Volume 123, Number 1 March 31, 2009 ISSN 0028-1344

A qua rterhj devoted to malacologii.

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Tlie Bailey-Matthews Shell Museum 3075 Sanibel-Captiva Road Sanibel, FL 33957


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Invertebres Marins et Malacologie Museum National dTIistofre NatureUe 55, rue Buffon Paris, 75005 France

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Dr. James PI. McLean Department of Malacolog)'

Natural Histoiy Museum of Los Angeles County 900 Exy)osition Boulevard Los Angeles, CA 90007

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1259 Trumansburg Road Ithaca, NY 14850 ^

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Volume 123, Nu))ihcr 1 March 31, 2009 ISSN 0028-1344

Diego G. Zelaya A redefinition of Pseudokelh/a Pelseneer, 1903 (Bivalvia: Cyainiidae) and tlie

Cristian Ituarte description of a new species from the Sontfiern Ocean 1

John D. Taylor Phylogenetic position ol the liivalve family Cvrenoididae remo\ al Irom (and

Eniily^ A. Glover further dismantling ol’) the siiperfamily Lncinoidea 9

Suzanne T. Williams

Donald F. MeAlpine Establishment and persistence of the copse snail, Arionfd arbusfonnn (Linnaeus,

Frederick W. Sehueler 1758) (Gastropoda; Helicidae) in Canada 14

John E. Maunder Ronald G. Noseworthy Man C. Sollows

Research Note

Juan M. Diaz Fernando Gasl Diana C. Torres

Research Note

Fred G. Thompson Michael \\^. Hevn Drew N. Camphell

Rediscoveiy ol a Caribbean living fossil: Plioladomi/a Candida G.B. Sow^erbv I, 1823 (Biv'alvda: Anomalodesmata: Pholadomyoidea) 19

Thiara scabra (O. F. Aliiller, 1774): Tlie introduction ol another Asian Ireshw'ater snail into the United States 21


Roland Hoiiart Carole M. Hertz

A review ol Ti/phisopsis jousseaume, 1880, and Ti/phisala |ousseanme, 1881 (Gastropoda: Muricidae) ol the eastern Pacific (2006) 23







\ i'


THE NAUTILUS 123(1): 1-8, 2009

Page 1

A redefinition of Pseiidokellija Pelseneer, 1903 (Bivalvia: Cyamiidae) and the description of a new species from the Southern Ocean

Diego G. Zelaya

Division Zoologia Im'ertebrailos Mnseo cle la Plata, Paseo del Bosque s/n 1900 La Plata, Buenos Aires, ARGENTINA dzelaya@fcnvni.unlp.edu.ar

Cristian Ituarle

Division Zoologia Invertehrados Mnseo Argentine de Cieneias Naturales Av. Angel Gallardo 470 C1405DJR, Buenos Aires, ARGENTINA


A new species oi Pseitclokelli/a, Pseiiclokclh/a fninki Ironi Soutli Shetland Islands, is described. P. fninki is characterized by its subcircular shell outline, the periostracum forming low lamel- late commarginal folds, radial sculpture absent, and by the presence of a single posterior siphonal opening, a fact that is in contrast with that reported for the t\pe species of Pseiulo- kelh/a, Kcllia cardifonnis Smith, 1SS5. The presence of a com- plete follicle surrounding each developing ooc)4e, persisting throughout vitellogenesis, a condition not currently knowi for other bivalves, is confirmed as a generic diagnostic character. The generic redefinition, based on shell morphology and ana- tomical features described for Pseudokclhja fninki. is given.

Additional Kci/icords: Cyamioidea, Ciiamiocanlimn. Kcllia, Perrierina. reproduction


Pseiidokelh/a was proposed by Pelseneer (1903) to real- locate Kcllia canlifonnis Smith, 1885, a species described from Kerguelen Islands. The diagnosis for the new genus was given in association wdtli description of the anatomy oi Kcllia carclifonnis. Species oi Pscudo- kellija were originally distinguished from those of Kcllia Tnrton, 1822, by having two, brancliial and anal, siphonal openings and for being dioecious, Pelseneer (1903) also reported a peculiar reproductive trait for Pseitdokelh/a carclifonnis: the presence of a complete follicular epithe- lium snrroimdiirg each developing oocyte, a condition not otheiwidse known for bivalves. Snbsecpiently, four nominal species of Pseudokelhja were described: Psetido- kelhja gradata Thiele, 1912, from Gauss Station, Pseudo- kellija stillwelli Hedley, 1916, from Adelie Land and Davis Sea (a synonym of F, carclifonnis, according to Dell (1990)), Pseudokelhja georgiana Dell, 1964, from South Georgia, and Pseudokelhja inexpectata Dell, 1964, from South Georgia and South Orkneys. The descriptions of these four species were based exclusively on shell

characters; after tliat not a single study provided infor- mation on their anatomy. Consequently, to date, it is not possible to confirm if the anatomical characters reported by Pelseneer (1903) are diagnostic for Pseudokelhja car- difonnis or shared by other species of the genus.

