Bull. nat. Hist. Mus. Lond. (Zool.) 62(2): 71-82

Issued 28 November 1996

Indian Ocean echinoderms collected during

the Sindbad Voyage (1980-81): 3. Ophiuroidea

and Echinoidea

ANDREW R.G. PRICE

Ecosystems Analysis and Management Group, Department of Biological Sciences, University of Warwick,

Coventry CV4 7AL, UK THE NATURAL

1} HISTORY MUSEUM

FRANCIS W.E. ROWE

100ca

Goldbrook Boarding Kennels, Nuttery Vale, Cross Street, Hoxne, Suffolk {P21 5BB, UK 11 ev 1990

PRESENTED

GENERAL LIBRARY

Synopsis. At least 44 ophiuroid and 11 echinoid species are recorded from echinoderm collections made during an

international expedition, the Sindbad Voyage, from Oman to China. Sampling localities include the little known Lakshadweep

(Laccadive), Islands and Pula Wé (Sumatra) from which 71% of the species were recorded. Following the zoogeographic

subdivisions of Clark & Rowe (1971), range extensions are recorded for ten of the ophiuroids: W. India (Amphioplus (Lymanella)

sp.); Sri Lanka (Ophiactis modesta, Ophiarachna robillardi, Ophiodyscrita instratus); Maldives area (Cryptopelta granulifera,

Ophiochaeta hirsuta); and Indonesia / East Indies (Amphiura (Amphiura) dejectoides, Amphiura (Amphiura) micra, Amphioplus

(Amphioplus) stenaspis, Ophiogymna pellicula). In addition to the taxonomic treatment, ecological information for each

echinoderm species (habitat types, depth range) is provided and broadly analysed.

INTRODUCTION

The systematics and distribution of Indian Ocean ophiuroids and

echinoids are treated in detail by Clark & Rowe (1971). Regions for

which limited information is available include the Lakshadweep

(Laccadive) Islands, Sumatra and other parts of SE Asia. Recent

studies including the systematics and zoogeography of ophiuroids

and echinoids for the Lakshadweeps include Nagabhushanam &

Rao (1972) and James (1989), the latter yielding many new species

records for both echinoderm classes, which fill in gaps in the

distribution records of Clark & Rowe (1971). Recent work has also

been undertaken in SE Asia, including Indonesia (Aziz, 1981) and

the west coast of Thailand (Bussarawit & Rowe, 1985; Bussarawit,

in prep.).

This paper reports on collections of ophiuroids and echinoids

from these areas and other localities during an international,

transdisciplinary voyage across the Indian Ocean from Oman to

China. The expedition, Sindbad Voyage, was undertaken in 1980-81

aboard a replica of an ancient Arab sailing vessel, “Sohar’. In

addition to a systematic account, the zoogeographic significance of

the results and the ecology of each species are broadly assessed.

Details of the holothurian collections (Price & Reid, 1985) and

asteroid collections (Marsh & Price, 1991) resulting from the expe-

dition have already been published. Details of the crinoids collected

are also being prepared (Marshall & Price, in prep.), and a detailed

analysis of the ecology and biogeography of all five echinoderm

classes will follow.

Address for correspondence: First author

MATERIALS AND METHODS

Specimens were collected by one of us (A.R.G.P.) and other expedi-

tion members from localities at Muscat, Oman; Chetlat, Laks-

hadweeps (Laccadives); SW India; SW Sri Lanka; and Pula Wé,

Sumatra. Details of the sampling localities are shown in Figure 1.

Sampling was undertaken principally on coral reefs using scuba. At

each locality details of habitat type and depth range were recorded,

along with the number of individuals of each species. The number of

specimens collected is placed in parenthesis after each station

number in the Material lists for each species.

Material was fixed and preserved using standard methods (Lin-

coln & Shields, 1979). Although several specimens (inadvertently

included with the asteroid collections) had been identified earlier by

L.M. Marsh and a few preliminary identifications were made in the

field by A.R.G.P., specimens were mostly identified by and all

species confirmed by F.W.E.R. who is also responsible for taxo-

nomic comments. The ophiuroid and echinoid collections are

deposited at the Natural History Museum, London, where the

holothurian collection (Price & Reid, 1985) and a representative

collection of the asteroids (Marsh & Price, 1991) have also been

lodged.

Following recent practice (e.g. Sloan, Clark & Taylor, 1979),

systematic references are kept to a minimum by citing major works

when possible (e.g. Clark & Rowe, 1971; Clark & Courtman Stock,

1976; Cherbonnier & Guille, 1978; Rowe & Gates, 1995) from

which the original species descriptions, recent authoritative diag-

noses and taxonomic decisions can be traced. In some instances,

further references are given (e.g. Sloan et al., 1979) to provide

additional systematic or biological information.

72 A.R.G. PRICE AND F.W.E. ROWE

)

90 100

Muscat

OMAN

Chetlats ANDAMANS$

LACCADIVES «,° ‘s

5 SRI LANKA

NICOBARS +!

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Fig. 1. (a) Map of northern Indian Ocean showing sampling areas (¢) during Sindbad Voyage, with insert (b) for Pula Wé Sumatra.

INDIAN OCEAN ECHINODERMS

RESULTS

Class Ophiuroidea

Family GORGONOCEPHALIDAE

1. Astroboa nuda (Lyman, 1874)

SEE. Clark & Rowe, 1971: 78; 92; Clark & Courtman Stock, 1976:

108; 130; Baker, 1980: 60; Rowe & Gates, 1995: 364.

810504D/3 (1), 810504D/4 (1).

NW Klah, Pula Wé, Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Subtidal rock/coral; 13 m.

Family AMPHIURIDAE

2. Amphiura (Amphiura) dejectoides H.L. Clark, 1939

SEE. Clark & Rowe, 1971: 80; 97; Cherbonnier & Guille, 1978:

38:

MATERIAL. 810S01E/8 (4); ?810428D/5 (2).

COLLECTION SITES. Ug Tapa Gadja & Ug Seukundo, Pula Wé,

Sumatra.

HABITAT AND DEPTH. Subtidal rock / coral, coral reef; 10 & 15 m.

REMARKS. The specimens from stn 810501E/8 appear to accord

well with the original description (Clark, 1939) of the species and

descriptions in Clark & Rowe (1971) and Cherbonnier & Guille

(1978). The 2 specimens from stn 810428D/5 differ in their firmer

disc, with coarser ventral scaling and in having 6 arm spines

proximally instead of fine ventral scaling and 5 proximal arm spines.

They are identified as A. dejectoides with reservation. Clark (in

Clark & Rowe, 1971) suspected Amphiura inhacensis Balinsky may

be conspecific with A. dejectoides H.L. Clark, a conclusion con-

firmed by Cherbonnier & Guille (1978). The records included herein

extend the distribution of this species eastwards across the Indian

Ocean from the Red Sea, East Africa and Madagascar to the Indo-

Malayan region. In the latter region it may prove to be widespread.

3. Amphiura (Amphiura) micra H.L. Clark, 1938

SEE. Clark & Rowe, 1971: 80; 97; Cherbonnier & Guille, 1978:

46; Rowe & Gates, 1995: 350.

MATERIAL. 810423B/2 (1).

COLLECTION SITES. Ug Bau, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral, coral reef; 10—30 m.

REMARKS. This species is recorded across the tropical coast of

Australia and from Madagascar. Its discovery at Pula Wé suggests a

wider distribution in the Indo-Malayan region for this very small

species.

4. Amphiura (Amphichilus) ochroleuca (Brock, 1888)

SEE. Clark & Rowe, 1971: 78; 100; Rowe & Gates, 1995: 344.

810502C/1 (1), 810427B/3 (1).

SE Klah, SE Lho Pria Laot, Pula Wé, Sum-

MATERIAL.

COLLECTION SITES.

atra.

HABITAT AND DEPTH. In sponge and on subtidal rock; 0-10 m.

REMARKS. This species is known from the Indo-Malayan region

and more or less circumscribes the Australian continental coastline

(Rowe & Gates, 1995). Pula Wé appears to be the most westerly

point of its distribution known to date.

5. Amphioplus (Amphioplus) stenapsis H.L. Clark, 1938

SEE. Clark & Rowe, 1971: 78; 101; Rowe & Gates, 1995: 344.

810422B/4 (1).

Nr. Klah / Seukundo, Pula Wé, Sumatra (disc

MATERIAL.

COLLECTION SITES.

only).

HABITAT AND DEPTH. Coral reef, 2—8 m.

REMARKS. Although the single specimen comprises only a com-

plete disc with the bases of 2 arms (6 & 9 segments respectively),

there is little doubt of its identity. This record extends the range of the

species to Pula Wé from its type locality, Darwin, N Australia. The

record of A. stenapsis from Madagascar by Cherbonnier & Guille

(1978) is almost certainly based on a misidentification, judging by

the very small size of the radial shields of their specimens. The

confirmation of this species in the western Indian Ocean therefore

requires confirmation.

6. Amphioplus (Lymanella) sp.

MATERIAL. 810109A/Ib (2).

COLLECTION SITES. Beypore, India (west coast).

HABITAT AND DEPTH. Subtidal mud, 9 m.

REMARKS. Only the mouthparts and bases of the arms are avail-

able to identify this taxon, which clearly represents a species of

Amphioplus (Lymanella). The dorsal arm plates are trilobed, sug-

gesting either species A. (L.) andreae (Liitken, 1872) or A. (L.)

laevis (Lyman, 1874) in the key provided by Clark & Rowe (1971:

102). Cherbonnier & Guille (1978) indicate that /aevis has a wide

range in the Indian Ocean and Indo-Malay region, whereas Clark &

Rowe (1971) record andreae only from the Malay region. Without

complete specimens it is not possible to determine the species nor

indeed whether andreae and laevis are taxonomically separable.

Family OPHIACTIDAE

7. Ophiactis modesta Brock, 1888

SEE. Clark & Rowe, 1971: 105; Rowe & Gates, 1995: 379.

MATERIAL. 810206A/8 (3).

COLLECTION SITES. Negombo, Sri Lanka.

HABITAT AND DEPTH. Coral/rock; 5 m.

REMARKS. The 3 specimens were collected in a batch of 6 from

stn 810206A/8 with 3 specimens of O. savignyi. They run

unequivocably to the species O. modesta in the key provided by

Clark & Rowe (1971: 105) where the relationship with other conge-

ners is discussed by A.M. Clark (notes 25—27, pp. 103—105). Rowe

(in Rowe & Gates, 1995) preferred to follow the views of Clark &

Rowe (1971) regarding recognising the validity of the species O.

modesta, a course also followed herein, rather than accept the

sweeping synonymy of O. savignyi, which includes O. modesta,

given by Cherbonnier & Guille (1978).

8. Ophiactis savignyi (Miiller & Troschel, 1842)

SEE. Clark & Rowe, 1971: 82; 103; Clark & Courtman Stock,

1976: 164; Cherbonnier & Guille, 1978: 125; Sloan et al., 1979:

102; Price, 1983: 61; Rowe & Gates, 1995: 380.

MATERIAL. 810206A/3 (5), 810206A/8 (3), 810426A/2 (1),

810501E/1 (1), 810501G/3 (1), 8105011/2 (1), 810502F/4 (2).

COLLECTION SITES. Negombo, Sri Lanka; W Rubiah, Ug

Seukundo, E Klah, Pula Wé, Sumatra.

HABITAT AND DEPTH.

5-14 m.

Sponge, coral/rock, subtidal rock, coral reef;

REMARKS. The specimens identified here are fissiparous and 6-

armed with trilobed dorsal arm plates and proximally 6 arm spines,

according well with the key characters given in Clark & Rowe

(1971).

Family OPHIOTRICHIDAE

9. Gymnolophus obscura (Ljungman, 1867)

SEE. Clark & Rowe, 1971: 82; 117; Rowe & Gates, 1995: 411.

810124A/11 (1), 810125A/2 (1), 810430A/20d (2).

COLLECTION SITES. Ala Gala & Deumba Gala, Galle, Sri Lanka;

Ug Seukundo, Pula Wé, Sumatra.

MATERIAL.

HABITAT AND DEPTH. Coral reef and epizoic on crinoids on subtidal

rock; 8-15 m.

REMARKS. This species is commonly epizoic on comasterid

crinoids, the host species for which have not been identified for the

specimens recorded herein.

10. Ophiothela danae Verrill, 1869

SEE. Clark & Rowe, 1971: 84: 116; Clark & Courtman Stock,

1976: 141; Price, 1983: 63; Rowe & Gates, 1995: 419.

MATERIAL. 810125B/1 (3), 810206A/3/28 (4), 810425F/8 (10+),

810428A/2 (7), 810428A/14 (3), 810501A/3 (30+), 810501 A/4 (1),

810428B/1 (2), 810428D/3c (3), 810501E/9 (15+).

COLLECTION SITES. Ala Galla, Galle & Negombo, Sri Lanka; N.

Udjung Lo Me (NE Sabang Bay), Ug Bau, Ug Seukundo, Ug Tapa

Gadja, Pula Wé, Sumatra

HABITAT AND DEPTH. Epizoic on macroalgae, gorgonian, fire coral

(Millepora sp.) sponge and on holothurians (Thelenota ananas), all

on rock /coral; 2—30 m.

A.R.G. PRICE AND F.W.E. ROWE

11. Ophiothrix exigua Lyman, 1874

SEE. Clark & Rowe, 1971: 84; 110; Cherbonnier & Guille, 1978:

140; Rowe & Gates, 1995: 422.

810206A/8 (5), 810502C/1 (2), 810502E/2 (3).

Negombo, Sri Lanka; E Klah, Pula Wé,

MATERIAL.

COLLECTION SITES.

Sumatra.

HABITAT AND DEPTH.

rock; 5—10 m.

Coral/rock, sponge on coral reef and subtidal

REMARKS. One specimen from stn 810206A/8, both from

810502C/1 and two from 810502E/3 are very juvenile specimens.

12. Ophiothrix savignyi (Miiller & Troschel, 1842)

SEE. Clark & Rowe, 1971: 84; 109; Cherbonnier & Guille, 1978:

142; Price, 1983: 65.

MATERIAL. 801114B/1 (1).

COLLECTION SITES. Muscat, Oman (1 specimen).

HABITAT AND DEPTH. Coral reef; 2 m.

13. Ophiothrix trilineata Liitken, 1869

SEE. Clark & Rowe, 1971: 84; 111; Clark & Courtman Stock,

1976: 145; Sloan et al, 1978: 103; Rowe & Gates, 1995: 423.

MATERIAL. 810420A/5 (2), 810422B/3 (3), 810426A/2 (1),

810428A/9 (2), 810428C/7 (1), 810428D/3a&b (6&2), 810430A/8

(1), 810430A/18 (1), 810430A/21c (1), 810501D/2 (1), 810501E/2

(3), 810501E/5 (1), 810501E/8 (1), 810501E/9 (2), 810501E/11 (1),

810502F/2 (1), 810501F/3 (1), 810501G/1 (2), 810501G/3 (1 & 1

juvenile), 810501G/5 (3), 810502C/2 (1 very juvenile), 810502D/4

(4), 810502E/3 (4 juvenile), 810502F/2 (2 juvenile), 810502G/3 (2

juvenile).

COLLECTION SITES. Klah/E Klah, Nr. Seukundo, Ug Seukundo,

Pula Wé, Sumatra, W Rubiah, Ug Bau, Ug Tapa Gadja, Pula Wé,

Sumatra.

HABITAT AND DEPTH. Coral reef, soft coral / gorgonian, subtidal

rock, sponge/subtidal rock, sponge; 2-30 m.

REMARKS. The majority of specimens exhibit the characteristic

arm colour pattern of 5 longitudinal lines alternating white and dark

blue. However, a few specimens bear a wide median pale longitudi-

nal line along the arms, and at least one specimen (810501E/2) is

distinctively patterned with cream blotches, the linear pattern being

discernable only near the ends of the arms (see Clark & Rowe, 1971:

111). Next to O. (A.) purpurea, this is the most common ophiuroid

species collected.

14. Ophiothrix (Acanthophiothrix) armata Koehler,

1905

SEE. Clark & Rowe, 1971: 84; 111; Rowe & Gates, 1995: 423.

810422B/4 (15+), 810502F/6 (2).

Klah / Nr. Seukundo, Pula Wé, Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral reef, 2—8 m.

REMARKS. This species is recorded from the Indo-Malay region,

tropical Australian coasts and the South Pacific (Clark & Rowe,

INDIAN OCEAN ECHINODERMS

1971). The present record is the most westerly so far known for the

species.

15. Ophiothrix (Acanthophiothrix) purpurea von

Martens, 1867

SEE. Clark & Rowe, 1971: 86; 112; Cherbonnier & Guille, 1978:

148; Sloan et al., 1978: 103: Rowe & Gates, 1995: 423.

MATERIAL. 810204A/4 (3), 810421A/2 (1), 810421A/9 (1 juve-

nile), 810421B/1 (1), 810422D/3 (2), 810423A/4 (1), 810423B/2

(1), 810425D/2 (1), 80425D/4b (1), 810425F/7 (7), 810425F/8 (1),

810426A/2 (3), 810427A/2 (2), 810428A/2 (2), 810428A/7 (3),

810428A/8 (4), 810428A/9 (2), 810428D/3f (23), 810430A/3 (1),

810430A/21c (6), 810430A/22b (1), 810430A/26 (5), 810501 A/1

(1), 810501A/2 (1 juvenile), 810501A/4 (1 juvenile), 810501A/6

(9), 810SO01E/7 (2), 810501E/9 (1), 810501E/14 (1), 810501E/15

(1), 810504B/2 (1).

COLLECTION SITES. SW Kalpitiya, Sri Lanka; Ug Bau, Rubiah, Ug

Seukundo, Ug Tapa Gadja, N Klah, ?N. Udjung Lo Me, NE Sabang

Bay, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral reef, soft coral, fire coral (Millepora

sp.), subtidal rock/coral (epizoic on soft coral / gorgonian & crinoid,

sponge); 2-30 m.

REMARKS. The most common ophiuroid species collected.

16. Ophiothrix (Acanthophiothrix) spinosissima

Koehler, 1905

SEE. Clark & Rowe, 1971: 86; 112.

810422B/4 (4), 810501G/5 (2), 810502F/6 (1).

Ug Seukundo, Klah/ Ug Seukundo, Pula Wé,

MATERIAL.

COLLECTION SITES.

Sumatra.

HABITAT AND DEPTH. Coral reef, 2—8 m.

REMARKS. The specimens run down well to O. (A.) spinossima in

the key provided by Clark & Rowe (1971). However, 2 specimens

from stn 810422B/4 have a single dark line running the length of the

dorsal side of the arms, rather than a series of dark spots.

17. Macrophiothrix aspidota (Miller & Troschel, 1842)

SEE. Clark, 1968: 285; Clark & Rowe, 1971: 114; Clark &

Courtman Stock, 1976: 137; Hoggett, 1992: 91.

MATERIAL. 810123B/6 (1), 810124A/8 (1), 810206A/6 (1),

810206A/7 (1).

COLLECTION SITES.

Galle, Sri Lanka.

Negombo, Closenburg Point, Galle, Ala Gala,

HABITAT AND DEPTH. Subtidal rock, coral / rock; 5-15 m.

18. Macrophiothrix demessa (Lyman, 1861)

SEE. Clark, 1968: 289; Clark & Rowe, 1971: 82; 114; Hoggett,

1991: 1089; 1992: 117; Rowe & Gates, 1995: 412.

801212B/1 (1), 810424B/4 (2).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) Islands;

Seulakoe, Pula Wé, Sumatra.

MATERIAL.

HABITAT AND DEPTH. Coral rubble, coral reef; 8 m & 20-30 m.

REMARKS. A.M. Clark (1968) transferred this species to the genus

Macrophiothrix referring Ophiothrix (Amphiophiothrix) H.L. Clark,

1946, of which demessa is type (and only) species to the synonymy

of Macrophiothrix H.L. Clark, 1938.

19. Macrophiothrix elongata (H.L. Clark, 1938)

SEE. Clark, 1968: 291; Clark & Rowe, 1971: 82; 114; Price, 1983:

61; Hoggett, 1992: 125.

MATERIAL. 801111A/5 (1), 801114A/5 (2), 801114B/2 (1).

COLLECTION SITES. Muscat harbour, Oman.

HABITAT AND DEPTH.

Coral reef, subtidal rock/coral/sand; 0.5—3

20. Macrophiothrix longipeda (Lamarck, 1816)

SEE. Clark, 1968: 300; Clark & Rowe, 1971: 82; 114; Clark &

Courtman Stock, 1976: 139; Hoggett, 1991: 1103; Hogett, 1992:

151; Rowe & Gates, 1995: 413.

MATERIAL. 801212B/3 (1), 810206A/5 (1), 810430A/24a (1).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) Islands;

Negombo, Sri Lanka; Ug Seukundo, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral/rock, coral rubble; 5—10 m.

21. Macrophiothrix lorioli A.M. Clark, 1968

SEE. Clark, 1968: 302; Clark & Rowe, 1971: 82; 115; Hoggett,

1991: 1108; Hoggett, 1992: 161; Rowe & Gates, 1995: 414.

810502D/2 (1), 810502E/1 (1).

E Klah, Pula Wé, Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral reef, coral reef/subtidal rock; 5 &

10 m.

22. Macrophiothrix nereidina (Lamarck, 1816)

SEE. Clark & Rowe, 1971: 86; 107 (as Ophiothrix (Keystonea)

nereidina); Hoggett, 1992: 228 (as Macrophiothrix); Rowe & Gates,

1995: 426 (as O. (Keystonea) nereidina).

MATERIAL. 810421A/4 (1), 810422B/3 (2), 810430A/20d (1),

810430A/21c (2), 810430A/22b (1), 810501E/6 (1).

COLLECTION SITES. Ug Seukundo, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral reef, coral / rock; 2-10 m.

REMARKS. The species nereidina (which was placed in the

subgenus Ophiothrix (Keystonea) by A.M. Clark, 1967) is included

herein in the genus Macrophiothrix. Hoggett (1991) stated that ‘it is

particularly difficult to determine the respective boundaries between

Macrophiothrix H.L. Clark, 1938 and two subgenera of Ophiothrix,

O. (Placophiothrix) H.L. Clark, 1938 and O. (Keystonea) A.M.

Clark, 1967. The differences between these taxa have traditionally

relied principally on arm length, shape of dorsal arm plates, relative

spinular armament of the disc plates including cover of the radial

plates (see A.M. Clark, 1967; Clark & Rowe, 1971). The difficulty

in recognising the supraspecific limits of these taxa is made all the

more obvious by the treatment of the species Macrophiothrix

propinqua, placed in the subgenus Keystonea by A.M.Clark (1967),

whilst Devaney (1974) described O. (Placophiothrix) westwardi

which has been considered conspecific with propinqua by Hoggett

(1991). Later, in a far-reaching and critical treatment of Macro-

phiothrix, Hoggett (1992: PhD thesis) commits both the taxa

Placophthiothrix and Keystonea to the synonymy of Macrophio-

thrix, transferring the included species of the former two taxa to the

latter taxon and to whom this move is herein credited.

23. Macrophiothrix propinqua (Lyman, 1861)

SEE. Clark & Rowe, 1971: 86; 107 (as Ophiothrix (Keystonea)

propinqua); Clark, 1980: 537; Hoggett, 1991: 1130; Hoggett, 1992:

204; Rowe & Gates, 1995: 415.

MATERIAL. 810428D/5 (5), 810501C/3 (1 juvenile), 810501D/1

(1 juvenile), 810501E/13 (1), 810501DF/1 (1 juvenile), 810501G/1

(1), 810501G/5 (3), 810S011/2 (2), 810502F/3 (1), 810502G/3 (1).

COLLECTION SITES. Ug Tapa Gadja, Ug Seukundo, E Klah, Pula

Wé, Sumatra.

HABITAT AND DEPTH.

soft coral; 2-20 m.

Subtidal rock/coral, coral rubble, coral reef,

REMARKS. This species was first transferred to the genus

Macrophiothrix H.L. Clark, 1938 by A.M. Clark (1980) from

Ophiothrix (Keystonea) A.M. Clark, 1967.

24. Macrophiothrix variabilis (Duncan, 1887)

SEE. Clark, 1968: 308; Clark & Rowe, 1971: 115; Hoggett, 1991:

1138; Hoggett, 1992: 218; Rowe & Gates, 1995: 416.

MATERIAL. 810206A/4 (1).

COLLECTION SITES. Negombo, Sri Lanka.

HABITAT AND DEPTH. Coral / rock, 5 m.

25. Macrophiothrix virgata (Lyman, 1861)

SEE. Clark & Rowe, 1971: 86; 113 (as Ophiothrix (Placophio-

thrix) virgata); Hoggett, 1992: 236.

MATERIAL. 810423D/2 (1).

COLLECTION SITES. Ug Bau, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral reef; 2—8 m.

REMARKS. See remarks under Macrophiothrix nereidina.

26. Ophiogymna pellicula (Duncan, 1876)

SEE. Clark & Rowe, 1971: 84; 117; Clark & Courtman Stock,

1976; 140 (as O. fulgens); Rowe & Gates, 1995: 417.

810504B/2 (1).

Rubiah, Pula Wé, Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Soft coral; 10 m.

REMARKS. The single specimen has a d.d. = 2.7 mm, a.l. = c. 20

mm. The disc is mottled cream and pink, and the arms are banded

with wide pink and narrow cream bands. An irregular longitudinal

line of cream spots is evident along the dorsal midline of the arms.

The disc is covered (except for the radial shields) with minute,

A.R.G. PRICE AND F.W.E. ROWE

pointed granules with larger, conical spines interradially towards the

edge of the disc. Clark & Courtman Stock (1976) include

Placophiothrix phrixa H.L. Clark as a synonym of O. fulgens

(Koehler) which in turn is included in the synonymy of O. pellicula

by Rowe (in Rowe & Gates, 1995). The species therefore appears to

to be distributed from the Gulf of Aden to the Indo-Malay region and

the NW coast of Australia in depths of 10-116 m.

27. Ophiopteron elegans Ludwig, 1888

SEE. Clark & Rowe, 1971: 84; 115; Rowe & Gates, 1995: 419.

MATERIAL. 810428D/3e (2), 810428D/5 (8).

COLLECTION SITES. Ug Tapa Gadja, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral reef, subtidal rock/coral; 15 m.

Family OPHIOCOMIDAE

28. Ophiarthrum pictum Miller & Troschel, 1842

SEE. Clark & Rowe, 1971: 86; 121; Rowe & Gates, 1995: 385.

810502H/1 (1).

E Klah, Pula Wé, Sumatra.

