) individual subscription to A/ytes: 1120 FF / 224$.

Five-year (1997-2001) individual subscription to Alytes + ISSCA + Circalytes: 1500 FF / 300 $.

Life individual subscription to Alytes from 1997 on: 5600 FF / 1120 $.

Life individual subscription to Alytes + ISSCA + Circalytes from 1997 on: 7000 FF / 1400 $.

Patron individual subscription to Alytes from 1997 on: 11200 FF / 2240 $ or more.

Patron individual subscription to Alytes + ISSCA + Circalytes from 1997 on: 14000 FF / 2800 $ or

more.

Important notice: from 1996 on, any new life or patron individual subscriber to A/ytes will be offered a free

complete collection of back issues of A/ytes from the first issue (February 1982) until the start of her/his

subscription.

Circalytes is the internal information bulletin of ISSCA. Back issues of this bulletin are also available:

prices can be provided upon request by our Secretariat.

Inclusive Section or Group affiliation to ISSCA: 250 FF / 50 $.

Individual subscription to the ISSCA Board Circular Letters: 200 FF / 40 $.

MODES OF PAYMENT

— In French Francs, by cheques drawn on a French bank payable to “ISSCA”, sent to our Secretariat

(address above).

— In French Francs, by direct postal transfer to our postal account: “ISSCA”, Nr. 1-398-91 L, Paris:

if you use this mode of payment, add 15 FF to your payment for postal charges at our end.

— In US. Dollars, by cheques payable to “ISSCA”, sent to Mark L. WyGoDA, Department of Biological

and Environmental Sciences, PO. Box 92000, MeNeese State University, Lake Charles, Louisiana

70609-2000, U.S.A.

Source : MNHN, Paris

AITTES

INTERNATIONAL JOURNAL OF BATRACHOLOGY

June 1997 Volume 15, N° 1

Alytes, 1997, 15 (1): 1-12. 1

A review of the fusion of trigeminal

and facial ganglia during larval development

of some neobatrachian anurans

Marissa FABREZI & Teresa CHALABE

Museo de Ciencias Naturales,

Universidad Nacional de Salta, Mendoza 2, 4400 Salta, Argentina

The intracranial relations of the trigeminal (V) and facial (VII) nerves have

been examined in larval sequences of Ceratophrys cranwelli, Dermatonotus

muelleri, Hyla pulchella andina, Lepidobatrachus llanensis, Phyllomedusa

sauvagii, Physalaemus biligonigerus and Scinax fuscovaria. Whole mounts

stained for peripheral nerves and transverse histologic sections were prepared

for this purpose. H. pulchella andina, P. sauvagi, S. fuscovaria and P.

biligonigerus have the trigeminal and facial ganglia fused at similar stages of

larval development. In later larval stages this fusion progresses to the roots of

these nerves. In early stages of development of D. muelleri the trigeminal and

facial roots are fused; in later larval stages this fusion occurs at the ganglia. C.

cranwelli and L. llanensis have the trigeminal and facial nerves separated

throughout their larval development. In C. cranwelli fusion of the ganglia takes

place before metamorphosis, whereas the separation continues in L. Ilanensis

until metamorphosis ends.

Bibliothèque Centrale Muséum

QUIL

3001 00050383 8

The importance of larval characters in anuran classification has been stressed by

ORTON (1957), STARRETT (1973) and SokoL (1975). Some of these characters have been

incorporated into phylogenetic analyses of the taxon in order to define monophyletic

groups (DUELLMAN & TRUEB, 1985; FORD & CANNATELLA, 1993). Among such characters

one refers to the relation between the trigeminal (V) and facial (VII) nerves.

INTRODUCTION

In the majority of anurans, as distinct from other vertebrates, the ganglia of the

trigeminal and facial nerves are fused in a single prootic ganglion, and all rami of both

nr A

8IBLDU

MUSEUM)

PARIS, Source : MNHN, Paris

2 ALYTES 15 (1)

nerves emerge from the skull through a single prootic foramen, which lies immediately

anterior to the otic capsule (GoopriCH, 1930; DE BEER, 1937). The fusion of these ganglia

was proposed by SokoL (1975) as a derived condition for a group of anurans and their

larvae. Anurans with Type III larvae (Discoglossoidei) have separated trigeminal and

facial nerves, with their rami transversing the skull through two foramina separated by the

prefacial commissure. Anurans with Type IV, II and I larvae (Ranoidei) have a prootic

ganglion and a single cranial foramen for exit of the trigeminal and facial rami. Different

degrees of fusion of the nerve roots among the Ranoïdei tadpoles were mentioned by

SokoL (1975, 1977, 1981).

The Ranoidei proposed by SOKkoL (1975) were later renamed Pipanura by FORD &

CANNATELLA (1993). Fusion of trigeminal and facial ganglia is included among their

synapomorphies, although the information related to this character among the taxa

involved is scant.

The existing information on trigeminal and facial nerves in anurans is summarized in

tab. 1. This calls attention to: (1) the limited number of species in which the character has

been investigated; (2) the lack of uniformity in the information, which makes comparison

difficult, because different stages of ontogeny were studied.

Because data in the literature exist for only six genera, we decided to review this

character in neobatrachian anurans. For this purpose, we investigated premetamorphic

larval sequences of species belonging to three major anuran groups which are not closely

related.

Ceratophrys cranwelli, Lepidobatrachus llanensis and Physalaemus biligonigerus are

included in the “Leptodactylidae”, considered a paraphyletic group (FORD & CANNA-

TELLA, 1993). C. cranwelli and L. lanensis are in a subfamily different from that of P.

biligonigerus (DUELLMAN & TRUEB, 1985).

Hyla pulchella andina, Phyllomedusa sauvagii and Scinax fuscovaria are members of

the Hylidae, a taxon defined by a single synapomorphy (ForD & CANNATELLA, 1993). Both

H. p. andina and S. fuscovaria are grouped in a subfamily different from that of P. sauvagii

(DUELLMAN & TRUEB, 1985).

Dermatonotus muelleri is included in the Microhylidae, whose monophyly has been

supported by some synapomorphies (FORD & CANNATELLA, 1993).

We analyzed trigeminal and facial nerves relation during development in these species

and reviewed the available literature on this subject in order to evaluate an important

character that has been considered in recent anuran phylogenies.

MATERIAL AND METHODS

The larval specimens were examined at different stages up to the beginning of

metamorphosis, in accordance with GosnER’s (1960) table. The larval stages analyzed are

specified for each species because representative specimens of the complete sequence were

not available. The skulls of larvae and adult specimens were also analyzed in order to

Source : MNHN, Paris

FABREZI & CHALABE

Tab. 1. - Condensed information from literature in which there are observations of trigeminal and facial

ganglia and roots, and prefacial commissure in anurans.

Family Specimens | Vand VII | Vand vit | Prefaciat

Genus Author .

(LAURENT, 1986) analyzed | ganglia | roots |commissure

Leiopelmatidae Ascaphus Ontogeny | Separated | Separated | Present

Ontogeny Separated | Separated Present

Leiopelma Ontogeny | Separated | Separate | Present

VAN EEDEN, 1951 Ontogeny | Separated | Separated | Present

STEPHENSON, 1951 Ontogeny | Separated | Separated | Present

Discoglossidae Bombina PUSEY, 1938 Adult | Separated | Separated | Present

VAN EEDEN, 1951 Adult | Separated | Separated | Present

SokoL, 1975 Larval stage | Separated | Separated | Present

Alytes DE BEER, 1937 Larval stage | Separated | Separated Present

PUSEY, 1938 Adult |Contiguous| Separated | Present

VAN EEDEN, 1951 Adult |Contiguous| Separated | Present

Discoglossus PUSEY, 1943 Adult Fused | Separawd | Present

VAN EEDEN, 1951 Adult Fused | Separated | Present

SCHLOSSER & ROTH, 1995 | Larval stage | Separated | Separated ?

Pelobatidae Pelobates PLASOTA, 1974 Ontogeny | Fused ? Absent

ROCEK, 1980 Ontogeny | Fused ? Absent

SokoL, 1975 Larval stage | Fused | Separated | Absent

Scaphiopus SokoL, 1975 Larval stage | Fused Fused | Absent

Pelodytidae Pelodytes SokoL, 1981 Larval stage | Fused ? Absent

Rhinophrynidae Rhinophrynus SokOL, 1975 Larval stage | Fused Absent

Pipidae Xenopus SokoL, 1977 Larval stage | Fused ? Absent

Pipa SokoL, 1977 Larval stage | Fused ? Absent

Hymenochirus SokoL, 1977 Larval sage | Fused ? Absent

PATERSON, 1951 Adult Fused | Separated | Present

Myobatrachidae Heleophryne | VAN DER WESTHIZEN, 1961 | Ontogeny | Fused ? Absent

Pseudophryne| … JACOBSON, 1968 Larval stage | Fused ? Absent

Pleurodema SokoL, 1975 Larval stage | Fused | Separated | Absent

Ranidae Rana DE BEER, 1937 Ontogeny | Fused ? Absent

PUSEY, 1938 Ontogeny | Fused ? Absent

DEJONGH, 1968 Ontogeny | Fused ? Absent

PLASOTA, 1974 Ontogeny Fused ? Absent

Microhylidae Breviceps SWANEPOEL, 1971 Ontogeny Fused Fused Absent

Hspopachus SoKOL, 1975 Larval stage | Fused Fused | Absent

Source : MNHN, Paris

4 ALYTES 15 (1)

verify the state of the foramen for exit of trigeminal and facial nerves. The preparations

studied are listed in app. 1. They have been deposited in the herpetological collections of

the Museo de Ciencias Naturales (MCN), Universidad Nacional de Salta, Argentina, and

of the Fundacién Miguel Lillo (FML), Argentina.

The whole mounts stained for peripheral nerves were prepared with Sudan Black B

and maceration in trypsin (FiLipsk1 & WiLsON, 1984, 1985; NisHiKAWA, 1987). The 10 pm

transverse serial sections were obtained using current histologic techniques, with

hematoxylin-eosine coloration. The whole mounts stained for bone and cartilage were

processed by the technique described in WAssERSUG (1976).

Observations and photographs were made using a stereomicroscope and an optical

microscope.

We consider it necessary to explain that the term “root” is used for describing the

preganglionic part of the nerve.

RESULTS

?’LEPTODACTYLIDAE”

Ceratophrys cranwelli

The specimens at larval stage 31-34 show the trigeminal and facial nerves completely

separated (fig. la-b) and the trigeminal ganglion is clearly defined. The skeletal

preparations of larvae and adults present an undivided prootic foramen.

The facial nerve (VII) enters the rhombencephalon with the vestibulo-cochlear nerve

(VID) posterior to the root of the trigeminal nerve (fig. 2a). The facial root and the

lateral-line nerves are together. They take a rostro-ventral course and diverge at the

prootic foramen level in the prominent truncus hyomandibularis and the antero-dorsal

lateral-line nerve. The truncus hyomandibularis lies below the ascendent process and

subocular arch of palatoquadrate and extends toward the anterior elements of the

hyobranchial skeleton (fig. 2b). The antero-dorsal lateral-line nerve is thin and branches

in two rami.

The trigeminal nerve has its root in an anterior position and dorsal to the facial root

(fig. la-b, 2b). The ganglion of this nerve is prominent (fig. 1b, 2b), and two branches

diverge from it, namely: (1) the ramus ophthalmicus profundus lies ventral to the

ascendent process of the palatoquadrate and runs anteriorly along the orbit wall toward

the ethmoidal area (fig. 1a); (2) the truncus maxillo-mandibularis lies above the ascendent

process of the palatoquadrate and diverges in the middle of the orbit into maxillaris and

mandibularis branches (fig. 1a).

The specimen at stage 42 presents complete fusion of the trigeminal, facial,

lateral-line, and vestibulo-cochlear roots. The roots and ganglia of trigeminal and facial

nerves show no separation, and it is possible to differentiate the components of each nerve

only at the prootic foramen level.

Source : MNHN, Paris

FABREZI & CHALABE 5

Fig. 1. — (a) Whole mount larval specimen of Ceratophrys cranwelli (stage 33) stained for peripheral

nerves. The trigeminal, facial, lateral-line, and vestibulo-cochlear nerves are shown. Bar: 0.59

mm. — (b) Detail of trigeminal and facial nerves of the same specimen as seen from dorsal

view. The trigeminal ganglion shows no connections with facial nerve. — (c) Whole mount

larval specimen of Lepidobatrachus llanensis (stage 33) stained for peripheral nerves. Ventral

view in which the trigeminal, facial, lateral-line, and vestibulo-cochlear nerves are observed.

Bar: 1.20 mm. — (d) Detail of the trigeminal and facial nerves in same specimen as in (c). No

fusion of trigeminal and facial nerves can be observed. — Abbreviations: adil, antero-dorsal

lateral-line nerve; gtr, trigeminus ganglion; md, ramus mandibularis of trigeminus; mx, ramus

maxillaris of trigeminus; pro, ramus ophthalmicus profundus of trigeminus; rfall, facial and

lateral-line roots; rtr, trigeminal root; thm, truncus hyomandibularis; tmxmd, truncus

maxillo-mandibularis of trigeminus; vbc, vestibulo-cochlear nerve.

Source : MNHN, Paris

6 ALYTES 15 (1)

Fig. 2. — (a) Transverse section of larval specimen of Ceratophrys cranwelli (stage 33) at the level of

the anterior half of the otic capsule; the facial and lateral-line roots are dorsal to the

vestibulo-cochlear nerve. — (b) Transverse section of larval specimen of Ceratophrys cranwelli

(stage 33) at the level of prootic foramen; trigeminal ganglion is defined and separated from the

truncus hyomandibularis and antero-dorsal lateral line nerve. — (c) Transverse section of larval

specimen of Phyllomedusa sauvagii (stage 33) at the level of anterior half of the otic capsules,

in which the position of trigeminal, facial and lateral line roots is marked. — (d) Transverse

section in larval specimen of Phyllomedusa sauvagii (stage 33) at the level of a plane anterior

to that of (c). Structure of the prootic ganglion is shown. — (e) Transverse section of larval

specimen of Phyllomedusa sauvagii (stage 33) at the level of the prootic foramen, in which the

outlet of the ramus ophthalmicus profundus and truncus hyomandibularis of the prootic

ganglion are observed. — (f) Tranverse section of larval specimen of Dermatonotus muelleri

(stage 33) at the level of the otic capsule, in which the fusion of the trigeminal, lateral-line and

facial roots is observed. — (g) Transverse section of larval specimen of Dermatonotus muelleri

(stage 33) at the level of the anterior limit of the otic capsule, in which the prootic ganglion is

observed. — Abbreviations: gpro, prootic ganglion; rfa, facial root; ril, lateral-line root; other

abbreviations as in fig. 1.

