Journal of Conchology 42 (5), February 2017

ISSN 2755-3531


Celebrating John A. Allen’s contributions to malacology in his 90th year


The publications and new nominal taxa introduced by John A. Allen

P. Graham Oliver & Fiona Hannah

Date of publication: February 2017


Thyasiridae (Mollusca: Bivalvia) from the Kemp Caldera hydrothermal site, South Sandwich Islands, Antarctica

P. Graham Oliver & Clara F. Rodrigues

Abstract Two species of thyasirid bivalve are described from the Kemp Caldera hydrothermal site, South Sandwich Island back arc system, Antarctica. Spinaxinus caldarium n. sp. is hemosymbiotic and closely related to S. emicatus from the Gulf of Mexico with which it shares the same phylotype of symbiotic bacterium. Parathyasira cf. dearborni is not symbiotic and most closely resembles P. dearborni a widespread circum antarctic species. The gill anatomy is described for both species and molecular data on the bivalves and the symbiotic bacteria are presented.

Key words. Thyasiridae, Antarctica, chemosymbiosis, anatomy, new species

New taxon. Spinaxinus caldarium Oliver & Rodrigues, 2017

Date of publication: February 2017


Paleocene protobranch bivalves from Urahoro town in eastern Hokkaido, northern Japan

Kazutaka Amano & Robert G. Jenkins

Abstract. Eleven protobranch species are described from deep-sea deposits of the Paleocene Katsuhira Formation. Among them, one new genus and three new species are included; Meganuculana n. gen., M. alleni n. sp., Neilonella alleni n. sp. and Tindaria paleocenica n. sp. Acila (Truncacila) hokkaidoensis, Pristigloma? sachalinensis, Ezonuculana and Menneroctenia survived the End-Cretaceous Mass Extinction and became extinct by the end of Paleocene. Such a pattern of extinction is similar to that of the deep-sea benthonic foraminifers.

New taxa. Meganuculana Amano & Jenkins, 2017; Meganuculana alleni Amano & Jenkins, 2017; Neilonella alleni Amano & Jenkins, 2017; Tindaria paleocenica Amano & Jenkins, 2017

Date of publication: February 2017


The burrowing behaviour of symbiotic and asymbiotic thyasirid bivalves

Heather Zanzerl & Suzanne C. Dufour

Abstract. The bivalve family Thyasiridae includes species living in symbiosis with chemoautotrophic, sulphur-oxidizing bacteria and others that are asymbiotic. Chemosymbiotic thyasirids create extensive ramifying burrows (pedal tracts), presumably to acquire reduced sulphur for their symbionts. Here, we investigate whether asymbiotic thyasirids may also form pedal tracts. We compared the behaviour of asymbiotic (Parathyasira sp. and Thyasira cf. gouldi operational taxonomic unit 3) and symbiotic (Thyasira cf. gouldi operational taxonomic units 1 and 2) thyasirids from Bonne Bay, Newfoundland Canada, maintained in thin tanks in flow-through aquaria. Photographs and X-radiographs of thin tanks showed that all thyasirids established pedal tracts, with no discernible difference in the depth, total length or number of pedal tracts among taxa. We interpret thyasirid pedal tract formation as an early adaptation for pedal feeding, likely combined with the farming of chemosynthetic bacteria along burrow walls. Pedal tract formation could also be a precursor to chemosymbiosis establishment in the Thyasiridae.