Subtidal rock, 2m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

29. Ophiocomella sexradia (Duncan, 1887)

SEE. Clark & Rowe, 1971: 86; 118; Devaney, 1974: 162;

Cherbonnier & Guille, 1978: 179: Rowe & Gates, 1995: 389.

81042D8/3d (1).

Ug Tapa Gadja, Pula Wé, Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral reef; 15 m.

REMARKS. The single specimen from Pula Wé measures d.d. = 3

mm; a.l. = 10+ mm (broken near tip). With the exception that the

uppermost of the 4 arm spines is distinctly longer than the lower

ones, the character separating Ophiomastix sexradiata A.H. Clark

1952 (known only from its type locality: Bikini Atoll, Marshall Is,

SW Pacific) from Ophiocomella sexradia (Duncan)(identified

throughout the Indo-West Pacific region and possibly tropicopolitan)

in Clark & Rowe’s (1971) key, all other skeletal characters of the

present specimen accord with those described as fitting O. sexradia

(note 65, p. 118) by A.M. Clark. Cherbonnier & Guille (1978),

following their study of Malagasy material, concur with the com-

ments expressed by A.M. Clark (in Clark & Rowe, 1971) and

tentatively consider Ophiomastix sexradiata to be conspecific with

Ophiocomella sexradia simultaneously agreeing with A.M. Clark

that the status of the genus Ophiocomella as distinct from Ophio-

coma remains doubtful. Although the present specimen does nothing

to clarify the generic status of Ophiocomella, it does support strongly

the view that the two nominal species are conspecific and confirm

the synonymy proposed by Cherbonnier & Guille (1978).

30. Ophiocoma dentata Miiller & Troschel, 1842

SEE. Devaney, 1970: 13; Clark & Rowe, 1971: 86; 119; Rowe &

Gates, 1995: 386.

MATERIAL. 810502H/2b (1).

INDIAN OCEAN ECHINODERMS

COLLECTION SITES. E Klah, Pula Wé, Sumatra.

HABITAT AND DEPTH. Subtidal rock, 2m.

REMARKS. This single specimen (d.d. c. 11.3 mm, distorted)

exhibits two of the described colour forms for the species. At the

centre of the dorsal surface of the disc is a cream spot (c. 1.1 mm

diameter). This is surrounded by an irregular ring (c. 2.2 mm wide)

which is uniformly dusky/grey with darker spots. The remainder of

the disc dorsally and ventrally is reticulated dusky/grey on a cream

background.

31. Ophiocoma erinaceus Miiller & Troschel, 1842

SEE. Clark & Rowe, 1971: 114;119; Clark & Courtman Stock,

1976: 173; Sloan et al, 1979: 106; Bussarawit & Rowe, 1985: 1 (as

O. similanensis n. sp.); Rowe & Gates, 1995: 387.

MATERIAL. 801212A/3 (1), 810422B/3 (10), 810427B/1 (1),

810427D/5 (1), 810428C/6 (2 juveniles), 810428E/5 (1 juvenile),

810430A/3 (2), 810501F/1 (1), 810501G/5 (3), 810501G/6 (2),

810501K/1 (2).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) Islands;

Ug Seukundo, Ug Bau, Lho Pria Laot, Ug Murung, Ug Tapa Gadja,

Pula Wé, Sumatra.

HABITAT AND DEPTH.

subtidal rock; 2-25 m.

REMARKS. This is the commonest species of Ophiocoma col-

lected. The collection comprises some 26 specimens, ranging in size

from d.d. = 3.6—22.2 mm, which show clearly both colour changes

and development of disc granulation with growth. Juveniles up to

d.d. = c. S mm bear no granules and are usually marked radially

across each radial shield with acream line, as described by Bussarawit

& Rowe (1985) for their new species O. similanensis. By d.d. = 5.7

mm granules are developed at the centre of the disc and along 10

radiating lines to the edge of the disc where an irregular line of

granules is developed around the periphery joining these radiating

lines and thus leaving bare the dorsal interradial and radial portions

of the disc. By d.d. = c. 11 mm granules are developed over the

interradial but not radial regions of the disc, but granules are still not

developed ventrally. By d.d. = 12.5 mm granules cover the whole

surface of the disc except for the radial shields which remain bare,

while granules begin to extend in a wedge shape, on the ventral side

of the disc. This arrangement may remain in specimens up to d.d. =

14 mm but generally from about d.d. = > 13 mm the radial shields

become covered by granules. In specimens up to d.d. = 12.5 mm

some central and peripheral granules may be more prominent by

their slightly more elongate shape, but in larger specimens granules

are more evenly rounded and more or less evenly sized. The cream

colour pattern disappears with increased d.d. and is absent in speci-

mens with d.d. > 11 mm.

It is very clear that Ophiocoma similanensis Bussarawit & Rowe,

1985 is based on juvenile specimens of O. erinaceus, to the syn-

onymy of which O. similanensis is herein committed.

Coral reef, coral conglomerate, coral rubble,

32. Ophiocoma pica Miiller & Troschel

SEE. Devaney, 1970: 25; Clark & Rowe, 1971: 86; 118; Clark &

Courtman Stock, 1976: 173; Sloan et al, 1979: 106; Rowe & Gates,

1995: 387.

MATERIAL. 801212A/3 (1).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) islands.

HABITAT AND DEPTH. Coral reef; 20 m.

33. Ophiocoma pusilla (Brock, 1888)

SEE. Devaney, 1970: 25; Clark & Rowe, 1971: 86; 118; Clark &

Courtman Stock, 1976: 174; Sloan et al, 1979: 106; Rowe & Gates,

1995: 388.

MATERIAL. 810422E/4 (1), 810425C/2 (1), 810430A/21c (1),

810501E/3 (1), 810501K/4 (1).

COLLECTION SITES.

Pula Wé, Sumatra.

N Klah island, Sabang Bay, Ug Seukundo,

HABITAT AND DEPTH. Coral/sand, coral conglomerate, coral reef;

2-10 m.

REMARKS. The 5 specimens range in size from d.d. = 3—7.5 mm.

The characteristic, enlarged, tissue-covered arm spines (see Clark &

Rowe, 1971) appear on specimens from d.d. > 5 mm.

34. Ophiomastix annulosa (Lamarck, 1816)

SEE. Clark & Rowe, 1971: 86; Rowe & Gates, 1995: 390.

810123A/3 (1), 810212A/3 (2), 810213A/4 (1).

COLLECTION SITES. Kakoni rocks, Pigeon Island & Unawatuna,

Galle, Tangalla, Sri Lanka.

MATERIAL.

HABITAT AND DEPTH.

rock; 3-10 m.

Coral reef, subtidal rock/coral, subtidal

35. Ophiomastix caryophyllata Liitken, 1869

SEE. Clark & Rowe, 1971: 86; 120; Cherbonnier & Guille, 1978:

185; Rowe & Gates, 1995: 390.

MATERIAL. 810425C/1 (2), 810428C/7 ('/,), 810430A/21b (2).

COLLECTION SITES.

Wé, Sumatra

E Sabang Bay, Ug Bau, Ug Seukundo, Pula

HABITAT AND DEPTH. Coral reef, coral/rock; 3—10 m.

Family OPHIONEREIDAE

36. Ophionereis dubia (Miiller & Troschel, 1842)

SEE. Clark & Rowe, 1971: 122; Clark & Courtman, 1976: 179;

Price, 1983: 67; Rowe & Gates, 1995: 408.

810502D/5 (1).

E Klah, Pula Wé, Sumatra.

Subtidal rock/sand; 10 m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

37. Ophionereis fusca Brock, 1888

SEE. Clark, A.M. 1953: 69; 78; Clark & Rowe, 1971: 88; 122;

Rowe & Gates, 1995: 408.

810421B/2 (1).

Nr. Seukundo, Pula Wé, Sumatra.

Subtidal sand; 10-20 m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

Family OPHIODERMATIDAE

38. Cryptopelta granulifera H.L. Clark, 1909

SEE. Clark & Rowe, 1971: 88; 128; Rowe & Gates, 1995: 394.

MATERIAL. 801212B/1 (1).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) Islands.

HABITAT AND DEPTH. Coral rubble; 8 m.

REMARKS. Originally described from Mauritius. Rowe & Gates

(1995) describe the distribution as including tropical Australia, the

Indo-Malayan region and Philippine Islands. The specimen is iden-

tified here from the Laccadive Islands for the first time.

39. Ophiarachna affinis Liitken, 1869

SEE. Clark & Rowe, 1971: 88; 123; Sloan et al., 1979: 111; Rowe

& Gates, 1995: 395.

MATERIAL. 810425C/la,b (1).

COLLECTION SITES. E. Sabang Bay, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral conglomerate; 3—6 m.

REMARKS. A.M. Clark (in Clark & Rowe, 1971: Note 83, p. 123)

describes in detail colour variation in Ophiarachna affinis and O.

mauritiensis de Loriol, concluding that specific distinction between

the two is difficult to make. In the present specimens with d.d. = 22

mm, the disc is uniformly brownish-grey and the dorsal side of the

arms has a broad longitudinal central dusky band either side of

which is a narrower pale band, the 3 bands being demarcated by 4

irregular, very narrow longitudinal dark bands. This corresponds to

A.M. Clark’s form C colour pattern. If O. affinis and O. mauriti-

ensis are conspecific the species is clearly widely distributed in the

Indo-West Pacific region.

40. Ophiarachna robillardi de Loriol, 1893

SEE. Clark & Rowe, 1971: 88; 123.

810126B/4 (1), 810213A/3 (2).

Galle, Tangalla, Sri Lanka.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral reef, 3—5 m.

REMARKS. This is a significant extension of range for this species

described from Mauritius. The species is recorded as having 5 arm

spines (H.L. Clark, 1909; size not recorded) but the present 3

specimens have 7—9 arm spines at d.d. = 21.5 mm; 9-10 arm spines

at d.d. 31.5 mm and 10-11 arm spines at d.d. = 36.5 mm.

41. Ophiochaeta hirsuta Liitken, 1869

SEE. Clark & Rowe, 1971: 88; 127; Sloan et al, 1979: 115; Rowe

& Gates, 1995 398.

801212B/1 (1), 810425C/2 (1).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) Islands; E.

Sabang Bay, Pula Wé, Sumatra.

Coral rubble, 3—8 m.

MATERIAL.

HABITAT AND DEPTH.

REMARKS. Sloan et al. (1979) concluded that variation in the

A.R.G. PRICE AND F.W.E. ROWE

occurrence of spinelets on the discs of 4 specimens from Aldabra,

western Indian Ocean and 2 specimens from Palau in the western

Pacific Ocean which they examined suggested that Ophiochaeta

boschmai A.H. Clark, 1964 is a synonym of Ophiochaeta hirsuta

Liitken, 1869. They pointed out that Cherbonnier & Guille,1978,

had described a new species, O. crinita, based on a single specimen,

from Madagascar, but did not comment further. In the present

collection the specimen from the Lakshadweep Islands accords with

the description of boschmai in that the disc is granule-covered

dorsally but bears spinelets on its ventral surface. The specimen

from Pula Wé, on the other hand, accords with the description of

crinita in that the disc is covered dorsally and ventrally by elongate

spines. Considering the comments by Sloan et al. (1979), the two

specimens reported herein are referrred to O. hirsuta, with the

implication that O.crinita Cherbonnier & Guille should also be

referred to the synonymy on the basis that it exhibits the extreme

spiny form of O. hirsuta.

42. Ophiodyscrita instratus (Murakami, 1944) n. comb.

SEE. Murakami, 1944: 272 (as Ophiostegastus instratus);

A.M.Clark, 1968: 320 (as Ophiostegastus instratus; discussion)

810124A/4 (1).

Ala Gala, Galle, Sri Lanka.

Subtidal rock, 10-15 m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

REMARKS. This specimen, apart from its smaller size and fewer

naked disc plates, accords so well with Murakami’s (1944) descrip-

tion of Ophiostegastus instratus that its identity is in no doubt. The

species is, however, transferred to the genus Ophiodyscrita H.L.

Clark, 1938 (type-species O. acosmeta H.L. Clark), with

Ophiostegatus Murakami, 1944 (of which instratus is the type-

species) reduced to a junior synonym of Ophiodyscrita. The

distinctness of two genera has been questioned by A.M. Clark

(1968) and Guille & Vadon (1985) on the grounds of variation of

granulation with increased specimen size. Tabulation of measure-

ments (Table 1) taken from original species descriptions and similar

details of the specimens from Sri Lanka, shows an interesting

picture. From this table it becomes apparent that only two species

can be recognised: a) Ophiodyscrita instratus (Murakami, 1943)(d.d.

=7 mm) of which the larger Ophiostegastus novaecaledoniae Guille

& Vadon (d.d. = 9-11 mm) is a synonym, being an extreme form of

instratus in which many disc plates, including the radial shields,

have become prominent (convex) and naked of granules; this species

possesses supplementary oral shields (granule covered in small

specimens < 7 mm d.d.) and b) O. acosmeta H.L. Clark (d.d. = 5

mm) with which O. pacifica (Murakami, 1943)(d.d. 4 mm) and

Ophiostegastus compsus A.M. Clark (1968) type locality Bahrain

(d.d. = 8-10.5 mm) appear to be conspecific. O. acosmeta has an

even covering of granules over the disc which are gradually lost only

from the oral shields (as in the type of acosmeta; d.d. = 5 mm) and

adoral plates (as in the type series of compsus; d.d. = 8—10.5 mm;

though A.M. Clark (1968) does note that the largest paratype of

compsus (d.d. = 10.5 mm) has a small bare patch dorsally at the base

of 4 of the arms). Supplementary oral shields are absent from

compsus, according to A.M. Clark, and are not recorded for either

acosmeta or pacifica. In both instratus and acosmeta, as recognised

herein, it is clear that arm spine number increases with size.

There is clearly insufficient justification for recognising

Ophiodyscrita and Ophiostegastus as separate genera on the basis of

the extent of disc granulation, for it is clear (see Clark & Rowe,

1971) that such differences occur between species included within

INDIAN OCEAN ECHINODERMS

Table 1. Details of species Ophiodyscrita acosmeta H.L. Clark* and O. instratus (Murakami)*

Taxon d.d.(mm)_ a.sp. l.a.sp. S.0.S. Granulation (disc)

Ophiocryptus* 4.00 6-5 1/3 seg. -? Complete cover dorsal and ventral

pacificus Murakami, 1943

Ophiodyscrita* 5.0 8(7) 1/2 seg. -? Complete cover dorsal and ventral except 2 oral shields (Clark & Rowe

acosmeta H.L. Clark, 1938 (1971: 135)

Sindbad spec.* 5.3 6-5 <1/2 seg. +(granule Complete cover dorsal and ventral except radial plate at base of deach arm,

covered each mid marginal plate and ventrally, each of the oral shields

Ophiostegastus* 7.00 7 1/3 seg. +(naked) | Complete except 3 plates at base of each arm; each mid marginal; each oral

instratus Murakami, 1944 shield and supplementary oral shield

Ophiostegastus* 8-10.5 9 <l/2seg. —- Complete except each oral shield and adoral shield (A.M. Clark notes a

compsus A.M. Clark, 1968 small bare patch as base of 4 arms of one paratype d.d. = 10.5 mm)

Ophiostegastus* 9-11 9-10 <1l/2 seg. +(naked) Many dorsal plates, including radial shields, marginal plates and ventral

novaecaledoniae plates including oral, supplementary oral and adoral shields bare of

Guille & Vadon, 1985 granules

d.d. = dise diameter; a.sp. = number of arm spines; |.a.sp. = length of arm spines; s.o.s. (+/—) = presence/absence of supplementary oral shields.

the recognised limits of other ophiodermatid genera (e.g. Ophiopeza

& Ophiarachnella). Similarly, the occurrence of supplementary oral

shields is also a variable character. The recognition of Ophiodyscrita

within the family appears, therefore, to rely, more or less solely, on

the extension of granulation along the arms. The genus is closely

related to Ophiopezawith which it shares the possession of a triangle

of 3 plates between the radial shields (see Vail & Rowe, 1989). The

record of O. instratus from Sri Lanka greatly extends the known

distribution of the species from Japan and New Caledonia (S.W.

Pacific). The distribution of the genus, Ophiodyscrita (syn:

Ophiostegastus ) is clearly widespread in the Indo-West Pacific

region.

43. Ophiopsammus yoldii (Liitken, 1856)

SEE. A.M. Clark, 1968: 317; Clark & Rowe, 1971: 90; 127; Vail &

Rowe, 1989: 277; Rowe & Gates, 1995: 402.

MATERIAL. 810430A/22b (1).

COLLECTION SITES. Ug Seukundo, Pula Wé, Sumatra.

HABITAT AND DEPTH. Coral rubble; 9 m.

REMARKS. Nearly half of the disc of this small specimen has been

lost leaving the remaining disc (d.d. = c. 6 mm) and three of the

original arms, which are also damaged (a.l. = c. 17 mm; d.d./a.l. =c.

3+: 1). Arising from the damaged edge of the disc are three new,

minute arms at slightly different stages of growth judging by the

relative development of the ventral arm plates on each arm. These

arms are also damaged but the longest is judged to have been not

more than c. 3-4 mm in length. Following Vail & Rowe’s (1989)

revision of the genus Ophiopsammus, there is no reason for not

identifying the specimen from Pula Wé as O. yoldii, for it appears to

match their criteria for the species even though it is of small size. The

species is not known to be fissiparous. Although this may be the first

observation of fissiparity in O. yoldii, the development of six arms,

in this case, may be an unusual response to severe damage, rather

than being related to an asexual reproductive strategy. This matter

requires further investigation.

Family OPHIURIDAE

44. Ophiolepis cincta Miiller & Troschel, 1842

SEE. Clark & Rowe, 1971: 90; 129: Clark & Courtman Stock,

1976: 189; Sloan et al, 1979: 115-117; Rowe & Gates, 1995: 399.

MATERIAL. 801212B/I1 (1).

COLLECTION SITES. Chetlat, Lakshadweep (Laccadive) Islands.

HABITAT AND DEPTH. Coral rubble; 8 m.

Class Echinoidea

Family CIDARIDAE

1. Eucidaris metularia (Lamarck, 1816)

SEE. Clark & Rowe, 1971: 140; 150; Clark & Courtman Stock,

1976: 215; Sloan et al., 1979: 117 Rowe & Gates, 1995: 195.

810426A/4 (1), 810S501E/12 (1).

Rubiah, Ug Seukundo, Pula Wé, Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral reef, coral aggregate; 10 & 14 m.

Family DIADEMATIDAE

2. Diadema setosum (Leske, 1778)

SEE. Clark & Rowe, 1971: 140; 153; Clark & Courtman Stock,

1976: 226; Sloan et al., 1979: 118; Price, 1983: 73; Rowe & Gates,

1995: 207.

MATERIAL. 801027A/1 (1), 801030A/la,b (4), 810212A/1 (1),

810420A/1 (1), 810420A/4 (1), 810426A/3 (1), 810426B/5 (2),

810426B/12 (1), 810427D/S (1 juvenile), 810428D/4 (2), 810501G/

4 (1 juvenile), 8105011/1 (1), 810502D/1 (1, broken).

COLLECTION SITES. Muscat, Oman; Unawatuna, nr Galle, Sri

Lanka; Rubiah, Klah, Ug Murung, Ug Tapa Gadja, Ug Seukundo,

Pula Wé, Sumatra.

HABITAT AND DEPTH. Subtidal rock, subtidal rock / sand, subtidal

rock / coral, coral reef; 0-20 m.

REMARKS. A number of these specimens are juveniles, as small as

10 mm h.d., and with banded spines. The characteristic elongate,

tridentate pedicellariae of D. setosum (see Clark & Rowe, 1971) are

absent from all specimens examined. The remaining character of the

red (or in some cases a faded, cream) ring on the anus is the only

means of distinguishing this species from D. savignyi. In the field

the two species are easily distinguished by the colour pattern, D.

savignyi lacking the red ring and having characteristic, irridescent

blue lines along the upper interamulacra.

3. Echinothrix calamaris (Pallas, 1774)

SEE. Clark & Rowe, 1971: 140; 153; Clark & Courtman Stock,

1976: 226; Rowe & Gates, 1995: 208.

MATERIAL. 801111A/2 (1), 810422B/1 (1), 810425C/4 (1),

810426B/4 (1), 810426B/13 (1), 810501K/2 (1), 810501K/3 (1).

COLLECTION SITES. Muscat, Oman; S. Sabang Bay (to S. of Klah),

E. Sabang Bay, Rubiah, Ug Seukundo, Pula Wé, Sumatra.

HABITAT AND DEPTH.

coral reef; 0-20 m.

Subtidal rock, subtidal rock / coral / sand,

Family STOMECHINIDAE

4. Stomopneustes variolaris (Lamarck, 1816)

SEE. Clark & Rowe, 1971: 140; 153; Clark & Courtman Stock,

1976: 228; Sloan et al., 1976: 118; Rowe & Gates, 1995: 246.

810123B/4 (1).

Galle, Sri Lanka.

Subtidal rock; 5 m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

Family TEMNOPLEURIDAE

5. Mespilia globulus (Linnaeus, 1758)

SEE. Clark & Rowe, 1971: 140; 155; Rowe & Gates, 1995: 250.

810502F/5 (1).

Klah, Pula Wé, Sumatra.

Subtidal rock; 5 m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

6. Microcyphus ceylanicus Mortensen, 1942

SEE. Clark & Rowe, 1971: 140; 156.

820204A/11 (1).

SW Kalpitiya, Sri Lanka.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral reef; 3—5 m.

7. Salamacis bicolor L. Agassiz, 1846

SEE. Clark & Rowe, 1971: 140; 156; Clark & Courtman Stock,

1976: 232.

MATERIAL. 810126B/I1 (1).

Galle, Sri Lanka.

Coral reef; 4—5 m.

COLLECTION SITES.

HABITAT AND DEPTH.

A.R.G. PRICE AND F.W.E. ROWE

Family TOXOPNEUSTIDAE

8. Toxopneustes piloleus (Lamarck, 1816)

SEE. Clark & Rowe, 1971: 142; 156; Clark & Courtman Stock,

1976: 234; Rowe & Gates, 1995: 258.

801114C/1 (1); 810424A/1 (1).

Muscat, Oman; W. Klah, Pula Wé, Sumatra.

Coral reef; 10-12 m.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH.

Family PARASALENIIDAE

9. Parasalenia gratiosa A. Agassiz, 1863

SEE. Clark & Rowe, 1971: 142; 157; Rowe & Gates, 1995: 233.

810422B/5 (2).

S. Sabang Bay (to S. of Klah), Sumatra.

MATERIAL.

COLLECTION SITES.

HABITAT AND DEPTH. Coral conglomerate; 2—8 m.

Family ECHINOMETRIDAE

10. Echinometra mathaei (de Blainville, 1825)

SEE. Clark & Rowe, 1971: 142; 157; Clark & Courtman Stock,

1976: 239; Sloan et al., 1979: 119; Price, 1983: 76; Rowe & Gates,

1995: 211.

MATERIAL. 801111A/1 (5), 810204A/10 (1).

COLLECTION SITES. Muscat, Oman; SW Kalpitiya, Sri Lanka.

HABITAT AND DEPTH. Coral reef, rock / coral / sand; 0-5 m.

REMARKS. Two forms of this species are represented. The speci-

men from Sri Lanka is relatively large, with h.d. = 48.7 mm. It has 4

pore-pairs per arc, the spines are uniformly pale blue/green and the

test, when cleaned, is whitish in colour. The 5 specimens from

Muscat, Oman are smaller, ranging in size from h.d. = 10-21 mm.

They have 5 pore-pairs per arc, the spines are dark olive green tipped

with lilac/brown and the test, when cleaned, is greenish in colour.

Echinometra mathaei is clearly a complex species which is in need

of critical investigation to determine whether, as it is currently

identified, it comprises a single species or more than one closely

related species (see Mortensen, 1943; Tsuchiya & Nishira, 1984).

11. Echinostrephus molaris (de Blainville, 1825)

SEE. Clark & Rowe, 1971: 142; 157; Clark & Courtman Stock,

1976: 239-240; Sloan et al., 1979: 119; Rowe & Gates, 1995: 212.

MATERIAL. 801210B/6 (1), 810423A/5 (1), 810427B/3 (1),

810427D/5 (1), 810502G/4 (1)

COLLECTION SITES. Chetlat, Lakshaweep (Laccadive) Islands; Ug

Bau, Lho Pria Laot, Ug Murung, Klah, Pula Wé, Sumatra.

HABITAT AND DEPTH.

coral; 0-40 m.

Coral reef, subtidal rock, subtidal rock /

te eee

INDIAN OCEAN ECHINODERMS

DISCUSSION

Echinoderm collections from the Sindbad Voyage have yielded at

least 44 species of ophiuroids and 11 species of echinoids. Species

totals for each area sampled, with the corresponding zoogeographic

subdivision used by Clark & Rowe (1971), are given in Table 2.

Despite the small size of Pula Wé (c. 20 km x 12 km), 32 ophiuroids

and 7 echinoids (71% of all species recorded) were encountered at,

although not necessarily restricted to, this island. This high species

richness is partly a reflection of the sampling intensity in Pula Wé,

but is equally or more an indication of high biodiversity known for

coral reefs in the SE Asia region (Sheppard, 1987; Wells & Price,

1992).

Of the ophiuroids collected, O (A.) purpurea and O. trilineata

were the most common, occurring in more than 20% of the ophiuroid

Table 2. Ophiuroid and echinoid species numbers for each area of the

Indian Ocean sampled during the Sindbad Voyage. (total ophiuroid

species recorded for all regions = 44 ; total echinoid species recorded

for all regions = 11)

Sampling area and equivalent No. of species recorded

zoogeographic subdivision OPHIUROIDS ECHINOIDS

Oman (SE Arabia) ps) 4

S India (W. India & Pakistan) 1 0

Laccadive (Maldive area) 7 l

Sri Lanka (Sri Lanka area) vi |

Sumatra (Indonesia / East Indies) 31 7

Of the 44 ophiuroid species collected, ten result in new area

records (Table 3), as follows: W India (Amphioplus (Lymanella)

sp.); Sri Lanka (Ophiactis modesta, Ophiarachna robillardi,

Ophiodyscrita instratus); Maldives area (Cryptopelta granulifera,

Ophiochaeta hirsuta); and Indonesia / East Indies (Amphiura

(Amphiura) dejectoides, Amphiura (Amphiura) micra, Amphioplus

(A.) stenaspis, Ophiogymna pellicula).