In the present paper, a new species of Pseudokelhja from South Shetland Islands is desciibed; details on anatomy, reproductive traits and shell morphology provide additional information for a better definition of the genus.


The specimens studied were originally deposited at the Zoologisches Museum (ZMB), Germany. They were col- lected during the 1982, 1985, and 1986 Soviet Antarctic Expeditions to King George Island, South Shetland Archipelago. Voucher specimens are deposited at the ZMB, Mnseo de La Plata (MLP), and Mnseo Argentine) de Cieneias Naturales (MACN), Argentina.

We studied the holoRqre of F gradata (ZMB 63109), specimens of F. cardiforniis (ZMB 63136), F inexpectata (ZMB 114683), and F. georgiana (MLP 12999) from t\qre localities, and specimens of F. gradata from Zoo- logische Staatssarnmlnng Miinich (ZSM), Germany (ZSM 20012865: 63° 01.10' S, 61° 09.10' W'; ZSM 20041320: 62° 00.09' S, 60° 19.31' W). Specimens cur- rently assigned to Kcllia suhorbicularis (Montagu, 1803) (MLP 11563); Kcllia niagellanica Smith, 1881 (MLP 13000); and Kcllia sp. (AILP 13001) from Argentine waters were also used for comparative purposes.

The anatomical description of Pseudokelhja franki was based on dissections under stereoscopic microscope; seven specimens were pi'ocessed for histology, inclusion was performed either in Paraplast® or 1 listoresin®; specimens were completely sectioned at 5 pm thick, using a Leica RM 2355 microtome.

Shell morphology was studied throngli scanning electron microscopy (SLM). Shell measurements were

Page 2

THE NAUTILUS, Vol. 123, No. 1

obtained according to the following criteria: L: niaxininin antero-posterior distance; H: inaxinmm dorsoventral dis- tance perpendicular to L; W: maximnin distance across \ al\ es. Mean value and standard deviation for the ratios H/L and VV/H are given (n = 16 specimens). Hinge teeth nomenclature is indicated in figures 10 and 11.

SYSTEM ATICS PseiiclokeUi/a Pelseneer, 1903

T>pe Species: KcUi/a cardiformis Smith, 18S5 (hy


Pscudokelhja franki new species (Figures 1-26)

Diagnosis: Shell suhcircnlar, inflated, only sculptured

with marked growth lines; periostracum forming lamel- late commarginal folds. Posterior portion of the right cardinal tooth (C3b) well developed. A single posterior siphonal opening, the anal, present.

Description: Shell small, maximnm ohsei'ved L = 4.2

mm, shell outline subcircular, slightly longer than high (H/L = 0.94±0.04), inflated (W/H = 0.74T0.04) (Figures 2-5, 12). Anterior margin short and round, imperceptibly connected w4th dorsal margin, forming a \\4de cun^e with the anterior part of ventral margin (Figures 2-5). Ventral margin markedly cun'ed. Posterior margin rounded, nearly vertical in larger speci- mens following the posteroventral cun'e (Figures 2-4). Posterior part of dorsal margin snherect or slightly cmved. Beaks prosogyrous, inflated, globose at tip, strongly discernible above dorsal margin, slightly dis- placed anteriorly (Figure 2-5, 7). Prodissoconch ovate, about 400 pm in diameter, surface sculptured with minute granules (Figures 6, 13). Shell surface whitish, shiny, with veiy low and I'onnded commarginal grow'th lines, irregularly distrilnited (Figure 15). Periostracum translucent, forming low lamellate periostracal folds (Figure 14). Inner shell surface whitish, dull. Hinge plate narrow, somewdiat enlarged anterior to beaks, just at the point of insertion of cardinal teeth (Figures 8-11). Hinge: left valve (Figures 8, 10): cardinal tooth 2 (C2) solid, triangular, cusp subceutral; cardinal tooth 4 (C4) relatively short, straiglit, and solid, with cusp displaced posteriorly; lateral posterior tooth (LIl) long, narrow, and low, well separated from posterioi' margin. Right valve (Figures 9, 11): cardinal tootli (C3) hook-like, formed by large, solid anterior portion (C3a), bifid at base, and sliort and narrow posterior portion (C3h), In

larger specimens, C3a and C3b form a nearly right angle (Figure 11). whereas in smaller ones the angle between C3a and C3b is more acute and C3b longer (Figure 9). Right inner posterior lateral tooth (LI) long, moderately solid, with centrally located cusp; outer pos- terior lateral tooth (LIII) merged with dorsal shell mar- gin. Internal ligament set in a small, short, shallow resilifer posterior to cardinal teeth; e.xternal ligament short, posterior to beaks. Scars of anterior and posterior adductor muscles ovate, the anterior, slightly longer (Figure 7). Pallial line entire.