Source : MNHN, Paris

FABREZI & CHALABE 7

Lepidobatrachus llanensis

The specimens at larval stages 31, 33 and 35 present complete separation of trigeminal

and facial nerves (fig. 1c-d). The skeletal preparations of larvae and adults present a single

prootic foramen.

The facial and lateral-line roots are in a posterior and ventral location with respect

to the trigeminal nerve root (fig. 1d). The same trigeminal, lateral-line, and facial rami as

those described for C. cranwelli are observed here (fig. 1c).

In the stage 37 specimen an approximation of the trigeminal and facial roots is

observed. In the stage 42 specimen the ganglion of the trigeminal nerve and its root

maintain their distinctness. The prootic ganglion is completely formed in the adult

specimen.

Physalaemus biligonigerus

The specimens analyzed present trigeminal and facial roots separated from each other

(fig. 3a), but anteriorly the prootic ganglion is already evident at the earliest stages (31-35).

In whole mounts stained for bone and cartilage the prootic foramen is present. All the

trigeminal, facial, and lateral-line rami described for C. cranwelli are recognized (fig. 3a).

The separation of the nerve roots becomes less evident from stage 37 onward.

HYLIDAE

Hyla pulchella andina, Phyllomedusa sauvagii and Scinax fuscovaria

The ontogenetic sequences analyzed in these species present similar characteristics.

The prefacial commissure is absent in larval and adult skeletal preparations. The

formation of a prootic ganglion is evident (fig. 2d-e, 3b), although trigeminal and facial

roots are separated (fig. 2c-d, 3b). In more advanced stages of development, the proximal

portion of each nerve can only be recognized at the level of the roots.

MICROHYLIDAE

Dermatonotus muelleri

The prootic foramen is evident in osteologic preparations of larval and adult

specimens. In the stage 27 specimen the truncus hyomandibularis and the trigeminal rami

are clearly differentiated. They are independent; they enter the encephalon very close

together. The lateral-line nerve crosses its fibers from the facial nerve to trigeminal nerve.

No structure recognizable as a prootic ganglion can be distinguished. In stage 29, facial

and trigeminal roots are fused. In the stage 33 specimen, facial and trigeminal nerves are

integrated to form the prootic ganglion (fig. 2f-g, 3c-d).

Source : MNHN, Paris

8 ALYTES 15 (1)

Fig. 3. — (a) Whole mount of larval specimen of Physalaemus biligonigerus (stage 33) stained for

peripheral nerves. The trigeminal, facial and vestibulo-cochlear nerves are indicated; the

trigeminal and facial-lateral-line roots are separated, but the presence of the prootic ganglion

is evident. Bar: 0.48 mm. — (b) Whole mount of larval specimen of Phyllomedusa sauvagii

(stage 33) obtained for peripheral nerves. The relations of trigeminal and facial nerves are as

in (a). Bar: 1 mm. — (c) Whole mount of larval specimen of Dermatonotus muelleri (stage 33)

obtained for peripheral nerves. The trigeminal, facial-lateral-line, and vestibulo-cochlear nerves

are illustrated. The trigeminal and facial-lateral-line roots are fused and the presence of the

prootic ganglion is evident. Bar: 0.52 mm. — (d) Detail of the trigeminal and facial

relationships in the same specimen as in (c). — Abbreviations: rtr-fall, trigeminal, facial and

lateral-line roots; other abbreviations as in fig. 1-2.

Source : MNHN, Paris

FABREZI & CHALABE 9

DISCUSSION AND CONCLUSIONS

The fusion of the trigeminal and facial ganglia presented by the anurans is an

important character in their phylogeny, although, as mentioned, it has not been

sufficiently investigated.

Some data from the literature are not entirely in agreement with observations made

by SokoL (1975). For instance, fusion of the trigeminal and facial ganglia has been

described in postmetamorphic stages of Discoglossus (PUSEY, 1943; VAN EEDEN, 1951) —

although trigeminal and facial ganglia can be clearly distinguished in D. pictus tadpoles

(SCHLOSSER & ROTH, 1995) — and the presence of the prefacial commissure has been

observed in Hymenochirus adults (PATERSON, 1951).

Information available for Pipanura is limited to seven genera of Mesobatrachia and

only six genera of Neobatrachia. This information is insufficient for a discussion in depth,

because for some taxa the character is described in a single larval stage, whereas for others

the condition for adult forms or final stages of larval development has been superficially

mentioned (see tab. 1).

The presence of a prootic ganglion and separate trigeminal and facial roots observed

in Physalaemus biligonigerus, Hyla pulchella andina, Phyllomedusa sauvagii and Scinax

fuscovaria larvae is in agreement with the observations in Pleurodema (SokoL, 1975) and

Rana (PUSEY, 1938). These species have the roots fused only near the ganglion. In later

ontogenetic stages, this fusion extends proximally.

The trigeminal and facial nerves are found completely separated in larvae of

Ceratophrys cranwelli and Lepidobatrachus llanensis, a characteristic which continues in L.

Ulanensis until the start of metamorphosis. As this condition has not been referred to in

Pipanura (tab. 1), the observations made on these species give grounds for not accepting

the generalization proposed by SokoL (1975) that Type IV, II and I larvae have a single

prootic foramen and fused facial and trigeminal ganglia.

The early fusion of the trigeminal and facial roots and subsequent formation of the

prootic ganglion observed in Dermatonotus muelleri larval development are in agreement

with the information available on Breviceps adspersus (SWANEPOEL, 1971). Although

ontogenetic aspects of the trigeminal and facial relations have not been described for B.

adspersus, it is possible to deduce the process of fusion from roots to ganglia from the

schema included (SWANEPOEL, 1971). In Hypopachus — another microhylid — a larval

stage occurs in which ganglia and roots are found completely fused (SOkoL, 1975).

Although the information analyzed in this work is still very limited, the following

conclusions are obtained:

(1) The prootic ganglion is not present in all neobatrachian larvae.

(2) In neobatrachian ontogeny, formation of the prootic ganglion can occur in two

ways: in some species, formation of the ganglion precedes fusion of the trigeminal and

facial roots; in others, fusion of the roots occurs first.

(3) There are interspecific heterochronies in the formation of the prootic ganglion.

Source : MNHN, Paris

10 ALYTES 15 (1)

(4) Analyses of the intracranial relation of the trigeminal and facial nerves during

neobatrachian ontogeny will provide new information to clarify their phylogenetic

relationships.

ACKNOWLEDGEMENTS

We thank Marcela ROMERO for her technical assistence in preparing the histologic sections. This

research was supported by a grant from the Consejo de Investigaciôn, Universidad Nacional de Salta,

00375/93 and Consejo Nacional de Investigaciones Cientificas y Técnicas (Argentina) to M. FABREZI.

LITERATURE CITED

DE B£ER, G. R., 1937. — The development of the vertebrate skull. Oxford, Clarendon Press; reprint

1985, Chicago, Univ. Chicago Press: i-xlvi + 1-554, pl 143.

DE JonGu, H. J., 1968. — Functional morphology of the jaws apparatus of larval and

metamorphosing Rana temporaria L. Neth. J. Zool., 18: 1-103.

DuELLMAN, W. E. & TRUEB, L., 1985. — Biology of amphibians. New York, McGraw-Hill, “1986”;

reprint 1994, Johns Hopkins University Press: i-xxi + 1-670.

Fiipski, G. T. & WiLsoN, M. H. V., 1984. — Sudan Black B as a nerve stain for whole cleared fishes.

Copeia, 1984: 204-208.

ue 1985. — Staining nerves in whole cleared amphibians and reptiles using Sudan Black B. Copeia,

1985: 500-502.

Forp, L. S. & CANNATELLA, D. C., 1993. — The major clades of frogs. Herp. Mon., 7: 94-117.

GoopriCH, E. S., 1930. — Studies on the structure and development of vertebrates. Chicago, Univ.

Chicago Press; reprint 1958, Dover Publications Inc.: i-Ixix + 1-837.

Goswer, K. L., 1960. — A simplified table for staging anuran embryos and larvae with notes on

identification. Herpetologica, 16: 183-190.

JacoBson, C. M., 1968. — The development of the chondrocranium in two species of the Australian

anuran genus Pseudophryne Fitzinger. Aus. J. Zool., 16: 1-16.

LAURENT, R. F., 1986. — Sous-classe des Lissamphibiens (Lissamphibia). Systématique. In: P.-P.

GRaSssé & M. DELSOL (eds.), Traité de zoologie, tome 14, Batraciens, fasc. 1 B, Paris, Masson:

594-797.

NisikawA, K. C., 1987. — Staining amphibian peripheral nerves with Sudan Black B: progressive

vs. regressive methods. Copeia, 1987: 489-491.

ORTON, J. L., 1953. — The systematics of vertebrate larvae. Syst. Zool., 2: 63-75.

PATERSON, N. F., 1945. — The skull of Hymenochirus curtipes. Proc. zool. Soc. London, 115: 327-354.

PLAsorA, K., 1974. — The development of the chondrocranium (neurocranium, and the mandibular

and hyoid arches) in Rana temporaria L. and Pelobates fuscus (Laur.). Zool. Pol., 24: 99-118.

PuseY, H. K., 1938. — Structural changes in the anuran mandibular arch during metamorphosis, with

reference to Rana temporaria. Q. J. micr. Sci., 80: 479-465.

ES 1943. — On the head of the leiopelmid frog, Ascaphus truei. 1. The chondrocranium, jaws, arches,

and muscles of a partly-grown larva. Q. J. micr. Sci., 84: 105-185.

ROËEK, Z., 1981. — Cranial anatomy of frogs of the family Pelobatidae Stannius, 1856, with outlines

of their phylogeny and systematics. Acta Univ. Carolinae, Biol.: 1-164.

SCHLOSSER, G. & ROTH, G., 1995. — Distribution of cranial and rostral spinal nerves in tadpoles of

the frog Discoglossus pictus (Discoglossidae). J. Morph., 226: 189-212.

SokoL, O. M., 1975. — The phylogeny of anuran larve: a new look. Copeia, 1975: 1-23.

nue 1977. — The free-swimming Pipa larvae, with a review of pipid larvae and pipid phylogeny

(Anura: Pipidae). J. Morph., 154: 357-425.

Source : MNHN, Paris

FABREZI & CHALABE 11

AE 1981. — The larval chondrocranium of Pelodytes punctatus, with a review of tadpoles

chondrocrania. J. Morph., 169: 161-183.

SrarrerT, P. H., 1973. — Evolutionary patterns in larval morphology. /n: J. L. VIAL (ed.),

Evolutionary biology of the anurans, Columbia, Univ. Missouri Press: 252-271.

STEPHENSON, N. G., 1950. — On the development of the chondrocranium and visceral arches of

Leiopelma archeyi. Trans. zool. Soc. London, 27: 203-253.

SWANEPOEL, J. H., 1970. — The ontogenesis of the chondrocranium and of the nasal sac of the

microhylid frog Breviceps adspersus pentheri Werner. Ann. Univ. Stell., 45 (A): 1-119.

VAN EEDEN, J. A. 1951. — The development of the chondrocranium of Ascaphus truei Stejneger, with

special reference to the relations of the palatoquadrate to the neurocranium. Acta zool., 32:

1-136.

WASsERSUG, R. J., 1976. — A procedure for differential staining of cartilage and bone in whole

formalin-fixed vertebrates. Stain Technol., 51: 131-134.

WesrHuIzEN, C. M. V. D., 1961. — The development of the chondrocranium of Heleophryne purcelli

Sclater with special reference to the palatoquadrate and the sound-conducting apparatus. Acta

zool., 42: 1-72.

Corresponding editor: Marvalee H. WAKE.

APPENDIX 1

LIST OF SPECIMENS EXAMINED

FAMILY LEPTODACTYLIDAE

Ceratophrys cranwelli. — MCN 021: whole mounts stained for peripheral nerves of

20 specimens at stages 31-34 and 2 specimens at stage 42; transverse serial sections of

2 specimens at stage 33; whole mounts stained for bone and cartilage of 10 specimens at

stages 31-34. FML 4534: whole mounts stained for bone and cartilage of 7 specimens at

stages 40-46. FML 4573: dry skeleton of 1 adult specimen. FML 4574: dry skeleton of

1 adult specimen.

Lepidobatrachus llanensis. — FML 4678: whole mounts stained for peripheral nerves

of 5 specimens at stages 31, 33, 35, 37 and 42; whole mounts stained for bone and

cartilage of 4 specimens at stages 31, 33, 37 and 44. FML 0420: dry skeleton of 1 adult

specimen. FML 1016: dry skeleton of 1 adult specimen. FML 5220: dry skeleton of 1 adult

specimen. FML 5221: dry skeleton of 1 adult specimen. MCN 081: dissection of 1 adult

specimen.

Physalaemus biligonigerus. — MCN 043: whole mounts stained for peripheral nerves of

22 specimens at stages 31-42; whole mounts stained for bone and cartilage of 10 specimens

at stages 32-41. MCN 157: whole mounts stained for bone and cartilage of 4 adult

specimens.

FAMILY HYLIDAE

Hyla pulchella andina. — MCN 024: whole mounts stained for peripheral nerves of

14 specimens at stages 31-42; whole mounts stained for bone and cartilage of 10 specimens

at stages 33-39. MCN s/n: whole mounts stained for bone and cartilage of 2 adult

specimens.

Source : MNHN, Paris

12 ALYTES 15 (1)

Phyllomedusa sauvagi. — MCN 061: whole mounts stained for peripheral nerves of

18 specimens at stages 31-42; transverse serial sections of 2 specimens at stage 33; whole

mounts stained for bone and cartilage of 7 specimens at stages 33-38. FML 3823: whole

mounts stained for bone and cartilage of 2 adult specimens.

Scinax fuscovaria. — MCN 027: whole mounts stained for peripheral nerves of

19 specimens at stages 31-41; whole mounts stained for bone and cartilage of 7 specimens

at stages 33-38. MCN 072: whole mounts stained for bone and cartilage of 2 adult

specimens.

FaMiLY MICROHYLIDAE

Dermatonotus muelleri. — FML 4694: whole mounts stained for peripheral nerves of

6 specimens at stages 27, 29, 30, 33, 35 and 37; whole mounts stained for bone and

cartilage of 3 specimens at stages 33-35. MCN 056: whole mounts stained for peripheral

nerves of 5 specimens at stages 31-36; transverse serial sections of 3 specimens at stage 33;

whole mounts stained for bone and cartilage of 7 specimens at stages 35-41. FML 1074:

whole mounts stained for bone and cartilage of 1 adult specimen.