Table 3. New area records and previously known distribution of

ophiuroid species recorded in the Indian Ocean during the Sindbad

Voyage

Species New arearecord Previously known distribution

Amphiura Indonesia/East Red Sea; E. Africa (Madagascar)

(Amphiura) Indies

dejectoides

Amphiura Indonesia/East N. Australia and possibly E. Africa/

(Amphiura) micra Indies Madagascar

Amphioplus (A.) Indonesia/East N. Australia and possibly E. Africa/

Stenaspis Indies Madagascar

Amphioplus West India A. (L.) andreae from Indonesia/

(Lymanella) sp. _ (Beypore) East Indies, and A. (L.) laevis from

Indo-West Pacific

W. India & Pakistan, and eastwards

from Bay of Bengal to Hawaiian

Is. but not Philippines, and

possibly also E.Africa/Madagascar

Ophiactis modesta Sri Lanka

Ophiogymna Indonesia/East Bay of Bengal and N. Australia

pellicula Indies

Cryptopelta Maldives Mascarene Is. (Mauritius, Réunion,

granulifera Rodrigues group) and N. Australia

Ophiarachna Sri Lanka Mascarene Is.

robillardi

Ophiochaeta Maldives Is. of W. Indian Ocean, Indonesia/

hirsuta East Indies, N. Australia and S.

Pacific Is.

Ophiodyscrita Sri Lanka Japan and New Caledonia

instratus (SW Pacific)

samples. These species also occupied a wide range of substrata and

depths (2-30m). Other species occurred in less than 10% of the

ophiuroid samples, and generally occupied fewer habitats and a

narrower depth range. The echinoid fauna was less diverse, although

some species were very common, in particular D. setosum, E.

calamaris and E. molaris (a coral rock borer), which occurred in

36%, 19% and 14 % of the echinoid samples respectively. These

echinoids were found in a wide range of habitats and depths, up to 40

m in the case of E. molaris. A more comprehensive ecological

analysis of echinoderms of Pula Wé, Sumatra is to be undertaken

following completion of the taxonomic appraisal of the crinoids.

ACKNOWLEDGEMENTS. We wish to thank the staff at the Natural History

Museum, London, for access to the collections and other facilities. We are

grateful of Dr R. Dalley, P. Hunnam, P. Dobbs and D. Tattle for their

considerable assistance during field work. One of us (A.R.G.P.) would also

like to thank T. Severin, leader of the Sindbad Voyage, for the kind invitation

to participate in the expedition which was made possible by generous support

from the Ministry of Natural Heritage and Culture, Sultanate of Oman.

Thanks are due to L. Marsh for identifying several ophiuroids. Financial

assistance to A.R.G.P. from the Leverhulme Trust is gratefully acknowl-

edged.

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Bull. nat. Hist. Mus. Lond. (Zool.) 62(2): 83-99

Issued 28 November 1996

Rare cyclopoid copepods (Crustacea) from

Mediterranean littoral caves

D. JAUME AND G.A. BOXSHALL

Department of Zoology, The Natural History Museum, Cromwell Road, London SW7 SBD, UK

SYNOPSIS. Three cyclopoid copepods are reported from anchihaline cave habitats on Mallorca. Both sexes of Cyclopina esilis

Brian are redescribed. Sexual dimorphism in the mandibular exopod, as discovered in C. esilis, has not previously been reported

for any cyclopinid. The male of the primitive marine cyclopid Neocyclops (Protoneocyclops) mediterraneus (Kiefer) is described

in detail for the first time and the characters distinguishing this species are discussed. Both sexes of Euryte longicauda Philippi

are redescribed. The genus Euryte Philippi is briefly reviewed and the characters used to differentiate species are critically

reevaluated. It is concluded that all three genera, the cyclopinid genus Cyclopina Claus and the primitive cyclopids Neocyclops

Gurney and Euryte, are in urgent need of revision, but that this process will be hampered by the inadequacy of published

descriptions and the lack of available type material.

INTRODUCTION

Anchihaline cave habitats are rich sources of interesting and unusual

crustaceans. Copepods of immense phylogenetic significance have

been discovered in such caves in the last decade, including the

platycopioid Antrisocopia Fosshagen, the misophrioid

Speleophriopsis Jaume & Boxshall, and the calanoid Erebonectes

Fosshagen (Fosshagen & Iliffe, 1985; Jaume & Boxshall, 1996).

There have been few reports of cyclopoid copepods in anchihaline

caves. Recently, however, Rocha & Iliffe (1991, 1994) described a

new family of cyclopoids, the Speleoithonidae, and the primitive

cyclopid Troglocyclops, from caves on the Bahamas Islands. During

our studies of the copepod fauna of Mallorcan caves we discovered

numerous cyclopoids, including the three rare species described in

this account. All three species were originally described from the

Mediterranean Basin. All have been the subject of considerable

taxonomic confusion because their original descriptions were inad-

equate and we have attempted to clear up some of this confusion at

the same time as presenting full redescriptions.

THE CAVES

The copepods were collected from four caves located on the East

coast of Mallorca, less than 20 m inland. These caves occur in two

different types of substratum. Cova ‘C’ de Cala Varques and Es

Secret des Moix are in Tortonian (10 Myr BP), coral reef-derived,

porous calcarenites and mixing-zone corrosion processes seem to

have played an important role in their development. Cova de na

Barxa and Cova de na Mitjana are in Triassic, fissured limestones.

All these caves have subaerial entrances; the difficulty of access can

be deduced from their topographies, published elsewhere (see be-

low). The water conditions varied from cave to cave: In Es Secret des

Moix, the sampled lake (that located closest to the entrance) was

completely marine (i.e., in water salinity, a detectable swell, the

nature of the accompanying fauna), as was the lake in Cova de na

Mitjana. Cova ‘C’ de Cala Varques and Cova de na Barxa are typical

anchihaline caves (in the sense of Stock et al., 1986), with a thin

layer of fresh water on the top of the deeper saline waters of the

lakes.

Sampling was undertaken using meat-baited traps placed at dif-

ferent depths in the cave lakes and left for several days, and by using

a hand-held plankton net with an extensible handle. The terminology

used in the descriptions follows Huys & Boxshall (1991).

SYSTEMATICS

Order CYCLOPOIDA Burmeister, 1834

Family CYCLOPINIDAE Sars, 1913

Subfamily CYCLOPININAE Kiefer, 1927

Genus Cyclopina Claus, 1863

Cyclopina esilis Brian, 1938

(Figs 1-4)

Cyclopina cf. kieferi: Herbst (1953; 1962)

MATERIAL EXAMINED. Cova de na Mitjana (Capdepera). UTM

coordinates: 539.10; 4390.95. Topography published by Ginés et al.

(1975): 96 individuals, both sexes (BMNH 1995. 1331-1340).

Collected by D. Jaume, 17 July 1994.

ADULT FEMALE. Body (Figs 1A, B) cyclopiform, up to 0.37 mm

long. Prosome 5-segmented, about 1.7 times longer than urosome.

Rostrum developed, oval. Posterolateral margins of cephalosome

vaulted. First pedigerous somite free, partially concealed by dorsal

and posterolateral extensions of cephalosome. Second to fourth

pedigerous somites with evenly rounded posterolateral angles.

Urosome 5-segmented, with genital and first abdominal somites

completely fused to form genital double-somite. Serrate hyaline frill

adorning posterodorsal margin of fifth pedigerous somite, posterior

margins of genital double-somite and abdominal somites 2 and 3,

and posterolateral margins of anal somite; degree of serration vary-

ing directly with body size. Genital double-somite (Fig. 1D)

symmetrical, 1.6 times longer than wide, expanded anteriorly. Sin-

gle copulatory pore opening mid-ventrally at about two-fifths of

distance along double-somite. Paired gonopores located laterally,

each covered by operculum armed with short spinous process, |

84 D. JAUME AND G.A. BOXSHALL

Fig. 1. Cyclopina esilis Brian, 1938, adult female. A, body, dorsal view; B, lateral; C, antennule; D, genital double-somite, lateral; E, fifth leg; F—G, dorsal

view of anal somite and caudal rami, showing variation with body size in the position of the lateral seta of the caudal ramus.

seta, and | long flanged spine (Fig. 1D). Anal somite (Figs 1F, G) variable, ranging from two-fifths (Fig. 1G) to three-fifths of distance

bearing smooth operculum. Caudal rami longer than anal somite, along distal margin (Fig. IF).

about 2.6 to 3.3 times longer than wide; proportional length related Antennules (Fig. 1C) symmetrical, 10-segmented, shorter than

to body size. Armature consisting of 6 setae; position of seta II prosome (Fig. 1B). Segmental fusion pattern and armature as fol-

CYCLOPOIDS FROM LITTORAL CAVES

Fig. 2. Cyclopina esilis Brian, 1938, A and C-F, adult female, B, adult male. A, antenna; B, mandible; C, maxillule; D, maxilla; E, maxilliped; F,

mandibular exopod.

lows: segment | (corresponding to fused ancestral segments I and

Il), 3 setae; segment 2 (corresponding to fused ancestral segments III

to V), 5 setae; segment 3 (fused segments VI to IX), 8 setae; segment

4 (fused segments X and XI), 4 setae; segment 5 (fused segments XII

to XIV), 6 setae; segment 6 (fused segments XV to XX, partial

suture present between segments XVI and XVII), 6 setae + aesthetasc;

segment 7 (fused segments XXI to XXIII), 3 + aesthetasc; segment

8 (XXIV), 2 setae; segment 9 (XXV), 1 + aesthetasc; segment 10

(fused segments XX VI to XXVIII), 7 + aesthetasc.

Antenna (Fig. 2A) 4-segmented. Fused coxa and basis short,

about 1.5 times longer than wide, armed with | inner basal seta

distally and 1 long seta (representing exopod) on outer margin.

Endopod 3-segmented. Proximal segment with | seta at about two-

thirds of distance along inner margin; segment covered by long

spinules on anterior surface. Second segment with 2 lateral and 3

distal setae (one of them claw-like) along inner margin. Distal

segment with 7 distal setae, one of them claw-like. Secondary

ornamentation on segments as figured.

Mandible (Figs 2B, F) with gnathobase armed with 10 unequal,

sharp teeth plus 1 dorsal seta; row of 13 spinules located subdistally.

Palp well developed; basis elongate, with patch of setules and 1

subdistal seta along inner margin. Exopod (Fig. 2F) inserted at about

midway of distance along outer margin of basis; 4-segmented; setal

formula 1|,1,1,2; distal, brush-like seta somewhat shorter and thicker

D. JAUME AND G.A. BOXSHALL

ke iy

> on

We”

i (NE / ars

ee eee we

= SASS aie Tanyas

Fig. 3. Cyclopina esilis Brian, 1938, adult female swimming legs, posterior view. A, leg 1; B, leg 2; C, leg 3; D, leg 4.

than others, with brush of 6 setules on tip. Endopod 2-segmented,

shorter than exopod, setal formula 3,6.

Maxillule (Fig. 2C) with well developed praecoxal arthrite, armed

with 9 thick, unequal spines around distal margin plus isolated seta

on posterior surface. Coxa and basis fused: coxal epipodite repre-

sented by 2 unequal setae; coxal endite represented by small

cyclindrical knob armed with | seta. Proximal and distal endites of

basis discrete, bearing 3 and 2 setae respectively. Endopod 1-

segmented, bearing 7 setae. Exopod 1|-segmented, armed with 4

distal setae and marginal row of long setules.

Maxilla (Fig. 2D) well developed, 4-segmented. Praecoxa and

coxa partially fused, endites with setal formula 3,1,3,3. Basis with

large endite bearing claw-like spine plus 2 unequal setae. Endopod

2-segmented; proximal segment representing fused first and second

ancestral endopodal segments; distal representing fused third and

fourth ancestral segments; endopod setation formula (2+2),(2+4).

Maxilliped (Fig. 2E) slender, 6-segmented. Praecoxa and coxa

fused forming syncoxa, bearing 3 (coxal) endites with setal formula

1,3,2. Basis with medial margin swollen, ornamented with marginal

row of long setules; 2 setae implanted subdistally on medial margin.

CYCLOPOIDS FROM LITTORAL CAVES

Fig. 4. Cyclopina esilis Brian, 1938, adult male. A, body, dorsal; B, lateral; C, genital somite, ventral; D, antennule; E, fifth leg.

Endopod 4-segmented, setal formula 0,0,1,4; transverse row of

setules on segment 3.

Swimming legs 1 to 4 (Fig. 3) biramous, both rami 3-seg-

mented. Legs subequal in size except first, somewhat reduced.

All legs richly ornamented with denticles, as figured; anterior

surface of coxae covered by small denticles, omitted from fig-

ures. Spines on exopodal segments flanged with serrate hyaline

frill; distal spine on third exopodal segment of legs 1 and 2, and

spines on endopod of leg 4 flanged only on one side. Armature as

follows:

Coxa Basis Exopod Endopod

Leg | 0-1 1-I I-1;I-1; 101,14 O-1;0-1;1,2,3

Leg 2 0-1 1-0 -1;-1;10,15 0-1;0-2;1,2,3

Leg 3 0-1 1-0 I-1;1-1;11,1,5 0-1;0—2;1,2,3

Leg 4 0-1 1-0 I-1;I-1;IL,1,5 O-1;0-I;1,2,1+I

Fifth legs (Fig. 1E) uniramous, 2-segmented, joined by naked

intercoxal sclerite. Coxa and basis fused forming trapezoidal

protopodal segment; inner margin with row of long setules; outer

margin with long, smooth seta subdistally. Distal segment (exopod)

about 1.6 times as long as wide, produced distally into median

process bearing | long, plumose seta; 1 flanged spine present

subdistally on each side of process, outer stouter, longer than

segment; inner spine less than half length of outer spine; spinule

ornamentation on segment as figured.

ADULT MALE. Body (Figs 4A, B) up to 0.38 mm long, more

slender than female. Urosome 6-segmented, with genital somite

(Fig. 4C) symmetrical, slightly expanded laterally; paired gonopores

opening ventrally at posterior border of somite; genital opercular

flaps each armed with tiny inner spine plus 2 long, outer setae.

Antennules (Fig. 4D) 15-segmented, symmetrical, digeniculate.

Geniculations between segments homologous with ancestral seg-

ments XV and XVI (9 and 10), and between XX and XXI (13 and

14). Segment 9 (XV) cup-shaped, forming sheath around proximal

half of segment 10 (XVI). Segmental fusion pattern and armature as

follows: segment | (corresponding to fused ancestral segments I and

II), 3 setae + aesthetasc; segment 2 (fused ancestral segments III to

V), 5 setae; segment 3 (fused ancestral segments VI and VII), 4 setae;

segment 4 (VIII), 2 setae; segment 5 (partially fused ancestral

segments IX to XI), 6 setae; segments 6 to 9 (XII to XV), 2 setae

each; segment 10 (XVI), 1 pectinate spine, 1 seta + aesthetasc;

segments 11 and 12 (XVII and XVIII), 1 pectinate spine and | seta

each; segment 13 (fused ancestral segments XIX and XX), | pecti-

nate spine, | modified flattened spine, and 1 seta; segment 14 (fused

ancestral segments XXI and XXII), 1 modified flattened, spine

plate, 1 seta + aesthetasc; segment 15 (fused ancestral segments

XXIII to XXVIII), 11 + aesthetasc.

Segmentation and setation of other cephalosomic appendages and

swimming legs | to 4 as in female, except mandibular palp (Fig. 2B);

distal brush-like seta on exopod much shorter and thicker, setules on

tip longer than in female.

Fifth legs (Fig. 4E) resembling female condition, but with 2

additional setae implanted subdistally along inner margin of exopod.

REMARKS. The Cyclopina from the cave on Mallorca belongs to

the group of species in the genus that displays a female leg 5 with the

inner spine of distal segment less than half the length of the outer

spine, the latter being longer than the segment itself. This group

comprises Cyclopina esilis Brian, 1938, C. americana Herbst, 1982,

and C. cuipora Lotufo, 1994. The taxon from Mallorca differs

clearly from C. cuipora. The female antennule is 10-segmented (not

12-segmented as in C. cuipora), and the intercoxal sclerite of leg 4

is almost completely smooth (not powerfully ornamented with

several rows of thick spinules as in C. cuipora) (Lotufo, 1994).

Differences from C. americana include the short, subquadrate cau-

dal rami (Herbst, 1982) which contrast with the elongate (2.5 to 3.2

times as long as wide) caudal rami of the Mallorcan taxon.

The Cyclopina from Mallorca is identified as C. esilis, based on

the segmentation of the female antennule, the setation of leg 5 and

the proportions of the caudal rami. We noted variation in the

proportional length of the caudal rami within the Mallorcan popula-

tion. A similar degree of variability in length of the caudal rami has

been reported in C. esilis (Brian, 1938; Monchenko, 1979).

Apparent differences in the armature of mouthparts have not been

evaluated since we suspect that the armature of mouthparts in C.

esilis (as in most species of Cyclopina) were inadequately described

in the original descriptions. This is evident in the presence of a coxal

endite, armed with | seta, on the maxillule of the Cyclopina from

Mallorca. This character state (presence of coxal endite) had never

previously been noted in Cyclopina and was known only from

Cyclopinodes elegans (T. Scott, 1894) in the family Cyclopinidae

(Huys & Boxshall, 1991). The coxal endite may well be present on

the maxillule of all Cyclopina species. It is present in C. gracilis

Claus, 1863 from the coast of Scotland (BMNH 1986.377) (pers.

D. JAUME AND G.A. BOXSHALL

obs.), and perhaps also in C. oblivia Monchenko, 1981, according to

Monchenko (1989: Fig. 9).

The Cyclopina reported by Herbst (1953; 1962) from Banyuls

(South France) and from Brittany (NW France) as C. cf. kieferi

Schafer, 1936 was recorded living as a commensal with polychaetes

(Bretagne) and free-living in the marine interstitial (Banyuls). The

illustrations provided by Herbst differ from the original description

by Schafer (1936) in an important character for the taxonomy of the

genus, the relative length of the female leg 5 exopodal spines. This

discrepancy was already noted by Lotufo (1994) when he presented

the differential diagnosis of C. yutimaete Lotufo in comparison to C.

kieferi. As the female leg 5 of C. cf. kieferi figured by Herbst (1953;

1962) is identical to that of C. esilis, we here consider Herbst’s

material as belonging to C. esilis.

The distribution of Cyclopina esilis thus encompasses the littoral

zone from the Black Sea to the western approaches of the English

Channel; a distribution equivalent to the Mediterranean and

Lusitanian provinces of classical marine biogeography (Ekman,

1953).

Family CYCLOPIDAE Dana, 1846

Subfamily HALICYCLOPINAE Kiefer, 1927

Genus Neocyclops Gurney, 1927

Neocyclops (Protoneocyclops) mediterraneus (Kiefer,

1960)

(Figs 5-7)

Pareuryte mediterranea: Kiefer (1960).

Neocyclops remanei mediterraneus: Pesce & Galassi (1987)

MATERIAL EXAMINED. Cova ‘C’ de Cala Varques (Manacor). UTM

coordinates: 525.27; 4372.19. Topography in Trias & Mir (1977):

Two adult males (one not preserved) and 2 copepodids (one not

preserved) (BMNH 1995. 1329-1330). Collected by authors, 29

March 1995.

ADULT MALE. Body (Fig. 5A) cyclopiform, up to 0.58 mm long,

colourless. Nauplius eye absent. Prosome about 1.4 times as long as

urosome, 5-segmented, first pedigerous somite completely con-

cealed by carapace-like, posterior extension of cephalosome. Rostrum

(Fig. 5B) triangular in frontal view. Urosome 6-segmented, robust.

Fifth pedigerous somite with pointed posterolateral angles; entire

hyaline frill adorning posterodorsal margin of somite. Genital somite

(Fig. 5C) slightly expanded laterally, with ventrolateral fold each

side of somite at about one-third distance from posterior margin;

folds slightly projecting dorsally. Paired gonopores opening ventrally,

each covered by opercular flap derived from sixth leg; flaps each

armed with | inner flanged spine and 2 outer plumose setae.

Abdominal somites 1 to 3 subequal, with posterior margins adorned

with entire hyaline frill. Anal somite bearing operculum dorsally at

about midlength; operculum ornamented with serrate hyaline frill; 4

rows of transverse setules adorning sides of anal cleft; posterolateral

margins of somite bearing serrate hyaline frill. Caudal rami 2.6

times as long as wide, inserted widely separate from each other;

secondary ornamentation of pores and tiny spinules distributed as

figured; armature consisting of 7 setae; seta I reduced, tiny, im-

planted ventrolaterally about one-third of distance along ramus; seta

II implanted dorsolaterally at about three-quarters of distance along

ramus.

Antennules (Fig. SE) 16-segmented, not extending beyond poste-

rior margin of prosome, symmetrical, digeniculate (Fig. 5A).

CYCLOPOIDS FROM LITTORAL CAVES

ee 005mm

A B

ee FOZ 5mm

= Wi

Ui i

Ze AL

Fig. 5. Neocyclops (Protoneocyclops) mediterraneus (Kiefer, 1960), adult male. A, body, dorsal; B, detail of rostral plate; C, genital somite, ventral; D,

anal somite and caudal rami, dorsal; E, antennule; F, fifth leg.

Geniculations between segments homologous with ancestral seg-

ments XV and XVI (10 and 11), and between XX and XXI (14 and

15). Segment 10 cup-shaped, forming sheath around proximal half

of segment 11. Segmental fusion pattern and armature as follows:

segment | (corresponding to fused ancestral segments I toV), 8 setae

+3 aesthetascs; segment 2 (partially fused ancestral segments VI and

VII), 4 setae; segment 3 (VIII), 2 setae; segment 4 (IX), 2 setae +

aesthetasc; segments 5 to 8 (X to XIII), 2 setae each; segment 9

(XIV), 2 setae + aesthetasc; segments 10 and 11 (XV and XVI), 2

setae each; segment 12 (XVII), 2 setose spines; segment 13 (X VIID,

1 setose spine, | seta + aesthetasc; segment 14 (fused segments XIX

and XX), 1 modified flattened spine and 3 setae; segment 15

(partially fused segments XXI and XXII), 2 modified flattened

spines, | seta + aesthetasc; segment 16 (fused segments XXIII to

D. JAUME AND G.A. BOXSHALL

Fig. 6. Neocyclops (Protoneocyclops) mediterraneus (Kiefer, 1960), adult male. A, antenna; B, labrum, ventral; C, mandible; D, maxillule; E, maxilla; F,

maxilliped.

XXVIII), 11 + 2 aesthetascs.

Antenna (Fig. 6A) well developed, 5-segmented. Coxa and basis

separate, coxa small, unarmed. Basis with 2 distal setae on inner

margin and long distal seta, representing exopod, on outer margin.

First endopod segment with seta inserted midway along inner mar-

gin. Second endopod segment with 2 lateral and 3 distal setae along

inner margin; outer margin covered by patch of setules. Third

endopod segment with 7 unequal setae on tip; outer margin adorned

with 2 patches of setules, as figured.

Labrum (Fig. 6B) with laterally serrate distal margin and row of 9

rounded teeth midway along margin; paired transverse rows of long

spinules located subdistally on anterior surface of labrum.

Mandible (Fig. 6C) with coxal gnathobase armed with 9 sharp,

unequal teeth, 2 dorsal setae, and 1 naked setiform element located

between third and fourth ventralmost teeth; inner dorsal seta with

long spinules along one side; outer dorsal seta longer, with short

spinules on both sides; transverse row of 7 long spinules disposed

subdistally on cutting blade. Mandibular palp reduced to knob

bearing 3 unequal setae.

Maxillule (Fig. 6D) with well developed praecoxal arthrite; arma-

ture consisting of 3 stout spines, 1 tiny spine and 3 slender setae

proximally, and distal lobe armed with 4 thick, denticulate spines; 2

CYCLOPOIDS FROM LITTORAL CAVES

LE:

ZEB

LELZA

ase

~—

=<S a a > i

SA; ASME A

nner, 7, > ne —~ !

TE Le a} —

os wh ‘ a \\ eX,

SO"

S77

Fig. 7. Neocyclops (Protoneocyclops) mediterraneus (Kiefer, 1960), adult male swimming legs, posterior view. A, leg 1; B, leg 2; C, leg 3; D, leg 4.

patches of tiny denticles on segment, as figured. Palp comprising

coxobasis with | spinulate spine and 2 setae distally and | seta

(representing exopod) implanted on outer margin, and 1-segmented

endopod bearing 3 setae (obscured in Fig. 6D).

Maxilla (Fig. 6E) 4-segmented, powerfully developed. Praecoxa

and coxa separate. Praecoxa with single, distal endite armed with 2

elements. Proximal coxal endite represented by single seta; distal

coxal endite discrete, armed with 1 spine fused to endite and

ornamented with 2 strong spinules, and | pectinate spine. Basis with

endite bearing 2 stout pectinate elements, one fused to segment, plus

reduced pinnate seta. Endopod 1-segmented, bearing 3 stout pecti-

nate elements plus 2 reduced, unequal setae.

Maxilliped (Fig. 6F) somewhat reduced in size, 4-segmented.

Syncoxa bearing 2 weakly developed endites with spine formula

2,1. Basis with 2 distal setae on inner margin; secondary ornamen-

tation of spinules and setules on segment as figured. Endopod

2-segmented, setal formula 2,3. Ornamentation on spines and setae

of maxilliped as figured; setae on distal endopodal segment naked.

Swimming legs 1 to 4 (Fig. 7) biramous, both rami 3-segmented,

except leg 4 with 2-segmented endopod; distal endopodal segment

subdivided by posterior surface suture marking plane of fusion

between second and third segments. Legs subequal in size except

first somewhat reduced. Intercoxal sclerites lacking ornamentation.

Legs richly ornamented with spinules, setules and denticles, as

figured. Armature as follows:

Coxa Basis Exopod Endopod

Leg | 0-1 1-1 I-1;I-1;0L1,4 0-1;0—2;L,1+1,3

Leg 2 0-1 1-0 I-1;J-1;01,1,5 0-1;0—2;1, 11,3

Leg 3 0-1 1-0 I-1;I-1;01,1,5 0-1;0—2;I, 11,3

Leg 4 0-1 1-0 -1;-1;0L11V 0-1;1,,0,0+1

Spines on legs | and 2 adorned with spinules, those on leg 3

flanged with serrate hyaline frill. Outer spines on exopod and outer

and distal spines on endopod of leg 4 ornamented with serrate

hyaline frill; inner margin setae on both rami modified, spine-like,

ornamented with short pinnules proximally and serrate membrane

distally.

Fifth legs (Fig. 5F) 4-segmented, joined by smooth intercoxal

sclerite. Coxa and basis separate, coxa unarmed, basis bearing

plumose seta on outer margin. First exopodal segment elongate,

about as long as coxa and basis combined, outer margin with

subdistal spine flanged with serrated hyaline frill; spinous process

just anterior to insertion point of spine; flanged spine longer than

segment; inner margin of segment bearing | distal spine adorned

with sparse setules and about as long as segment. Distal margin of

second exopodal segment bearing | seta flanked by 2 spines flanged

with serrate hyaline frill; spinous process just proximal to insertion

point of outer spine; outer spine slightly longer than inner, and

longer than first exopod segment; inner spine about as long as first

endopod segment; seta shorter than spines. Secondary ornamenta-

tion on fifth leg segments as figured.