Anatomy: Mantle margin largely unfused, forming a

long pedal gape (Figure 20), fused at the posterior quar- ter, delimiting the anal opening; below this point, an enlarged portion of the middle mantle fold corresponds to the position of the absent branchial mantle opening (Figure 19). The anal opening and the enlarged portion of the mantle margin are flanked Iry a row of 12 to 16 micropapillate tentacles on each side, placed in an alter- nating pattern (Figures 18, 19). Auteilor and posterior adductor muscles almost equal in size, the posterior one ovate in section, the anterior more elongated and nar- rower (Figure 16). Foot long, w4th a well differentiated heel (Figure 16); a small byssal gland, functional

Figures 2-15. Fficiidokclhia franki new' species. Specimens from Maxwell Bay, King George Island, 100 m (station 30/49). 3, 4. Holop pe. 2, 5-15. Otlier specimens. 2-5. Outer view. 2, 3. Riglit \ alve. 4. Left valve. 5. juvenile. 6. Prodissoconch. 7. Inner view, lelt valve. 8-11. Details of hinge plate. 8, 9. Specimen 4.2 mm L. 10, 1 1. Specimen 5.5 mm L. 8, 10. Left valve. 9, 11. Bight valve. 12. Dorsal v'iew. 1.3. Detail of prodissoconch .sculpture. 14. Periostracal folds. 1.5. Periostracal folds and grow'th lines. Scale bars: 2-4, 7 = 1 mm; 5 = 250 pm; 6 = 100 pm; 8-11 = 200 pm; 12 = 500 pm; 13 = 25 pm; 14 = 100 pm; 15 = 5()^pm. Abbreviations: C2, C.3a, C3b, C4 = cardinal teeth; 14-1411 = lateral teeth I-llI; ilig = internal ligament; elig = external ligament.

D. C;. Zelava and C. Itiiartc', 2009


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THE NAUTILUS, Vol. 123, No. 1

Figures 16-20. Psciidokelh/a franki: anatomy. 16. Gross anatomy from the right side. 17-20. Transverse sections showing details of demihrancli Insion and mantle border. 17. Posterior fusion of tlie inner demiliranchs. 18. Detail o( mantle folds and tentacle. 19. Fusion ol posterior portion of the mantle border. 20. Anterior portion of tire mantle border. Scale bars: 16=1 mm; 17, 19, 20 = 300 pm; 18 = 1.50 pm. Abbreviations: aain = anterior adductor muscle; al = ascending lamella of inner demibraiich; bf = branchial fusion; dl = descending lamella of inner demihrancli; e = embiyo; f = foot; id = inner demibraiich; imf = inner mantle fold; h = heel; mb = mantle liorder; nimf = middle mantle fold; od = outer demihrancli; omf = outer mantle fold; paiii = posterior adductor muscle; I = tentacle.

in adults, present; byssns comprising a single, long fila- ment. Outer and inner demibranelis present, witli well -developed ascending and descending lamellae (Fig- ure 16). Height of outer demibraiich representing one- third the height ol inner one; posterior end ol outer demibraiich (used to the mantle; left and right inner

demibranelis, also fused at posterior end, determining defining a siiprabranchial chamber eontinuons with the anal opening (Figure 17). Length ol descending lamella of outer demibraiich about a half of ascending one; filaments of ascending lamella of inner demibraiich decreasing in length toward the posterior end.

D. (t. Zelaya and C. Itnarte, 2009

Page 5

Figures 21-26. Pseudokelhja franki: oocytes ami enibry'os. 21-24. Histological sections. 25, 26. SEM photomicrographs. 21. Pre- vitellogenic and early vitellogenic oocytes. 22. Vitellogenic oocvte. 23-26. Einhi-vos attached to the inner deinihranch. Scale bars: 21, 24-26 = 100 pm; 22 = 50 pm; 23 = 200 pm. Abbre\’iations: aw = acinar wall; bf = brancliial lilaments ol the inner demibranch; dg = digestive gland; e = embiyo; evo = early pre-vitellogenic oocvte; fe = follicle cell; g = gonad; h = heel: ifj = interfilamental junction: nu = nnclens; pg = pedal gap; pvo = pre-\itellogenic ooc\te; st = stalk.

Reproductive Traits: Pseudokelhja frauki is dioe-

cious, brooding its einbmts within the inner denii- Itranchs attached to the ascending Filaments by short stalks (Figures 16, 23-26). The architecture ol oogenesis sliows a peculiar Feature, cousistiiig of tire Formation oFa complete oue-cell-thick Follicle surrounding each devel- oping oocyte, whicii persi.sts to the end of vitellogenesis (Figiu-es 21, 22, 24).

Tyiie Locality: Maxwell Bay, 62° 10-19' S, 58°35-5.S'

VV', King George Island, South Shetland Islands, 100 m (station 30/49)'.

Tx'jjc Material: Holotvpe (ZMB 114680-a) and 10

paratxpes from the tvpe locality' (five at ZVIB 114680-b; three at ML? 12997;' two at MACN-ln 37535).