Source : MNHN, Paris

Alytes, 1997, 15 (1): 13-18. 13

Description of the tadpole of Bufo kisoloensis

Alan CHANNING * & Robert C. DREWES **

* Biochemistry Department, University of the Western Cape, Private Bag X17, Bellville 7535, South Africa

** California Academy of Sciences, Golden Gate Park, San Francisco, California 94118, USA

The tadpole of Bufo kisoloensis from the Impenetrable Forest of extreme

southwestem Uganda is described and compared with the tadpole of Bufo

maculatus. The morphology of the B. kisoloensis tadpole reflects the conser-

vative morphology of the tadpoles in this genus but can be distinguished by a

set of internal buccal characters, particularly the number and arrangement of

the papillae.

INTRODUCTION

African tadpoles are relatively poorly known, especially those in the central and

eastern parts of the continent. Tadpoles of 18 of 31 species of bufonids in central and

southern Africa have been described (WAGER, 1965; VAN Duxk, 1971; CHANNING, 1972,

1973, 1978), and although buccal features provide useful taxonomic characters, these

structures have been described for very few African Bufo tadpoles.

Bufo kisoloensis is a large (males to 80 mm; females to more than 90 mm),

high-altitude species known from above 2000 m in the highlands associated with the

Albertine Rift of Kenya west of the Great Rift, northern Malawi and adjacent southern

Tanzania (TANDY & KEITH, 1972). À member of the B. regularis complex, it was described

as a subspecies of B. regularis (LOVERIDGE, 1932) and elevated to specific rank by LAURENT

(952). ScHminT & INGER (1959) confirmed the specific status and provided additional

diagnostic characters.

The bright chrome yellow color of breeding males of B. kisoloensis is unique among

African Bufo. Except during breeding periods, males are cryptically colored like females.

Sexual dichromatism (which may be permanent) also occurs in several other species of

Bufo, such as Bufo canorus of California, B. luetkenii of Nicaragua and Costa Rica, the

possibly extinct B. periglenes of Costa Rica, and B. peripatetes of Panama (SAVAGE, 1966;

VILLA, 1972; SAVAGE & DOoNNELLY, 1992).

The B. kisoloensis tadpoles were collected from a small stream (altitude 1700 m)

within an area dominated by Cyathea and Lobelia. Adults in breeding condition and

amplecting pairs were found in various habitats in the forest ranging from disturbed areas,

through simple rush-sedge swamps, to complex Acanthocleista-Cyperus-Thelypteris-

Begonia swamps (DREWES & VINDUM, 1994). The identification of the tadpoles is based on

Source : MNHN, Paris

14 ALYTES 15 (1)

B. kisoloensis being the only bufonid in the forest proper (DREWES & VINDUM, 1994). Bufo

maculatus, considered by TANDY & KEITH (1972) to be in a group of its own, occurs at

lower elevations in the savannas of west and east Africa south to northeastern

Kwazulu-Natal and breeds in low-elevation, disturbed habitats on the periphery of the

Impenetrable Forest.

DESCRIPTION

Staging follows the table of Gosner (1960), buccal features (stained with Fast Green)

are described with the terminology of WassErsUG (1976, 1980), descriptive characters and

nomenclature are based on VAN Dux (1966), and the keratodont formula follows the

recommendations of Dugois (1995).

The description is based on one tadpole (stage 34, 19 mm total length) from over 90

tadpoles (California Academy of Sciences 180664) collected from the Impenetrable Forest

Reserve in extreme southwestern Uganda by R. C. DREWES, H. W. GREENE, J. P. O’BRIEN

and J. V. ViNDuM on 5 November 1990. Comparisons with four other tadpoles from the

sample that ranged from stages 31 to 41 and from 18 to 20 mm total length showed no

appreciable differences in the characters we examined.

EXTERNAL FEATURES

The tail length (fig. 1) is 51 % of the total length, and tail height is slightly greater

than body height. The tail tip is bluntly rounded. The maximum height of the dorsal fin

occurs midway along the tail. The tail is euthyoural with the extrapolated axis passing

through the eye. The basal height of the caudal muscle is less than half (44 %) the height

of the body.

The kidney-shaped nostrils with a slightly raised medial projection on the proximal

margin are positioned slightly closer to the eye than to the snout. The nasal passages are

visible dorsolaterally. The ratio nostril width/internarial distance is 0.15. The orbitonasal

line and pineal spot are not visible. The ratio rostronasal distance (measured between

closest margins)/orbitonasal distance is 1.6.

The eyes are dorsolateral, and the extra-ocular proportion (head width minus distance

between the lateral limits of the eyes/distance between the lateral limits of the eyes) is 0.48.

The spiracle is sinistral, visible dorsally, and situated 60 % posteriorly along the body; the

flattened aperture is oval and visible laterally. The medial vent is situated on the ventral

margin of the fin.

The ventral oral disc is not visible dorsally and is 75 % of the width of the head at

the level of the disc. A single row of papillae is present laterally on the disc margin, and

the mental gap is half the width of the disc. The suprarostrodont is finely serrated, edged

with black and grading to a dark brown on the basal half. The widely V-shaped

infrarostrodont is also finely serrated, and the distal half is deeply pigmented in brown.

The keratodont formula is 1:1+ 1/3 (fig. 2).

Source : MNHN, Paris

CHANNING & DREWES 15

Fig. 1. — Left lateral view of a tadpole of Bufo kisoloensis (California Academy of Sciences 180664;

stage 34, 19 mm total length).

Fig. 2. — Mouthparts of a tadpole of Bufo kisoloensis.

Source : MNHN, Paris

16 ALYTES 15 (1)

Tab. 1. - Comparison of the buccal anatomy of Bufo maculatus and Bufo kisoloensis tadpoles.

Bufo maculatus Bufo kisoloensis

1 postnarial lateral papilla 2 postnarial lateral papillae:

lateral one forms lateral

margin of median ridge

Inner pair of postnarial Inner pair of postnarial

arena papillae simple arena papillae notched

4 pairs of lateral papillae 3 pairs of lateral papillae

in buccal roof arena in buccal roof arena

A very large pustulation on No such large pustulations

either side of the anterior

border of the velum

5-6 major papillae on each 13 major papillae on each

side of buccal floor arena side of buccal floor arena

Dorsally the tadpoles are uniform dark brown rather than black as is common in

many species of Bufo, and the venter a uniform lighter brown. The tail is evenly pigmented

almost to the ventral margin over the anterior two thirds. The dorsal fin is uniformly

pigmented, while the ventral fin is only pigmented anteriorly. Some tadpoles have a diffuse

mottling on the ventral fin.

INTERNAL FEATURES

The internal nares are anteriorly convergent at about 50° to the midline. A pair of

large, finely scalloped postnarial papillae form the lateral margin of the postnarial arena.

This arena has a few small pustulations and two pairs of papillae. The median ridge is

defined by a large central papilla and an elongated lateral papilla on each side. The buccal

roof arena has a number of minute pustulations and three long lateral roof papillae on

each side. À rounded area on the posterior midline stains darkly.

The buccal floor has an anterior raised lingual pad flanked by trilobed infralabial

papillae and three smaller lingual papillae. The arena is flat with regularly-spaced minute

pustulations and flanked by 13 elongated papillae on each side.

Source : MNHN, Paris

CHANNING & DREWES 17

COMPARISONS AMONG AFRICAN BUFONID TADPOLES

The head ornaments of the tadpoles of the bufonid genera Mertensophryne,

Schismaderma and Stephopaedes make them quite distinctive, but tadpoles of Bufo are

quite uniform in morphology and size. Although internal buccal characters provide good

characters for species identification, very little is presently known about these features in

African Bufo. Bufo maculatus is the only other bufonid occurring near the Impenetrable

Forest. The internal buccal anatomy of B. kisoloensis differs from that of B. maculatus

(LaAMBIRIs, 1994, as Bufo pusillus) as listed in tab. 1. Although all known Bufo tadpoles

have similar overall morphology, it appears that buccal characters are diagnostic at the

species level. As more tadpoles become known, it will be possible to review the internal

buccal anatomy for the members of the genus in Africa.

ACKNOWLEDGEMENTS

We thank Jenny CHANNING for preparing figure 1, Colleen SUDEKUM for preparing figure 2, and

Jens VINDUM for assisting with the fieldwork in Uganda.

LITERATURE CITED

CHANNING, À., 1972. — A description of Bufo pusillus tadpoles (Anura: Bufonidae). Ann. Natal Mus.,

21: 509-511.

1973. — A description of Bufo pardalis tadpoles (Anura: Bufonidae). Zool. Afr., 8: 153-156.

1978. — A new bufonid genus (Amphibia: Anura) from Rhodesia. Herpetologica, 34: 394-397.

DREWES, R. C. & VINDUM, J. V., 1994. — Amphibians of the Impenetrable Forest, southwest Uganda.

J. afr. Zool., 108: 55-70.

Dugois, A., 1995. — Keratodont formulae in anuran tadpoles: proposals for a standardization. J.

zool. Syst. Evol. Res., 33: I-XV.

Goswer, K. L., 1960. — A simplified table for staging anuran embryos and larvae with notes on

identification. Herpetologica, 16: 183-190.

LAMBIRIS, A. J. L., 1994. — Laryngeal and buccopharyngeal morphology of some South African

Bufonidae: new data sets for anuran taxonomy. Ann. Natal Mus., 35: 261-307.

LAURENT, R. F., 1952. — Bufo kisoloensis Loveridge and Chama !0 ituriensis Schmidt revived.

Herpetologica, 8: 53-55.

LOVERIDGE, A., 1932. — Eight new toads of the genus Bufo from east and central Africa. Occ. Pap.

Boston Soc. nat. Hist., 8: 43-54.

SAVAGE, J. M., 1966. — An extraordinary new toad (Bufo) from Costa Rica. Rev. Biol. trop., 14:

153-167.

SAVAGE, J. M. & DonNELLY, M., 1992. — The second collection of, and variation in, the rare

neotropical toad, Bufo peripatetes. J. Herp., 26: 72-74.

Scmior, K. P. & INGER, R. F., 1959. — Explorations du Parc National de l'Upemba. Amphibians

exclusive of the genera Afrixalus and Hyperolius. Expl. Parc natn. Upemba, Miss. G. F. De

Witte, 56: 1-256.

Source : MNHN, Paris

18 ALYTES 15 (1)

TANDY, M. & KEITH, R., 1972. — Bufo of Africa. In: W. F. BLAIR (ed.), Evolution in the genus Bufo,

Austin, University of Texas Press: 119-170.

VAN Dux, D. E., 1966. — Systematic and field keys to the families, genera and described species of

southern African tadpoles. Ann. Natal Mus., 18: 231-286.

1971. — A further contribution to the systematics of southern African anuran tadpoles — the

genus Bufo. Ann. Natal Mus., 21: 71-16.

ViziA, J, 1972. — Anfibios de Nicaragua. Managua, Inst. Geogr. Nac. & Banco Central de

Nicaragua: 1-216.

Wacer, V. A., 1965. — The frogs of South Africa. Cape Town, Purnell & Sons: 1-242.

WassERsUG, R. J., 1976. — Internal oral features in Hyla regilla (Anura: Hylidae) larvae: an

ontogenetic study. Occ. Pap. Mus. nat. Hist. Univ. Kansas, 49: 1-24,

—— 1980. — Internal oral features of larvae from eight anuran families: functional, systematic,

evolutionary and ecological considerations. Misc. Publ. Univ. Kansas Mus. nat. Hist., 68: 1-146.

Corresponding editor: Ronald G. ALTIG.

Source : MNHN, Paris

Alytes, 1997, 15 (1): 19-25. 19

La larva de

Melanophrvniscus rubriventris rubriventris

(Vellard, 1947) (Anura, Bufonidae)

E. O. LavicLa * & Marcos VAIRA **

* Instituto de Herpetologia, Fundaciôn Miguel Lillo — CONICET, Miguel Lillo 251,

4000 Tucumän, Argentina

** Museo de Ciencias Naturales, U.N.Sa — CONICET, Mendoza 2, 4400 Salta, Argentina

Melanophryniscus rubriventris rubriventris larvae are described based on

18 individuals in stages 31-34 of Gosnen's (1960) developmental table. They

are similar to other tadpoles of Melanophryniscus in terms of overall

morphology, but differ from Melanophryniscus moreirae, M. orejasmirandai

and M. sanmartini in the formula of keratodont rows, from M. stelzneri

montevidensis in characters of the proctodeal tube and spiraculum, and from

M. steleneri stelzneri in characters of the spiraculum and size of the oral disc.

No larval information is available regarding the remaining taxa of the genus.

INTRODUCCION

Melanophryniscus rubriventris es una especie caracteristica de las selvas de montaña

del noroeste argentino y sur de Bolivia, en la que se reconocen tres subespecies: la nominal,

descripta por VELLARD (1947), registrada en los departamentos Orän (Salta) y Ledesma y

Valle Grande (Jujuy) y M. r. subconcolor y M. r. toldosensis, descriptas por LAURENT

(1973) para las regiones de Tiraxi (Jujuy) y Los Toldos (Salta), respectivamente.

Como parte de un estudio mayor sobre la batracofauna de los Yungas comenzamos

una serie de anälisis sobre el modo de reproducciôn y desarrollo de Melanophryniscus

rubriventris rubriventris en el Parque Nacional Calilegua, y en esta contribucion

describimos los estadios larvales de dicha subespecie.

MATERIAL Y MÉTODOS

Se estudiaron larvas de Melanophryniscus rubriventris rubriventris en estadios

comparables a 31-34 de GosnER (1960). Las mismas, fijadas y conservadas en formol

10 %, fueron descriptas siguiendo las pautas establecidas por LAviLLA (1983) y medidas

segün lo establecido en dicho trabajo y en LAviLLA & SCROCCHI (1986). El largo total fue

Source : MNHN, Paris

20 ALYTES 15 (1)

Tab. 1. - Medidas de una serie de 18 larvas de Melanophryniscus rubriventris rubriventris en

estadios 31 a 34 de la tabla de GOSNER (1960). x: promedio; s: desviaciôn eständard.