Key words. Thyasiridae, symbiosis, burrows, Thyasira, Parathyasira

Date of publication: February 2017


Deep-sea bivalves of the North American and Argentine basins: a comparison of species diversity and functional diversity using John Allen’s (2008) database

Carol T. Stuart & Michael A. Rex

Abstract. We analyzed bathymetric trends in species diversity and feeding types in deep-sea bivalves of the North American and Argentine Basins in the western Atlantic using Allen’s (2008) taxonomic database, and related these trends to energy availability. Chemical energy was assessed as particulate organic carbon (POC) flux to the seafloor, and kinetic energy by bottom water temperature. POC flux and temperature show significant and highly regular exponential declines with depth, the Argentine Basin having higher POC flux and lower temperature across most of the depth range sampled (upper bathyal to abyss). Both basins show unimodal diversity-depth patterns. Peak diversity is deeper and abyssal diversity higher in the Argentine Basin. POC flux was the primary predictor of species diversity. Bivalve taxa were classified as deposit feeders, filter feeders, or carnivores as an indication of functional diversity. In both basins, deposit feeders increased with depth and filter feeders decreased, probably as a function of sediment and suspended food resources respectively. Carnivores were a minor constituent throughout the depth range. POC flux was the most effective predictor of feeding categories.

Key words. Deep-sea, bivalves, North American Basin, Argentine Basin, diversity

Date of publication: February 2017


Phylogenetics of British saddle oysters (Bivalvia: Anomiidae)—a review of the shell morphology, internal anatomy and genetics of Pododesmus in British waters

Anna M. Holmes

Abstract The number of saddle oyster species (Anomiidae) in British waters has long been a contentious subject and the genus Pododesmus the main cause of this confusion. To clarify the issue a study was carried out on several samples of Pododesmus species from around the coast of the United Kingdom. Integrative taxonomy using anatomy, shell morphology and molecular methods revealed 2 species of Pododesmus. Conclusive results in all three areas of study provide evidence of two distinct species of Pododesmus: Pododesmus patelliformis (Linnaeus, 1761) and Pododesmus squama (Gmelin, 1791).

Key words. Saddle oyster, Pododesmus patelliformis, Pododesmus squama, COI, Anomiidae, radial striations

Date of publication: February 2017


Relic land snails in the Caucasian glacial refugium: a first non-fossil record of Vallonia tenuilabris from western Eurasia

I. Balashov & P. Kijashko

Abstract. In the upper part of the Sophia River Valley near Arkhyz village (Northern Caucasus, Russia) at an altitude of 2000–3000 m an unusual species composition of land snails was observed. The species composition herewith reported is similar to that known from the Pleistocene of the East European Plain and consists of 14 species, including 3 extremely rare and with fragmented distributions: Vallonia tenuilabris, Zoogenetes harpa and Pupilla sterrii. Most of other species are common and widespread and only 2 of the 14 are Caucasian endemics. It suggests that this species composition originates from the Pleistocene malacofauna of the Ciscaucasia and adjacent territories of the East European Plain and the Sophia River Valley is a glacial refugium. The 56 collected specimens of P. sterrii are not quite usual—all their shells have no white callus that is normally present in this species and several specimens are toothless or have 3 teeth (normally 2 teeth are present).

Key words. Pleistocene, relics, terrestrial molluscs, Caucasus

Date of publication: February 2017


Late Cretaceous Pupoides Pfeiffer 1854 (Gastropoda: Pupillidae) from Uruguay (Queguay Formation)

F. Cabrera & S. Martínez

Abstract. A new species of Pupoides Pfeiffer 1854, subgenus Ischnopupoides Pilsbry 1926, is described for the Late Cretaceous of Uruguay (Queguay Formation), being the oldest record of the genus and subgenus. Pupoides (I.) gnocco new species is characterized by a small dextral fusiform shell, constituted by a spire comprising five slightly convex whorls, oblicuous axial ornamentation, subrounded aperture, and an expanded outer lip that lacks dentition.

Key words. Pupillidae, Ischnopupoides, Late Cretaceous, Uruguay

New taxon. Pupoides (Ischnopupoides) gnocco Cabrera & Martínez, 2017

Date of publication: February 2017


Heterobranchia Mollusca from Ghana: the traditionally called Dendronotacea and Arminacea

Malcolm Edmunds & Leila Carmona

Abstract. Seven species of Dendronotacea and three of Arminacea collected in Ghana between 1963 and 1973 are described. Three are new species: Marionia ghanensis, Kabeiro atlantica and Janolus kinoi, while two more require further material before they can be definitively identified: Doto species A and Armina species A. Hancockia uncinata, Scyllaea pelagica, Tethys fimbria, Tritonia manicata and Janolus hyalinus occur widely in the north-east Atlantic. Specimens of five species were found on Sargassum so these could easily drift considerable distances across the ocean, which could account for their wide geographical occurrence.