Other Material Examined: 36 specimens. Maxwell

Bay, King George Island (station 30/43), 50 m (ZMB 114679); 84 .specimens. Maxwell Bay, King George Island, 100 m (station 30/49) (ZMB 1 14680-0); 1 speci- men, VlaxAvell Bay, King George* Island, 10-15 m (station 11/134) (ZMB 114682); 6 specimens, Ma,xwell Bay, King George Island, 40-50 m (station B 301) (ZMB 114681).

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THE NAUTILUS, Vol. 123, No. 1

I'igures 27-38. Psciidoki'Uiia spcde.s. 27-29. P. rardifonitis (ZMB 63136). 30-32. P. inexpeciaiu (ZMB 114683). .3.3-.3I5. P Amdahl. 33. .Spcdiiicii from 62° OO.OT S 60° 19.31' W' (ZSM 2()()41.320). 34, 3.5. Svnhpe (ZMB 63109). 36-38. P georoianu (,M1,B 12999). 27, .30, 33, 36. Oiilcr viow Irit valve, and eletail ol .sliell .sciipOire at the n'glit .side. 28, 31, 34, 37. Hinge plate left valve. 29, 32, .3.5, 38. I linge plate right valve. Seale Bars: 27, 30, 33, 36 = I nun; 28, 29, 31, 32, .34, 35, 37, 38 = 500 pin.

D. G. Zelaya and C. Ituarte, 2009

l^age 7

Distribution: Only known from South Slietland

Islands (Figure 1).

Etymology: The species is named alter Frank Kdhler,

Australian Museum, Sydney, and associated \rith the Museum fiir Naturkunde, Berlin.

Remarks: In general shell outline, PseiidokeUi/a franki

is most similar to Pseuclokelli/a cardifonnis (Figures 27-29), from which it differs in having a relatively longer and more straight posterior part of dorsal margin and a ventral margin comparatively more strikingly cuiwetl. The shell outline of T georgiana (Figures 36-38) differs from that of Psciidokelhja franki in being markedly ti'apezoidal; P. grodata (Figures 33-35) and P. inexpectata (Figures 30-32) have snbtrapezoidal shell outlines.

The absence of radial scidpture on the outer shell surface is a distinctive character of Pseud okelh/a franki (Figures 2-5). Also distinctive in P. franki is the pres- ence of widely separated and low lamellate commarginal periostracal folds (Figure 14); in other species of Pscu- dokeJhja, the periostracum shows densely packed and fine commarginal threads (Figures 27, 30, 33, 36). Pseu- dokellija franki shows a weak commarginal sculpture represented by low and rounded irregular ridges, which seems to originate through growth disruptions (Figure 15); in the remaining species this sculpture is less evident, being represented only by shallow growth lines (Figures 27, 30, 33, 36). In the case ok PseudokeUi/a gradata, 3-4 shaqr growth disruptions, described as “grades”, appear (Figure 33).

The hinge of the largest specimens of Pseiidokelh/a franki is similar to that of the other species of the genus, mainly differing in haring a larger cardinal tooth 3b and a more solid cardinal tooth 2 with a triangular base. In the smaller specimens the cardinal 3 is arched, with C3b more developed.

Anatomically, Psciidokelhja franki differs from P. car- difonnis (the only other species in the genus for whicli anatomy is known) iii having only one defined mantle opening, the anal, and a differentiated portion of middle mantle fold below the anal opening that seems to repre- sent the inhalant branchial aperture (lacking only a ven- tral point of fusion delimiting the opening). Pelseneer (1903) reported two posterior siphonal openings in P. cardiformis. As it was described by Pelseneei' (1903) for P. cardiformis, P. franki showed to be dioecious. Out of the seven specimens histologically studied, four were males and three females, with no signals of a possible consecutive sexualitv detected.


The generic definition of PseudokeUtja given by Pelse- neer (1903) when describing P. cardiformis was based on three characters: the presence of two posterior (branchi- al and anal) siphonal openings, the dioecious condition, and a peculiar mode of oogenesis comprising the

formation of a complete follicle surrounding each devel- oping ooc)4e (a condition not known, at that times, lor any other bix alve).

According to Thiele (1934: 858) the diagnostic char- acters of Pseudokelli/a are: “shell roundish or somewhat angular, nnifonuly bulging, with weak radial sculpture; umbo moderately elevated, situated in the center: hinge margin posterior to the ligament prolonged somewhat ridge-shaped; anterior hinge teeth of the left \ alve fairly long, diverging in an acute angle".

After the new infoi'iuation coming from the new spe- cies described here and the species described after tlie diagnosis by Thiele, an e.xpanded redescription of the genus is needed.