Medida Rango

LT: longitud total 14,5 - 18,2

LC: longitud del cuerpo 5,7-6,8

LCo: longitud de la cola 8,1-11,4

AM: ancho mäximo del cuerpo 4,1-4,9

AO: ancho del cuerpo a nivel de los ojos 3,4-4,3

AOn: ancho del cuerpo a nivel de los orificios nasales 2,4-3,3

HM: altura mâxima del cuerpo 3,3-4,3

HMU: altura de los müsculos de la cola 1,2-1,5

HA: altura aletas 3,2-4,0

DRE: distancia rostro-espirâculo 3,9-5,0

FN: distancia frontonasal 1,1-1,3

NO: distancia naso-ocular 0,3 -0,4

IN: distancia intranasal 0,7-0,9

10: distancia intraocular 1,0-1,3

EN: distancia extranasal 1,2-1,5

EO: distancia extraocular 2,2 -2,6

O: diâmetro del ojo 0,6-0,8

ON: diâmetro del orificio nasal 0,2-0,4

DO: ancho del disco oral 1,8-72,1

CR: ancho del claro rostral 1,2-1,7

CM: ancho del claro mental 1,1-1,4

tomado utilizando un calibre con precisiôn 0,02 mm y las restantes medidas con ocular

micrométrico bajo lupa binocular.

El material analizado (18 ejemplares) forma parte de un lote mayor depositado en la

colecciôn del Instituto de Herpetologia de la Fundacion Miguel Lillo (FML) bajo el

nümero 04731, proveniente de Abra de Cañas, aproximadamente a 23°35'S 64°50°W y a

1700 m s.n.m., en el Departamento Ledesma, Jujuy, Argentina, colectados el 2 de enero

de 1991. La identificaciôn se realizé en base a una serie completa de desarrollo.

Los valores señalados en el texto (en milimetros) corresponden al promedio y a la

desviaciôn eständar (s), mientras que los rangos se presentan en la tab. 1.

Source : MNHN, Paris

LAVILLA & VAIRA 21

RESULTADOS

Las larvas de Melanophryniscus rubriventris rubriventris fueron colectadas en charcos

temporarios de menos de 20 cm de profundidad, con sustrato arcilloso y sin vegetaciôn en

una region de selva de montaña. La subespecie se reproduce después de fuertes

precipitaciones en grandes agrupaciones, observändose gran cantidad de amplexos

mültiples y büsqueda activa por parte de los machos. Observaciones realizadas han

mostrado que existen variaciones en la puesta de huevos segün los sitios escogidos, que van

desde huevos colocados individualmente y dispersos en el fondo del agua a huevos

agrupados en masas y adheridos a la vegetaciôn sumergida. Melanophryniscus rubriventris

rubriventris es el ünico taxon del género registrado en selvas de montaña de Argentina, y

los caracteres de puesta lo diferencian de los restantes bufonidos de la region (Bufo

paracnemis, B. arenarum, B. rumbolli y B. gallardoi), quienes colocan sus huevos en

cordones gelatinosos.

En estadios 31-34 de GosnER (1960), las larvas de Melanophryniscus rubriventris

rubriventris (fig. 1) presentan una longitud total entre 14,5 y 18,2 mm (7 = 18 ejemplares);

el cuerpo es deprimido (la altura es menor que el ancho = 0,82; s = 0,05) y su aspecto

dorsal muestra la region anterior a los ojos subtriangular, en tanto que la porciôn

posterior del cuerpo presenta märgenes subparalelos a convergentes hacia atrâs, no

existiendo constricciones notables. El ancho mäximo se ubica inmediatamente por deträs

de los ojos, todavia sobre la region cefälica del cuerpo. El hocico es redondeado en vistas

dorsal y lateral, las regiones gular y branquial son plano-céncavas y la region abdominal

es plano-convexa.

El disco oral, de tamaño pequeño (ancho del disco oral/ancho mäximo del cuerpo =

0,44; s = 0,01) es de posiciôn subterminal ventral. Los märgenes anterior y posterior son

lisos y lateralmente presentan aspecto dentado, estando divididos por una hendidura

angular a cada lado. La hilera marginal de papilas esta interrumpida por un claro rostral

grande (ancho del claro rostral/ancho del disco oral = 0,72; s = 0,05) y un claro mental

mediano (ancho del claro rostral/ancho del disco oral = 0,61; s = 0,04). Las papilas

marginales, limitadas a las regiones laterales del disco, son simples y se disponen en una

hilera ünica tanto supra como infraangularmente; pueden existir o no papilas intramar-

ginales en la regiôn supraangular, ubicadas prôximas a las de la hilera marginal, de las que

se diferencian por su tamaño mayor. También pueden aparecer papilas aisladas en la

region angular.

El suprarostrodonte (pico crneo superior) es mäs ancho que alto y su margen libre

es uniformemente concavo, presentando aserraduras subtriangulares agudas; sélo estä

queratinizada y pigmentada (castaño oscuro) su mitad distal. El infrarostrodonte (pico

corneo inferior) tiene forma de V muy abierta, està queratinizado y pigmentado sélo en

el tercio distal y posee aserraduras similares a las del suprarostrodonte. Los queratodontes

se disponen segün formula 2/3, y cada denticulo es simple y con extremo romo.

Los orificios nasales son circulares y presentan un reborde bajo; no estän protruidos,

carecen de inflexiones y presentan una proyecciôn poco notable en el margen interno. Se

abren a nivel de la superficie del cuerpo y estân ubicados mäs cerca del ojo que del extremo

del hocico (distancia frontonasal/distancia naso-ocular = 2,90; s = 0,56), en posiciôn

Source : MNHN, Paris

22 ALYTES 15 (1)

RTE

PAPE ma

qu ” We,

MODNNR LUTTE Us,

s Wine nes

KG UML

dl NT “oi Ty, Hi

ur, y

re A x”

Re ?? NE fn Pr gg A2

NAPTITTUU

Œe: “u, ANTDIEOIEEN

Poe RNOUTrS

Fig. 1. — Larva de Melanophryniscus rubriventris rubriventris, estadio 31 de GOsNER (1960). (a) Vista

lateral. (b) Vista dorsal. (c) Disco oral.

Source : MNHN, Paris

LAVILLA & VAIRA 23

dorsolateral (distancia extranasal/ancho del cuerpo a nivel de los ojos = 0,48; s = 0,05).

Son visibles dorsal, frontal y lateralmente, y la pigmentacin alrededor de ellos es

levemente mäs oscura que la superficie circundante. El pasaje nasal es invisible.

Los ojos son de tamaño mediano (diämetro del ojo/ancho del cuerpo a nivel de los

ojos = 0,18; s = 0,01), estän ubicados dorsolateralmente (distancia extraocular/ancho del

cuerpo a nivel de los ojos = 0,61; s = 0,04) y la linea orbitonasal es invisible.

El espiräculo es ünico, izquierdo y visible dorsalmente. El tubo espiracular es corto

y no estä proyectado, por lo que su abertura, subcircular, abre a nivel de la superficie

general del cuerpo en posiciôn ventrolateral. Estä, ademäs, desplazado hacia la mitad

posterior del cuerpo (distancia rostro-espiräaculo/longitud cuerpo = 0,69; s = 0,03).

El tubo proctodeal es de aspecto cônico, mäs ancho en la base que en el extremo libre

y abre a la derecha de la aleta ventral. Un caräcter peculiar observado es que los pliegues

del intestino son laxos y el asa intestinal està desplazada hacia la izquierda del cuerpo,

ubicändose muy préxima a la abertura del espiräculo.

La cola es mediana (longitud cola/longitud total = 0,62; s = 0,02), y su altura es

variable con relacién a la altura del cuerpo (altura aletas caudales/altura mäxima del

cuerpo = 0,91-1,06); las aletas dorsal y ventral poseen el margen libre uniformemente

curvado y el extremo es ampliamente redondeado. El nacimiento de la aleta dorsal estâ

levemente desplazado sobre el cuerpo, mientras que el nacimiento de la aleta ventral estä

asociado al tubo proctodeal; el eje de la cola es recto (eutiural).

Coloracién en fijador (formol 10%). — La piel del cuerpo es translücida a

transparente; en vista dorsal la region cefälica es de color castaño mediano y la region

posterior algo mâs oscura, observändose el mismo patrôn lateralmente. Ventralmente son

transparentes, pudiendo haber puntos agrupados en el ârea central de la region branquial;

una fascia melänica recubre parcialmente a la region abdominal, pero a pesar de ello el

intestino es claramente visible. El tubo proctodeal presenta una estrecha banda de

pigmento a nivel de la abertura, muy poco notable en algunos ejemplares. El resto de su

superficie ventral carece de manchas. La musculatura caudal es castaña, con âreas no

pigmentadas irregulares, mâs abundantes en la mitad posterior; toda la superficie ventral

de la musculatura hipaxial carece de pigmento. La aleta dorsal es translücida, con manchas

alargadas y estrechas distribuidas irregularmente en toda su superficie; la aleta ventral es

translücida y generalmente inmaculada, aunque en algunos ejemplares pueden aparecer

pequeñas manchas de distribuciôn irregular.

DISCUSIÉN

La informaciôn disponible sobre las larvas de Melanophryniscus es proporcionalmente

escasa; de los catorce taxa que componen el género, se han descripto las larvas de

M. moreirae (AHL, 1938; BOKERMANN, 1967; STARRETT, 1967), M. orejasmirandai (PRIGIONI

& LANGONE, 1990), M. sanmartini (PRIGIONI & ARRIETA, 1992), M. stelzneri montevidensis

(GARRIDO-YRIGARAY, 1989) y M. stelzneri stelzneri (FERNANDEZ, 1926, y una sintesis

en Cr, 1980). Por su parte, MCDiarMID (1971) present una diagnosis en base a

Source : MNHN, Paris

24 ALYTES 15 (1)

caracteres larvales, aunque algunos taxa se apartan de ella en uno o mâs caracteres (vide

infra).

Ninguna de las descripciones disponibles hace menciôn a caracteres del intestino, por

lo que resaltamos la disposiciôn particular del asa intestinal que se presenta en todas las

larvas examinadas de M. rubriventris rubriventris.

Las larvas de Melanophryniscus rubriventris rubriventris cumplen con las caracteris-

ticas genéricas (MCDiaRMID, 1971), presentando espirâculo ünico e izquierdo, tubo

proctodeal que abre a la derecha de la aleta caudal, formula dentaria 2/3, papilas labiales

marginales en hilera simple y de posiciôn lateral, y disco oral de posicién subterminal

ventral.

Difieren de las larvas de M. moreirae, M. orejasmirandai y M. sanmartini por el modo

en que se disponen las hileras de queratodontes (1:1+1/1+1:2, 2/1+1:2 y 1+1/1+1:2

respectivamente, contra 2/3 en M. r. rubriventris).

Difiere de M. s. montevidensis por caracteres del tubo proctodeal y del espiräculo: el

primero abre en la linea media (contra abertura dextral en M. r. rubriventris) y el segundo

en la mitad del cuerpo (contra abertura en el tercio posterior).

Algunas diferencias con larvas de M. stelzneri stelzneri pueden ser inferidas a partir

del trabajo de FERNANDEZ (1926). Se destacan: ancho del disco oral 1 mm (contra 1,8 a

2,15 en M. r. rubriventris) y espiraculo ubicado en el tercio medio (contra espiräculo

ubicado en el tercio posterior).

Es necesario resaltar que estas comparaciones deben ser tomadas como preliminares,

dado que una constante en todas las descripciones analizadas es que estän basadas en un

sélo ejemplar, y los estadios analizados por los diversos autores son variables o no han

sido definidos.

RESUMEN

Describimos las larvas de Melanophryniscus rubriventris rubriventris en base a 18

individuos que se encontraban en estadios 31-34 de GosneR (1960). Por sus caracteres

generales son similares a las restantes larvas conocidas para el género Melanophryniscus,

pero difieren de Melanophryniscus moreirae, M. orejasmirandai y M. sanmartini en el

nümero de hileras de queratodontes; difieren de M. stelzneri montevidensis por caracteres

del tubo proctodeal y del espiräculo y difieren de M. stelzneri stelzneri por caracteres del

espiräculo y el tamaño del disco oral. No existe informaciôn disponible para las larvas de

los restantes taxa del género.

AGRADECIMIENTOS

Agradecemos a la Delegacion Noroeste de la Administraciôn Nacional de Parques Nacionales de

Argentina por constante colaboraciôn. La IUCN/SSC/Declining Amphibian Populations Task Force

apoyé los estudios de los anfibios de Yungas y Chaco en la Repüblica Argentina a través de una Seed

Grant, 1995.

Source : MNHN, Paris

LAVILLA & VAIRA 25

LITERATURA CITADA

AuL, E., 1938. — Über die Kaulquappe des Dendrophryniscus moreirae Miranda-Ribeiro. Zool. Anz.,

124 (5/6): 158-159.

BOKERMANN, W. C. A., 1967. — Observaçoes sobre Melanophryniscus moreirae (Mir. Rib.) (Amphibia

— Brachycephalidae). An. Acad. bras. Ci., 39 (2): 301-306.

Cu, J. M. 1980. — Amphibians of Argentina. Monit. zool. ital., (n.s.)., Mon. 2: i-xi + 1-609.

FERNANDEZ, K., 1926. — Sobre la biologia y reproducciôn de batracios argentinos. Segunda Parte.

Bol. Acad. nac. Ci. Cordoba, 29: 271-320, 4 läm.

GARRIDO-YRIGARAY, R. R., 1989. — Descripciôn de la larva de Melanophryniscus stelzneri

montevidensis (Philippi, 1902). Bol. Soc. zool. Uruguay, (2), 5: 7-8.

Goser, K. L., 1960. — À simplified table for staging anuran embryos and larvae with notes on

identification. Herpetologica, 16: 183-190.

LAURENT, R. F., 1973. — Variaciôn geogräfica de Melanophryniscus rubriventris (Vellard). Acta zool.

lilloana, 26 (23): 319-334.

LaviLLA, E. O., 1983. — Sistemätica de larvas de Telmatobünae (Anura: Leptodactylidae). Tesis

inédita, Facultad de Ciencias Naturales, Universidad Nacional de Tucumän: i-v + 1-354.

LaviLLa, E. O. & ScroccHI, G. J., 1986. — Morfometria larval de los géneros de Telmatobiinae

(Anura: Leptodactylidae) de Argentina y Chile. Physis, (B), 44 (106): 39-43.

McDiarmD, R. W., 1971. — Comparative morphology and evolution of frogs of the neotropical

genera Atelopus, Dendrophryniscus, Melanophryniscus and Oreophrynella. Bull. Los Angeles Co.

Mus. nat. Hist., 12: 1-66, 1 läm.

PRIGIONI, C. M. & ARRIETA, D., 1992. — Descripcion de la larva de Melanophryniscus sanmartini

Klappenbach, 1968 (Amphibia: Anura: Bufonidae). Bol. Soc. zool. Uruguay, (2), 7: 57-58.