REMARKS. The genus Neocyclops Gurney, 1927 contains 15 spe-

cies distributed in coastal waters of the Northeast and Tropical

Atlantic (including the Caribbean), the Mediterranean, the Black

and Red Seas, the Indian Ocean, as well as the Pacific (Papua New

Guinea) (Petkovski, 1986; Fiers, 1986; Pesce & Galassi, 1993;

Lotufo & Rocha, 1993; Rocha, 1995). Petkovski (1986) has split the

genus into two subgenera according to the number of exopodal

segments of the male fifth legs. The subgenus Neocyclops, charac-

terized by a 3-segmented male leg 5, embraces the following species:

N. medius Herbst, 1955, N. vicinus (Herbst, 1955), N. affinis (Plesa,

1961), N. salinarum (Gurney, 1927) and N. remanei (Herbst, 1952).

The subgenus Protoneocyclops, with 4-segmented male fifth legs,

comprises P. stocki Pesce, 1985, P. geltrudeae Pesce & Galassi,

1993, P. papuensis Fiers, 1986, P. mediterraneus (Kiefer, 1960), P.

herbsti Petkovski, 1986, P. wellsi Petkovski, 1986 and P. ferrarii

Rocha, 1995. This subgenus displays the so-called full Tethyan

pattern of distribution (Stock, 1993), i.e., circum-tropical in the

entire region of the former Tethys Sea.

Three other species, viz. N. improvisus Plesa, 1973 from Cuba,

and N. magnus (Sewell, 1949) and N. parvus (Sewell, 1949) from

islands in the Indian Ocean, cannot be assigned to either subgenus as

their males are unknown.

Three representatives of the genus are known so far from the

Mediterranean region. Neocyclops (N.) salinarum, originally de-

scribed from the Suez Canal, was reported also from the Camargue

(South France) and the Sirbonian lagoon (Mediteranean coast of

Sinai) (Gurney, 1927a; 1927b;Aguesse & Dussart, 1956; Por, 1973).

As Petkovski (1986) pointed out, the identity of the French popula-

tion needs to be confirmed. Similarly the single copepodid from the

D. JAUME AND G.A. BOXSHALL

Andaman Islands (Indian Ocean), assigned by Sewell (1949) to this

species, should be reexamined. Neocyclops (N.) vicinus, a species

distributed along the coasts of Brazil and the Lesser Antilles (Pesce

& Galassi, 1993; Lotufo & Rocha, 1993), has been also reported

from the Black Sea (as Eurycyclops remanei vicinus) by Plesa

(1963) and Monchenko (1975). As pointed out by Lotufo & Rocha

(1993), this record is dubious since their material seems more

closely related to N. (N.) remanei than to N. (N,) vicinus.

The single representative of the subgenus Protoneocyclops in

Mediterranean waters is Neocyclops (P.) mediterraneus, originally

described by Kiefer (1960) as Pareuryte mediterranea from an

anchihaline cave on Menorca (Balearic Islands). Later, Pesce &

Galassi (1987) reported it from an anchihaline cave in Southern

Italy. Plesa (1981) cited the same species from Cuba, but this record

has been reassigned by Petkovski (1986) to N. (N.) stocki, a taxon

widespread in the Caribbean region (Pesce & Galassi, 1993).

The Neocyclops from Mallorca has been identified on the basis of

the 4-segmented condition of the male fifth legs and the relative

lengths of the armature elements on this leg. Mallorca is also close

to the type-locality of the species (Menorca). Other characters could

not be checked against Kiefer’s (1960) original description since this

contained only 5 drawings (viz. female anal somite and caudal rami,

distal segment of endopod of female leg 4; fifth leg of both sexes, and

genital operculum of male). In addition, Kiefer did not designate

types for the species. Pesce & Galassi (1987) had only 2 females at

their disposal for their supplementary description.

A differential diagnosis of Neocyclops (Protoneocyclops)

mediterraneus (Kiefer, 1960) can be constructed based on charac-

ters of the male fifth leg. It differs from N. (P.) geltrudeae Pesce &

Galassi (1993) from Curacao (Antilles) in the number of armature

elements on the distal segment (3, compared to 4 inN. (P.) geltrudeae).

Differences from N. (P.) papuensis Fiers, 1986 from New Guinea

and N. (P.) ferrarii Rocha, 1995 from Brazil involve the relative

lengths of the spines on the distal segment (the inner spine is clearly

longer than the outer in both these species whereas in N. (P.)

mediterraneus the outer spine is subsimilar, slightly longer than the

inner). Differences from N. (P.) herbsti Petkovski (1986) from the

Red Sea, and N. (P.) stocki Pesce, 1985 from the Caribbean, are

based on the relative lengths of the flanged spines on the 2 distal

segments of leg 5 (these are clearly shorter than the first exopodal

segment whereas in N. (P.) mediterraneus they are longer than the

segment). In addition, in NV. (P.) herbsti the armature element on the

inner margin of the first exopodal segment is a plumose seta,

whereas in WN. (P.) mediterraneus it is a thick spine. Differences from

N. (P.) wellsi Petkovski (1986) from Mozambique lie only in the

nature of the armature element on the inner margin of the first

exopodal segment, which is also a seta in this species instead of a

thick spine.

Subfamily EURYTEINAE Monchenko, 1975

Genus Euryte Philippi, 1843

Euryte longicauda Philippi, 1843 emend. Giesbrecht,

1900

(Figs 8-11)

MATERIAL EXAMINED. Cova de na Barxa (Capdepera). UTM coor-

dinates: 539.30; 4393.10. Topography in Andrews et al. (1989): Two

adult females, 1 adult male, and 1 copepodid (BMNH 1995. 1323—

1326). Collected by authors, 3 April 1995. — Cova de na Mitjana

(Capdepera): 19 adult males, 7 adult females, and 5

CYCLOPOIDS FROM LITTORAL CAVES 93

0125mm

0.05 mm

Fig. 8. Euryte longicauda Philippi, 1843, adult male. A, body, dorsal; B, lateral; C, detail of rostral plate; D, genital and first abdominal somites, ventral;

E, same, lateral; F, anal somite and caudal rami, dorsal; G, antennule; H, fifth leg.

copepodids (BMNH 1995. 1313-1322). Collected by authors, 1 (BMNH 1995. 1327). Collected by D. Jaume, 25 May 1994.

April 1995. — Es Secret des Moix (Manacor). Coordinates: 523.69; ADULT MALE. Body (Figs 8A, B) cyclopiform, up to 0.61 mmlong,

4365.53. Topography in Ginés et al. (1975): One adult female —_ body surface completely covered by tiny cuticular granulations.

D. JAUME AND G.A. BOXSHALL

Fig. 9. Euryte longicauda Philippi, 1843, adult male. A, antenna; B, mandible; C, maxillule praecoxal arthrite; D, maxillulary palp; E, maxilla; F,

maxilliped.

Prosome about 1.4 times longer than urosome, comprising

cephalosome plus 4 free pedigerous somites; first pedigerous

somite completely concealed beneath posterior extension of

cephalosome, with lateral margins weakly sclerotized; second to

fourth somites with evenly rounded posterolateral corners. Ros-

trum (Fig. 8C) fused at base, well developed, subtriangular in

frontal view. Urosome 6-segmented; first abdominal somite with

pointed posterolateral angles; entire hyaline frill adorning

posterodorsal margin. Genital somite (Figs 8D,E) symmetrical,

laterally expanded, with entire hyaline frill around posterodorsal

margin; pair of gonopores opening ventrally at posterior border of

somite; opercular flaps each armed with 1 inner flanged spine plus

2 outer setae. Third to fifth urosome somites subequal, narrower

than genital somite, with entire hyaline frill adorning posterior

margin. Anal somite (Fig. 8F) about same size as preceding

somites; smooth anal operculum present at one third of distance

along somite; serrate hyaline frill around posterolateral margins of

somite. Caudal rami (Fig. 8F) of variable length, from 4.4 to 6.4

times longer than wide, slightly divergent; distal part slightly

wider; armature consisting of 6 setae; seta II located subdistally.

Antennules (Fig. 8G) 16-segmented, symmetrical, digeniculate

with geniculations between segments homologous with ancestral

segments XV and XVI (10 and 11), and segments XX and XXI (14

and 15). Segment 10 cup-shaped, forming sheath around proximal

half of segment 11. Segmental fusion pattern and armature as

follows: Segment | (corresponding to fused ancestral segments I to

V), 8 setae + 3 aesthetascs; segment 2 (corresponding to fused

ancestral segments VI and VII), 4 setae; segment 3 (VIII), 2 setae;

segment 4 (IX), 2 + aesthetasc; segments 5 to 8 (X to XIII), 2 setae

each; segment 9 (XIV), 2 + aesthetasc; segment 10 (XV), 2 setae;

segment 11 (XVI), 2 + aesthetasc; segment 12 (XVII), 1 short

denticulate spine and | seta; segment 13 (XVIII), 1 short denticulate

spine, 1 seta + aesthetasc; segment 14 (fused ancestral segments

XIX and XX), 1 short denticulate spine, 1 modified flattened spine,

CYCLOPOIDS FROM LITTORAL CAVES

Fig. 10. Euryte longicauda Philippi, 1843, adult male swimming legs, posterior view. A, leg 1; B, leg 2; C, leg 3; D, leg 4.

1 seta + minute aesthetasc; segment 15 (fused ancestral segments

XXI to XXIII), 2 modified flattened spines, 1 seta + aesthetasc;

segment 16 (fused segments XXIV to XXVIII), 11 setae + 2

aesthetascs.

Antenna (Fig. 9A) 4-segmented. First segment representing par-

tially fused coxa and basis, armed with 2 inner basal setae distally,

and 1 outer seta representing exopod; patch of setules present

midway along outer margin of segment. Endopod 3-segmented; first

segment about as long as coxa and basis combined, armed with 1

seta at three-quarters of distance along inner margin; outer margin

ornamented with setules. Segments 2 and 3 subsimilar in size, each

about half length of segment 1. Segment 2 armed with 2 lateral and

3 distal setae, one of latter (seta VIII in scheme of Boxshall &

Evstigneeva, 1994) claw-like, along inner margin. Segment 3 armed

with 7 distal setae, one claw-like; outer margin with 2 rows of

setules, as figured.

Mandible (Fig. 9B) with large coxal gnathobase bearing 11

unequal, sharp blades, plus 2 dorsal spines; outer dorsal spine

spinulate; transverse row of 6 thin spinules located adjacent to

cutting edge. Palp reduced to knob bearing 3 setae.

Maxillule with praecoxal arthrite (Fig. 9C) well developed, armed

distally with 4 stout, denticulate spines, plus 6 more proximal

elements, ranging from a tiny seta to a thick denticulate spine. Palp

(Fig. 9D) comprising coxobasis with medial gnathobase-like struc-

ture and minute endopodal segment bearing 2 setae; distal margin of

coxobasal gnathobase provided with 9 irregular blades; coxobasis

with 2 setae located subapically on dorsal margin and single seta,

representing exopod, located proximally on distal surface.

Maxilla (Fig. 9E) well developed, 4-segmented. Praecoxa and

coxa incompletely separate. Praecoxa naked, lacking endites. Coxa

with proximal endite represented by single seta; distal endite power-

fully developed, bearing 2 stout, spinulate spines, proximal spine

bearing single, conspicuous strong spinule on outer margin and row

of thinner spinules on inner margin. Basis with endite bearing 3

unequal, claw-like setae. Endopod |-segmented, armed with total of

3 stout spine-like setae, 1 naked seta and | very reduced seta.

Maxilliped (Fig. 9F) 5-segmented, prehensile. Syncoxa bearing 2

weakly developed endites provided with single seta each. Basis with

inner margin covered by patch of setules and single seta positioned

distally. Endopod 3-segmented, first segment short, unarmed; sec-

ond segment elongate, inner margin covered by patch of setules,

armed with 2 setae laterally; small distal segment with 2 stout,

curved claws plus 2 accessory setae.

Swimming legs | to 4 (Fig. 10) biramous, both rami 3-segmented.

Legs subequal in size except first somewhat smaller. Intercoxal

sclerites lacking ornamentation and getting progressively narrower

from legs | to 4. All spines on segments flanged bilaterally with

serrate hyaline frill except distalmost spine on exopod of leg 1,

which is flanged with frill on outer side only, inner side adorned with

row of setules. Secondary ornamentation and pore pattern on seg-

ments as figured; pores on coxa and basis possibly overlooked.

Armature as follows:

Coxa Basis Exopod Endopod

Leg 1 0-1 1-1 I-1;I-1;0L,1,4 0—1;0-2;I-HI

Leg 2 0-1 1-0 I-1;I-1;01L1.0V+1 0-1;0—2;I-1-Il1

Leg 3 0-1 1-0 I-1;I-1;0,1,V 0-1;0—2;I-I-Il

Leg 4 0-1 1-0 I-1;I-1;10,1,V O—1;0—-II;I--II

Fifth legs (Fig. 8H) uniramous, 3-segmented, joined by smooth

intercoxal sclerite. Coxa and -basis separate, former naked, latter

with single seta on outer margin. Distal segment (exopod) elongate,

about 2.5 times as long as wide; armature consisting of flanged spine

as long as segment located two-thirds of distance along outer

margin, plus 2 flanged spines and single seta on distal margin; distal

seta shorter than both spines and segment itself; distal spines located

either side of seta, flanged, both clearly longer than segment, inner

longer, about 1.5 times as long as segment. Secondary ornamenta-

tion of spinules present on outer margin of exopod of some

individuals, similar to that figured on female leg 5 (Fig. 11E), not

present in figured specimen (Fig. 8H).

ADULT FEMALE. Body (Figs 11A, B) up to 0.74 mm long, resem-

bling male. Urosome 5-segmented; genital and first abdominal

somites partially fused to form genital double-somite. Genital dou-

ble-somite (Fig. 11C) symmetrical, subdivided dorsally by partial

suture line; single copulatory pore opening mid-ventrally about

one-third of distance along somite, connected via copulatory duct

to fused seminal receptacles. Paired gonopores located laterally;

gonopores covered by opercula, each consisting of lobe projecting

dorsally bearing 2 setae and | tiny spine. Tapering soft lobe point-

ing posteriorly located at both sides of somite just behind

D. JAUME AND G.A. BOXSHALL

operculum. Entire hyaline frill present along posterior margin of

somite.

Antennules (Fig. 11D) 21-segmented, not extending beyond pos-

terior margin of cephalosome (Figs 11 A, B), symmetrical. Segmental

fusion pattern and armature as follows: Segment | (corresponding to

fused ancestral segments I to V), 8 setae; segment 2 (fused ancestral

segments VI and VII), 4 setae; segments 3 to 9 (VIII to XIV), 2 setae

each; segments 10 to 13 (XV to XVIII), 1 seta each; segment 14

(XIX), naked; segment 15 (XX), 1 seta; segment 16 (XXI), | seta +

aesthetasc; segment 17 (XXII), naked; segment 18 (XXIII), 1 seta;

segment 19 (XXIV), 2 setae; segment 20 (XXV), 2 + aesthetasc;

segment 21 (fused XXVI to XXVIII), 7 + aesthetasc.

Segmentation and setation of other cephalosomic appendages and

swimming legs | to 4 as in male.

Fifth legs (Fig. 11E) resembling those of male, but with shorter

exopod, about twice as long as wide; inner distal spine almost twice

as long as segment; spine on outer margin clearly longer than

segment. Secondary ornamentation of spinules on outer margin of

exopod not discernible in some individuals.

REMARKS. The genus Euryte typically contains shallow water

hyperbenthic species, although Brady (1910) reported the genus

from depths of 320 m in the Antarctic and some species have been

found living in the interstices of coarse sand, or in association with

seaweed or corals. Ten species are currently recognized, distributed

worldwide (Gurney, 1927b; Sewell, 1949; Herbst, 1989; Humes,

1991; 1992), with the possible exception of the Pacific coast of

South America. Apart from the original contributions by Giesbrecht

(1900) and Sars (1913-1918), new species have been described

mainly on the basis of a biometric analysis of characters that have

otherwise proved to exhibit high intra-populational variability (such

as the relative legth of caudal rami), or that may vary significantly in

their measurements simply according to the precise angle of obser-

vation (such as the relative length of the armature elements on the

distal segment of the endopod of leg 4). Such characters are widely

used in the two identification keys available for the genus (Vervoort,

1964; Herbst, 1989), and their use has resulted in the false impres-

sion of cosmopolitanism of some taxa (viz. E. longicauda and E.

robusta Giesbrecht, 1900; see Kiefer (1929) and Sewell (1949)).

The type material for most species of Euryte is no longer extant.

This hampers the necessary revision of the genus, that could permit

the critical reevaluation of all those taxa established on the basis of

variable characters.

Using material from the type locality of both species (the Gulf of

Naples), Giesbrecht (1900) differentiated E. longicauda Philippi,

1843 from E. robusta Giesbrecht, 1900 mainly by the proportions of

the caudal rami and by details of the armature of the male antennule.

The proportions of the caudal rami of the Mallorcan population

overlap the characteristic values for both species given by Giesbrecht

(1900). The armature of the male antennule, however, corresponds

to that of E. longicauda: the cup-shaped segment 10 carries 2 slender

setae, whereas in E. robusta it carries a characteristic robust, S-

shaped spine plus a seta. On this basis we have assigned the Euryte

from the Mallorcan caves to E. longicauda.

The differential diagnosis separating E. longicauda from Mallorca

from E. robusta can be completed as follows (see the detailed

illustrations of the latter species in Huys & Boxshall, 1991): in E.

longicauda the proximal spine on the distal coxal endite of the

maxilla of both sexes is armed with a single, strong spinule on one

side and a row of thinner spinules on the other side; in E. robusta

both sides are armed with thin spinules. Additionally, in E. longicauda

there is a transverse dorsal suture midway along the female genital

double-somite that seems to be absent in E. robusta.

CYCLOPOIDS FROM LITTORAL CAVES

Fig. 11. Euryte longicauda Philippi, 1843, adult female. A, body, dorsal; B, lateral; C, genital double-somite, lateral; D, antennule; E, fifth leg.

The distribution of E. longicauda apparently encompasses all

European coasts from the Black Sea to the Arctic Ocean (Franz-

Joseph Land) and the East coast of Greenland (Giesbrecht, 1900;

Herbst, 1989) but many of the records of this species are accompa-

nied by inadequate descriptions, if any. Geographically remote

records from outside the European region, such as those of Gurney

(1927b) from the Suez Canal and Samoa, or those of Thomson

(1882) (as Thorellia brunnea var. antarctica) from New Zealand,

require verification.

The body size of the Euryte longicauda from Mallorca falls in the

range characteristic of the variety E. longicauda var. minor Scott,

1905, which was elevated, rather inconsistently, to full specific

status by Sars (1919-1921). This variety is supposed to inhabit

deeper waters and never to occur in the littoral zone (Sars, 1913—

1918; 1919-1921).

According to Sars (1913-1918) E. longicauda carries only modi-

fied flanged spines on the inner margin of the third exopodal

segment of leg 2. In our material the proximalmost element on the

inner margin of this segment is a plumose seta (Fig. 10B). However,

this may be an observational error by Sars since material of E.

longicauda from Raunefjorden in Norway (BMNH 1986.387) and

from Scotland (BMNH 1951.8.10.587) in the collections of the

Natural History Museum possesses a plumose seta in this position,

as in the Mallorcan material.

REVIEW OF EURYTE SPECIES

The eight remaining species of Euryte are briefly reviewed here, in

order to facilitate the identification of representatives of this prob-

lematic genus. The review is essentially comparative and emphasises

the most robust and reliable characters available in published de-

scriptions.

E. curticornis Sars, 1913 is characterised by short, 21-segmented

female antennules and the shortened third segment of the maxilliped;

the curved distal claws on this appendage are also reduced in size

and subsimilar in length. These features contrast with the maxilliped

of E. longicauda, which is provided with an elongate third segment

and with long, unequal distal claws. The distal spines on the third

segment of endopod of leg 1 are clearly unequal in length in E.

curticornis, whereas in E. longicauda they are about equal.

E. longicauda can be distinguished from E. grata Herbst, 1989

and E. verecunda Humes, 1992 by some features of the maxilla and

maxilliped. In E. verecunda, the proximal spine on the distal coxal

endite of maxilla is adorned on both sides with slender spinules. On

the maxilliped, the armature element on the proximal syncoxal

endite is a seta in E. longicauda, whereas in E. grata and E.

verecunda this endite is represented by a stout spine. E. verecunda

differs additionally in the setose condition of the armature elements

on the inner margin of the second endopodal segment of leg 4; these

elements are flanged spines in E. longicauda. The generic placement

of E. verecunda needs verification since, according to Humes (1992),

this species displays a 2-segmented condition of leg 5. This is a

characteristic of the genus Ancheuryte Herbst, 1989, whereas in

Euryte leg 5 is 3-segmented in both sexes.

In E. pseudorobusta Vervoort, 1964 two distal setae are present in

the outer margin of the antennary coxobasis, whereas there is only 1

seta in E. longicauda. The proximal spine on the distal coxal endite

of maxilla has a different armature in the two species, with a row of

setules along each side in E. pseudorobusta. Finally, the caudal rami

of E. pseudorobusta are short, about as long as the anal segment, and

differ significantly from the elongate caudal rami of E. longicauda.

Two other species, each described from a single female from the

Addu Atoll (Maldives), viz. E. brevicauda Sewell, 1949 and E.

sewelli Vervoort, 1964 (= “Euryte sp. of Sewell, 1949) also differ

from E. longicauda in their very short caudal rami. The status of E.

sewelli Vervoort, 1964 as a distinct species from E. brevicauda is

equivocal (Vervoort, 1964; Sewell 1949). The main difference be-

tween them is the apparently 18-segmented female antennule in the

former species. Unfortunately, Sewell’s (1949) original material is

not preserved, thus precluding verification. However, if Sewell’s

illustrations are accurate, the 18-segmented antennule, combined

with the absence of the inner seta on the proximal segment of exopod

of leg 1, can be used as diagnostic characters of this taxon.

D. JAUME AND G.A. BOXSHALL

E. longicauda differs from E. bellatula Humes, 1991 in the nature

of the two armature elements on the inner margin of the second

endopodal segment of leg 4; these are flanged spines in the former

species, whereas in the latter they are setae. E. bellatula also has the

proximal spine on the distal coxal endite of maxilla armed with a row

of thin spinules on both sides.As commented above for E. verecunda,

the generic placement of E. bellatula must be confirmed due to the

apparently 2-segmented condition of the leg 5. The association with

corals of the two taxa described by Humes is similar to the life-style

of Ancheuryte, a closely related genus characterized by its 2-seg-

mented leg 5.

The status of E. similis Scott, 1912, originally described from the

South Orkneys and never found since, is debatable. Scott pointed out

its similarity to E. robusta, and that it appeared ‘. . . to differ in one

or two minor points, such as in the armature of the first and fourth

pairs of thoracic legs and in the proportional lengths of the abdomi-

nal segments’ (Scott, 1912). The differences in the armature of the

swimming legs mentioned by Scott in the text do not correspond

with his figures. Also, as Sewell (1949) already pointed out, it seems

certain that Scott had confused the legs so that his second leg is in

reality the fourth, and his fourth leg is either the second or third. In

fact, the original description is very superficial and does not permit

any conclusion other than that the taxon belongs to Euryte. The only

apparent diagnostic features displayed by this taxon could be the

lack of an inner seta on both the first endopodal and first exopodal

segments of leg 4 (Scott’s leg 2). This is unreliable, however, since

the number of armature elements on the swimming legs is a very

conservative character at the generic level in the Cyclopidae. In our

opinion, given the lack of type material, this taxon should be

considered species inquirendum.

ACKNOWLEDGEMENTS. We want to thank J. Pons-Moya and G. Pons their

support during fieldwork, and Dr Rony Huys and Prof Carlos Eduardo

Falavigna da Rocha for their detailed comments and improvements to the

manuscript. Contribution to project DGICYT PB91—0055 and EC Training

Research Contract ERBCHBICT941306.

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—i—m.

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Notodelphyoida. Scientific Reports of the John Murray Expedition, 7: 117-382, |

chart.

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Journal of Natural History, 27: 807-819.

lliffe, T.M. & Williams, D. 1986. The concept ‘Anchialine’ reconsidered.

Stygologia, 2: 90-92.

Thomson, G.M. 1882. On the New Zealand Copepoda. Transactions and Proceedings

of the New Zealand Institute, 15: 93-116.

Trias, M. & Mir, F. 1977. Les coves de la zona de C’an Frasquet — Cala Varques.

Endins, 4: 21-42.

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with notes on related species. United States National Museum Bulletin, 236: \-

431.

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Issued 28 November 1996

Studies on the deep-sea Protobranchia

(Bivalvia): the family Neilonellidae and the

family Nuculanidae.

J.A. ALLEN

University Marine Biological Station, Millport, Isle of Cumbrae, Scotland, KA28 0OEG

H.L. SANDERS

The Woods Hole Oceanographic Institution, Massachusetts, 02543, USA

CONTENTS

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Synopsis. The morphology and distribution of four deep-water protobranch species of the family Neilonellidae and ten deep-

water protobranch species of the family Nuculanidae are described. These include four new species. The evolution of the

nuculanoid siphonate form is discussed.

INTRODUCTION

This is the ninth paper in a series on the deep-sea species of

Protobranchia of the Atlantic. While a few undescribed species of

families reported upon in earlier papers have been found in later

samples and remain to be described, this paper is the last of our

major descriptive accounts of the morphologies of this exceptionally

important group of deep sea bivalves.

In this paper we give an account of a number of nuculanacean

species belonging to the families Neilonellidae and Nuculanidae

present in our collections from the deep Atlantic. Related species

already described are refered to only when essential for descriptive

and comparative purposes. Unlike previous papers in this series

most of the species described below are known, but only from their

shell characters. This is in part due to the fact that many species come

from upper-slope depths, and thus more likely to have been sampled

in the past, and in part due to the fact that they are relatively large and

thus less likely to have been lost due to the coarseness of nets used

in earlier expeditions. Many earlier descriptions of the shell are far

from adequate and new descriptions are given.