Redescriplion of PseudokeUija: Shell small, shell

outline subcircular to snbtrapezoidal, ventral margin uniformly cun'ed or more sharply cuiwed at pcisterior half; beaks prosog)'rous, snbcentrally located. Prodisso- conch sculptured witli microscopic granules; teleo- conch usually sculptured \rith a \ariable number of more or less marked radial cords, sometimes absent. Periostracum usually elevated in fine threads or low lamellate folds. Growth lines variably marked, some- times looking like commarginal sculpture. Hinge plate narrow, enlarged anterior to beaks, just at the cardinal teeth insertion. Right valve \rith a hook-like cardinal tooth (C3), formed by an anterior part (C3a) \ amng from short and stout to long and slender, witli a trian- gular base, bifid to a variable degree; and a smaller posterior portion (C3b), sometimes extremely reduced in size; a well-developed, elongated, narrow, and low inner posterior lateral tooth (PI), and an outer poste- rior lateral tooth (PHI) not well-separated from dorsal margin. Left valve: two cardinal teeth, the anterior (C4) running parallel to the anterior part of dorsal margin, and the posterior (C2), usually elongated and smaller, parallel or forming an acute angle with C4; a single and elongated posterior lateral tootli (PII), present. Resilifer small and shallow, located below beaks. Internal and e.xternal ligaments, present. Man- tle witli one or two posterior siphonal openings. Gills each composed of two demibranchs. Foot witli a w'ell- differentiated heel, having a small byssal gland. Ani- mals dioecious, retaining the embiyos attached by short stalks to the inner demibranch filaments; a complete follicle surrounds each developing oocyte throughout \itellogenesis.


Coiiipari,son with Other Genera: When describing

PseudokeUija, Pelseneer (1903) focused in the pres- ence of two siphonal (branchial and anal) openings and the dioecious condition, in oposition to Kellia wliich is a hermaphrodite and has only one posterior siphonal opening, the anal. It is to be noted that, in ccmtrast to that described by Pelseneer (1903) Pseudo- keUija franki show's a single posterior mantle opening. Additional characters differentiating Kellia from Pseu- dokeUija are found in the hinge morphology: the

THE NAUTILUS, Vol. 123, No. 1

Page 8

former has a simple and triangular right cardinal tooth C3 and two left cardinal teeth (C2 and C4) arranged in a chevron pattern. Moreover, in Kellia both right and left posterior lateral teeth are consistently stron- ger than in Pseiiclokelh/a. In addition, KeUia only has the internal ligament. Lastly, the radial sculpture and periostracal folds present in some species of Pseudo- kelh/a are absent in Kellia.

The hinge of Pseudokelh/a closely resembles that of Ci/amiocarditnn Soot-Ryen, 1951, and Penieiina Ber- nard, 1897, two genera also occurring in the Southern Ocean. However, in the last two an additional tooth behind the cardinal C2 (referred to as cardinal tooth 4b) appears (Lamy, 1917; Zelaya, 2008; pers.obs.). Adult specimens of Ci/omiocardiiim and Penieiina have an always well-developed C3b, which is reduced in size in larger specimens of PseiidokeUi/a . Penieiina also has tnlrercles anterior and posterior to the beaks resembling a taxondont hinge, a character absent in members of PsendokeUi/a (see Zelaya, 2008).

The Geographic Di.strihiition of Pseiidokellya:

Currently known species of PseudokeUt/a are restricted to Sub-Antarctic and Antarctic waters. According to Dell (1990), P. cardifonnis and P. gradata are probably ciren- mantarctic, e.xtending to the Scotia Arc Islands and the former, reaching Mahdnas and Kerguelen Islands. The remaining three species are restricted to the Scotia Arc islands: P. inexpectata known from South Georgia and South Orkneys Islands (Dell, 1964), P. georgiana from South Georgia (Dell, 1964), and P. franki from South Shetland Islands (present study).


DZ would like to express his gratitude to Matthias Glaubrecht for his kind invitation for a short term stay at ZAIB and all the staff of the museum for the facilities and help provided during that stay; Enriko Schwabe and Michael Schrodl kindly provided assistance during the \4sit to the ZSM. The visits to the ZMB and ZSM were possible thanks to a DAAD - GONIGET grant. P. Mikkelsen and G. Goan provided valuable criticisms, here acknowledged. The authors are members of the Gonsejo Nacioual de Investigacion Gientihca y Tecno- logica (GONIGET), Argentina. This paper was partly funded by PIGT2005 38015 from ANPGyT.


Dell, R. K, 1964. Antarctic and sub-Antarctic Mollusca: Amphineura, Scaphopoda and Bi\alvia. Discovery Reports 33: 93-250, pis. 2-7.

Dell, R. K. 1990. Antarctic Mollusca wdth special reference to the fauna of the Ross Sea. Bulletin of the Royal Society of New Zealand 27: 1-311.

Lainy, E. 1917. ReHsion des Crassatellidae vivants du Museum d’Histoire Naturelle de Paris. Journal de Conchyliologie 62(4); 197-270, pi. 6.