PRIGIONI, C. M. & LANGONE, J. A., 1990. — Descripciôn de la larva de Melanophryniscus

orejasmirandai Prigioni & Langone, 1986 (Amphibia, Anura, Bufonidae). Com. Mus. nac. Hist.

nat. Montevideo, 12 (173): 1-9.

STARRETT, P., 1967. — Observations on the life history of frogs of the family Atelopodidae.

Herpetologica, 23 (3): 195-204.

VELLARD, J., 1947. — Un nuevo batracio del norte argentino. Acta zool. lilloana, 4: 115-119.

Corresponding editor: Ronald G. ALTIG.

Source : MNHN, Paris

Alytes, 1997, 15 (1): 26-36.

Microanatomy of the buccal apparatus

and oral cavity of Hvla minuta Peters, 1872

larvae (Anura, Hylidae),

with data on feeding habits

Dinorah D. ECHEVERRIA

Facultad de Ciencias Exactas y Naturales, Departamento de Ciencias Biolôgicas,

Laboratorio de Vertebrados, Universidad de Buenos Aires, 1428 Buenos Aires, Argentina

Histological and SEM observations of the buccal structures and reduced

mouthparts of the tadpole of Hyla minuta revealed new anatomical features.

There are few columns of cells that produce labial teeth in rows A-1 and P-2,

and each column has only a few cells that produce teeth. The labial teeth are

lightly pigmented, short and with 3-5 short cusps. Tooth development seems

to be abbreviated and not continuous during ontogeny.

Tooth densities vary among rows, and tooth rows A-1, P-1 and P-2 may be

incomplete or A-1 and P-2 may be absent. The number of conical cells in

different stages of keratinization in the cellular columns of the jaw sheaths

also varies.

Buccal roof arena papillae are sparse and tall, there are no lingual

papillae, the ventral velum has reduced marginal projections, median and

lateral ridges are present, and there are secretory pits on the dorsal velum and

posterior buccal roof. Based on intestinal contents (1e., periphytic algae,

pieces of filamentous algae and cyperaceous plants including meristematic

tissue, and free starch granules), these tadpoles have a broad, herbivorous

macrophagous diet that appears to be harvested primarily by the jaw sheaths.

INTRODUCTION

The oral apparatus of anuran larvae usually consists of an oral disc with keratinized

jaw sheaths and labial teeth positioned on transverse tooth ridges. The jaw sheaths are

usually strongly pigmented and have a serrated edge, and labial teeth usually have cusps

on the head. Histological features (e. g., Alytes obstetricans: BEAUMONT & DEUNFF, 1959;

BOURGES & BACHELERIE, 1974; Discoglossus pictus: DEUNFF & BEAUMONT, 1959; Rana

pipiens: CHENG, 1964, fide KUANG, 1975; LUCKENBILL, 1965) and development of these

mouthparts (e.g., Rana pipiens: LUCKENBILL, 1965; KUANG, 1975; Bufo arenarum: FIORITO

DE Lopez & ECHEVERRiA, 1984, 1989) have been reported for a number of species with a

labial tooth row formula of 2/3. This formula is extremely common in anuran tadpoles in

many taxa and several ecomorphological guilds (ALTIG & JOHNSTON, 1989), but there are

two general patterns that deviate from the norm: increases in tooth row number in lotic

Source : MNHN, Paris

ECHEVERRIA 27

tadpoles and decreases in tooth rows in several groups. Tooth row reductions accompa-

nied by various other modifications of the oral apparatus are assumed to have occurred

independently in four groups of small South American Hyla: leucophyllata, microcephala,

minuta and parviceps. The pattern of reduction also varies among groups. Hyla microps

larvae have neither labial ridges nor labial teeth (HEYER et al., 1990). In Hyla nana, labial

teeth are absent, and the mouth is modified into a tube (LAviLLA, 1990). Hyla

sarayacuensis tadpoles have labial ridges but lack teeth (ALTIG & JOHNSTON, 1989).

In an attempt to supply the comparative morphological information required to

evaluate the assumption that tooth row reductions reflect a change in feeding mode

compared with more typical tadpoles, I report the oral and buccopharyngeal anatomy of

the tadpole of Hyla minuta.

MATERIAL AND METHODS

Hyla minuta tadpoles were obtained from semipermanent pools (maximum depth 40

cm) with rooted vegetation near the Iguazü River, Iguazü National Park, Provincia

Misiones, Argentina. Samples were obtained from April to December (autumn to summer)

in 1989-1993. Some tadpoles were reared through metamorphosis and preserved (SBM 38)

to ascertain identification. Ten tadpoles were examined histologically, eight were observed

with SEM, and two were dissected for camera lucida drawings. AÏl specimens (stages

25-39) were staged by the table of GosNER (1960), preserved in 10 % formalin when they

were captured, and stored in the dark in 5 % formalin.

For light microscopy, the tadpole body was dehydrated, cleared, and embedded in

paraffin (56-58°C), and serial sagittal and longitudinal sections cut at 4 and 7 um were

stained with Masson’s trichrome (MARTOIA & MARTOIA-PIERSON, 1970). For scanning

electron microscopy, the oral disc and buccal structures were critical-point dried and

coated with gold-palladium. These specimens also were drawn with a camera lucida, and

a video recording of some of the SEM observations is kept in the MEB-VIDEO (1993-94)

collection. Lengths of labial tooth rows P-1 and P-2 were taken in conjunction with the

SEM observation, according to ECHEVERRIA’S (1992) proposal. Drawings of the buccal

structures were made with a camera lucida from specimens in stages 30 and 37.

Terminology follows ALTIG (1970) and DEUNFF & BEAUMONT (1959) for oral disc and

tooth features, and VIERTEL (1982) for internal oral features. The descriptions of the

histological features are based on FIORITO DE LOPEZ & ECHEVERRIA (1989).

Pieces of the anterior intestine were dissected from two specimens at stages 25 and 32

for qualitative examination of the intestinal content by histological sections and with

SEM.

Source : MNHN, Paris

28 ALYTES 15 (1)

RESULTS

SEM OBSERVATIONS

The oral disc has a single row of large marginal papillae along the lateral and ventral

sides, and submarginal papillae are absent (fig. 1A). There are one upper and two lower

labial ridges, and teeth are present on P-1 but often absent in A-1 and P-2. Row P-1

extends almost across the transverse diameter of the disc, but teeth in P-2 are frequently

restricted to the medial area. If teeth are present in row A-1, the labial teeth are less dense

(ca. 10-15 pm apart) than in P-1 and P-2. Individual teeth have a short head and no neck

with modal total lengths of 15 um and modal widths of 9 im in P-1. There are 3 or 5 short,

sharp, sharply angled cusps on each tooth, and the short sheath is tightly anchored to the

soft tissue of the tooth ridge. In different rows (A-1 and P-1) and in different clutches,

labial teeth morphology may vary (figs. 1B-C). The wide jaw sheaths have regular, conical

serrations on the cutting edge (figs. 1A, D). The total modal length of these serrations is

20 um, and modal width is 15 um.

BUCCAL FLOOR AND ROOF FEATURES (FIGS. 2A-B)

The floor of the buccal cavity is triangular, and the branchial traps beneath the buccal

floor are not evident. Two infralabial papillae (IP) present behind the jaw sheath are

compressed and have a flat base and low projections on the free edge. Between these, a

pair of prelingual papillae arranged in a transverse row have a rugose or slightly

denticulate edge (fig. 3). The tongue anlage is large and lingual papillae are absent. The

buccal floor arena is very broad but not well defined and has a densely pustulate surface,

and no lateral papillae outline the arena. The complex prepocket papillae arise from a

common base, and the obliquely oriented buccal pockets are ovoid with the long axis

directed anteromedially. There are 1-2 pairs of medial projections on the posterior edge of

the velum, and large secretory pits occur along the velum.

The roof of the buccal cavity is shaped like an equilateral triangle. The large, elongate

internal nares are oriented obliquely, and the walls have a smooth narial valve. Postnarial

papillae are absent. The postnarial arena contains (stages 25-36) a triangular pre-median

ridge with three primary projections; the middle one is the largest (fig. 4A). By stage 37,

this ridge is shaped like an inverted V (fig. 2B). Pustulations are present in the postnarial

arena, and the lateral ridge is composed of a pair of long, simple and conical papillae. The

anterior papillae have smooth or rugose edges, and the posterior ones are the tallest and

are compressed laterally.

The triangular or crescent-shaped median ridge has small projections medially, and

the poorly defined buccal roof arena has a dense field of pustules and a pair of long,

conical, smooth marginal arena papillae on the posterior side of the arena. The glandular

zone is straight, transverse, and bears secretory pits. The dorsal velum and marginal

projections are absent (fig. 4B).

Source : MNHN, Paris

ECHEVERRIA 29

Fig. 1. — (A) SEM micrograph of the oral apparatus of Hyla minuta, stage 25. Scale line: 100 pm.

(B) Three labial teeth (1, 2, 3) emerging in row A-I, stage 25. Scale line: 10 pm. (C) Labial teeth

of row P-1, stage 25. Scale line: 10 um. (D) Front view of upper jaw serrations, stage 25. (E) Rear

view of same as in (D). Scale line: 10 um.

LIGHT MICROSCOPE OBSERVATIONS

Sagittal sections show that the lower jaw sheath is longer than wide, and the

infrarostral cartilage is subcircular in section. The suprarostral cartilage is long and

narrow, and the upper jaw sheath is deeply convex and thicker than the lower sheath (fig.

5A). The upper and lower jaw cartilages are covered with a modified stratified epithelial

tissue that gives rise to the cells that form the jaw sheaths. The core of the epithelium

consists of several rows of cellular columns that contain several morphological cell types

(figs. 5B-C): basal columnar cells lying over the basal membrane, flattened precone cells

with basophilic cytoplasm, and cone cells in different stages of progressive keratinization

from the proximal to distal end of the column. A layer of stratified epithelial tissue forms

the oral (internal side) and labial (external side) surfaces of the sheath. When the jaw

sheaths are closed, the edge of the lower jaw fits against the inner curvature of the upper

jaw.

Source : MNHN, Paris

30 ALYTES 15 (1)

Ds)

à PL

A \

Fig. 2. — Camera lucida drawings of the (A) floor and (B) roof of the oral cavity, stage 37. A:

marginal arena papilla; BRA: buccal roof arena; BFA: buccal floor arena; C: choana: G: area

of secretory pits; H: buccal pocket; IP: infralabial papillae; LR: lateral ridge; M: median ridge;

P: pre-median ridge; PJ: projections; PL: prelingual papillae; PP: prepocket papillae; T: tongue

anlage. Scale line: 500 um.

There is one upper and two lower labial tooth ridges with a modified stratified

epithelium. The columns of cells that develop teeth are positioned in the core of this

epithelium (fig. 5D). The sequence of cells from the base of a tooth ridge to the top is as

follows: basal column cells near the basal membrane, cylindrical odontoid cells with a

cornified distal edge, 1-3 cells in different stages of keratinization and pigmentation, and

1-4 labial teeth. Few cells occur in the columns for rows A-1 and P-2 and these may be

absent (figs. 5C-D). The external and apical surface of the tooth ridge for A-1 is covered

by a stratified epithelium (3-4 layers) that continues backwards as a bistratified epithelium.

The inner and external faces of the posterior labial ridges are covered by stratified

epithelium.

Remains of macrophytes of the family Cyperaceae and pieces of filamentous green

algae were found in the intestine (figs. 6A-B). Starch grains typical of macrophytes were

seen in the histological preparations observed with polarized light, and diatom frustules

were also found.

Source : MNHN, Paris

ECHEVERRIA 31

Fig. 3. — (A) SEM micrograph of the floor of the oral cavity, stage 30. Scale line: 100 um. (B) SEM

micrograph of the median ridge and pre-median ridge of the buccal roof, stage 30. Scale line:

100 um. (C) Glandular zone of the posterior part of the buccal roof, stage 30. Scale line:

1000 pm. A: buccal roof arena papilla; G: glandular zone; IP: infralabial papilla; M: median

ridge; P: pre-median ridge; PL: prelingual papilla; PP: pre-pocket papillae; T: tongue anlage.

DISCUSSION

Labial tooth histogenesis in Hyla minuta occurs in the same pattern as in other species

(e.8., Bufo arenarum and Rana pipiens), but the final result is different in each row. During

the development of B. arenarum, histogenesis of the jaw sheaths and labial tooth is

continuous (FIORITO DE LOPEZ & ECHEVERRIA, 1989). The spatial sequence of the cells in

each column in the sheaths of Rana pipiens represents a chronological sequence by their

differentiation from basal epithelial cells (LUCKENBILL, 1965). In Hyla minuta the jaw

sheath column cells are similar in size to those in R. pipiens and B. arenarum, but when

labial ridge column cells of Hyla minuta are compared with those of B. arenarum, several

differences are evident at the same stages. Labial ridge columns are shorter in Hyla minuta

and component cells are not produced continuously throughout the larval period. The

labial tooth columns of H. minuta also differ from those of B. arenarum by the

Source : MNHN, Paris

Fig. 4. — (A) Sagittal section of the buccal apparatus, stage 32. Scale line: 100 um. Closed arrowhead:

second lower tooth ridge; open arrow: first upper labial ridge; I: infralabial cartilage; K: labial

tooth; L: labial surface of lower jaw sheath; M: marginal papilla; OC: buccal cavity; S:

suprarostral cartilage; U: upper jaw sheath. (B) Sagittal section of lower jaw sheath, stage 32.

Scale line: 100 um. Asterisk: column of tooth cells in process of keratinization; B: basal cells; C:

cone cells; D: dermis; O: oral surface of lower jaw sheath; P: precone cells. (C) Sagittal section

of the (U) upper jaw sheath and (arrow) A-1 labial ridge, stage 32. Scale line: 50 um. C: cone

cells; D: dermis; K: labial tooth; P: precone cells; Q: keratinized oral surface of upper jaw sheath;

R: jaw serration; S: suprarostral cartilage. (D) Transverse section of (K) P-1 with labial teeth and

(arrow) P-2 labial ridge with a tooth emerging, stage 32. Scale line: 30 um. B: basal cells; C:

keratinization; D: dermis; T: odontoid cell.

Source : MNHN, Paris

ECHEVERRIA 33

Fig. 5. — SEM micrographs of intestinal contents showing (A) a piece of a cyperaceous plant (C; scale

bar: 0.1. mm) and (B) a piece of a filamentous alga (scale bar: 10 um).

discontinuity of the column, and the morphological cell types forming each column are less

evident than in B. arenarum. The distance between column cells differs according to the

row being examined.