We have followed the methods and approach of earlier papers in

this series (Allen and Hannah, 1989; Allen and Sanders, 1973, 1982;

Allen, Sanders and Hannah, 1995; Rhind and Allen, 1992; Sanders

and Allen, 1973, 1977, 1985). From stereoscopic microscope ex-

amination of shell features and whole mounts of the body stained in

haemotoxylin, from dissected specimens and serial sections stained

with trichome techniques, we give detailed descriptions of the shell

and internal morphology of key species. Descriptions of related

species are limited to points of difference and importance.

Much of the material was taken by ourselves on numerous

expeditions by research vessels of the Woods Hole Oceanographic

Institution. These include the ‘Atlantis’, “Atlantis II’, ‘Chain’ and

‘Knorr’. Other samples were taken by JAA on the British research

102

vessels ‘Sarsia’ and ‘Discovery’. In addition to these, deep-sea

bivalves from a series of French expeditions using the research

vessels “La Perle’, “Cryos’ and ‘Jean Charcot’ were kindly donated

by our French colleagues. At present this material, other than the

types of new species and cited specimens, is housed at the Woods

Hole Oceanographic Institution and the University Marine Biologi-

cal Station Millport. On completion of our studies, it is our intention

to return the French collections to the Museum National d’ Histoire

Naturelle, Paris and our own collections to the U.S. National Mu-

seum and the Natural History Museum, London.

Museums are abbreviated as follows: ANSP — Academy of

Natural Sciences, Philadelphia; BMNH — Natural History Mu-

seum, London; MCZ — Museum of Comparative Zoology, Harvard;

MNHN — Museum National d’ Histoire Naturelle, Paris; SAM —

South Africa Museum; USNM — United States National Museum,

Washington, D.C.; ZMHU — Zoologisches Museum, Humbolt—

Universitat, Berlin; ZMUC — Zoological Museum, University of

Copenhagen.

Sampling gear is abbreviated as follows:- AD — anchor dredge; CP

— beam trawl; CV — Blake trawl; DS — epibenthic sledge Sanders

(COB); ES — epibenthic sledge (WHOI); KG — USNEL boxcorer;

OS — epibenthic sledge (SMBA); WS — epibenthic sledge (IOS).

ABBREVIATIONS TO THE TEXT-FIGURES

AA anterior adductor muscle

AN anus

AR anterior pedal retractor muscle

AS anterior sense organ

BG ‘byssal’ gland

CG cerebral ganglion

CM caecum

CV cerebro-visceral commissure

DD _ digestive diverticula

DH dorsal hood

DT digestive ducts

FA feeding aperture

FG fused gill tissue

FR faecal rod

Jet foot

GA _ gill axis

GI gill

GP gill plate

GS gastric sheild

HG hind gut

HP hinge plate

HT hinge teeth

LI internal ligament or resilium

LO opisthodetic external ligament

MG _ combined mid gut

mantle margin

OE oesophagus

PA posterior adductor muscle

PE sensory papilla

PG pedal ganglion

PL palp

12 palp proboscis

PR posterior pedal retractor muscle

PS posterior sorting area

SE siphonal embayment

SP combined siphon

J.A. ALLEN AND H.L. SANDERS

SR siphonal ridge

SS style sac

Sil sensory tentacle

SM _ stomach

VG visceral ganglion

Family Neilonellidae Schileyko 1989

Shell usually robust, inflated, moderately large, not particularly

elongate, more or less ovate, shell posteriorly extended to some

degree and may be acutely rounded or carinate, usually marked

concentric sculpture; umbo prominant, anterior to midline; hinge

teeth taxodont, continuous or interrupted below the umbo; ligament

external, sometimes with an internal component; siphons present;

hind gut either a single loop or a series of loops and coils to the left

and right of the body.

The family comprises four genera, Neilonella, Pseudotindaria,

Neilo and Protonucula (Allen and Hannah, 1986). By reason of their

external ligament, the neilonellids in the past have been included in

the family Malletiidae, however this family was shown to be an

assemblage of unrelated taxa and is now much restricted (Sanders

and Allen, 1985). The robust, ovate, concentically ridged shells of

the neilonellids are in marked contrast to the thin, translucent,

elongate shells, lacking any marked concentric sculpture, of the

malletiids.

Genus NEILONELLA Dall 1881

TYPE SPECIES. Leda (Neilonella) corpulenta Dall 1881; OD.

Shell moderately robust, relatively wide, strong concentric sculp-

ture, anterior margin rounded, posterior margin slightly attenuate

and may be acutely rounded, not carinate; umbo prominant, anterior

to the midline; hinge plate moderately strong, many chevron teeth,

small gap between anterior and posterior series; external ligament

opisthodetic, inserting in an external gutter in each valve, with

minute internal resilifer, siphonal embayment shallow; hind gut

single loop to the right of the body.

Genus PSEUDOTINDARIA Sanders and Allen 1977

TYPE SPECIES. Pseudotindaria erebus (Clarke 1959); OD.

Shell robust, relatively wide, anteriorly and posteriorly rounded,

not carinate, strong concentric sculpture; hinge plate strong with

numerous chevron teeth continuous below umbo; ligament external,

anterior part short, posterior part elongate; hind gut with complex

series of loops and coils to the right and left of the body.

Genus NEILO Adams 1854

TYPE SPECIES. Neilo cumingii Adams 1854; by monotypy.

Shell robust, relatively wide, moderately elongate and posteriorly

extended, postero-dorsal margin straight or slightly concave, cari-

nate, posteriorly truncate or slightly rostrate, postero-ventral margin

may be somewhat sinuous, two rounded radial ridges from umbo to

posterior margin, concentric sculpture; hinge plate well-developed:

numerous chevron teeth, anterior and posterior series separate and

may differ in size (anterior larger); ligament external.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

Genus PROTONUCULA Cotton 1930

TYPE SPECIES. Protonucula verconis Cotton 1930; OD.

Shell relatively fragile, oval, compressed, glossy, concentric sculp-

ture; umbo prominent; hinge plate narrow, chevron teeth squat,

broad, continuous; ligament relatively small, external, amphidetic.

Neilonella salicensis (Seguenza 1877)

TYPE SPECIMEN. Whereabouts unknown.

TYPE LOCALITY. Upper Pliocene fossil, southern Italy.

CITED SPECIMENS. BMNH 1995051.

Leda pusio var.latior Jeffreys 1876a, p.190, nom. nud.; 1876b,

p.430.

Leda pusio Jeffreys 1879, p.578, in part.

Leda pusio var.salicensis Seguenza 1877, p.1178, pl.4, fig.20.

Yoldia sericea vat.striolata Verrill 1884, p.226; 1885, p.576.

Leda salicensis Locard 1898, p.348, pl.14. figs 22-25.

Neilonella subovata Verrill and Bush 1897, p.57, figs 7, 8, 22; type

locality: Georges Bank to Cape Hatteras, 125—1731fms; syntype:

USNM 34826 (examined by HLS).

Tindaria (Neilonella) guineensis Thiele 1931, in Theile and Jaeckel

1931, p.50, pl.3, fig.70; type locality; Gulf of Guinea, 710-

2492m; type: ZMHU (not seen).

Neilonella guineensis Knudsen 1970, p.59, text-fig.39, pl.5, fig.3,

pl.6, figs 8-10.

Neilonella schepmani Prashad 1932, p.27, pl.1, figs 50, 51; type

locality; Banda Sea, Siboga sta.221, 2798m; ZMHU (not seen).

Pseudoneilonella salicensis Laghi 1986, p.191, text fig.1, pl.5, figs

1-7.

Pseudoneilonella latior Laghi 1986, p.192, text fig.1, pl.7, figs 7a-c.

Pseudoneilonella salicensis atlantica Laghi 1986 p.192, text fig.1,

pl.6, figs 1-7.

Pseudoneilonella montanaroe Laghi 1986, p.193, text fig.1, pl.9,

figs 4-8; type locality: off Portugal, Porcupine Expedition, 400m,

USNM No. 199739 (not seen).

Neilonella striolata (Brugnone) Warén 1989, p.252, figs 3a, 16a—d.

Warén (1989) gives a lengthy and detailed discussion of much of

the nomenclatoral history of this species although, the history is

even more complex than he reports. Warén (1989) synonymized N.

salicensis with an earlier described species N. striolata (Brugnone,

1876). The type of N. striolata is lost but from the original descrip-

tion and figure by Brugnone (1876) and those of Seguenza (1877)

(who synonymized it with Yoldia abyssicola Torrell) and later au-

thorities (e.g. Jeffreys, 1879; Locard, 1898) it is clear that the

posterior part of the shell of N. striolata is significantly different in

form to that of NV. salicensis. Whereas the posterior shell margin of

N. salicensis is acutely rounded that of N. striolata is sub-rostrate

with the posterior limit of the shell more ventral in position and the

distal postero-dorsal margin more steeply angled (Figs 1,2 & 4).

The brief description of N. guineensis by Theile in Theile and

Jaeckel(1931) was enlarged upon by Knudsen (1970) who com-

pared specimens from the Galathea Expedition with those of the

Valdivia and Siboga Expeditions. From our examination of the

Galathea material from 02°17'S 08°10'E (2770m) and our own speci-

mens from 02°32'S 08'18'E (2514m) we conclude that N. guineensis

and N. salicensis are the same species. Knudsen (1970) also

synonymized N. schepmani with N. guineensis. Although N.

schepmani is from the Banda Sea (Prashad, 1932) which might cast

doubt on this synonymy, it must be remembered that N. salicensis is

a very widespread species and we believe that it is comparable to

103

Fig. 1. ‘Yoldia abyssicola’ Torell. Right valve, redrawn from Seguenza

(1877), synonymized with Leda producta Monterosato and Yoldia

striolata Brugnone. Scale = 1mm.

Ledella sublevis, which also has a widespread distribution in the

Atlantic and extends into the southwest Pacific (Allen and Hannah,

1989).

Further compexity in the synonymy of N. salicensis concerns so-

called varieties of “Leda pusio Philippi’ a species that has recently

been investigated by Laghi (1986).

Fig. 2. Neilonella salicensis. a, view of shell, from Atlantis II station 73

in the North America Basin, drawn from the left side; b, outline of shell

from Biogas VI station DS 86 in the West European Basin to show

difference in shape. Scale = 1mm.

L. pusio is rostrate and not a neillonellid, but a ledellid, possibly

synonymous withL.acuminata (Jeffreys 1870)(Laghi, 1986). Jeffreys

(1879) reporting on Leda pusio taken by the ‘Lightning’ and *Porcu-

pine’ Expeditions, refers to what he thought was a variety of this

species which he had previously named L. pusio var.latior

(Jeffreys,1876) and which he changed to L. pusio var.salicensis of

Seguenza (1877). Laghi (1986) proposed a new genus

Pseudoneilonella to accommodate this latter and raised to species

level a number of the records of Jeffreys (1876, 1879). Since then,

Waren (1989) has synonymized these with Neilonella salicensis and

this we confirm.

Jeffreys (1879) also listed a further variety which he called

semistriata and which is now regarded as a separate species (Warén,

1989). In his detailed analysis Warén (1989, figs 17E & F) also

104

figures what he describes as ‘Neilonella latior (Jeffreys)?, young

syntype of Leda sericea Jeffreys, Valorous Expedition, Stn 12,

USNM 199595’ These valves are equilateral in shape and differ in

outline from N. salicensis. We have specimens of this species in our

collections and these we intend to describe in a later paper.

Locard (1898), not mentioned by Warén (1989), came to the same

conclusion as ourselves and recognized three entities, Leda pusio,

L. striolata and L. salicensis, accurately separating them on shell

characters, the most significant of these being the more elongate,

triangular form and greater post-umbonal length of L. salicensis as

compared with L. pusio, both of which he figures.

There is a relatively wide degree of variation in the height, length

and post-umbonal length of the shell in N. salicensis and this

variation is similar in populations from different basins (Figs 4 & 5).

This may, in part, explain why this species has been described anew

so many times.

MATERIAL:

Cruise Sta. Depth No Lat Long Date Gear

(m)

NORTH AMERICA BASIN

Atlantis] 62 2496 13 39°26.0'N 70°33.0'W 21.8.64 ES

12 64 2886 2 38°'46.0'N 70°06.0'W 21.8.64 ES

73 1330- 495 39°46.5'N 70°43.3'W 25.8.64 ES

1470

Chain50 87 1102 6 39°48.7'N 70°40.8'W 6.7.65 ES

Chain 58 103 2022 217 39°43.6'N 7037.4';W 4.5.66 ES

AtlantisII 30131 2178 119 39°38.5'N 70°36.5'W 18.12.66 ES

Chain88 210 2024 48 39°43.0'N 70°55.5'W 23.2.69 ES

2064

GUYANA BASIN

Knorr25. 293s 1456— 2 08°58.0'N 5404.3'W 27.2.72 ES

1518

295 1000— 1575 0804.2'N 5421.3'W 28.2.72 ES

1022

297 508- 194 0745.3'N 5424.0'W 28.2.72 ES

523

299 1942- | 0755.1'N 55°42.0'W 29.2.72 ES

2076

307 3835- 2 12°34.4'N 58'59.3'W 3.3.72 ES

3862

WEST EUROPEAN BASIN

Sarsia $33 1537- 6 43°41.0'N 0336.0'W 13.7.67 ES

1830

S37 7) 2 43°39.2'N 0330.2'W 15.7.67 ES

S40 860 4 43°35.6.N 0324.8'W 15.7.67 ES

S44. 1739 60 43'40.8'N 0335.2';W 16.7.67 ES

S50 2379 16 4346.7'N 03°38.0'W 18.7.67 ES

SO QPP 7 46°15.0'N 04°50.0'W 25.7.67 ES

Chain 106 313 1491— 432 51°32.2'N 12°35.9'W 17.8.72 ES

1500

316 §=2173— 583 50°58.7'N 1301.6'W 18.8.72 ES

2209

La Perle DS11 2205 1 4735.5'N 0833.7'W 8.8.72 DS

Biogas I

J.Charcot DS25 2096 9 44°08.2'‘N 04°15.0'W 1.11.72 DS

Polygas

J.Charcot DS32 2138 2 4732.2N 0805.3'W 19.4.73 DS

Biogas II

BiogasHI DS38 2138 2 4732.2'N 0835.8'W 25.8.73 DS

DS49 1845 70 4405.9'N 04°15.6';W 31.8.73 DS

BiogasTV DS52 2006 16 4406.3'N 0422.4'W 18.2.74 DS

DS63 2126 5 4732.8'N 08°35.0'W 26.2.74 DS

Cryos CROT2 ORS 44°09.8'N 0416.4';W 21.6.74 CP

Biogas V

J.Charcot DS77 4240 1 4731.8'N 09°34.6'W 24.10.74 DS

Biogas VI DS80 4720 4 46°29.5'N 1029.5'W 26.10.74 DS

DS82 4462 1 44°25.4'N 04°50.8'W 29.10.74 DS

DS86 1950 198 44°04.8'N 04°18.7'W 31.10.74 DS

J.A. ALLEN AND H.L. SANDERS

DS87 1913 173 4405.2'N 04°19.4';W 1.11.74 DS

DS88 1894 31 44°05.2.N 0415.7'W 1.11.74 DS

Incal DSO1 2091 98 57°59.2'N 1041.3'W 15.7.76 DS

DSO2 2081 91 5758.2N 1048.5'W 16.7.76 DS

CPO1 2068 19 5757.7'N 10°55.0'W 16.7.76 CP

DSOS 2503 3 5628.1'N 11°11.7';W 18.7.76 DS

OSO1 2634 4 50'14.4'N _13°'10.9'W__30.7.76 OS

WS02 2498 1 50°19.3'N _12°55.8'W__30.7.76 WS

CP10 4823 2 A825.N I500.7°W 31776 CP

WS03 4829 1 48°19.2'N 15°23.3'W 1.8.76 WS

Challenger 232 2195 3 5717.0'N 1016.0'W 19.5.83 ES

7/83

CANARY BASIN

Discovery 6701 1934 8 2745.2'N 14°'13.0'W__ 16.3.68 ES

STIERRE LEONE BASIN

Atlantis] 142 1624— 20 10300N 1751:S'W 52:67 ES

3] 1796

147 2934 16 1038.0'N 17°52.0'W 23.2.67 ES

ANGOLA BASIN

Atlantis] 191 1546— 52 23,05:0'Sy 1231-515 al7es68 Bs

42 1559

200 2644— 7 09°43.5'S 10°57.0'E 22.5.68 ES

2754

201 1964— 41 09'25.0S 1135.0'E 23.5.68 ES

2031

202 1427- 21 08°56.0'S 12°15.0'E 15.5.68 ES

1643

Walda DS20 2514 4 02°32.0'S O818.1'E -——71 DS

DS25 2470 31 02°19.8'S_ 0749.7E --71 DS

In addition to the material listed above we have examined the

following specimens from the Porcupine and Valorous Expeditions

housed in the BMNH:-— 85.11.5.397-402; 6.9.27,28; 85.11.5.494—5;

89.11.11.10-13; 89.9.5.26—-9; 77.11.28.24. We have also examined

specimens from the Galathea Expedition housed in the ZMUC, and

specimens mostly from the U.S.Fish Commission expeditions housed

in the USNM and MCZ.

DISTRIBUTION. Common throughout the Atlantic north of the

Argentine and Cape Basins and south of the Norwegian and Arctic

Basins. It is also found in the southwestern Pacific. It mainly occurs

at slope depths, occasionally at abyssal depths (West European

Basin), from 508m to 4829m.

Fig. 3. Neilonella salicensis. a, internal inclined ventral view of the

hinge plate and teeth of a left valve; b, dorsal view of shell to show the

extent of the external ligament and detail of sculpture. Both specimens

taken from Walda station DS 25 in the Angola Basin. Scale = 1mm.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

Fig. 4. Neilonella salicensis. A series of shells, from Atlantis II station 73

from the North Atlantic Basin, in lateral view from right side to show

change in shape with increasing size. Scale = Imm.

SHELL DESCRIPTION (Figs 2-4)

Shell robust, moderately elongate, moderately wide, ornamented

alse

Boe

BC;e

105

with concentric ridges sometimes in groups of three to four well-

defined ridges alternating with two to to three slighty less

well-defined ridges slightly wider spaced than the former, light to

dark straw-coloured periostracum; umbos moderately prominant,

somewhat anterior to mid-line (postumbonal length c.54% of total

length), inward and slightly anterior facing; dorsal shell margins

deep set close to umbo but no lunule or true escutcheon, antero-

dorsal margin slopes down to join anterior and ventral margins in

smooth curve, postero-dorsal margin almost straight, may be

slightly angled at posterior limit of hinge short of acutely rounded

posterior margin; posterior limit of shell somewhat dorsal to mid

horizontal line, anterior limit of shell at mid line; posterior margin

of smaller specimens less acutely rounded; hinge plates elongate,

moderately broad, increasing slightly in width distally, anterior

and posterior hinge teeth series meet below umbo with no edentu-

lous space between, teeth numerous, up to 19 in posterior series

and 14 in anterior series depending on size of specimen, obtuse

chevron-shape, proximal hinge teeth very small, those more distal

elongate and so closely articulated that it maybe impossible to

separate valves without damage to them; internal ligament

(resilium) microscopic, present ventral to umbo at outer margin of

hinge plate, external ligament opisthodetic, relatively short, short

anterior part present. Maximum total length of present specimens

8.0mm.

As in most deep-sea protobranchs, there is a change in the shape

of the shell outline as growth occurs (Figs 4 & 5), although this is not

as marked as in many protobranch species (e.g. Ledella spp. Allen

and Hannah, 1989). The ratio of postero-umbonal length to total

length increases and at the same time the height to total length

decreases so that larger shells (>3mm total length) are more

posteriorly attenuate than smaller specimens. There is a fair degree

of variation in the ratios which is not related to the different

populations sampled. Unusually in some samples the length fre-

quency histograms are skewed to the right (Fig. 6) and with clearly

Length (mm)

Fig. 5. Neilonella salicensis. The ratios height to total length (H/TL)(large symbols) and post-umbonal length to total length (PL/TL)(small symbols)

plotted against total length to show changes in shell proportions with increasing length. Open circles are specimens from Biogas III station DS 49 West

European Basin, closed circles from Sarsia Station S44 West European Basin and closed squares, from Chain 58 station 103 North America Basin.

106

220

syJwawn

J.A. ALLEN AND H.L. SANDERS

LENGTH (mm)

Fig. 6. Neilonella salicensis. Length/frequency histogram of a sample taken from Atlantis II station 73 from the North America Basin.

marked size groups. It is unclear whether these latter relate to annual

settlements or to fortuitous periodic settlements.

INTERNAL MORPHOLOGY (Figs 7 & 8)

This was one of the few deep-sea species that were kept alive for a

few weeks following the processing of the sample. The external drab

olive/yellow of the shell is in marked contrast to the spectacularly

vivid array of colours of the body organs. The stomach is a bright

emerald green, the digestive gland a bright olive green and the gills

are bright red. The gill plates are particularly vivid below the frontal

cilia and dorso-laterally, in addition the mantle overlying the gills is

also red. The margins of the palps are a diffuse pink as too is a band

underlying the crest of the inner folds. The red and pink pigments are

probably a cytochrome. The blood is not red in colour and probably

contains a haemocyanin as do other protobranchs (Taylor, Daven-

port and Allen, 1995). Elsewhere the palps are pale yellow and the

yellow/pink effect is in marked contrast to the palp proboscides

which are pure white.

Fig. 7. Neilonella salicensis. Semidiagrammatic view of the internal

morphology as seen from the right side. See abbreviations to text-figures

on p. 102. Scale = 1mm.

The mantle has three marginal folds of which the inner is fused at

the posterior end to form the siphon. Fusion is minimal, restricted to

the dorsal margin of the siphon (Fig. 8). Ventrally the siphonal

margins are unfused as too are the longitudinal ridges that mark the

division between the dorsal exhalent and ventral inhalent channels.

The gill axes attach to the inner ends of the longitudinal ridges.

There is a shallow siphonal embayment and attached to its inner

limit on the left or the right side is a siphonal tentacle which in living

specimens extends beyond the shell margin at distance equal to a

third of the shell length. Ventral to the anterior adductor muscle there

is an elongate anterior sense organ, which consists of a flap of tissue

derived from the middle sensory fold. A major ciliated rejection tract

is present on the inner face of the inner mantle fold. The adductor

muscles are relatively small, unequal in size, with the posterior the

smaller. The posterior muscle is round in cross-section while the

anterior is bean-shaped.

The gills, with up to 26 plates, are slung from a horizontal axis

extending from the base of the siphon to a point about half way

across the body. Individual gill plates are exceptionally elongate for

a deep-sea protobranch. The foot is broad and the divided sole has

papillate margins, the anterior papillae are the more pronounced.

There is a small median papilla present posterior to the aperture to

the ‘byssal’ gland. The latter is extremely large. The pedal muscles

consist of a pair of broad posterior retractors, one on each side of the

hindgut anterior to the posterior adductor, and a series of four pairs

of anterior retractors posterior to the anterior adductor. The two

inner muscles of the four lie more close together than to the two

outer.

The palps are relatively large with up to 27 inner ridges depending

on the size of the specimen. Each bears a long narrow palp probos-

cis. A ciliated rejection tract traverses the lateral face of the foot at

the junction of of the muscular and visceral parts and the posterior

ventral point of the palp is positioned at the posterior limit of this

tract in the living animal.

The mouth is set far posterior to the anterior adductor. The

oesophagus curves first antero-dorsally to meet the inner face of the

anterior adductor then postero-dorsally to open on the anterior face

of the stomach. The stomach is large and slung diagonally within the

visceral mass. The pedal muscles form a ventral ‘basket’ in which

the stomach rests. The stomach, which is similar to that of other

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

Fig. 8. Neilonella salicensis. Detail of internal morphology; a, lateral

view from the right side of the stomach and style sac; b, internal view of

a dissected gastric shield; c, diagrammatic enlargement of the siphonal

region to show the relationship of the parts. See abbreviations to the

text-figures p. 102. Scales = 0.5mm (A); 0.1mm (B).

protobranchs (Purchon, 1956), is one third lined with a gastric shield

dorsally and to the left (Fig.8). The unlined right wall bears very few

sorting ridges. The style sac is flask-shaped rather than the more

usual conical outline of other protobranchs. The combined mid gut

is guarded by minor and major typhlosoles. The hind gut penetrates

the foot to a point ventral to the pedal ganglia before taking a course

posterior to the stomach and thence to form a loop to the right side

of the body. This single loop extends anteriorly as far as the anterior

adductor muscle and where it then takes a dorsal course along the

margin of the body to the anus. The hind gut has a particularly wide

diameter compared with most other deep-sea protobranchs and has

a well-marked typhlosole present along its entire length. The diges-

tive gland which lies anterior and dorso-lateral to the stomach has

three sections each connecting with the stomach via a duct. The

apertures of the ducts are ventral, and left latero-ventral to the

oesophageal aperture.

The nervous system is of a typical protobranch design with

elongate pairs of cerebral and visceral ganglia and large ovoid pedal

ganglia. These are connected by very stout cerebro-visceral and

cerebro-pedal commissures. A statocyst lies dorsal each pedal gan-

107

glion. From visceral ganglia three main nerves pass to the gill, hind

gut and mantle/siphon, and from the cerebral ganglia nerves pass to

the palps and mantle.

The sexes are separate, specimens greater than 4mm total length

have gonads. The gonad first develops at the periphery of the visceral

mass and as it matures it spreads across the lateral surface of the

viscera. On the right side of the body, apart from a small portion

postero-dorsal to the loop of the hind gut the gonad does not extend

beyond the confines of the of the loop. While different samples show

different degrees of maturity, the specimens of each sample appear

to be maturing synchronously. The ratio of males to females is

approximately 50:50.

Neilonella hampsoni new species

TYPE SPECIMEN.

1995050.

Holotype BMNH 1995049; paratype BMNH

TYPE LOCALITY. Atlantis II cruise 31, station 155, Sierra Leone

Basin, 00'03.0'S 27'48.0'W, 3730-3783m.

MATERIAL:

Cruise Sta. Depth No Lat Long Date Gear

(m)

SIERRA LEONE BASIN

Atlantis 11 155 3730-3 00°03.0'S 27°48.0'W 14.2.67 ES

31 3783

J.Charcot DS035150 1 10°59.0'N 45°15.0'W 16.11.77 DS

Vema

DISTRIBUTION. Anabyssal species, to date only found in the Sierra

Leone Basin at depths from 3730m to 5150m.

SHELL DESCRIPTION (Figs 9 & 10)

Shell robust, oval, wide, ornamented with concentric ridges, straw-

coloured periostracum; umbo prominant, anterior to midline

(postumbonal length c.60% of total length in large specimens),

inward facing; lunule and escutcheon, both well-defined; postero-

dorsal margin in lateral view almost straight, slopes relatively

steeply from umbo to proximal limit of hinge, rounded angle to

posterior margin, anterior and ventral margins form a smooth curve,

distally antero-dorsal margin slightly concave then slopes steeply in

smooth curve to anterior margin; anterior limit of shell coincides

Fig. 9. Neilonella hampsoni. Lateral view of the right valve of the

holotype, from Atlantis II station 155 from the Sierra Leone Basin.