Pelseneer, P. 1903. Mollusques (Ainplrineures, Gastropodes et Lamellihranches). Resultats du Voyage du S.Y. 'Belgica'. Expe- dition Antarctique Beige 1897-1899, zoologie 3: 1-85, 9 pis. Thiele, J. 1934. Handbuch der systeinatischen Weichtier- kunde. Gustav Eischer Verlag, Jena. Bd 3, Dritter Teil, pp. 119.3-1528.

Zelaya, D. G. 2008. Reallocation of Cyamiacardium crassilab- niin Dell, 1964, into Penieiina Bernard, 1897 (Bivalvia: Gyamiidae). The Nautilus 122: 52-55.

THE NAUTILUS 123(1):9-13, 2009

Page 9

Phylogenetic position of the bivalve family Cyrenoididae removal from (and further dismantling of) the superfamily Lncinoidea

John D. Taylor Emily A. Glover Suzanne T. Williams

Department of Zoology

The Natural History Miiseuiir




s.\villiams@nhm. ac.uk


A molecular analysis using sequences from I8S and 28S rKNA genes of the brackisli and freshwater bivalve Cijrenoida flori- dana, in conjunction wdth a wide range of other heterodont biwilves, demonstrated a close I'elationship with the families Corbiculidae and Glauconomidae and distant from the laici- noidea, wliere the Cyi'enoididae liad been usually classified. Based on this result it is proposed that the Cyrenoididae be removed from the Lucinoidea, which, for lixing taxa, now includes only tire family Lucinidae.

Additional Kci/words: Bixalvia, fleterodonta,

Cijrenoida floridana, 18S rKNA, 28S rRNA


Until recently, most ' classifications of bivalve mollusks included within the snperfamily Lucinoidea several component families (Lucinidae, Fimbriidae, Thyasiri- dae, Ungulinidae Cyrenoididae, and fossil iVIactrom)-!- dae) (e.g. Dali, 1901; Chavan, 1969; Boss, 1982, Vaught, 1989; Amler, 1999). The Lucinidae and some Thyasiri- dae are notable for the chemosvmbiosis wdth sulphide- oxidizing bacteria housetl in the ctenidia (Southward, 1986; Taylor and Glover, 2006). Molecular analyses of tlie Lucinoidea, compared wdth a wdde range of other heterodont bivalves, demonstrated that superfamily was not monophyletic, wdth the Thyasiridae and Uugiili- nidae not closely related to the Lucinidae (Williams, Tay- lor, and Glover, 2004; Taylor, Williams, and Glover, 2007; Taylor et ah, 2007). The Ungulinidae group near families such as the Veueridae, Corbiculidae, and Mactridae, while the Thyasiridae form a basal clade within the Euheterodonta and are considered as a distinct snperfamily Thyasiroidea. Fimbria fimhriata, one of the two living species of Fimbriidae, nested together

wdth Lucinidae species, wdth no support for separate lamilial status, and the nominal family w'as syuonymized accordingly. Apart from the Lucinidae, the only other family wdth living species still classified wdthin Luciuoi- dea is the Cvrenoididae, but lack of suitably presen’ed material has precluded inclusion in molecular analyses. From morphological exidence, Williams et ah (2004) and Taylor and Glover (2006) thought a relationship to the Lucinidae unlikely, Cijrenoida havdng medium to long fused siphons, well developed labial palps and ctenidia wdth two demibrauchs. These statements led Bieler and Alikkelsen (2006) to place Cyrenoididae as incciiae scdis.

The Cyrenoididae Adams and Adams, 1857 (= Cyre- nellidae Gray, 1853) comprise a small group of around ten nominal species of little-studied bixalves inhabiting brackish to freshwaters, classified into a single genus, Cijrenoida (txq^e species C. diiponfia joannis, 1835) (Figures 1-3), distributed in western Africa, eastern and w^esteru Americas and some islands of the Garibbe- an. The West African species inhabit brackish mangrove habitats (Pilsbiy and Bequaert, 1927). In the eastern USA, Cijrenoida floridana Dali, 1901 (Figures 4-7) ranges from Dehuvare to the coast of the Gulf of Mexico, maybe as far west as Yucatan (\"okes and Wkes, 1983), w'here it inhabits fresh and brackish water habi- tats (Leathern, Kinuer, and Maurer, 1976; Kat, 1982; Bishop and Hackney, 1987).

Dali (1895) was the first to place the Gyrenoididae within the Lucinoidea, .stating (p. 545) “These are estua- rine Lucinacea.” Later (Dali, 1901: 817) stated “. . .shells ol this group with a Luciuoid animal and Diplodonta- like shell, exhibit a hinge .structure w'hich is w'holly distinct from any other of the Lucinacea.” Many later classifications, inciudiug the iulluential Treatise of Inver- tebrate Paleontology (Ghavau, 1969), lollow^ed Dali in placing the Gyrenoididae within the Lucinoidea (e.g. Yokes, 1980; Boss, 1982, Vaught, 1989, Skelton and Ben- ton, 1993; Amler, 1999).