Compared with oral histogenesis of other species (LUCKENBILL 1965; FIORITO DE

Lopez & ECHEVERR{A, 1989), the formation of labial teeth in Hyla minuta is short-lived,

especially in row A-1. Within these differences, the order of appearance of the tooth rows

does not seem to fit the general pattern of appearance of the tooth rows that THIBAUDEAU

& ALTIG (1988) proposed for 2/3 formulas. In H. minuta tadpoles at stage 25, P-1 may be

the only row, but labial tooth row formulas of 0/1, 1/1 and 1/2 have been reported for

specimens from Iguazü National Park (see also BOKERMANN, 1963; Cet, 1980; HEYER et al.,

1990; MONTANELLI, 1991; KAPLAN, 1994), and DUELLMAN (1978) reported 0/2 for a

population from Ecuador. It is possible to find more than one labial tooth row formula

in certain species at the same stage, but tooth density and distribution usually do not

change very much among specimens at the same stage and row (ECHEVERRIA et al., 1987).

Hyla crucifer has few teeth in P-3, and up to 50 % of the tadpoles may normally have a

formula 2/2 instead of 2/3 (GosnEeR & BLACK, 1957). BRESLER (1954) reported that

abnormalities of labial teeth and jaw sheaths occurred in tadpoles of Rana berlandieri and

in Bufo cognatus more frequently at higher developmental temperatures; spotty distribu-

tions and absences of teeth and jaw sheaths also occur. This is not the case in H. minuta,

and the situation in this species may represent a polymorphism.

Hylid tadpoles have 0, 2 or 4 lingual papillae (WASsERSUG, 1980; LAVILLA & FABREZI,

1987; HERO, 1990; HEYER et al., 1990; ECHEVERRIA & MONTANELLI, 1992). Hylid tadpoles

that lack lingual papillae (including Hyla minuta) include some tadpoles with labial teeth

reduced or absent: e.g., Hyla ebraccata, H. sarayacuensis, H. mixe, H. microps, H.

Source : MNHN, Paris

34 ALYTES 15 (1)

microcephala (WASSERSUG, 1980) and some non-feeding tadpoles (WASSERSUG & DUELL-

MAN, 1984). Hyla minuta tadpoles share some of the larval features found in H.

sarayacuensis (H. leucophyllata group): few teeth, reduction of oral papillation and roof

and floor arena papillae, and absence of lingual papillae. Tooth formation is abbreviated

in H. minuta, at least for rows A-1 and P-2, and they can be considered vestiges even if

the tooth ridges are well developed. Several authors (HEYER & CROMBIE, 1979; LANNOO et

al., 1987; WaAssERsUG, 1980; HEYER et al., 1990) refer to tiny or weakly developed teeth

relative to tadpoles with dispersed or few labial teeth.

Conversely, the jaw sheaths of H. minuta are strong and well pigmented and

keratinized, which suggests that they are efficient cutting instruments for harvesting large

pieces of material by biting or ripping pieces from a substrate. The internal structure of

the sheaths also supports this idea. Similar species may include Hyla phlebodes and H.

sarayacuensis (WASSERSUG, 1980). The shape of the borders of the plant pieces found in the

larval intestine of H. minuta indicates that they were cut with the jaw sheaths.

CONCLUSIONS

The labial teeth of Hyla minuta are short and weakly pigmented with a short basal

sheath, and each tooth head has 3-5 sharp cusps. The tooth ridges have few columns of

cells and each column produces few tooth generations. The development of labial teeth is

abbreviated at least in some rows (A-1 and P-2).

Labial tooth rows have different tooth densities. Row A-1 has widely spaced teeth

that may be distributed all along the tooth ridge. Row P-1 is well developed and most

common with teeth distributed throughout the length of the tooth ridge. Teeth present in

row P-2 row occur in sporadic patches of 3-5 teeth.

Judging from the anatomical features of the buccal cavity and oral apparatus of these

tadpoles and their intestinal contents, I suggest that the tadpole of Hyla minuta functions

as a herbivorous macrophagous feeder.

RESUMEN

Las observaciones del aparato bucal y de la cavidad oral de las larvas de Hyla minuta,

efectuadas con microscopio 6ptico y electronico de barrido, han revelado nuevos

caracteres anatomicos para tomar en consideraciôn. Las columnas formadoras de dientes

(o columnas de células) de las hileras A-1 y P-2 son escasas. Cada columna presenta un

nümero bajo de células epiteliales que darän desarrollo a los dientes crneos. Estos son

cortos, sin cuello, y presentan poco pigmento. Cada espätula tiene de tres a cinco

denticulos cortos y carenados, ubicados en el extremo distal. En el pico, las columnas

formadoras de dientes estân bien desarrolladas y muestran una acumulacién de células

cônicas en diferentes estadios de queratinizaciôn que refuerzan sus extremos y las paredes

laterales. El pico superior es delgado y su extremo es filoso; el pico inferior es agudo y

Source : MNHN, Paris

ECHEVERRIA 35

presenta una posiciôn proclive cuando se halla inactivo. Los dientes del pico tienen una

cüspide. El desarrollo de los dientes labiales parece estar abreviado o incompleto, y no

seria continuo durante la ontogenia. Cada hilera de dientes labiales puede presentar

diferente densidad dentaria. La distribuciôn de los mismos sobre los pliegues labiales de

A-1, P-1 y P-2 puede estar incompleta o ausente en A-1 y en P-2. Las caracteristicas de

la cavidad oral son las siguientes: papilas del arena del techo y del piso de la boca altas

y escasas, sin papilas linguales; velo ventral con proyecciones marginales reducidas;

puentes lateral y medio presentes; fosetas glandulares en el velo dorsal y en la region

posterior del techo bucal. En el contenido intestinal se hallaron algas perifiticas, grandes

trozos de algas filamentosas, de cyperaceas (Cyperaceae), y de tejido meristemätico, y

gränulos de almidôn, que permiten considerar a la larva de H. minuta con una tendencia

trofica del tipo macréfago herviboro, por lo menos en términos cualitativos. El pico

côrneo es el elemento del aparato bucal de H. minuta que tiene mäs importancia en la

supervivencia de la larva.

ACKNOWLEDGMENTS

Tam most grateful for the assistance from several people: Dra. Elena ANCIBOR, Laboratory of

Vegetal Anatomy, University of Buenos Aires, for identifying plant material, Dr. Jorge WRIGHT,

Laboratory of Mycology, University of Buenos Aires, for critically reading the typescript; Dr. Ronald

ALriG, Mississippi State University, for advice and comments; Lic. Maria F. RoCA, Department of

Biological Sciences, University of Buenos Aires; Mr. Dante GIMENEz, SEM Service of CITEFA, for

technical assistance; and the Director of Administracion de Parques Nacionales and staff of the Iguzü

National Park for allowing me to capture the tadpoles for this study.

LITERATURE CITED

ALTIG, R., 1970. — A key to the tadpoles of continental United States and Canada. Herpetologica,

26: 108-207.

ALTIG, R. & Jonnsron, G. F., 1989. — Guilds of anuran larvae: relationships among developmental

modes, morphologies and habits. Herp. M : 81-109.

BEAUMONT, A. & DEUNFF, J., 1959, — La kératinisation des dents et du bec larvaires chez A/ytes

obstetricans L. Arch. Anat. Micr. Morph. exp., 48: 307-324.

BOKERMANN, W. C. À., 1963. — Girinos de anfibios brasileiros. I. (Amphibia-Salientia). Anais Acad.

bras. Cienc., 35: 464-474.

BOURGES, M. & BACHELERIE, C., 1974. — Rôle des cellules épithéliales adjacentes aux colonnes

dentaires dans la dynamique des odontoïdes cornés chez le têtard d'Alytes obstetricans

Laurenti. C. r. Soc. Biol., 168: 1335-1339.

BRESLER, J., 1954. — The development of labial teeth of salientian larvae in relation to temperature.

Copeia, 1954: 207-211.

CE, J. M., 1980. — Amphibians of Argentina. Monit. zool. ital., Mon. 2: 1-609.

CHENG, H., 1964. — The development of the horny beak in Rana pipiens tadpoles. Thesis, Univ. Iowa.

DEUNFF, J. & BEAUMONT, A., 1959. — Histogénèse des dents et du bec cornés chez les larves de

Discoglossus pictus Otth. C. r. Soc. Biol., 153: 1162-1164.

DuELLMAN, W. E., 1978. — The biology of an equatorial herpetofauna in Amazonian Ecuador. Misc.

Publ. Mus. nat. Hist. Univ. Kansas, 65: 1-352.

Source : MNHN, Paris

36 ALYTES 15 (1)

Ecneverria, D. D., 1992. — Microscopia electrônica de barrido del aparato bucal de la larva de Hyla

pulchella pulchella (Anura, Hylidae). Cuad. Herp., 7: 24-29.

ECHEVERRiA, D. D., FIORITO DE Lopez, L. E., VACCARO, O. B. & FiLIPELLO, A. M., 1987. —

Consideraciones acerca de las férmulas dentarias de las larvas de Bufo arenarum Hensel

(Anura, Bufonidae). Cuad. Herp., 3: 33-39.

ECHEVERRIA, D. D. & MONTANELLI, S. B., 1992. — Estereomorfologia del aparato bucal y cavidad

oral de las larvas de Ololygon fuscovaria (Lutz, 1925) (Anura, Hylidae). Rev. Mus. arg. Ci. nat.

Bernardino Rivadavia, (Zool.), 16: 3-13.

FioriTo DE Lopez, L. E. & ECHEVERRIA, D. D., 1984. — Morfogénesis de los dientes larvales y pico

corneo de Bufo arenarum (Anura, Bufonidae). Rev. Mus. arg. Ci. nat. Bernardino Rivadavia,

(Zoo!.), 13: 573-578.

—— 1989. — Microanatomia e histogénesis del aparato bucal en las larvas de Bufo arenarum (Anura,

Bufonidae). Cuad. Herp., 4: 4-10.

Gosner, K. L., 1960. — A simplified table for staging anuran embryos and larvae with notes on

identification. Herpetologica, 16: 183-190.

Gosner, K. L. & BLACK, I. H., 1957. — Larval development in New Jersey Hylidae. Copeia, 1957:

31-36.

HERO, J. M., 1990. — An illustrated key to tadpoles occurring in the central Amazon rainforest,

Manaus, Amazonas, Brasil. Amazonia, 11: 201-262.

Hever, W. R. & CROMBIE, R. L., 1979. — Natural history notes on Craspedoglossa stejnegeri and

Thoropa petropolitana (Amphibia: Salientia, Leptodactylidae). J. Washington Acad. Sci., 69:

17-20.

HEYER, W. R., RAND, A. S., GONÇALVES DA CRUZ, C. A., PEIXOTO, O. L. & NELSON, C. E., 1990. —

Frogs of Boracéia. Arg. Zool., 31 (4): 231-410.

KapLaw, M., 1994. — A new species of frog of the genus Hyla from the Cordillera Oriental in

northern Colombia with comments on the taxonomy of Hyla minuta. J. Herp., 28: 19-81.

KUANG, H. C., 1975. — Development of beaks of Rana pipiens larvae. Anat. Rec., 182: 401-414.

LaNNoo, M. J., TOWNSEND, D. S. & WAssERSUG, R. J., 1987. — Larval life in the leaves: arboreal

tadpole types, with special attention to the morphology, ecology, and behavior of the

oophagous Osteopilus brunneus (Hylidae) larva. Fieldiana: Zool., (n. s.), 38: 1-31.

LavizLa, E. O., 1990. — The tadpole of Hyla nana (Anura: Hylidac). J. Herp., 24: 207-209.

LAviLLa, E. O. & FABREZI, M., 1987. — Anatomia de las larvas de Hyla pulchella andina (Anura:

Hylidae). Physis, 45B: 77-82.

LuckENBILL, H. C., 1965. — Morphogenesis of the horny jaws of Rana pipiens larvae. Dev. Biol., 11:

25-49.

MaRTOJA, R. & MARTOJA-PIERSON, M., 1957. — Técnicas de histologia animal. Barcelona,

Torray-Masson: 1-350.

MONTANELLI, S. B., 1991. — Estudio preliminar de las larvas de Hyla minuta Peters, 1872 (Anura,

Hylidae) de la selva subtropical argentina. Bol. Asoc. herp. arg., 7: 6.

THIBAUDEAU, G. & ALTIG, R., 1988. — Sequence of ontogenetic development and atrophy of the

apparatus of six anuran tadpoles. J. Morph., 197: 63-69.

VierTEL, B., 1982. — Oral cavities of central European anuran larvae (Amphibia): morphology,

ontogenesis and generic diagnosis. Amphibia-Reptilia, 4: 327-360.

WASsERSUG, R. J., 1980. — Internal oral features of larvae from eight families: functional, systematic,

evolutionary and ecological considerations. Misc. Publ. Mus. nat. Hist. Univ. Kansas, 68: 1-146.

WaASSERSUG, R. J. & DUELLMAN, W. E., 1984. — Oral structures and their development in

egg-brooding hylid frog embryos and larvae: evolutionary and ecological implications. J.

Morph., 182: 1-37.

Corresponding editor: Ronald G. ALTIG.

Source : MNHN, Paris

Alytes, 1997, 15 (1): 37-48. 37

Sexual size and shape difference

in the crested newt (Triturus carnifex):

ontogenetic growth aspects

D. Cverkovié *, M. L. KALEzié * & G. DZUkIÉ **

* Institute of Zoology, Faculty of Biology, Studentski trg 16, 11000 Beograd, Yugoslavia

** Institute for Biological Research “Sinisa Stankovic”, 29 Novembra 142, 11000 Beograd, Yugoslavia

The pattems of emergence and development of sexual size and shape

differences (SSSD) in the crested newt were examined. The results of our study

indicate that differences in size and shape between females and males appear

mostly in the period between the first and the second hibemation, which

seems particularly important for development of SSSD. Conceming the

questions of time and speed of morphological divergence between sexes, we

can conclude that the establishment of SSSD precedes reproduction. The

process is not gradual; two periods can be distinguished. The second period is

characterized by rapid change, resulting in considerable intersexual differ-

ences in various parameters. Juveniles exhibited pronounced sexual

dimorphism of growth rates, as well as differences in level and timing of

departures from isometric growth, and in values of the Wolterstorf index (WI).

The existence of two distinct periods in development of SSSD was also

confirmed at the multivariate level.