Scale = 1mm.

108

Fig. 10. Neilonella hampsoni. a, lateral view of the hinge plate of the

right valve of a paratype; b, dorsal view of the shell of the holotype.

Both specimens taken from Atlantis II station 155 from the Sierra Leone

Basin. Scales = Imm.

with horizontal midline, posterior limit of shell immediately ventral

to mid line; hinge plate stout extending along most of the dorsal shell

margin, anterior and posterior tooth series meet below umbo, with

faint suggestion of an edentulous space between, 13 posterior and 10

anterior teeth in specimen 3.9mm total length, teeth increase in size

distally, teeth chevron-shaped, obtuse, so much so that teeth appear

to be a straight line transverse to hinge plate; ligament opisthodetic,

external, short, anterior outer layer extremely short, hidden beneath

umbo, no resilium.

Maximum total length of present specimens is 7.5mm.

Apart from N. salicensis, from which it differs in having a shorter,

wider shape, and well-marked lunule and escutcheon, the only other

protobranch species with which it has some similarity is ‘Leda’

sericea vat ovata Jeffreys 1876 (Jeffreys, 1879). One of us (JAA) has

examined specimens of this latter species in the Natural History

Museum, London, (BMNH 85 11 5483-84) and find that L. sericea

is more ovate, with the dorsal margins much less sloping, a more

anteriorly positioned umbo and a much more narrow hinge plate.

INTERNAL MORPHOLOGY

The morphology is similar to Neilonella salicensis. Such differences

that do exist include the adductor muscles, both of which are small,

similar in size, but with the posterior oval and the anterior round in

cross section. The foot is somewhat smaller but with a moderately

large byssal gland with a small, hooked, median papilla posterior to

its aperture. Except for the posterior quarter of their length, the

margins of the divided foot are finely papillate. There are approxi-

mately 20 gill plates and 25 ridges on the palps of a specimen 3.9mm

total length. The hind gut makes a simple loop to the right side of the

body, it has a wide lumen (0.21mm in diameter) with a single well-

defined typhlosole running its entire length. The stomach is large

and the mouth lies some distance posterior to the inner wall of the

anterior adductor. The kidney extends in a narrow band from the

posterior margin of the posterior adductor, anteriorly narrowing over

the viscera, and terminating at the posterior edge of the digestive

diverticula.

J.A. ALLEN AND H.L. SANDERS

It is named after our good friend and colleague George Hampson

who accompanied us on so many of our cruises and without whom

sampling at abyssal depths would not have been the resounding

success that it proved to be.

Neilonella corpulenta (Dall 1881)

TYPE LOCALITY. Blake station off Havana, 823m (station number

not recorded but, only station 51, 23°11.0'N 82°21.0'W, is listed as

having a depth of 450fm (823m) (Smith, 1888)).

TYPE SPECIMEN. Holotype, U.S. National Museum 63169. Cited

specimen: BMNH 1995048.

Leda (Neilonella) corpulenta Dall, 1881, 125; 1886, 254, pl. 7, figs.

la, 1b.

Neilonella (N.) corpulenta Laghi 1986, pl.9, figs 1-3.

MATERIAL:

Cruise Sta Depth No Lat Long Date Gear

(m)

BRAZIL BASIN

Atlantis] 162 1493 1 08°02.2'S 34'03.0'W 19.2.67 ES

The type specimen has been examined by us.

DISTRIBUTION. An upper slope species previously recorded only

from the Gulf of Mexico but here found in the Brazil Basin. It occurs

at depths from 347m to 1493m.

SHELL DESCRIPTION (Fig. 11)

Dall (1881) gave an adequate description which was later (Dall,

1886) augmented by good internal and external lateral views of the

shell. The specimen collected from the Brazil basin differs little

from the type (Dall, 1881, 1886)(Fig. 11):-

Shell elongate, solid, oval, ornamentated with concentric ridges;

umbo not particularly large or elevated, somewhat anterior to the

mid line; postero-dorsal margin almost straight, slightly upturned

posterior to the distal limit of the hinge, then sharply and smoothly

curved to posterior margin, ventral margin shallow smooth curve,

not posteriorly sinuous, anterior margin smoothly curved, antero-

dorsal margin relatively steeply angled, distally slightly raised;

hinge plate elongate, relatively wide, hinge teeth chevron-shaped, 9

in anterior and 12 in posterior series; external ligament slightly

opisthodetic, short; resilium small ventral to umbo.

Dall (1881) states that there are an equal number of teeth in the

anterior and posterior series (15), however the type specimen which

is larger than the present specimen, has 17 anterior and 20 posterior

teeth.

The total length of present specimen is 3.1mm.

INTERNAL MORPHOLOGY

Both adductor muscles are oval in cross section, the anterior is

somewhat larger than the posterior but neither is particulaly large.

The foot is relatively short with large marginal papillae. The palps

are relatively short with 7 broad internal ridges. The gill is also short.

The siphonal embayment is shallow and the siphons similar to those

described for N. salicensis. The hind gut forms a single loop to the

right side of the body and has a typhlosole along its entire length.

Neilonella whoii new species

TYPE SPECIMEN.

1995053.

Holotype BMNH 1995052; paratypes BMNH

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

Fig. 11. Neilonella corpulenta. a, an external lateral view of the right valve of specimen No 63169 from the USNM and an internal lateral view of the

109

central region of the hinge of the same valve; b, lateral view of the intact shell, from Atlantis II station 162 from the Brazil Basin, and an internal view of

the left valve of the same specimen to show detail of the hinge plate. Scales = 1mm.

CITED SPECIMEN. BMNH 1995054.

TYPE LOCALITY. Chain cruise 50, station 78, North America Ba-

sin, 38°00.8'N 69°18.7'W, 3828m.

MATERIAL:

Cruise Sta Depth No

(m)

WEST EUROPEAN BASIN

Chain 106 323 3356-7

3338

326. )3859) .5

328 4426-6

4435

330 4632

J.Charcot DS20 4226

Polygas DS22 4144

DS23 4734

DS28 4413

J.Charcot CV23 2034

Biogas III DS41 3548

CV27 4023

CV30 4518 53

DS47 4230 2

J.Charcot CV34 4406 1

io)

eS = ee DO ND)

Lat

50°08.3'N

50'04.9'N

50°04.7'N

50°43.5'N

4733.0'N

4734.1'N

46°32.8'N

44°23.8'N

4732.7'N

4728.3'N

4734.2'N

46°32.8'N

44°26.8'N

44°27.2'N

Long

13°53.7'W

14°23.8'W

15°44.8'W

Date

21.8.72

22.8.72

23.8.72

17°51.7'W 24.8.72

09°36.7'W

09°38.4'W

10°21.0'W

04°47.5'W

08°34.2'W

09°04.2'W

09°32.4'W

10°20.0'W

04°50.7'W

04°49. 1'W

24.10.72

25.10.72

26.10.72

2.11.72

25.8.73

26.8.73

28.8.73

S873

19.2.74

Gear

Biogas IV

Cryos

Biogas V

J.Charcot

Biogas VI

J.Charcot

Incal

DS53 4425

DS54 4659

DS56 4050

DS60 3742

DS66 3480

DS75 3250

DS76 4228

CP14 4237

DS78 4706

DS79 4715

CP18 4721

DS81 4715

CP19 4434

DS82 4462

OSO1 2634

DS11 4823

CP11 4823

OS02 4829

OS05 4296

OS06 4316

DS16 4268

WS09 4277

CANARY BASIN

Discovery

6711 2988

NSH WWW RR We We KS YL OO f

44°30.4'N

46°31.1'N

47°32.7'N

4726.8'N

4728.2'N

4728.1'N

47°34.8'N

47°32.0'N

46°31.2'N

46°30.4'N

46°30.5'N

46°28.3'N

44°24.9'N

44°25.4'N

50°15.2'N

48°18.6'N

48°21.2'N

48°19.1'N

4732.9'N

4727.9'N

4730.3'N

4727.9'N

27 14.9'N

04°56.3'W

10°29.2'W

09'28.2'W

09°07.2'W

09°00.0'W

09°07.8'W

09°33.3'W

09°35.9'W

10°23.8'W

10°27.1'W

10°26.0'W

10°24.6'W

04°51.3'W

04°52.8'W

13°11.0'W

15°12.0'W

15°13.7'W

15°15.5'W

09°34.7'W

09°36.0'W

09°33.4'W

09°34.0'W

15°36.3'W

19.2.74

21.2.74

23.2.74

24.2.74

17.6.74

22.10.74

23.10.74

25.10.74

26.10.74

27.10.74

28.10.74

29.10.74

30.7.76

1.8.76

2.8.76

7.8.76

9.8.76

10.8.76

19.3.68

CP.

WSs

110

SIERRA LEONE BASIN

Atlantis II 146 2842-2 1039.5'N 1744.5'W 6.2.67 ES

31 2891

147 2934 4 1038.0N 1752.0'W 6.2.67 ES

148 3814 4 1037.0N 1814.0'W 7.2.67 ES

3828

149 3861 1 1030.0'N 1818.0'W 7.2.67 ES

GUINEA BASIN

J. Charcot DS28 1261 2 04°21.2'N 0435.2'E 7.8.71 DS

Walda

ANGOLA BASIN

Atlantis II 195 3797 46 14°49.0'S 09°56.0'E 19.5.68 ES

42 197 4595 25 1029.0'S 0904.0'E 21.5.68 ES

198 4559- 20 1024.0'S 09°09.0'E 21.5.68 ES

4566

199 3764—- 3 09°49.0'S 1033.0E 22.5.68 ES

3779

200 2644 8 09°43.5'S 1057.0E 22.5.68 ES

2754

NORTH AMERICA BASIN

Atlantis II 2 Sis 2 38°05.0'N 6936.0W 22.5.61 AD

264

Atlantis II 64 2886 2 38°46.0'N 7006.0'W 21.8.64 ES

12 YP 2864 9 38°16.0'N 71°47.0'W 24.8.64 ES

Chain 50 76 2862 3 39°38.3'N 6757.8'W 29.6.65 ES

Vl 3806 752 3800.7'N 69°16.0'W 30.6.65 ES

78 3828 199 3800.8'N 6918.7';W 30.6.65 ES

80 4970 1 34°49.8'N 6634.0'W 2.7.65 ES

85 3834 11503759.2'N 69°26.2'W 5.7.65 ES

Atlantis II 124 4862 1 3726.0'N 6359.5'W 22.8.66 ES

24 126 3806 48 3937.0'N 6647.0'W 24.8.66 ES

Atlantis II 175 4667- 1 3636.0'N 6829.0'W 28.11.67 ES

40 4693

Chain 106 334 4400 3 40°'42.6'N 4613.8'W 30.8.72 ES

335 3882-5 40°25.3'N 4630.0'W 31.8.72 ES

3919

Knorr 35 340 3264-95 3814.4'N 7020.3'W 24.11.73 ES

3356

BRAZIL BASIN

Atlantis II 156 3459 6 00°46.0'S 29°28.0'W 14.2.67 ES

GUYANA BASIN

Knorr 25 287), 24980 ISelOlOIN 5452) 2\Wie 242 2) ES

4934

288 4417-19 1102.2'N 5505.5'W 25.2.72 ES

4429

291 3859- 43 1006.1'N 55°14.0'W 26.2.72 ES

3868

301 2487— 23 0812.4'‘N 5550.2'W 29.2.72 ES

2500

303 2842- 8 O8'28.8'N 5604.5'W 1.3.72 ES

2853

307 3862-15 12344'N 58°59.3'W 3.3.72 ES

3835

J.Charcot DSO5 5100 3 1046.0N 4240.3'W 19.11.77 DS

Biovema

ARGENTINE BASIN

AtlantisII 242 4382- 1 38°16.9'S S15 Og Wael S347 E'S

60 4402

243 3815- 3 37 36.8'S 52°23.6W 14.3.71 ES

3822

247 5208- 6 43°33.0'S ASS Sell Wieeel-o- lS

5225

256 3906- 8 37 40.9'S 5210S Wee Sales

3917

AS) BR0S= il SBS 52°45.0W_ 26.3.71 ES

3317

DISTRIBUTION. An abyssal species, found widely within temper-

ate and tropical latitudes at depths ranging from 2487m to 5223m.

J.A. ALLEN AND H.L. SANDERS

SHELL DESCRIPTION (Figs 12 & 13)

Shell robust, ovate, moderately wide, ornamentated with marked

concentric ridges, straw-coloured periostracum; umbos prominant,

inwardly facing, clearly anterior of vertical midline in specimens

>3.0mm, more central in smaller specimens (post-umbonal length

c. 57% of total length); no clearly marked lunule or escutcheon,

but some specimens with faint indications; postero-dorsal margin

slight concave curve, very slightly angulate opposite limit of

hinge plate then steepening to posterior margin, posterior margin

may be somewhat flattened particularly in small specimens, ven-

tral margin moderately curved joining anterior and antero-dorsal

margins in a smooth curve, anterior and posterior limits of shell

dorsal to mid-horizontal line; hinge plate broad, continuous, elon-

gate, short chevron-shaped hinge teeth, up to 14 in posterior

series, 12 in anterior series, numbers varying with size of speci-

men, edentulous space below umbo very small; external ligament

short, opisthodetic, resilium microscopic, close to shell margin,

ventral to umbo. Maximum total length of present specimens is

9.8mm.

Neilonella whoii most closely resembles N. salicensis. It can be

separated from the latter species by its more rounded shape and

greater height. The posterior shell margin is not as acute and the

posterior limit of the shell is more dorsal in position as compared

with N. salicensis. Furthermore, the post-umbonal length of UN.

wholi 1s somewhat longer than in N. salicensis and the hinge plate

is not so broad having a smaller ratio of anterior to posterior

teeth.

We name this species in honour of the Woods Hole

Ocenanographic Institution, through whose auspices these studies

were carried out.

INTERNAL MORPHOLOGY (Figs 14 & 15)

For the most part the morphology of N. whoii is similar to that of

N.salicensis. Of the mantle structures, the construction of the siphon

is similar, although the siphonal embayment is less deep than in N.

salincensis. The posterior adductor muscle is oval in cross-section

and not much smaller than the anterior, probably reflecting the more

rounded shell outline of N. whoii. The anterior sense organ is poorly

developed, the least developed of all the deep-sea nuculanids that

have been described to date. The gills and palps of N. whoii are

similar in size and form to those in WN. salicensis with up to a

maximum of 18 gill plates and 17 palp ridges.

The foot is large with a few moderately deep papillae at the

margin. The mouth lies some distance posterior to the anterior

adductor. The stomach is large with 9 or 10 ridges forming the

porterior sorting area. The hind gut makes a single loop to the right

side of the body, the loop being somewhat larger and more smoothly

curved than that in N. salicensis. The ganglia and commissures are

not so stout as they are in the latter species.

Clearly Neilonella whoii is closely related to N. salicensis.

Although similar in form, they have markedly different depth

distributions, N. salicensis occurring mainly at lower slope

depths and N. whoii occurring mainly at abyssal depths. We believe

that in the past there may have been misidentifications, and speci-

mens of N. salicensis recorded from abyssal depths deserve

re-examination.

Specimens which are narrower and relatively smaller in height to

length ratio than those described above (Fig.16) are present in some

samples and do not occur other than with typical specimens of N.

whoii. In other respects they are no different in their morphology to

N. whoii. We consider them to be varients at the limit of a range of

shell outlines and not a subspecies.

DEEP-SEA PROTOBRANCHIA (BIVALVIA) taal

a un

2%,

| Mi,

Fig. 12. Neilonella whoii. Details of shell form of specimens, from Chain station 78 from the North America Basin, the type locality; a, left lateral, b,

dorsal and c, anterior views intact shells; d, the hinge plate of a specimen, from Incal station DSO5 from the West European Basin; e, detail of the

umbonal region of the hinge plate of a specimen, from Chain station 78. Scales = 1mm.

Fig. 13. Neilonella whoii. Four shells in outline, from Atlantis II station Fig. 14. Neilonella whoii. A semidiagrammatic view of the internal

72 from the North America Basin, in left lateral view to illustrate the morphology as seen from the right side. For the identification of the

small changes in shape with increasing size. Scale = 1mm. parts see text-figure 7, p. 106. Scale = 1mm.

112

Fig. 15. Neilonella whoii. The dissected stomach and style sac as seen

from a, in left lateral and b, frontal view. See abbreviations to text

figures on p. 102. Scale = 1mm.

Fig. 16. Neilonella whoii. a, right lateral view of shell of elongate form,

from Atlantis II station 242 from the Argentine Basin, in right lateral

view and b, detail of the umbonal region of the same shell in dorsal

view. Scales = 1 mm.

J.A. ALLEN AND H.L. SANDERS

Family Nuculanidae Adams and Adams 1858

A recent definition of the family is given by Allen, Sanders and

Hannah (1995).

Subfamily Ledellinae Allen and Sanders 1982

The subfamily is defined by Allen and Hannah (1989) and comprises

two genera, Ledella and Tindariopsis.

Genus LEDELLA Verrill and Bush 1897

TYPE SPECIES. Ledella bushae Warén 1978. SD — Warén 1981.

Shell small, short, robust, surface matt, concentric sculpture, in

some species scattered incomplete radial striae, usually rostrate,

single postero-dorsal ridge in some species, postero-ventral margin

very slightly sinuous, ventral margin in older specimens maybe

flattened, anterior and posterior hinge teeth series separated by

edentulous space bearing short internal amphidetic ligament

(resilium) which may be restricted to dorsal portion of hinge plate,

outer layer of ligament visible externally and maybe extended

anteriorly and posteriorly for a short distance, hind gut with various

configurations.

Genus TINDARIOPSIS Verrill and Bush 1897

TYPE SPECIES. Malletia (Tindaria) agatheda Dall 1889. OD.

Shell veneriform, matt surface, concentric sculpture, umbo large,

short rostrum defined by slight radial ridge and furrow, postero-

ventral margin slightly sinuous, anterior and posterior hinge teeth

separated by very small edentulous space, internal ligament small,

close to shell margin, external ligament robust, amphidetic.

Ledella acinula (Dall 1890)

TYPE SPECIMEN. Holotype USNM 95438.

TYPE LOCALITY. U.S. Fish Commission Steamer ‘Albatross’ Sta.

2754, 11.40'N 58°33'W, East of Tobago, 1609m.

CITED SPECIMENS. BMNH 1995047

Malletia (Tindaria) acinula Dall, 1890, 253, pl. XIII, fig.4.

Tindaria acinula Verrill and Bush 1898, 881.

‘Tindaria’ acinula Sanders and Allen 1977, 55, figs 44, 45.

MATERIAL:

Cruise Sta Depth No Lat Long Date Gear

(m)

BRAZIL BASIN

AtlantisII 167 943- 1 07°58.0'S 3428.0'W 20.2.67 ES

31 1007

GUYANA BASIN

Knorr 25 293 + 1456— 2 08°58.0'N 5404.3'W 27.2.72 ES

1518

295 1000— 4 O801.9'N 54°16.4';W 28.2.72 ES

1022

299 1942— 108 O755.1'N 5542.0'W 29.2.72 ES

2076

WEST EUROPEAN BASIN

50°43.5'N 17°51.7W 24.8.72 ES

4630.4'N 10°27.1'W_ 26.10.74 DS

Chain 106 330 4632 3

J.Charcot DS79 3226 15

Biogas VI

GUINEA BASIN

J. Charcot DS28 1261 4 04°21.2'N 0435.E --71 DS

Walda

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

The type specimen has been examined by us.

DISTRIBUTION. Found predominantly in tropical and subtropical

latitudes, and southern temperate latitudes in the eastern Atlantic, at

mid-slope to abyssal depths ranging from 943m to 4632m.

Many protobranch species with robust shells having subrostrate

or ovate outlines and with concentric ridges and external liga-

ments, in the past have been referred to the genera Malletia,

Neilonella orTindaria (e.g. Dall, 1890). Ledella acinula is a case

in point. Having addressed this problem in earlier papers (Sand-

ers and Allen, 1977, 1985), and the present, we have been able to

define more rigorously the families Tindariidae, Neilonellidae

and Malletiidae.

Dall (1890) who described large specimens of L. acinula referred

them to the subgenus Tindaria. Large specimens do show some

resemblance to neilonellids and tindariids, but had Dall seen the

shells of smaller specimens (Fig. 18), he would have been unlikely to

have made the error.

In our studies on Tindaria (Sanders and Allen, 1977) we re-

examined and briefly redescribed L. acinula, and recognized that

there was a problem in identification but deferred final judgment

until we had made further comparative studies. Now that the

Ledellinae have been reported upon (Allen and Hannah, 1989), the

taxonomic relationship of this species is clear.

That L. acinula is siphonate clearly distinguishes it from members

of the family Tindariidae. Although similar to the neilonellids in

having an external amphidetic ligament, it differs in having a small

but well-defined internal ligament and in being semi-rostrate with a

slightly sinuous postero-ventral margin. A further significant differ-

ence is the form of the hind gut and the course that it takes within the

body (Sanders and Allen, 1977). In L. acinula the hind gut is not

particularly wide in diameter and is not restricted to the right side of

the body (see below) having a configuration only known to occur in

species of the subfamily Ledellinae e.g.Ledella galatheae Knudsen

113

1970, L. oxira (Dall 1927), L. acuminata (Jeffreys 1870)(Allen and

Hannah, 1989).

SHELL DESCRIPTION (Figs 17 & 18)

Shell robust, posteriorly angulate, ornamented with concentric ridges

particularly well-defined on ventral part of shell, straw-coloured

periostracum; umbos relatively low in profile, inward facing, anterior

to midline; posterior rostral region characteristically broad and blunt

when seen in dorsal view; postero-dorsal shell margin almost straight,

angulate at posterior limit of hinge plate - particularly so in smaller

specimens, barely so in larger, posterior margin sharply rounded,

ventral margin deeply curved, postero-ventral margin slightly sinu-

ous, particularly in smaller specimens, antero-dorsal, anterior and

antero-ventral margins form a smooth curve; posterior and anterior

limits of shell at or slightly ventral to mid horizontal axis, ventral limit

of shell posterior to vertical axis through umbo; hinge plate elongate,

broad, anterior and posterior tooth series separated by relatively long

edentulous space, chevron-shaped teeth acutely angled, up to 10

anterior and 12 posterior teeth depending on size of specimen;

ligament amphidetic, external parts short, internal resilium small,

rounded, occupying upper central part of hinge plate below umbo.The

maximum total length of the present specimens is 6.0mm.

The shape of the shell changes significantly with growth (Figs 18

& 19). While the ratio of height to length remains more or less the

same, the postero-umbonal length increases from 50% to 60% of the

total length of the shell. With increasing size the postero-dorsal

margin also becomes less angulate at the posterior limit of the hinge,

also the postero-ventral margin becomes less sinuous, at most being

somewhat flattened.

INTERNAL MORPHOLOGY

This has been described and illustrated by us in our earlier studies on

the family Tindariidae (Sanders and Allen, 1977). Only essential

features relating to the taxonomy need be mentioned.

Combined siphons are present and there is a well-developed

Fig. 17. Ledella acinula. a & b, internal and external views of a left valve, from the type locality Albatross station 2754, USNM 95438; c, internal view

of left valve of specimen, from Atlantis II station 167 from the Brazil Basin; d & e, lateral view of left side and dorsal view of a shell, from Knorr station

299 from the Guyana Basin. Scale = 1mm.

114

J.A. ALLEN AND H.L. SANDERS

Fig. 18. Ledella acinula. Four shells in outline, from Knorr station 299 from the Guyana Basin, in right lateral view to illustrate changes in shape with

increasing size. Scale = 1mm.

feeding aperture ventral to the siphonal embayment. The adductor

muscles are relatively large, the anterior ovate and the posterior

more circular in cross section. The anterior sense organ lies far

anterior, ventral to the anterior adductor. The palps and gills are

moderate in size with relatively few ridges (up to 15) and plates (up

to 17) respectively. The foot has a well-defined neck, this is probably

related to the relatively large height of the shell. There is a large

‘byssal’ gland present in the heel of the foot. The hind gut first makes

a single loop on the right side of the body before passing to the left

side of the body between the oesophagus and the inner face of the

anterior adductor muscle. On the left side of the body the hind gut

forms a double coil. Because of the anterior penetration of the gut to

the left side, the mouth is displaced some distance posterior to the

anterior adductor muscle.

80 ie 2 @

H ee eg

h © aa ro) F

60 : — = e

oe, ~ ©

PL, one?

L ae e

50 e

1 2 3 4 5

Length (mm)

Fig. 19. Ledella acinula. The ratios of height to total length (H/L)(open

circles) and post-umbonal length to total length (PL/L)(closed circles)

plotted against total length to show changes in shell proportions with

increasing length. Specimens from Knorr station 299 from the Guyana

Basin.

Ledella aberrata (new species)

TYPE SPECIMEN.

1995046.

Holotype BMNH 1995045; paratypes BMNH

TYPE LOCALITY. Chain cruise 60, station 247, Argentine Basin,

43°33.0'S 48°58.1'W, 5208-5223m

MATERIAL:

Cruise Sta. Depth No Lat Long Date Gear

(m)

ARGENTINE BASIN

Atlantis] 242 4382-2 3816.9'S 51°56.1;W 13.3.71 ES

60 4402

247 5208- 34 43°33.0'S 48°58.1'W_17.3.71 ES

5223

252 4435 4 38729.8'S 5209.1'W 223.71 ES

GUYANA BASIN

J.Charcot KG135100 1 1047.6N 42°40.4';W 20.11.77 KG

Biovema

NORTH AMERICA BASIN

Chain 50 85 =. 338341 3759.2'N 69°26.2'W 5.7.65 ES

WEST EUROPEAN BASIN

Chain 106 330 4632 3 5043.4'N 17°51.7W 24.8.72 ES

J.Charcot DS23 4734 5 4632.8N 1021.0';W 1.11.72 DS

Polygas

Biogas II DS32 2138 1 4732.2'N 0805.3'W 17.4.73 DS

BiogasITV DS54 4659 7 4631.1'N 1029.2;W 21.2.74 DS

Cryos DS68 4550 2 4626.7'N 1023.9'W 19.6.74 DS

Biogas V

J.Charcot DS78 4706 18 4631.2'N 1023.8'W 25.10.74 DS

Biogas VI DS79 4715 17 4630.4'N 1027.1'W 26.10.74 DS

DS80 4720 3 4629.5'N 1029.5'W 27.10.74 DS

DS81 4715 2 4628.3'N 1024.6'W 27.10.74 DS

INCAL CP10 4823 1 4825.5 N 1510:7W 3157-716 YEP

DS11 4823 2 4818.8'N 15°11.5'W 1.8.76 DS

WS034829 18 4819.2'N 1523.3'W_ 1.8.76 WS

CP11 4823 1 48°20.4.N = 15'14.6'W_ 1.8.76 CP

OS02 4829 1 48°19.2.N 15°15.9'W_ 2.8.76 OS

WS104354 1 4727.3'N 09°39.9'W 11.8.76 WS

CAPE BASIN

J.Charcot DS05 4560 2 3320.5'S 0234.9'E 30.12.78 DS

Walvis

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

115

Fig. 20. Ledella aberrata. a, dorsal view of shell; b, dorsal, ventral and anterior view of thickened shell; ¢, lateral view of the hinge plate of a left valve, all

from Atlantis II station 247 from the Argentine Basin; d, lateral view of the hinge plate of a right valve, from Chain station 85. Scales = 1mm.