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Figures 1-7. Ci/reuoida (hipcnitid (1-3) and C. flohdana (4-7). 1. Cijrenoida dnpoiitia Joannis, left valve, Senegal (BMNH 2008 10.5.5). Scale bar = 10 nun. 2-3. Hinge teeth ol Ci/rcnoida dupontia. right \-alve (2) and left valve (3). Scale bar = 2 nun. 4. Cipvnoida floiidaiui Dali, left valve. Blue Hole, Big Pine Key, Florida (BMNH 200S1054). Scale bar = 2 niin, .5-6. Hinge teeth (SEM images) ol Ci/rcnoida floridtma, right \alve (.5) and left \'alve (6) (BMNH 20081054). Scale Irar = 500 [.nn. 7. Ciirenoida lloiidnna. liv ing specimen with short, fused sijrhons. Blue Hole, Big Pine Key, Florida. (Photo R. Bieler, September 2007).

Nevertheless, dillerent opinions were expressed hy other authors, I'ischer (1887: 1096), for exainple, placed Cyrenoididae (as Cyrenellidae) into a suborder Concha- cea, near [oCorhicuIn and Ungnlinidae hut apart from the Lncinoidea. W'hile Thiele (1934) included Cyrenoididae with other Iresh and brackish water bivalves in the.s7/rp,s' Sphaeriacea hut not positioned closely to laicinoidea. The lainily was elevated to siiperlaniily status by Olsson ( 1961 : 227) hut placed near to Lncinoidea, a decision also lol- lowed hy Keen (1971). The snperlaniily Cyrenoidoidea was also recognized hy Nevesskaya et al. (1971) and

placed along with Lncinoidea in the order Astartida. Alternatively, and rather hizarrely, Starohogatov (1992) placed Cyrenoidoidea within the infraorder Eiycinoinei along witli Cyainioidea, Galeonnnatoidea and Leptonoi- tlea, all contained within the order Lncinifornies.

Clearly, there e.xists ninch uncertainty concerning the pliylogenetic position of Cyrenoididae amongst the het- erodont bivalves hut this has never been tested hy either morphological or molecular analyses. In 2007, we obtained samples of Ci/reiioida floridana suitable for molecular analysis and in this paper we present 18S and

J. D. Taylor et al„ 2009

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28S rRNA sequences for the species that enable ns to establisli the phylogenetic position ol the lainily in rela- tion to a wade range ol heterodont bivalve taxa previous- ly analysed (Taylor et ah, 2007) and specilically address the question of whether the Lncinidae and Cyrenoidi- dae form a monophyletic group.


The sample ol Cifrenoida floriclaiia, presen-ed in 100% ethanol (BAINH 20081053), wars collected (18 Septem- ber 2007) from Bine Hole (24°42.4' N, 81°22.8' W) a freshwater pond on Big Pine Key, Monroe County, Elor- ida Keys, Elorida, USA, from slioreline mnd up to 0.5 m depth among roots of marginal reeds. Other material from the same site is lodged at the Eield Mnsenm ol Natural History (EMNH 314434; 317667).

Eor tlie molecular analysis, methods of DNA e.xtrac- tion, amplification anti sequencing followed by sequence analysis and phylogenetic reconstruction are as described in Taylor et al. (2007). Sequences for Ci/re- noicla florichina were analysed together wath the data set of heterodonts listed in Taylor et al. (2007, Table 1), with the addition of new 18S and 28S sequences for Mi/a arenaria Linnaeus, 1758 (family Myidae) from Gydnia, Poland. The new^ setjnences for Cifrenoida floridana anti Mija arenaria are lodged in GenBank (Accession nnm- bers: C. floridana F’M999789, EAI999790; M. arenaria EM999791, 779792). Voucher specimens t)l both species are housed in the Department of Zoology, The Natural History Museum, Lt)udon.

Phylogenies were constructetl using Bayesian meth- ods (MrBayes v3.1.2, Huelsenbeck and Rompiist, 2001) using a GTR+G+I mt)tlel. The analysis for each data set was run for 3,500,000 generations, with a sample fre- tjuency of 100. Each analysis wais run twice. The first 15,000 trees from each run were tliscartletl so that the final cotisensus tree was based ttn the ettmbination of accepted trees from each run (a total of 40,000 trees). Support for nodes w'as determinetl using pttstei'ior prt)b- abilities (PP, calculatetl by MrBayes).


The combined tree based on concatenated sequences from 18S rRNA and 28S rRNA genes is showm in Eigure 8. The individual trees based on single genes ai'e very similar in topolog)' to those published previously (Taylor et ak, 2007). In all analyses Cifrenoida floridana nests in a highly supported clade wath Corbiciila fliiininea (Corbiculidae) and Claiiconoine virens (Glauconomidae). This clade forms part of a major group of heterodonts named Neoheterodontei by Taylor et al. (2007). Cifre- noida is widely separated from both Thyasiridae and Lncinidae that appear in the more basal parts of the tree. The Ungnlinidae, althongh also a member of the Neoheterodontei, lorm a separate clade distinct from Cifrenoida.