INTRODUCTION

European newts (Triturus, Salamandridae) have the most pronounced morphological

sexual dimorphism among tailed amphibians, especially during the breeding season. Sexes

differ in coloration, skin texture and glandular development, as well as in body size and

shape. In most of 12 extant species, including Triturus carnifex, females are larger than

males (KALEZIÉ et al., 1992). Significant differences were found for most linear dimensions

(measures of size), as well as for some ratios of these dimensions (measures of shape),

though shape differences have attracted less interest so far. It was established that the

extent of sexual size difference in European newts is a variable condition not constrained

by species body size, spatial proximity of analysed populations or altitude (KALEZIÉ et al.,

1992).

However, patterns of emergence and development of sexual size and shape differences

(SSSD) still remain to be clarified. Many questions can be raised concerning the time and

speed of morphological divergence between sexes. Do the differences in body size and

shape fully develop prior to attainment of sexual maturity? Is the process of divergence

Source : MNHN, Paris

38 ALYTES 15 (1)

gradual during the juvenile phase of life or can a distinct period of rapid change be

observed? Moreover, it is still unknown which morphometric characters are most involved

in the above process.

Growth before the age of first reproduction (larval and juvenile stages) appears to be

the major determinant of body size in amphibians and reptiles in general (HALLIDAY &

VERRELL, 1988), and in newts in particular (e.g. HAGSTROM, 1980; GLANDT, 1981; VERRELL

& FRANCILLON, 1986; KaALEzié et al., 1994).

Thus, as the main concern of this paper was to find the pattern of SSSD appearance

in Triturus carnifex, we have studied morphometric growth aspects during the critical

ontogenetic period between the first and the second hibernation.

MATERIALS AND METHODS

LABORATORY PROCEDURES

Crested newt specimens were collected from Lokanj pond (Montenegro) in October

1991. We sampled 43 juveniles, as well as fully mature individuals, 21 females and 19 males

(‘adults” in the following text). Newts were anaesthetized by immersion in a 2:1000

MS-222 (Sandoz) solution, individually marked by toe clipping and measured. Shortly

after measuring, the newts were put into hibernation in a cold room at 7.5°C till next

February. On emergence from “wintering”, 43 juveniles (all survived hibernation) were

measured again and housed in a 300 1 aquarium. This aquarium had been established three

years before and contained diverse weeds, simulating a natural pond. It was exposed to a

natural photoperiod and daily changes in room temperature (10-25°C); the constant water

level was maintained. Water was continually recycled and filtered. Thus, the newts were

maintained in standard conditions with ad libitum access to food (earthworms and pieces

of beef meat). Juveniles were measured each subsequent 30 days for another 10 months.

Body mass was determined by blotting individuals dry and weighing them to the nearest

0.01 g.

Out of 43 juveniles, 23 survived till the second hibernation, 15 females and 8 males.

They were sexed according to the presence of secondary sexual characteristics, the

identification of males being easier through the appearance of a dorsal crest, a thin

crenulated skin flap, a bluish-white streak along the tail and a swollen black cloaca. At

that age, exclusively female secondary sexual feature, the presence of cloaca papillae, was

less apparent.

MORPHOMETRIC VARIABLES

In juveniles and adults, 9 morphometric characters were measured: SVL (snout-vent

length), Lep (the distance from the snout to the frontal edge of the cloaca), Ltc (head

width at the angle of the jaw), Le (head length from the snout to the corner of mouth),

Source : MNHN, Paris

Cverkovit, KALEZIÉ & DZUKIÉ 39

Lel (distance between the snout and the gular skin fold), Pa (fore limb length, measured

from axilla to the tip of the longest finger), Pp (hind limb length, from groin to the tip of

the longest finger), D (distance between fore and hind limbs) and Lh (the maximum fin

height measured at the base of the tail). All measurements were made with a dial caliper

with 0.1 mm precision.

STATISTICAL ANALYSIS

Two data sets are presented here: one consists of records of the same individual at

different time points, the other is based on samples of different individuals at the same

time point. According to CocKk (1966), they are defined as longitudinal and static data,

respectively. Consequently, we distinguish growth allometry, changes in size-shape

relationships with time, from static allometry, based on records of different individuals

(e.g. GouLp, 1966).

The growth of juvenile newts was expressed through relative growth rate (K),

calculated according to the following equation (ANDREWS, 1982):

K = (nS, — InS)/(t — ti),

where S,, S, and t,, t, were size (standard length) at and time of two measure points.

Linear regressions of SVL on time were also calculated for both groups of juveniles.

The Wolterstorff index (WI), widely recommended as a useful tool for distinguishing

crested newt taxa (e.g. HERRE, 1932; Sova, 1973; KALEZIÉ et al., 1990; LANZA et al., 1991),

was calculated as the ratio of forelimb length to interlimb distance (WOLTERSTORFF, 1923).

Apart from various uni- and bivariate statistical analyses (SOKAL & ROHLF, 1981; ZAR,

1984), multivariate procedures of principal-component analysis (PCA) and Mahalanobis

distance (D?) were applied. Due to the small sample size, multivariate procedures were

conducted on the set of seven morphometric traits (SVL, Lte, Lel, Pa, Pp, D, Lh) in

juveniles and adults.

Principal-component analysis allowed simultaneous analysis of morphometric data,

reducing dimensionality but retaining variation. It was performed on the variance-

covariance matrix of log-transformed data, a procedure recommended when dealing with

morphometric traits (e.g. BOOKSTEIN et al., 1985). Separate principal-component analyses

were computed for 4 time points (I: prior to the first hibernation; IV: April; VIII: August;

XI: November, prior to the second hibernation) in juveniles and for adults. The

Mahalanobis multivariate distance between the sexes was computed for all measurement

points. Mantel test was used to analyse the correspondence of character variance-

covariance matrices.

RESULTS

The range of standard length of 43 juveniles was 44.1-55.9 mm (mean + standard

error: 51.6 + 0.4 mm). This indicates that they hatched in the same season (spring 1991),

Source : MNHN, Paris

40 ALYTES 15 (1)

metamorphosed during a relatively short time span and therefore were suitable for this

study, though there is evidence of a plastic life-history including facultative paedomor-

phosis in the Lokanj population (KALEzIÉ et al., 1994). The mean SVL of 23 surviving

juveniles at the begining of the study was 51.7 + 0.6 mm (range 47.9-55.9 mm) for females

and 51.1 + 0.6 mm (range 48.8-53.7 mm) for males, the difference being statistically

insignificant (ANOVA, F = 0.445, P > 0.05). The mean value of SVL prior to the second

hibernation was 75.2 + 0.8 mm (range 69.7-79.1 mm) and 69.9 + 1.9 mm (range 56.9-73.8

mm) for females and males, respectively. Intersexual difference was significant (ANOVA,

F = 8.74, P < 0.01).

It was essential for our laboratory study to avoid competition for food among

juveniles and therefore allow the undisturbed development of SSSD. When density is low

(intraspecific competition low or absent), a normal distribution of individual growth rates

is expected. Otherwise, intense competition for food would result in a skewed or lognormal

distribution (WiLBUR & CoLLins, 1973; WiLBUR, 1976). The distribution of growth rates

in our data set showed good fit to normal distribution (Kolmogorov-Smirnov test, P >

0.05 in all cases). Thus, we can conclude that nutritional conditions were similar for all

individuals, i.e. there was no size-dependent advantage.

The analysis of relative growth rates indicated the existence of two distinct periods.

Up to July (the first half of the year) females invariably had faster growth, but the

difference was insignificant (ANOVA, P > 0.05 in all cases). The second period is

characterized by significantly increasing differences (ANOVA; July-August, P = 0.01;

August-September, P = 0.05; September-October, P < 0.01), except for the last month

before the second hibernation (P > 0.05). The comparison of linear regressions of SVL

on time over the whole time span studied indicated that females were growing significantly

faster than males (b® = 2.436 + 0.100, b$ = 1.925 + 0.097; r test, 1 = 3.66, P < 0.001).

It is of interest to note negative growth during hibernation. Indeed, the comparison

of the first two measurement points showed a significant decrease, not only in weight

(paired # test, 1 = 15.87, P < 0.0001), but in length as well (paired s test, 1 = 4.39, P <

0.001), with pronounced individual variability.

In the sample of adults, females were larger than males (mean SVL 74.4 + 1.4 and

72.6 + 1.0, respectively); however, the difference was insignificant (ANOVA, F = 1.16,

P > 0.05).

BIVARIATE ALLOMETRY

In order to analyse the pattern of changes in bivariate allometric coefficients during

ontogeny, regression analysis was performed on eight morphometric traits (using SVL as

the independent variable) for all measurement points in juveniles, as well as for adults

(tab. 1). Intersexual difference in departures from isometric growth is obvious in the

number of statistically significant allometric coefficients. In juvenile males, out of 88

values, 18 were statistically significant (20.4 %) vs. 6/88 (6.8 %) in juvenile females (?, P

< 0.05). Also, in males, contrary to females, most of the significant values appear in the

second half of the year. Negative allometry is apparent: 5/6 significant coefficients in

Source : MNHN, Paris

Cverkovié, KaLezié & DZuKkié 41

Tab. 1. - Significant bivariate allometric coefficients in males and females. Positive allometry:

+, P < 0.05; ++, P < 0.01. Negative allometry: —, P < 0.05; — -, P < 0.01; — -

—, P < 0.001. I - XI: measurement points in juveniles, AD: adults.

VI VI VIN IX

juvenile females, 2/2 in adult females and 12/18 in juvenile males. Traits showing

considerable ontogenetic allometry are: Lep, Ltc, Lel and Pa in males, Pa and Pp in

females.

WOLTERSTORFF INDEX AND MAHALANOBIS DISTANCE

Morphometric differentiation between the sexes in terms of multivariate distance

(Mahalanobis D?) and bivariate parameter WI (Wolterstorff index) is shown in fig. 1.

Mabhalanobis distance changed slightly between measurements I and VII (prior to the

first hibernation and next July) and then increased rapidly. At the time of the

second hibernation it was even higher than the value found in the sample of adults

(D'aa = 6.02).

Intersexual differences in WI values, characteristic for some salamander species

(particularly crested newts), were also calculated for all measurement points. The pattern

of change followed that of Mahalanobis distance — rapid change in the second half of the

year resulted in highly significant differences between sexes. The value just prior to the

second hibernation (0.071) was somewhat higher than in adults (0.062).

Source : MNHN, Paris

42 ALYTES 15 (1)

WIx100

T7]

‘

CEE LE PP PR EE 1

0 0

D OZ HI IV V VI VII VIIL IX X XI XII

pre] fesse]

hib time hib

— D? WI

Fig. 1. — Mahalanobis distance (D?) and differences in values of Wolterstorff index (WI) between

juvenile males and females; hib: hibernation. Measurement points II — XI correspond to months

(February to November).

Source : MNHN, Paris

Cverkovié, KALEZIC & DZuxié 43

DEVELOPMENT OF SSSD IN MULTIVARIATE SPACE

Mantel test was applied to examine the correspondence of character variance-

covariance matrices between the sexes. The absence of significant positive correlations

indicated the differences in character covariance structure between females and males,

juveniles as well as adults.

The results of PCA showed that the first two principal components account for a

considerable amount of total variation: 74.2-95.1 % in juvenile males, 91.0 % in adult

males, 78.7-86.2 % in juvenile females and 88.7 % in adult females. This indicates strong

correlations between variables, as is expected when dealing with morphometric traits.

Principal-component 1 can be considered a general size component, while PC2 represents

a shape component. The magnitudes of eigenvector elements indicate the contribution of

each original trait to principal components (fig. 2).

Principal-component 1 measures variation attributable to differences in size. AIl traits

load on PCI positively. Similar, but not identical, values of eigenvector coefficients

indicate the influence of allometric information. The most striking feature is the position

of fin height (Lh) in PCI-PC2 space. This trait dominates both axes and is opposed to all

other traits (this is less pronounced only for measure point IV in females). It has a

constant, stable position in morphological space, irrespective of sex, the only exception

being adult males. In adult males, the position of sets of traits is reverse, compared to

females, due to opposite signs of eigenvector loadings on PC2.

Traits related to locomotion, Pa and Pp, load as a group and show some intersexual

differences. Other traits do not show a recognizable pattern. Snout-vent length has a

relatively stable position in juveniles, irrespective of sex. Variation in head dimensions,

related to feeding (Ltc and Lei) and in interlimb distance (D) shows no simple trend

during ontogeny, though intersexual differences appear in the youngest juveniles

(measurement points I and IV).

The average values of PC scores (fig. 3) show time-related changes in size and shape

of studied individuals. The last pair of points represents adult males and females occupying

different morphological spaces; shape divergence is mostly influenced by one trait, fin

height.

THE ATTAINMENT OF SEXUAL MATURITY

The newts with well expressed secondary sexual characteristics were allowed to

court and oviposit shortly after the second hibernation. We observed courtship and

spermatophore deposition, but no oviposition took place during the expected breeding

season.

Source : MNHN, Paris

44 ALYTES 15 (1)

02 02

te a

0.6 0.6)

D Lh Le

0.4| Lot 04! D Le Pp\ Pa

Lev |IPP Lot

0.2] Pa 02

8 -04 O0 04 08

MI FIV

0.8) in 0.8]

0.8) 0.8| mr)

He "

04 D pa Le 0.4]

PT Le Lot D

0.2] 0.2l Pa

Lot

°! °!

08 -04 O0 04 08 08 -04 0 04 08

M vi F VI

0.0) 0.8)

o.e| ml 04

Lto

0.4 tte D 0.4 Le

Pa D D Let Lio is

0.4| La 0.4 CA

Lot pp Lie Pa

0.2] 0-2)

o! ol

-08 -04 0 04 08 -08 -04 O0 04 08

MxI FX

0.8) 0.8)

o. im | os

re c]

04 ALES 04] Le

(LOT Lio Let Pa

0.2) 0-2)

0! 0!

M AD F AD

0.8) 0.8)

4 0 04 08

08 -04 O0 04 08 -08 -0. o.

Fig. 2. — Plots of cigenvectors (X axis: PC2, Y axis: PCI) for 4 measurement points in juveniles (I,

IV, VII, XI) and for adults (AD); M: males, F: females.

Source : MNHN, Paris

Cverkovié, KALEzIÉ & DZukié 45

PC II

0.6 | x AD

0.2} I

o }

re ne vi

É XL + AD

cul VIII

—0.6 + IV XI

De i L i 2 L L 1

1 105 11 1.15 1.2 1.25 1.3 1.35 1.4

PCI

KM —F

Fig. 3. — Average values of PC scores for 4 measurement points in juveniles (I, IV, VIII, XI) and

for adults (AD); M: males, F: females.