Key words. Dendronotacea, Arminacea, taxonomy

New taxa. Marionia ghanensis Edmunds & Carmona, 2017; Kabeiro atlantica Edmunds & Carmona, 2017; Janolus kinoi Edmunds & Carmona, 2017

Date of publication: February 2017


A new alien species in Europe: first record of Austropeplea viridis (Quoy & GAIMARD, 1833) (Mollusca, Gastropoda, Lymnaeidae) in Spain

Katrin Schniebs, Peter Glöer, Maxim V. Vinarski, Sergio Quiñonero-Salgado, Joaquin Lopez-Soriano & Anna K. Hundsdoerfer

Abstract. Freshwater snails of the genus Austropeplea were found on rice fields in Spain. It is the first record of this genus in Europe, very distant from all previously known localities of this taxon. By comparison of sequence data of the nuclear marker ITS-2 two specimens analysed fell into one cluster with GenBank sequences from Austropeplea viridis (Quoy & Gaimard, 1833) from Thailand and Australia, a Radix sp. sequence (GenBank) from Turkey and own sequences from Orientogalba specimens from China and Mongolia. Morphologically, the newly found snails correspond to specimens of A. viridis from Central Asia as well as to the syntypes of Lymnaea viridis collected in Guam. This finding confirms the high potential of aquatic pulmonate snails as successful transcontinental invaders.

Key words. Austropeplea viridis, Lymnaeidae, alien Species, Europe, molecular genetics

Date of publication: February 2017


The gall-former Sabinella troglodytes (Caenogastropoda: Eulimidae) and its association with Eucidaris tribuloides (Echinodermata: Echinoidea)

Vinicius Queiroz, Elizabeth Neves, Licia Sales & Rodrigo Johnsson

Abstract. Eulimids snails are renowned for their parasitic habits on Echinodermata. These gastropods can be ectoparasites, endoparasites and some groups are able to make gall in their host. This is the case of the Caribbean eulimid Sabinella troglodytes, which lives in association with the cidaroid sea urchin Eucidaris tribuloides. The present work describes the lifecycle of S. troglodytes, studied in situ over four years and reports on unprecedented data on the species’ reproductive behaviour. During the dry season, from September to March, most galls are occupied by couples of snails and newly laid egg masses. In observations during the wet period of the year, May to August, adult specimens are rarely found and juvenile stages can be observed whilst settling and crawling the spines. The feeding mechanism can also be observed in live specimens maintained in the laboratory indicating that the snails erodes the epithelium and the calcareous matrix as well. Finally this work also records for the first time the occurrence of S. troglodytes in the South Atlantic Ocean, extending its range of distribution, previously restricted to Florida and Caribbean, to Brazil.

Key words. Eulimidae, gall, sea urchin, symbiosis

Date of publication: February 2017


First report of Antigona somwangi Huber, 2010 (Mollusca: Bivalvia: Veneridae) from India [Short Communication]

R.D. Rocktim, G. Kantharajan, S. Goutham, V. Deepak Samuel, P. Krishnan, R. Rajkumar & R. Purvaja

Date of publication: February 2017


Newly overlapping ranges: first records of Potomida littoralis (Cuvier, 1798) infestation by the European Bitterling Rhodeus amarus (Bloch, 1782) [Short Communication]

Vincent Prié

Date of publication: February 2017


Not yet extirpated! Potomida littoralis (Cuvier 1798) living in the Seine drainage [Short Communication]

Xavier Cucherat & Laurent Philippe

Date of publication: February 2017


A third locality for Helicella (H.) valdeona (Gastropoda: Hygromiidae) [Short Communication]

Ron Carr

Date of publication: February 2017