DISTRIBUTION. In temperate and tropical basins of the Atlantic at

abyssal depths >4000m, rare in the North America Basin. Depth

range, 2138-5223m.

SHELL DESCRIPTION (Figs 20 & 21)

Shell small, ovate, relatively high, moderately wide, ornamented

with concentric ridges; umbo moderate in size, inwardly turned,

anterior to mid-line but less so in juveniles; no lunule or escutcheon;

periostracum pale straw colour; postero-dorsal margin slightly con-

vex becoming more straight with increasing size, slightly angulate at

posterior limit of hinge plate and at posterior margin, postero-ventral

margin very slightly sinuous, otherwise ventral margin deeply curved

with ventral limit posterior to vertical axis through umbo, anterior

margin sharply curved, antero-dorsal margin slightly convex with

slight change in slope at anterior limit to hinge plate; shell outline

characteristically asymmetrical, shell margin in larger specimens

changes direction of growth producing a broad flattened ventral

margin; hinge plate broad, up to 6 chevron teeth in anterior series and

7 in posterior series, edentulous space between series relatively

broad; ligament small, amphidetic, internal part restricted to upper

part of hinge plate, external part extremely short situated below

umbo. The maximum length of the present specimens is 2.6mm.

INTERNAL MORPHOLOGY (Figs 22 & 23)

The adductor muscles are moderately large and oval in shape. The

combined siphon is relatively short The dorsal margins of the

exhalent part are fused proximally for a short distance and the

ventral margins of the inhalent part are not fused but are slightly

thickened and probably adhere in living specimens. Internally where

inhalent and exhalent parts join, there is a thickened median ridge on

each side which together together with the posterior continuation of

the gill axes probably act as guides when the faecal pellets are

extruded. The siphonal embayment is small and there is a small,

slender, tentacle attached to the left side at the inner limit of the

embayment. The anterior sense organ is small and is situated ventral

to the anterior adductor muscle.

The palps are small with up to 11 broad ridges. The gills are

also small each with up to 11 plates the most posterior of which

lies some distance from the siphon. The gills are attached to the

posterior limits of the median guides by slender extensions of the

gill axis.

The hind gut is greatly extended and takes a similar but more

complex course to that described for L. acinula. Like the latter, the

hind gut passes from the right side of the body to the left immedi-

ately posterior to the anterior adductor muscle and returns by the

116

Fig. 21. Ledella aberrata. Five shells in outline to show variation in

shape with growth. a, is a specimen with a thickened margin; b, has a

slightly thickened margin; the remaining three shells are unthickened.

Scale = Imm.

same route. Unlike the latter species, it makes a single coil on the

right side as well as a double twinned coil on the left.

The foot is unusual in having a large heel and a narrow muscular

anterior part. The marginal papillae are few in number and restricted

to the anterior margins of the sole. The sole is less deeply divided as

compared with other protobranchs. There is a large “byssal’ gland in

the heel of the foot.

Although the shell outline of the smaller specimens is more

characteristic of the genus Ledella than in larger mature specimens,

the general shell outline of L aberrata (and L. acinula) is much

deeper and more ovate than in other described species (Figs 18 & 21)

nor is it markedly rostrate. Despite this, the characters place them in

the Ledellinae (Allen and Hannah, 1989) and we see no reason for

erecting another genus.

Apart from L. aberrata, only two species of protobranchs, have

been reported as exhibiting a change in shell growth to produce a

flattened shell margin (Fig. 20). Both are ledellids, namely L. ultima

(Smith 1885) and L. solidula (Smith 1885) (Allen and Hannah,

1989). Like L. aberrata these two latter species also have elongate

hind guts. The hind gut of L. solidula is very similar to that of L.

aberrata in having double twinned coils to the left side of the body

(Fig.22), although it does not have an additional single coil to the

right as does the present species. The type of course taken by the

hind gut in L. acinula is also found in other species of Ledella (e.g.

L. oxira) (Allen and Hannah, 1989).

We named this species after the familiar appelation to which it

was referred during our original analysis of the samples.

Tindariopsis agatheda (Dall 1889)

TYPE SPECIMEN. USNM 95437, lectotype here designated.

TYPELOCALITY. U.S.Fish Commission Sta. 2754, east of Tobago,

11°40'N 58°33W, 1609m.

J.A. ALLEN AND H.L. SANDERS

Fig. 22. Ledella aberrata. Internal morphology as seen in a, right lateral

view, b, left lateral view and ec, left ventro-lateral view. For identification

of the parts see text-figure 7, p. 106. Scales = Imm.

CITED SPECIMEN. BMNH 1995062.

Malletia (Tindaria) agatheda Dall 1890, 252, pl. xiii, fig. 10.

Tindaria (Tindariopsis) agatheda Verrill and Bush 1897, 59.

Saturnia (Tindariopsis) agatheda McAlester 1969, N235.

Tindariopsis agatheda James 1972, 98, figs 60-62.

Neilonella (Tindariopsis) agatheda Laghi 1986, 190, pl.8, figs 2-6.

MATERIAL:

Cruise Sta Depth No _ Lat Long Date Gear

(m)

BRAZIL BASIN

Atlantis 11 167 943- 1 0758.0'S 34°28.0'W 20.2.67 ES

31 1007

GUYANA BASIN

Knorr 25 293 1456- 14 08°53.1'N 5404.3'W 27.2.72 ES

1518

299 1942-8 07°55.1'N 55°42.0'W 29.2.72 ES

2067

301 2487-7 0812.4'N 55°50.2'W 1.3.72 ES

2500

The type specimen has been examined by us.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

oOo

Fig. 23. Ledella aberrata. Siphonal region, as seen from the inside of the

mantle cavity. See abbreviations to the text-figures p. 102. Scale = 0.1mm.

This species occurs at upper to mid slope depths in the tropical

western Atlantic in the Brazil, Guyana, Caribbean and Gulf of

Mexico Basins (Dall, 1889; James 1972). Depth range; 943—2500m.

The holotype for 7: agatheda was not designated by Dall (1890),

nevertheless he did illustrate the left valve from Albatross Sta. 2754,

11°40'N 58°33'W (USNM 95437) which we have here nominated as

117

lectotype. We have redrawn the shell and added detail of the hinge

plate (Figs 24 and 25). In addition, James (1972) reported that two

valves of T: agatheda were included in USNM 63149 from Blake sta.

236, 2909m off Bequia, furthermore USNM 94326 from Blake stas

26 and 30 between Cuba and Yucatan, identified by Dall as Leda

pusio, are examples of T: agatheda.

SHELL DESCRIPTION (Figs 24 & 25)

Shell small, sub-ovate, wide, sub-rostrate, ornamented with con-

centric ridges, postero-lateral furrow ventral to sub-rostrum,

ill-defined lunule outlined by obscure ridge, escutcheon similarly

ill-defined and bounded by faint ridge; umbo prominant, poste-

rior to mid-line, inwardly directed; antero-dorsal margin concave,

with change in slope at anterior limit of hinge plate, slightly

flattened anteriorly dorsal to the anterior limit of shell, antero-

ventral and ventral margins smoothly curved, postero-ventral

margin slightly sinuate, posterior margin acutely angled, postero-

dorsal margin slightly concave, marked angle at posterior limit of

hinge plate and thereafter almost straight to form sub-rostrate

posterior margin; anterior and posterior limits of shell are ventral

to horizontal mid-line; hinge plate strong, with edentulous space

ventral to umbo, hinge teeth stout, chevron-shaped, up to 12 in

each series in shell 6mm total length; internal ligament small,

close to shell margin, external ligament amphidetic, moderately

short, stout.

Young shells are less rostrate, with the posterior and anterior

limits of the shell more dorsal in position.

Although there is variation in the shape of the shell, the height/

length and the post-umbonal length/total length ratios increase

slightly with increasing size (Table 1). The maximum total length of

the present specimens is 6.0mm.

Fig. 24. Tindariopsis agatheda. External lateral view of the right valve of the lectotype and an internal view of the hinge plate of the same valve, from

U.S.Fish Commission station 2754 East of Tobago, USNM 95437. Scales = 1mm.

118

J.A. ALLEN AND H.L. SANDERS

Fig. 25. Tindariopsis agatheda. External lateral views of right side of two specimens of differing size to show change in shape with growth. a, from Knorr

station 301 and b, from Knorr station 293, both from the Guyana Basin; c, external dorsal view of a shell also from station 293. Scale = 1mm.

Table 1. Measurements and ratios of shell parameters of the sample from

Knorr sta. 293.

Length(L) Height (H) Post-umbonal (PL) PL/L W/L

(mm) (mm) length (mm)

6.00 4.95 3.00 0.50 0.83

5.60 3.95 2.65 0.47 0.71

5.00 3.65 2.20 0.44 = 0.73

4.90 3.65 2.05 042" 075

4.70 ByII5) 1.95 0.42 0.67

4.50 3.10 1.85 0.41 0.69

4.45 3.20 1.85 042) 1072

3.70 2.55 1.70 0.46 0.69

3.45 2.50 1.45 0.42 0.73

2.35 1.58 0.93 OSS OlGy

2.05 1.43 0.93 0.45 0.70

1.95 1.30 0.88 0.45 0.67

1.83 1.28 0.83 0.45 0.70

1.10 0.88 0.48 0.43 0.80

INTERNAL MORPHOLOGY (Fig.26)

The siphonal embayment is shallow and dorso-ventrally narrow. In

contrast, the feeding aperture is broad and well-supplied with radial

pallial muscles. The adductor muscles are small, the posterior

muscle is oval and the anterior muscle is circular in cross section.

The foot is large with a well-developed heel containing a large

‘byssal’ gland. The gland opens into the posterior limit of the pedal

groove via a small papilla. The anterior two-thirds of the margins of

the divided sole are broadly papillate. The palps are large with up to

25 ridges in the largest specimens. The gills are narrow ill-defined

with about 16 plates in the largest specimens.

The mouth lies close to the posterior face of the anterior adduc-

tor muscle. The oesophagus opens into a large stomach and style

sac. The hind gut passes posterior to the style sac and stomach to

the dorsal side of the viscera and thence across the right side of

the body where it forms 8 coils before returning along the same

path to the dorsal side of the viscera and from there through the

heart and then dorsal to the posterior adductor muscle to the anus.

Usually not more than six coils are visible, the others being

overlain by those to the outside of them. The form of the hind gut

is derived by 4 complete turns of the closely parallel anterior and

posterior lengths of the hind gut on the right of the body. This

particular disposition of the hind-gut is to be found in other

ledellids (e.g. L. ultima) and yoldiellids (e.g. ¥. ella Allen, Sanders

and Hannah 1995) (Allen and Hannah, 1989; Allen, 1992: Allen,

Sanders and Hannah, 1995).

The nervous system is similar in its arrangement to that of other

deep-sea protobranchs, however the cerebral and visceral ganglia

are noticably smaller and the commissures much finer than observed

in other species.

Fig. 26. Tindariopsis agatheda. Internal morphology as seen from the

right side of a specimen from Knorr station 293. For identification of the

parts see text-figure 7, p. 106. Scale = 1mm.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

Tindariopsis aeolata (Dall 1890)

TYPE SPECIMEN. Holotype, USNM 95436.

TYPELOCALITY. U.S. Fish Commission Sta. 2754, East of Tobago,

11°40'N 58°33'W, 1609m.

CITED SPECIMEN. BMNH 1995061.

Malletia (Tindaria?) aeolata Dall 1890, 252.

Tindaria (Tindariopsis) aeolata Dall 1898, 582.

Tindariopsis aeolata James 1972, 97, figs 57-59.

MATERIAL:

Cruise Sta. Depth No _ Lat Long Date Gear

(m)

GUYANA BASIN

Knorr 25 299 1942-4 O755.I'N 55°42.0'W 29.2.72 ES

2076

301 2487-5 08°12.4'N 55°50.2'W_-.29.2.72 ES

2500

The type specimen has been examined by us.

This species occurs from mid to lower slope depths in the tropical

western Atlantic in the Guyana and Caribbean Basins and the Gulf of

Mexico. Depth range: 1609-3466m.

SHELL DESCRIPTION (Figs 27 & 28)

Shell small, subquadrate, rostrate, ornamented with marked concen-

tric ridges; periostracum pale yellow; umbos moderately large,

posterior to midline (post-umbonal length 45-48% of total length),

facing inwards, slightly separated by external ligament; distally

antero-dorsal shell margin horizontal, then curves smoothly and

steeply to anterior margin, postero-ventral margin sinuous, ventral

margin somewhat flattened, postero-dorsal distal margin slopes

gently to limit of hinge plate then curves sharply to rostral point,

latter rounded and somewhat eroded in large specimens, more

pointed in smaller, rostrum in mid horizontal plane in small speci-

mens and dorsal to it in large specimens, limit of anterior margin

Fig. 27. Tindariopsis aeolata. External lateral view of the right valve and

the hinge plate of the left valve of the holotype, from U.S. Fish

Commission station 2754, USNM 95436. Scale = 1mm.

119

Fig. 28. Tindariopsis aeolata. External lateral views of the right side of

shells of differing size to change in shape with growth. a, from Knorr

station 301 and b, from Knorr station 299 from the Guyana Basin; c,

external dorsal view of a shell also from Knorr station 299. Scales

= |mm.

ventral to the mid horizontal plane; hinge plate stout, small edentu-

lous space between tooth series, 9 chevron-shaped teeth in anterior

series and 10 in posterior series in largest specimens; ligament

amphidetic, external except for small resilifer at margin ventral to

umbo, external part thickened, particularly so in large specimens.

The maximum length of the present specimens is 5.8mm.

In lateral view the rostrum, although dorsal to mid horizontal line,

is reminiscent of Ledella, while the robust external ligament is more

reminiscent of Spinula.

INTERNAL MORPHOLOGY (Fig.29)

The siphonal embayment is relatively shallow and the contained

siphon is similar to that of 7: acinula. The adductor muscles are

moderately small, ovate in cross-section and equal in size. The foot

is large, with a divided sole fringed with large papillae. The “byssal’

gland is moderate in size. The palps are very large with many ridges

(c 26 in the largest specimen) and the palp proboscides are broad.

The gills are small with 11 gill plates in the largest specimen. The

kidney is long and narrow. The nervous system is of typical

protobranch design. The ganglia are relatively large and, in contrast,

the commissures are unusually slender.

The mouth lies some distance posterior to the anterior adductor

muscle (see below). The oesophagus opens on to the anterior face of

a moderately large stomach. The latter lies almost vertical within the

posterior part of the visceral mass. The hind gut is very small in

diameter and takes an extraordinarily complex course through the

body. There are two loops to the left side of the body (Fig.29B) and

one major loop to the right side of the body, all three pass from one

side to the other ventral to the umbo. There is also a complex series

of loops anterior and to the right of the stomach. This morphology

has not been encountered before in the protobranch bivalves and is

very different from that seen in 7: agatheda. Yet, it is debateable

120

Fig. 29. Tindariopsis aeolata. a, internal morphology as seen from the

right side of a specimen from Knorr station 301 from the Guyana Basin;

b, the form of the hind gut on the left side of the body. For identification

of the parts see text-figure 8, p.. Scale = 1mm.

whether the difference warrents generic status. Other protobranch

genera show an array of hind gut morphologies (e.g. Yoldiellidae,

Allen, 1992; Allen, Sanders and Hannah, 1995) which we believe

relate to changes in the benthic food resource as depth increases. For

this reason we are reluctant to erect a new genus when in other

respects 7: aeolata is clearly within the genus Tindariopsis.

Subfamily Nuculaninae Allen and Sanders 1982

The subfamily is defined by Allen and Hannah (1986) and comprises

three genera Nuculana, Propeleda and Adrana.

Genus NUCULANA Link 1807

TYPE SPECIES.

IWS, OIDY

Shell robust, moderately elongate, concentric sculpture, occa-

sionally with radial ribs, slightly rostrate, usually bicarinate; umbo

anterior; postero-dorsal margin straight or somewhat concave, pos-

terior margin may be slightly sinuous; escutcheon present; no

internal ridge from umbo to posterior margin; hinge moderately

robust, teeth chevron-shaped; ligament small, for most part internal,

usually amphidetic and vertical, sometimes posteriorly oblique.

Arca rostrata Gmelin 1791 = Arca pernula Miller

Genus PROPELEDA Iredale 1924

TYPE SPECIES. Leda ensicula Angas 1877. OD.

Shell very elongate, thin, glossy, concentric sculpture may be ill-

defined, 3/4 shell post-umbonal, usually with two marked carinae

from umbo to upper and lower limit of rostrum, posteriorly truncate;

umbo small; postero-dorsal margin concave, postero-ventral margin

not sinuous; internal ridge usually from umbo, skirts ventral margin

of posterior adductor to posterior margin, second ridge may be

present from hinge plate to rostral margin; hinge plate slender, hinge

J.A. ALLEN AND H.L. SANDERS

teeth chevron-shaped, one or both arms of the chevron may be

elongate, anterior tooth series curve round the outer margin of the

anterior adductor, posterior series extends posterior to adductor;

ligament in large part internal, opisthodetic and oblique.

Genus ADRANA Adams & Adams 1858

TYPE SPECIES. Nucula lanceolata Lamarck 1819. SD Stoliczka

1871.

Shell extremely elongate, slender, lanceolate, fragile, smooth or

with fine concentric and sometimes oblique sculpture, without

carinae, glossy; umbo almost central, barely raised; escutcheon

elongate, flattened, narrow; postero-dorsal margin straight, antero-

dorsal margin slightly convex, postero-ventral margin sinuous; hinge

plate slender, hinge teeth fine, obtuse, chevron-shaped; chondrophore

present; ligament internal, amphidetic.

Nuculana acuta (Conrad 1831)

TYPE SPECIMEN. Lectotype here designated, chosen from ANSP

30613, remainder of lot designated paralectotypes.

CITED SPECIMEN. BMNH 1995055.

TYPE LOCALITY. Tertiary fossil beds, near Suffolk, Virginia.

Nucula acuta Conrad 1831, 32, pl.6, fig.1.

Nucula cuneata Sowerby 1833, 198.

Nucula carinata H.C.Lea 1843, 163, (non M’Coy 1844).

?Leda jamaicensis ad’ Orbigny 1846, 263, pl.XXIV, figs 30-32.

?Leda inornata A.Adams 1856, 48.

Leda unca Verrill 1880, 401, (?non Gould 1862).

Leda acuta Dall 1886, 251, pl.7, figs 3a, 3b and 8.

Nuculana acuta Morris 1951, 7, pl.6, fig.2.

MATERIAL:

Cruise Sta’ Depth No Lat Long Date Gear

(m)

NORTH AMERICA BASIN

Atlantis Cl 97 24+2v 40°20.5'N 70°47.0'W 25.5.61 AD

264

Atlantis Slope 200 8+6v 4001.8'N 7042.0';W 28.8.62 AD

283 sta.2

AtlantisII 114 197 8 40°04.1'N 7027.8'W 15.8.66 ES

AtlantisII 172 119 7+2v 40°12.3'N 7044.7';W 27.11.67ES

40 Visi e23 4 40°10.8'N 70°43.6'W 28.11.67 ES

The type specimens have been examined by JAA.

Conrad (1831) described this species from fossils obtained from

the Miocene beds near Suffolk and the banks of the James and York

rivers, Virginia. He later redescribed the species (Conrad, 1845)

adding that he had found Recent specimens in deep water in the Gulf

of Mexico. His first account refers to specimens being in “Cabinet of

the Acad. Nat. Sciences, No.1738. This reference does not corre-

spond with any lot of NV. acuta, Recent or fossil, in the Academy of

Natural Sciences, Philadelphia today. There are specimens in the

Invertebrate Paleontology collection of the Academy (catalogue

number 30613) that up to now have been considered as possible

syntypes of the species. The lot comprises 4 right valves, 3 left

valves | left and | right broken valve, | intact shell, 1 shell with

rostrum tip missing and 3 fragments. These specimens, labelled by

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

121

Fig. 30. Nuculana acuta. a & b, lateral and dorsal external views of the lectotype, ANSP 30613; c, lateral internal view of a paralectotype from the same

lot. Scales = 1mm.

Conrad, may include those figured by him. Comparison with the

figures (Conrad, 1831 and 1845) shows that it is impossible to say

which, if any one, was figured nor is it possible to be absolutely

certain that these are the specimens from which the original descrip-

tion was made, although we believe that they are. Thus, the intact

shell from lot 30613 has been chosen as the lectotype, the remainder

being paralectotypes.

Campbell (1993) listed Leda jamaicensis d’Orbigny 1846, Leda

from Atlantis 283 station 2 from the North America Basin. Scales =

Imm.

inornata A.Adams 1856 and L.unca Gould 1862 as synonyms of N.

acuta. Verrill (1882) describes in detail differences that he found

between N. acuta and L.jamaicensis and L.unca which cast doubt as

to the synonymy, although Dall (1886) maintains the synonymy of

L. jamaicensis. Similarly, we have doubts as to synonymy with

L.inornata A.Adams which is a ‘gibbose’, “fuscous’, ‘sulcate’ spe-

cies from New Guinea, Thus, although Nuculana acuta is a

well-described species (e.g. Verrill 1882, 1884; Dall, 1886; Abbott,

1974) because there are closely related species in the Atlantic and

elsewhere, we include a description here. It occurs off the East coast

of North America, in the Caribbean Sea and off Brazil at depths from

the outer shelf to lower slope depths, 97—2909m (James, 1972).

SHELL DESCRIPTION (Figs 30, 31)

Shell moderately large, elongate, somewhat inflated, rostrate,

ornamented with deep concentric ridges flattened at the apex, rostral

ridge from umbo to ventral limit of rostrum, very faint radial ridge

from umbo to antero-ventral margin, yellow periostracum; lunule

Fig. 32. Nuculana acuta. Internal morphology as seen from the right side

of a specimen from Atlantis II station 197 from the North America Basin.

For identification of the parts see text-figure 7, p. 106. Scale = 1mm.

122

(Zp)

Miinacs

iN Ms

J.A. ALLEN AND H.L. SANDERS

Moga

Fig. 33. Nuculana acuta. Internal morphology, a, anterior, b, left lateral & c, posterior views of a dissected stomach and combined style sac; d, ventral

view of siphonal region. See abbreviations to text-figures on p. 102. Scales = 1mm.

broad, elongate, outlined with faint ridge, escutcheon broad, out-

lined by rostral ridge; umbos small, inwardly directed, anterior to

mid-line; antero-dorsal margin broadly concave, anterior, antero-

ventral, ventral and postero-ventral margins form smooth curve,

postero-dorsal margin raised, distally straight, proximally — poste-

rior to hinge plate — slightly concave, may be slightly upturned in

larger specimens; hinge plate elongate, relatively broad, hinge teeth

chevron-shaped, up to 18 teeth in each series depending on size of

specimen; ligament small, amphidetic, internal pear-shaped in sag-

ittal section, extends slightly ventral to hinge plate. The maximum

length of the present specimens is 9.2mm.

INTERNAL MORPHOLOGY (Figs 32, 33)

The siphonal embayment is deep, with an elongate tentacle attached

to the inner right or left side. The siphons are elongate, combined

and except anteriorly, the ventral margins are fused. In the con-

tracted state the line of fusion is marked by deep ventral furrow. The

anterior sense organ is far anterior, situated at the point where the

radial ridge meets with the shell margin. Between the feeding

(ventral to the siphonal embayment) and the pedal gape, the inner

folds of the ventral margin are applied to each other. In this section

of mantle margin approximately 30 small sensory papillae are

attached to each middle sensory fold in a specimen 6.5mm total

length. The adductor muscles are small the anterior unusually so.

The anterior adductor is circular in cross-section and the posterior

elongate-oval.

The foot is moderately large, elongate, the sole with papillate

margins. The heel is not marked but there is a a large “byssal’ gland

present internal to the posterior limit of the sole. The gills are well-

developed with up to 48 alternating gill plates. The dorsal margins of

the left and right inner demibranchs are fused. In life the gills are a

bright orange-red colour. In contrast the palps are cream. The latter

are relatively small, elongate and dorso-ventrally narrow and, for the

most part, hidden under a fold of the body wall. This latter is more

pronounced on the right side of the body where the hind gut loop

meets the ventral margin of the visceral wall. Each palp has up to 24

ridges on the inner face. The palp proboscides are also long and

tapering.

The digestive gland is bright orange in life. As in other species of

Nuculana, the course of the hind gut describes a single loop to the

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

right side of the viscera. There is a single typhlosole present along its

entire length. The stomach is of moderate size and internally is

similar in form to that of shallow water species of Nuculana (Yonge,

1939). The gastric shield lines much of the left wall of the stomach.

To the right there is a large posterior sorting area with 13 ciliated

ridges. A deep caecum is ventral to the oesophageal aperture. Two

digestive ducts open close to the antero-dorsal margin of the poste-

rior sorting area and a single duct opens antero-dorsally close to the

oesophageal opening.

As will be seen Nuculana acuta is remarkably similar in its shell

features and anatomy to Nuculana commutata. This similarity is

discussed under the latter species (p. 123).

Nuculana commutata (Philippi 1844)

TYPE SPECIMEN. ZMHU.

TYPE LOCALITY. Pliocene, Palermo, Sicily.

BMNH 1995212

Arca fragilis Chemnitz 1784, 199, pl.LV, fig.546.

Arca pella Gmelin 1790 (non Linné), 3307.

Arca minuta Brocchi 1814 (non Fabricius), 482, pl. XL fig.4.

Nucula pella Payraudeau 1826 (non Linné), 64.

Lembulus deltoideus Risso 1826 (non Lamarck), 320, pl. XI, fig.

164.

Nucula minuta Scacchi 1836 (non Fabricius), 4.