DISCUSSION

The results of our study indicate that differences in size and shape between females

and males appear mostly in the period between the first and the second hibernation, which

seems particularly important for development of SSSD. At least some juvenile crested

newts, maintained in our laboratory, attained sexual maturity at the age of 2 years. This

seems to be the minimum age at first breeding for Triturus cristatus superspecies; in the

field it usually takes longer — from 3 to 5 years (HAGSTROM, 1975; FRAZER, 1983;

FRANCILLON-VIEILLOT et al., 1990).

Thus, concerning the questions of time and speed of intersexual morphological

divergence, we can conclude that the establishment of SSSD precedes reproduction. The

process is not gradual; a period of rapid change can be distinguished, resulting in

considerable intersexual differences, confirmed by various uni-, bi- and multivariate

analyses.

In species with intersexual size difference, several patterns of juvenile growth are

possible (ANDREWS, 1982). One is for juveniles to grow at similar rates until individuals of

the smaller sex reach asymptotic length, while the larger sex continues to grow, so the

growth curves diverge. Another pattern is to grow at different rates, either from the

beginning (hatching) or from some point early in life. In our study, juveniles exhibited a

Source : MNHN, Paris

46 ALYTES 15 (1)

pronounced sexual difference in growth rates, according to the second pattern. Greater

importance of juvenile compared to adult growth rates has been stressed before (e.g.

HALLIDAY & VERRELL, 1988).

As far as adults are concerned, in the crested newt populations females are almost

invariably larger than males (KaALEZIé et al., 1992). In this sample of Lokanj adults, the

difference is not significant. However, another sample from the same population obtained

significant sexual size difference (unpublished results). The variation of body size

distributions and the extent of sexual size dimorphism at the inter- and intrapopulation

level is a common phenomenon (HALLIDAY & VERRELL, 1988; STAMPS, 1993). Many factors

can be responsible for this variation among the samples from the same population, such

as differences in growth rates or age structure (STAMPS, 1993).

Our results show a substantial sexual size divergence during the critical period prior

to sexual maturation, but the interpretation of adult size data requires more detailed

information on adult growth patterns.

Intersexual shape differences were revealed by various bi- and multivariate methods.

In terms of bivariate allometry, considerable differences in level and timing of departures

from isometric growth are found between females and males. Allometry is mostly negative

with respect to standard length. However, allometric coefficients for Pa, the trait involved

in WI, show intersexual differences. If we compare all coefficients, values are almost

without exception negative in females and positive in males. Hind limb length (Pp) shows

mostly isometric (to slightly negative allometric) growth in males and negative allometric

growth in females. This confirms some previous findings. REHAK (1983) found for the

crested newt females relative shortening of legs with respect to body length. This difference

in limb lengths between the sexes might be associated with the courtship behaviour in

males and sperm transfer (e.g. HALLIDAY, 1977; REHAK, 1983; RAXWORTHY, 1989).

The existence of two distinct periods in development of SSSD was confirmed at the

multivariate level (Mahalanobis distance). Differences in values of the Wolterstorff index

exhibited the same pattern, which confirms that this bivariate parameter is a good

indicator of size-shape changes. Principal-component analysis showed that the trait with

the largest contribution to both components, PCI and PC2, was fin height (Lh). Sets of

traits had a reverse position in adult females and males, occupying different morphological

spaces, mainly due to shape differences.

We are aware that the paucity of sample size in our study, especially of males,

precludes well-supported conclusions, though general trends are apparent. Additional data

are needed for a more rigorous assessment of these trends.

ACKNOWLEDGEMENTS

We thank Nikola Tucié for helpful discussion, Snezana PEJIÉ and Dragana Novakovié for

technical assistance, and Ana Dorovié, Ivan ALEKsIé and Davor BEJAKOvVIÉ for assistance in

collecting newts.

Source : MNHN, Paris

Cverkovié, KALEZIÉ & DZUKIé 47

LITERATURE CITED

ANDREWS, R. M., 1982. — Patterns of growth in reptiles. Jn: C. GAns & F. H. POUGH (ed.), Biology

of reptiles, New York, Academic Press, vol. 13: 273-320.

BOOKSTEIN, F., CHERNOFF, B., ELDER, R., HUMPHRIES, J., SMITH, G. & STRAUSS, R., 1985. —

Morphometrics in evolutionary biology. Philadelphia, Pennsylvania, Academy of Natural

Sciences of Philadelphia, Special Publication 15.

Cocx, A. G., 1966. — Genetical aspects of metrical growth and form in animals. Q. Rev. Biol., 41:

131-190.

FRANCILLON-VIEILLOT, H., ARNTZEN, J. W. & GÉRAUDIE, J., 1990. — Age, growth and longevity

of sympatric Triturus cristatus, T. marmoratus and their hybrids (Amphibia, Urodela): a

skeletochronological comparison. J. Herp., 24: 13-22.

FRAZER, D., 1983. — Reptiles and amphibians in Britain. London, Collins: 1-256.

GLANDT, D., 1981. — Zum Postmetamorphose-Wachstum von Triturus cristatus (Amphibia, Urodela,

Salamandridae) im Freiland. Zool. Jb. Anat., 106: 76-86.

Gouzn, S. J., 1966. — Allometry and size in ontogeny and phylogeny. Biol. Rev., 41: 587-640.

HAGsTROM, T., 1975. — Notes on growth and age distribution of adult Triturus vulgaris L. and T.

cristatus Laurenti (Urodela, Salamandridae) in SW Sweden. Bull. Soc. zool. Fr., 100: 680.

= 1980. — Growth of newts (Triturus cristatus and Triturus vulgaris) at various ages. Salamandra,

16: 248-251.

HaLuay, T. R., 1977. — The courtship of European newts: an evolutionary perspective. Jn: D. H.

TAYLOR & S. I GUTTMAN (ed.), The reproductive biology of amphibians, New York, Plenum

Press: 185-232.

HaLuay, T. R. & VERRELL P. A., 1988. — Body size and age in amphibians and reptiles. J. Herp.,

22: 253-265.

Herr, W., 1932. — Vergleichende Untersuchungen an den Unterarten des Triturus cristatus Laur.

Z. Anat. Entw.-Gesch., (1), 99: 1-62.

KaLEzié, M. L., CRNOBRNJA, J., Dorovié, A. & DZUkIé, G., 1992. — Sexual size difference in

Triturus newts: geographical variation in Yugoslav populations. Alytes, 10: 63-80.

KaLezié, M. L., Cverkovié, D., Dorovié, A. & Dzuxié, G., 1994. — Paedomorphosis and

differences in life-history traits of two neighbouring crested newt (Triturus carnifex) popula-

tions. Herp. J., 4: 151-159.

KaLezié, M. L., DZukié, G., STAMENKOVIÉ, S. & CRNOBRNIA J., 1990. -- Morphometrics of the

crested newt (Triturus cristatus complex) from Yugoslavia: relevance for taxonomy. 4rh. biol.

Nauka, Beograd, 42: 17-37.

LanzA, B., GENTILE, E. & TORRICELLI, 1., 1991. — Preliminary data on the number of presacral

vertebrae in Triturus cristatus-Artenkreis (Amphibia: Caudata: Salamandridae). In: G. GHiARI

et al. (ed.), Symposium on the evolution of terrestrial vertebrates, Modena, Mucchi, Selected

Symposia and Monographs ULZ.I. 4: 531-534.

RaxwoRTHY, C. J., 1989. — Courtship, fighting and sexual dimorphism of the banded newt, Triturus

vittatus ophryticus. Ethology, 81: 148-170.

REHAK, L., 1983. — Changes in body measures during the growth of the newts Triturus vulgaris, T.

alpestris and T. cristatus (Amphibia: Urodela). Vest. és. Spolec. zool., 47:

SokaL, R. R. & ROHLF, F., 1981. — Biometry. San Francisco, Freeman & C

Sova, C., 1973. — Morphometric researches in the genus Triturus from Rumania (Sereth River

Basin). Studii si Comunicari, Muzeul De Stiintele Naturi BacCau, 1973: 85-286.

Sramps, J. A., 1993. — Sexual size dimorphism in species with asymptotic growth after maturity. Biol.

J. linn. Soc., 50: 123-145.

VERRELL, P. A. & FRANCILLON H., 1986. — Body size, age and reproduction in the smooth newt,

Triturus vulgaris. J. Zool., (A), 210: 89-100.

‘WizBur, H. M., 1976. — Density-dependent aspects of metamorphosis in Ambystoma and Rana

sylvatica. Ecology, 57: 1289-1296.

Source : MNHN, Paris

48 ALYTES 15 (1)

WiLBUR, H. M. & COLLINS J. P., 1973. — Ecological aspects of amphibian metamorphosis. Science,

182: 1305-1314.

WoLTersTORFF, W., 1923. — Übersicht der Unterarten und Formen des Triton cristatus Laur. Blätter

Aquar. Terrarienk. Kde. Stuttgart, 34: 120-126.

ZaR, J. H., 1984. — Biostatistical analysis. New Jersey, Prentice-Hall: 1-718.

Corresponding editor: Tim HALLIDAY.

Source : MNHN, Paris

AVTES

International Journal of Batrachology

published by ISSCA

EDITORIAL BOARD

Chief Editor: Alain Dusois (Laboratoire des Reptiles et Amphibiens, Muséum national d'Histoire naturelle,

25 rue Cuvier, 75005 Paris, France).

Deputy Editor: Janalee P. CALDWELL (Oklahoma Museum of Natural History, University of Oklahoma,

Norman, Oklahoma 73019, USA).

Editorial Board: Jean-Louis ALBARET (Paris, France); Ronald G. ALTiG (Mississippi State University,

USA); Emilio BALLETTO (Torino, Italy); Alain COLLENOT (Paris, France); Günter GOLLMANN (Wien,

Austria); Tim HALLIDAY (Milton Keynes, United Kingdom); W. Ronald Hever (Washington,

USA); Walter HDi (Wien, Austria): Pierre JOLY (Lyon, France): Masafumi Marsui (Kyoto,

Japan); Jaime E. PÉFAUR (Mérida, Venezuela); J. Dale RoBErTs (Perth, Australia); Ulrich SINsCH

{Koblenz, Germany): Marvalee H. Wake (Berkeley, USA).

Technical Editorial Team (Paris, France): Alain DUBoIs (texts); Roger BoUR (tables); Annemarie OHLER

(figures).

Index Editors: Annemarie OHLER (Paris, France); Stephen J. RICHARDS (Townsville, Australia).

SHORT GUIDE FOR AUTHORS

(detailed Instructions to Authors are given in Alytes, 1997, 14 (4): 175-200)

Alytes publishes original papers in English, French or Spanish, in any discipline dealing with amphibians.

Beside articles and notes reporting results of original research, consideration is given for publication to synthetic

review articles, book reviews, comments and replies, and to papers based upon original high quality illustrations

(such as color or black and white photographs), showing beautiful or rare species, interesting behaviors, etc.

The title should be followed by the name(s) and address(es) of the author(s). The text should be

typewritten or printed double-spaced on one side of the paper. The manuscript should be organized as follows:

Énglish abstract, introduction, material and methods, results, discussion, conclusion, French or Spanish

abstract, acknowledgements, literature cited, appendix.

Figures and tables should be mentioned in the text as follows: fig. 4 or tab. 4. Figures should not exceed

16 x 24 cm. The size of the lettering should ensure its legibility after reduction. The legends of figures and tables

should be assembled on a separate sheet. Each figure should be numbered using a pencil.

References in the text are to be written in capital letters (BOURRET, 1942; GRAF & POLLS PELAZ, 1989;

INGER et al., 1974). References in the Literature cited section should be presented as follows:

Bouaer, R. 1942. + Les Batraciens de l'ndochine. Hanoi, Institut Océanographique de l'Indochine: x

+ 1-547, pl. I-IV.

Grar, J.-D. & POLLS PELAZ, M., 1989. - Evolutionary genetics of the Rana esculentacomplex. In: R. M. DAWLEY

& J. P. BoGarT (eds.), Evolution and ecology of unisexual vertebrates, Albany, The New York State

Museum: 289-302.

InGer, R. F, Voris, H. K. & Voris, H. H., 1974. - Genetic variation and population ecology of some

Southeast Asian frogs of the genera Bufo and Rana. Biochem. Genet., 12: 121-145.

Manuscripts should be submitted in triplicate either to Alain DuBois (address above) if dealing with

amphibian morphology, systematics, biogeography, evolution, genetics or developmental biology, or to Janalee

P. CALDWELL (address above) if dealing with amphibian population genetics, ecology, ethology or life history.

Acceptance for pEtion will be decided by the editors following review by at least two referees.

If possible, after acceptance, a £opy of the final manuscript on a floppy disk (3 % or 5 4) should be sent

to the Chief Editor. We welcome the following formats of text processing: (1) preferably, MS Word (1.1 to 6.0,

DOS or Windows), WordPerfect (4.1 to 5.1, DOS or Windows) or WordStar (3.3 to 7.0); (2) less preferably,

FT (ASCII) or DOS-formated MS Word for the Macintosh (on a 3 4 high density 1.44 Mo floppy

isk only).

Page charges are requested only from authors having institutional support for this purpose. The

publication of color photographs is charged. For each published paper, 25 free reprints are offered by ISSCA to

the author(s). Additional reprints may be purchased.

Published with the support of AALRAM

(Association des Amis du Laboratoire des Reptiles et Amphibiens

du Muséum National d'Histoire Naturelle, Paris, France).

Directeur de la Publication: Alain Duois.

Numéro de Commission Paritaire: 64851.

Alytes, 1997, 15 (1): 1-48.

Contents

Marissa FABREZI & Teresa CHALABE

A review of the fusion of trigeminal and facial ganglia

during larval development of some neobatrachian anurans.............. 1-12

Alan CHANNING & Robert C. DREWES

Description of the tadpole of Bufo kisoloensis ......................... 13-18

E. O. LaviLLa & Marcos VAIRA

La larva de Melanophryniscus rubriventris rubriventris

(Vellard, 1947) (Anura, Bufonidae)

Dinorah D. ECHEVERRIA

Microanatomy of the buccal apparatus and oral cavity

of Hyla minuta Peters, 1872 larvae (Anura, Hylidae),

with data on feeding habits 26-36

D. Cverkovié, M. L. KALEzIé & G. DZUKIC

Sexual size and shape difference in the crested newt

(Triturus carnifex): ontogenetic growth aspects ......................... 37-48

Alytes is printed on acid-free paper.

Alytes is indexed in Biosis, Cambridge Scientific Abstracts, Current Awareness in Biological

Sciences, Pascal, Referativny Zhurnal and The Zoological Record.

Imprimerie F. Paillart, Abbeville, France.

Dépôt légal: 2° trimestre 1997.

©ISSCA 1997

Source : MNHN, Paris