It would have been desirable to have included the t\pe species of Cifrenoida. namely, Cifrenoida diipontia [oan- nis, 1835, from West Africa, in the molecular analysis but no suitably presei'ved material wais a\’ailable. Al- though a much smaller species, C. floridana is similar to C. diipontia in shell characters, notably the unusual hinge dentition, and we feel confident that they are members of the same group, Cifrenoida dii))onlia has three cardinal teeth in the riglit valve, the anterior of these is tliin and elongate and tlie central tooth larger and sliglitly bifid (Eigures 2-3) wdiile the left \ alve has two cardinals, the posterior tooth smaller and bilid and the anterior tooth elongate. Lateral teeth are absent. The dentition of C. floridana is veiw similar (Eigures 4-6) w'ith three cardinal teeth in the right valve, the central being larger and two caixlinal teetli in the left wilve watli the posterior tooth Ihfid and the anterior tooth elongate. We have also e.xamined the gross anatomy of Cifrenoida rosea (d'Aillv, 1896) from Nigeria (National Mnsenm of Wales specimen NMW.Z.2()03.029.()2()4f ) and this has ctenidia with hvo demibranchs, with the inner demi- branch larger, paired triangular labial palps, and ftised medinm-length posterior siphons. Cifrenoida floridana is similar, wath small outer demibranchs, triangular labial palps and short I used posterior siphons, the inl ialant with papillae (Eigure 7), Despite the presence of siphons, there is no pallial sinus in any Cifrenoida .species.

The inain conclusion ol this study, based on our results lor Cifrenoida floridana, is that the Cyreuoididae sliould be removed h'om the Lucinoidea and classified close to, or possibly wathin, the Corbiculoidea. The status ol Cifre- noida in relation to Corbiculidae and Glauconomidae needs further analysis witli a larger dataset of corbicnlid species. Eor the present the family can be classified wdth- in a separate superfamily Cyrenoidoidea as proposetl by Olsson (1961). Molecular evidence for a liighlv sup- ported relationship betw^eeu Corbiculidae and (ilauco- nomidae was reported by Taylor et al. (2007) although the elongate shells with deep pallial sinus ami long siphons of Glaneonoine are less similar morphologically to Cyrenoididae and Corbiculidae. Species of Cyreuoidi- dae and Corbiculidae occur in botli brackish and Iresh- water habitats while Glauconomidae live intertidally among mangroves in em ironments ol lluctuating salinity.

Eor living taxa, w^e consider that tlie superfamily Imci- uoidea should uow' include only the lamily Lncinidae, wath the families Thyasiridae, Ungnlinidae and Cyreuoi- didae excluded. The position ol the entirely fossil families Mactromyadae, llionidae, ami Paracyclidae is unresolved althongh the latter two embrace species with Incinid characters.


It is pleasure to tliank Riidiger Bieler and Petra Sienvald for generous hospitality and help iu collection ol

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100 I


Neotngonia lamarcku TRiGONllDAE

Margantifera margantifera MARGARITIFERIDAE

Unopictorum (JNIONIOAE



Anodonta cygnea Card>ta leana CARDITIDAE As/arte sulcata ASTARTIDAE Eucrassatelia donaana Eucrassatella cuinmgn

TOO I' ■' Thyastra polygona

THVASIRIDAE Mendicula /erruginosa


Poromya iltevis POROMYIDAE



Lunuhcardium hemicardium




Chama senvpurpurata CHAMiOAE

Chama asparsa


Figure 8. Molecular phylogeny of heterodont hivalves including Cijrenoida produced by Bayesian analysis for concatenated se(jiiences from 18S and 28S rHNA genes. The tree was drawn using members ol the palaeoheterodonts Trigoniidae, Unionidae, and Margaritileridae as outgroups. Support values are posterior probabilities. Nodes with <50% support have been collapsed. Positions of Lucinoidea, Thyasiroidea, and Ungulinoidea marked by grey bars. Details of t;ixa in Taylor et al. (2007).

C. finridaua. We are grateful to Pat Dyal for assistance with molecular analysis and to Graham Oliver (National IVlnsemn ol Wales) for making a specimen of Ctireiwida rosea available. We thank Professor Idiil Rainbow and Department of Zoology, NIIM for continuing support.

Research on this exemplar species in the Bivalve Tree-of- Life project (www.bivatol.org <http://www.bivatol.org/>) was supported by the U.S. National Science Foundation AToL program (DEB-()732854/()7329()3/0732860). The specimens were collected under U.S. Fi.sh and Wildlife

J. D. T\iylor et al„ 2009

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Senice Special Use Permit 41580-2007-11 (to lliidiger

Bieler) for reseai'ch on native mollnscan species in the

National Key Deer Refuge.


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