Nucula striata Philippi 1836 (non Lamarck), 64.

Nucula commutata Philippi 1844, 101.

Leda fragilis Jeffreys 1879, 575.

Leda minuta Jeffreys 1856 (non Fabricius), 25.

Leda commutata Hanley 1863, pl.CCXVIILI, figs, 80, 81.

Lembulus commutatus Monterosato 1878, 6.

Leda (Portlandia) tenuis Sturany 1896, 6.

Nuculana (Jupiteria) fragilis Nordsieck 1969, 9, pl.1, fig.02.25.

Nuculana (Jupiteria) commutata Smith and Heppell 1991, 56.

CITED SPECIMEN.

MATERIAL:

Cruise Sta. Depth No Lat Long Date Gear

(m)

WEST EUROPEAN BASIN

Sarsia 529 119 16 4740.0'N 05°00.0'W 12.8.67 ES

SHELL DESCRIPTION (Fig.34)

Shell moderately large, elongate, slightly inflated, rostrate,

ornamented with concentric ridges, pale straw-coloured perio-

stracum; radial ridge from umbo to antero-ventral margin; rostral

ridge well-defined, delimits posterior dorsal area, within this area a

faintly outlined escutcheon extending half the length of postero-

dorsal margin; lunule elongate, defined by fine ridge; less

well-defined ventral rostral ridge extends from umbo to postero-

ventral margin; umbos anterior to midline, inwardly directed;

antero-dorsal margin proximally straight, distally slightly concave

merging with rounded anterior margin to where it meets with ventral

limit of anterior radial ridge, ventral margin broadly concave, postero-

ventral margin sinuate where ventral rostral ridge meets margin,

posterior margin acute, slightly upturned, postero-dorsal margin

slightly raised with shallow angulation at limit of hinge plate; hinge

plate elongate, relatively broad, acute chevron teeth, 16 on both

anterior and posterior hinge plates of specimen 8.3mm total length;

ligament internal, amphidetic, triangular, extends slightly ventral to

hinge plate.

Fig. 34. Nuculana commutata. Lateral and dorsal views of a shell, from

Sarsia station $29 from the West European Basin. Scale = 1mm.

Maximum length of present specimens is 8.3mm.

INTERNAL MORPHOLOGY (Fig.35)

The internal morphology differs little from that of NV. acuta (Fig.32).

The most noticable differences are that N. commutata has less

attenuate palps with fewer palp ridges and larger adductor muscles

than does N. acuta.

Other differences between the two species are that in. commutata

the ridge from the umbo to the antero-ventral margin is more

marked, the apices of the concentric ridges are less broad, the

postero-dorsal margin is not so raised and the shell is somewhat less

elongate in relation to its height.

These differences are of degree and at that point where separation

into species rather than subspecies is a subjective judgement. Never-

theless, these differences are more marked than those between N.

commutata andN. illiricaCarrozza 1987 (paratypes BMNH 1995213

examined by JAA), a species that has been recently described from

the northern Adriatic Sea (Carrozza, 1987). In contrastN. commutata

right side of a specimen from Sarsia station $29 from the West

European Basin. For identification of the parts see text-figure 7, p. 106.

Scale = 1mm.

124

is widely distributed throughout the Mediterranean and lusitanean

Atlantic. Prior to the paper by Carrozza (1987) there had been debate

as to whether N. fragilis and N. commutata were the same species

(Locard, 1891, 1898; Bucquoy et al, 1887-98). It is not possible to

determine whether this earlier debate was a presage to the study of

Carrozza (1987). In contrast NV. acuta is even more widely distrib-

uted off the eastern North America, West Indies and off Brazil

(Abbott, 1974). It must be assumed that these are three sibling

species.

Nuculana vestita (Locard 1898)

MNHN

TYPE LOCALITY. Talisman stas 96-98 & 101, West of Senegal,

2324-3200m, 19°12'N 17°57'W — 1638'N 18°24'W

CITED SPECIMENS. BMNH 1995056 and 1995211

Leda vestita Locard 1898, 340, pl.XIV, figs 12-18

Nuculana vestita Clarke 1962, 53.

Leda macella Barnard 1963, 448, fig.11d; type locality: West off

Cape Point, S.W.Africa, Africana II stas A190, A192, A317,

A319, 2268—-3200m, SAM (not seen).

TYPE SPECIMEN.

MATERIAL:

Cruise Sta Depth No Lat Long Date Gear

(m)

SIERRA LEONE BASIN

Atlantis II 146 2842 1 10°39.5'N 1744.5';W 6.2.67 ES

31 —2891

ANGOLA BASIN

AtlantisI] 201 1964 1 09°29.0'S S40. y 2356s ES

42 —2031

203 527 £742 0846.0'S 1247.0'E 23.5.68 ES

—542

J.A. ALLEN AND H.L. SANDERS

Specimens taken by the Galathea Expedition described by

Knudsen (1970) examined by JAA, ZMUC. Knudsen (1970) fol-

lowing examination of specimens synonymized L. macella with N.

vestita.

Nuculana vestitais a well-described species (Locard, 1898;Theile

and Jaeckel, 1931; Knudsen, 1970) occurring off West and South-

west Africa at lower slope depths (715—2891m) in the Sierra Leone,

Guinea and Angola basins.

SHELL DESCRIPTION (Figs 36 & 37)

Shell moderately large, inflated, somewhat elongate, rostrate,

ornamented with concentric ridges, pale brownish-yellow

periostracum; umbos large, inwardly directed, anterior to midline;

antero-dorsal distal margin horizontal for short distance, proximal

margin broadly convex forming smooth curve with anterior margin,

ventral margin broadly convex to rostrum, postero-dorsal margin,

raised in small specimens but less so in large, proximally straight or

slightly concave, in small specimens angulate at limit of posterior

hinge plate, distally slightly concave to posterior limit of rostrum;

broad ridge extends from umbo to rostrum forming outer limit of

escutcheon; anterior and posterior hinge plates broad, meet shell

margin ventral to umbo, hinge teeth broad chevrons, up to 19 and 16

in anterior and posterior series respectively in specimen 8.3mm total

length; ligament internal, amphidetic, pear-shaped in sagittal verti-

cal section, extends ventral to hinge plate. The maximum length of

the present specimens is 13.8mm.

INTERNAL MORPHOLOGY (Fig. 38)

The adductor muscles are moderately large and oval. The siphonal

embayment is deep with the siphonal tentacle to the right side. The

siphons are entire. The feeding aperture is small but well-defined

with the mantle surface ridged internally. Radial mantle muscles

are well-developed forming a broad band internal to the inner lobe

Fig. 36. Nuculana vestita. External right lateral and dorsal view of a large adult shell and a lateral view of the hinge plate of a right valve. Specimens are

from Atlantis II station 203 from the Angola Basin. Scale = 1mm.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

125

Fig. 37. Nuculana vestita. Lateral views of right side of four shells in outline to show differences in shape with increasing size. Specimens from Atlantis

II station 203 from the Angola Basin. Scale = 1mm.

of the mantle edge. The anterior mantle sense organ is well-

developed.

The foot is large with the margins of the sole finely papillate. The

palps are very small with up to 12 broad folds. The palp proboscides

are stout and elongate, even in the contracted state. The gills are

elongate and broad with up to 36 gill plates.

Propeleda carpenteri (Dall 1881)

TYPE SPECIMEN. Syntypes, USNM 63151 and MCZ 7936-7938.

TYPE LOCALITY. Off Barbados, ‘Blake’ stations 5, 9, and 21,

100fm—287fm.

BMNH 1995057

Leda carpenteri Dall 1881, 125; 1886, 249, pl.8, fig.10, pl.9, fig.3.

Nuculana carpenteri Johnson 1934, 16.

CITED SPECIMENS.

MATERIAL:

Cruise Sta. Depth No Lat Long Date Gear

(m)

ARGENTINE BASIN

AtlantisII 237 993- 194 3632.6'S 5323.0';W 11.3.71 ES

60 1011

239 1661-8 3649.0'S 53°15.4;W 11.3.71 ES

1679

240 2195-8 3653.4'S 53°10.2';W 12.3.71 ES

2323

Specimen USNM 63151 examined by JAA.

Previously reported off N. Carolina, Gulf of Mexico and Eastern

Caribbean (Dall, 1889; Rice and Kornicker, 1965; James, 1970), the

present specimens are from the Argentine Basin. This species has a

Fig. 38. Nuculana vestita. Internal morphology as seen from the right

side of a specimen from Atlantis II station 203 from the Angola Basin.

For identification of the parts see text-figure 7, p. 106. Scale = 1mm.

somewhat unusual distribution from shelf to lower slope depths,

200-2323m

SHELL DESCRIPTION (Figs 39-41)

Shell fragile, semi-transparent, slender, moderately elongate, rostrate

with two post umbonal carinae, ornamented with faint concentric

ridges; periostracum pale straw colour; umbos small, far anterior

(postumbonal length 60-68% of total length), inwardly facing;

antero-dorsal margin slightly flattened, ventral margin smoothly

curved, postero-dorsal margin raised, slightly sinuous, concave

proximally, convex distally, meets posterior margin at limit of dorsal

post-umbonal carina, posterior margin concave between posterior

126

J.A. ALLEN AND H.L. SANDERS

-—_—

Fig. 39. Propeleda carpenteri. External lateral view of the left valve and an internal view of the same valve of a syntype USNM 63151, from off

Barbados in 100fms. Scale = 1mm.

limits of dorsal and ventral carinae; escutcheon lanceolate; hinge

plates relatively broad, posterior plate short, occupying little more

than half of postero-dorsal margin, anterior plate approximately half

length of posterior, hinge teeth acute chevron-shape, relatively few

in number, up to 18 in posterior series and 16 in anterior; ligament

internal, oblique, posterior to umbo; internal shell ridge extends

from mid posterior margin to approximately opposite the mid-point

of the posterior hinge plate between and parallel to the lines of the

post-umbonal carinae.The maximum length of the present speci-

mens is 15.3mm.

In most specimens the posterior shell margin is damaged, often

being markedly shortened and specimens frequently show regenera-

tion of the shell posterior to the posterior adductor. The repaired

shell is without concentric ornamentation. It is possible that ex-

tended siphons are predated upon and that the shell is damaged when

this occurs.

——_

Fig. 40. Propeleda carpenteri. External lateral view of the right side of a shell and an internal lateral view of a right valve from Atlantis II station 237

from the Argentine Basin. Scale = 1mm.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

Fig. 41. Propeleda carpenteri. External lateral views of the right sides of

two small shells to show differences in shape from the specimen

illustrated in text-figure 40. Specimens taken from Atlantis II station 239

from the Argentine Basin. Scale = 1mm.

The concentric ridges on the shell of the present specimens while

not particularly marked are more so than those described by Dall,

though the syntypes that we have examined are dead valves that are

somewhat worn (Fig.39). Our specimens also are very slightly more

anteriorly extended than the syntypes, though the characteristic

antero-dorsal curvature of the shell margin is the same. Our speci-

mens correspond well with the figures given by James (1972, figs 67

and 68). These latter come are from similar depths (2340—2627m) to

some of our own. It would appear that specimens from mid to lower

slope differ slightly from those taken at shallower depths however,

we regard the differences as being at most infrasubspecific.

There is a marked change in shape during growth. Juveniles are

much shorter than the adults and subsequent growth involves in-

creasing elongation of the post-umbonal shell. The prodissoconch is

extremely large measuring 630um in length.

127

INTERNAL MORPHOLOGY (Fig.42)

The adductor muscles are oval in cross-section, the posterior being

the more fusiform, both are set some distance in from the shell

margin. The posterior adductor muscle lies opposite the limit of the

posterior hinge plate, the anterior muscle is attached to the shell just

dorsal of the mid-horizontal shell axis. The siphonal embayment is

elongate, the siphons are slender and entire. The anterior sense organ

is small in size.

The foot lies in the anterior half of the mantle cavity in preserved

specimens, it is relatively elongate and has numerous small papillae

present along the margins of the sole. The palps are small, each

bearing an extremely long, narrow, palp proboscis. Depending on

the size of the specimen there are up to 17 palp ridges. The gills are

elongate, slender, and have up to 17 plates.

The course of the hind gut is similar to that in Nuculana in that it

passes to the right side of the body where it forms a broad loop that

passes close to the posterior wall of the anterior adductor muscle.

The stomach is large and occupies a vertical position in the posterior

part of the visceral mass. The digestive gland is extensive occupying

much of the antero-dorsal visceral space.

Propeleda louiseae (Clarke 1961)

TYPE SPECIMEN. Holotype, MCZ 224958.

TYPE LOCALITY. R.V.Vema biology station 121, Argentine Basin,

1000 miles ESE of Buenos Aries, 5105 metres.

CITED SPECIMENS. BMNH 1995058

Nuculana (Thestyleda) louiseae Clarke 1961, 375, pl.1, fig. 7.

MATERIAL:

Cruise Sta Depth No Lat Long Date Gear

(m)

ARGENTINE BASIN

Atlantis II 242 4382— 25 3816.9'S 5156.1°W 13.3.71 ES

60 4402

243 3815— 2 3736.8'S 5223.6'W 14.3.71 ES

3822

247 = 5208- 2 43°33.0'S 48°58.1'W_17.3.71 ES

5223

256 3906- 3 3740.9'S 52°19.3'W 24.3.71 ES

3917

Fig. 42. Propeleda carpenteri. Internal morphology as seen from the right side of a specimen taken from Atlantis II station 239 from the Argentine Basin.

For identification of the parts see text-figure 7, p. 106. Scale = 0.5mm.

128

J.A. ALLEN AND H.L. SANDERS

Sse

Fig. 43. Propeleda louiseae. a & b, external lateral views of the right sides of shells of differing size to show differences in shell proportions with growth;

note outline internal morphology through semi-transparent shells, in particular the form of the hind gut and position of the adductor muscles; c, outline of

shell from the left side showing the outline of hind gut and adductor muscles; d, internal view of a left valve. All specimens taken from Atlantis II station

242 from the Argentine Basin. Scales = 1mm.

Type specimen examined by HLS.

Distributed at abyssal depths in the Argentine Basin; depth range:

3815-5223 metres.

SHELL DESCRIPTION (Fig.43)

Shell extremely elongate, slender, fragile, semi-transparent,

ornamented with moderately spaced concentric ridges, two post-

umbonal rounded ridges, one dorsal and one ventral at posterior

shell margin and crossed vertically by wavy continuations of the

concentric ridges, faint anterior radial ridge from umbo to antero-

ventral margin; umbo slightly raised, far anterior (post-umbonal

length 65-70% of total length), inwardly facing; antero-dorsal

margin with short proximal notch, distally margin raised and slightly

concave, faint angulation before anterior margin, anterior margin

joins with ventral margin in smooth curve, postero-ventral margin

very slightly sinuate, posterior margin angled and sinuate, postero-

dorsal margin notched at umbo, distally somewhat raised and keeled,

concave overall but slightly sinuous dorsal to hinge plate; hinge

plate relatively broad, posterior plate short occupying approxi-

mately half the postero-dorsal shell margin, hinge teeth elongate,

acute chevron shape, up to 12 in anterior and 20 in posterior series;

ligament small, internal, oblique, pear-shaped; rounded internal

ridge extends from umbo to posterior margin and marks junction

between inhalent and exhalent siphons. The maximum length of the

present specimens is 20.3mm. The prodissoconch is large measuring

300um in length.

Clarke (1961) records a long, thin, external ligament in the type

specimen — the latter being a single large valve. We find no evidence

of an external part to the ligament and believe that Clarke mistakenly

confused periostracum along the postero-dorsal margin for liga-

ment.

INTERNAL MORPHOLOGY

With one notable exception the internal morphology of Plouiseae

differs little from that of P carpenteri.

Unlike the latter species the hind gut of P. louiseae first passes to

the left side of the body where it forms a relatively small loop

immediately ventral to the umbo (Fig.43). From there it passes to the

right of the body and forms a loop that is considerably larger than

that on the left although not as extensive as that in P. carperteri (Figs

42 & 43).

The adductor muscles are relatively large, the elongate poste-

rior muscle is situated at the distal limit of the posterior hinge

plate. The gill is very short and slender with few (c. 13) gill-

plates.

Propeleda paucistriata (new species)

TYPE SPECIMEN.

1995060.

Holotype BMNH 1995059; Paratypes BMNH

TYPELOCALITY. Atlantis II station 203, Angola Basin, 08°48.00'S

12'52.00'E, 527-542m.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

MATERIAL:

Cruise Sta Depth No Lat Long Date Gear

(m)

ANGOLA BASIN

AtlantisII 203 527— 31 0848.00'S 12°52.00E 23.5.68 ES

42 542

DISTRIBUTION. Restricted to the Angola Basin at upper slope

depths, 527-542 metres.

SHELL DESCRIPTION (Fig.44)

Elongate, fragile, transluscent shell, moderately slender, two cari-

nate ribs from umbo to posterior margin, widely spaced prominant,

relatively broad, concentric ribs with overhanging ventral margin,

24 fine concentric lines between ribs, between carinae vertical ribs

and lines equally prominant; umbo moderately raised, far anterior in

largest specimens (post-umbonal length 79% of total length) but less

so in smaller specimens, beaks inwardly facing; antero-dorsal mar-

gin sloping, proximally convex but almost straight in small specimens,

joins with anterior and antero-ventral margins in smooth curve;

postero-ventral margin very slightly sinuous, posterior margin usu-

ally damaged in large specimens, intact margin angled and sinuate,

forming a hook dorsally where postero-dorsal margin and dorsal

carina meet, postero-dorsal margin concave, proximally raised,

elongate escutcheon outlined by dorsal carina; hinge elongate,

moderately broad, large, acute chevron-shaped teeth up to 16 in

anterior series and up to 28 in posterior series, anterior series extends

to anterior limit of anterior adductor muscle, posterior series extends

approximately half length of postero-dorsal margin to anterior limit

129

of posterior adductor muscle, ventral margin of hinge plate corre-

sponds to line of dorsal carina, ventral to umbo teeth approach shell

margin, anterior and posterior hinge plates continuous; ligament

internal, ventral to umbo and close to shell margin, slightly inclined

posteriorly; rounded internal ridge extends from umbo to posterior

margin. The maximum recorded shell length is 14.1mm. The

prodissoconch is very large and measuring 560um in length.

Juvenile shells are more ovate and, before posterior elongation

occurs, could be mistaken for a yoldiellid (Fig.44).

INTERNAL MORPHOLOGY (Fig.45)

The anterior adductor muscle is oval in cross section, while the

posterior adductor is smaller and more elongate. Both are set in from

the shell margin, the posterior is positioned at approximately two-

thirds the distance between the umbo and the posterior limit of the

shell. There is a small anterior sense organ formed from the sensory

fold of the mantle, ventral to the anterior adductor. The siphons are

joined with their ventral margins fused to form entire lumina. They

are slender and particularly elongate and when contracted are con-

tained in the elongate siphonal embayment. The foot and viscera lie

in the anterior half of the mantle cavity. The foot is elongate and

directed anteriorly. In most preserved specimens the tip of the foot

lies between the anterior adductor and the shell margin. The margins

of the sole are fringed with numerous relatively small papillae.

There are three anterior and two posterior pedal retractor muscles.

The palps and gills are markedly narrow and elongate. The are at

least 22 palp ridges in the largest specimens and the palp probosci-

des are attenuate each with a straight dorsal margin and a papillate

ventral margin. In a few preserved specimens the palp proboscides

extend from the feeding aperture. The gills are similarly attenuate

Fig. 44. Propeleda paucistriata. External lateral views of the right sides of four shells of differing size to show change of shape with growth and an

internal view of a right valve. All specimens taken from Atlantis II station 203 from the Angola Basin. Scale = 1mm.

130

J.A. ALLEN AND H.L. SANDERS

Fig. 45. Propeleda paucistriata. a, internal morphology as seen from the right side; b, part of the left side of the same specimen to show details of the

course of the gut; c, the internal morphology as seen from the left side of a much larger specimen. All specimens taken from Atlantis II station 203 from

the Angola Basin. For identification of the parts see text-figure 7, p. 106. Scales = 1mm.

and extend from the posterior visceral mass to the anterior limit of

the posterior adductor. There are at least 22 gill plates in larger

specimens. A slender extension of the axis extends from each gill

from ventral to the posterior adductor to the inner junction between

inhalent and exhalent siphons.

From the large combined stomach and style sac the course of the

hind gut takes it first dorsal and posterior to the stomach and then to

the left side of the body where it makes a small loop. From there it

passes ventral to the umbo to the right side of the body where it

makes a much larger loop at the perimeter of the viscera and passing

close to the inner face of the anterior adductor. From there it passes

mid-dorsally to the anus. The mouth is set some distance posterior to

the anterior adductor muscle. The oesophagus is broad and elongate

and the combined stomach and style sac is positioned vertically in

the posterior part of the visceral mass. The pedal ganglion is large

and lies immediately anterior to the junction of mid gut and hind gut.

The shell surface in some larger specimens is covered with

epifaunal solitary hydroids. This would indicate that P. paucistriata

lives close to the surface of the sediment. This is also suggested by

the fact that the posterior tips of the shells of larger specimens are

broken. We believe that this is the result of predation on the siphons.

The extreme post-adductor elongation of the shell is advanta-

geous in that it provides distance between predator and the more

vulnerable viscera with damage being restricted to more easily

generated tissue.

The shell of this species differs from others described by the small

number of pronounced concentric shell ridges and we name it with

reference to this characteristic feature. This is the first species of

Propeleda to be recorded off the south-west coast of Africa. At

approximately the same latitude off the east coast of Natal a species

named Leda lancetaby Boshoff (1968) occurs at upper slope depths.

Nijssen-Meyer (1972) believes that this latter species is a Propeleda,

and we concur with her. P. /anceta is more robust, more arcuate and

with far more numerous concentric ridges than is the case in P

paucistriata.

DISCUSSION

The major point of interest in this particular account of deep-sea

protobranch bivalves is the evidence it provides to further our

understanding of the evolution of the nuculanoid protobranchs. In

our earlier studies on the Tindariidae we speculated as to how the

nuculanoids could have evolved from the nuculoids (Sanders and

Allen, 1977). In functional terms, this involved a change in the

inflow of water into the mantle cavity from an antero-ventral posi-

tion to a posterior position and the begining of specialization of the

posterior mantle edge, a view also expressed by Yonge (1939). In the

tindariids this latter involves the development of sensory papillae

from the sensory fold of the mantle at the points of ingress and exit

of the circulatory water. Although infaunal and deposit feeding, the

tindariids, like the nuculids, live close to the surface and, like many

other bivalves that occupy this position, they are ovate and robust.

Many of these subsurface dwelling bivalves, including the tindariids,

have stout external ligaments.

The development of siphons was the next step in the evolutionary

process and the neilonellids are illustrative of this. The shell form and

ligamentas seen in the tindariids is largely retained in the neilonellids,

but short siphons, as yet only fused dorsally, are now present and these

are contained in a shallow siphonal embayment. Although the shell

remains stout and ovate there is some posterior elongation and an area

ventral to the inhalent siphon from where the palp proboscides are

extended is more defined. Like the tindariids the neilonellids are

deposit feeders living close to the surface of the sediment.

DEEP-SEA PROTOBRANCHIA (BIVALVIA)

The hind gut in Neilonella, like that in Tindaria, has a wide lumen

and single pronounced typhlosole. Although the course that the hind

gut takes in neilonellids makes a single loop on the right side of the

body, it does not penetrate mantle space as it does in tindariids

(Sanders and Allen, 1977). In this respect the hind gut of neilonellids

probably represents the more primitive condition. We have argued

elsewhere (Allen, 1992) that elongation and the complexity of form

of hind gut configuration are related to food procurement at great

depths, and this applies to the tindariids (Sanders and Allen, 1977).

The neilonellids are for the most part upper slope species and the

hind gut would be expected to be less specialized and less elongate.

In Nuculana posterior elongation becomes more extreme and the

ventral margins of the combined siphons are fused such that the

exhalent and inhalent lumena are separate and entire. The shell

remains robust, but is more slender The ligament is restricted to a

small internal structure separating elongated anterior and posterior

series of hinge teeth. We believe that elongation is correlated to the

almost vertical orientation of the animal in the sediment but which

retains contact with the surface via the extended posterior body and

siphons. The genus Nuculana is found mainly in shelf and upper

slope sediments and as such the available food resources are rela-

tively abundant. The hind gut is not greatly extended and remains as

a single loop to the right side of the body.

In Propeleda the evolutionary trend of posterior body elongation

seen in Nuculana becomes is more extreme, particularly posterior to

the posterior adductor muscle. The posterior adductor muscle is

more elongate and dorso-ventrally narrow, and the gill, gill axes,

siphons and the palp proboscides are exceptionally long and slender.

The shell of Propeleda, particularly in abyssal species, is much more

fragile and is further specialized in that it possesses an internal

posterior longitudinal ridge. The function of this ridge is not entirely

clear and has await examination of the living animal but, possibly, it

is involved in the separation of excretion, feeding and respiratory

functions in the extremely elongate posterior mantle cavity. It may

also help to strengthen the otherwise very fragile shell and assist in

predation damage limition. In Propeleda post-adductor elongation

involves body tissues that can be relatively easily regenerated, much

in the same way as has been reported in deposit feeding tellinids

(Edwards, Steele and Trevallion, 1970). Specimens showing shell

repair posterior to the posterior adductor are present in our samples.

The evolution of the Ledellinae and an assessment of their func-

tional morphology was discussed earlier (Allen and Hannah, 1989).

In respect of the species of Ledella and Tindariopsis described here,

little needs to be added to that account other than to note, again, that

the hind gut in these abyssal protobranchs is extraordinarily length-

ened and takes the most complex courses within the visceral mass.

The other item of note is the description of yet another ledellid in

which the shell, after reaching a certain length, changes its direction

of growth. In Ledella aberrata as in L. ultima the result of this

change is to produce a broad shell margin and lateral expansion of

the shell cavity. This adaptation has been construed as possibly

providing more space for the gonads that begin to develop at about

the time the change in direction occurs.

ACKNOWLEDGEMENTS. It is fitting that in this paper we thank our numer-

ous friends and colleagues, particularly French colleagues of the Biogas and

Walda cruises, who provided much material and gave much advice and

encouragement. We would like to mention three colleagues by name. George

Hampson of the Woods Hole Oceanographic Institution and Fiona Hannah

(Lonsdale) of the University Marine Biological Station, Millport, who have

given us tremendous close support over the years and without their help it is

likely that we would not have succeeded in this task within our lifetimes, and

Kathy Way of the Natural History Museum, London, who has been so quick

131

in responding to our requests for help particularly in our quest for early

literature and specimens for comparison. Much of the work was supported by

grants from the Natural Environment Research Council.

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