Journal of Conchology 41 (4), November 2013

ISSN 2755-3531

 

Opisthobranchiate Mollusca from Ghana: Onchidorididae and Aegiridae, with a checklist and a review of the ecology and diversity of the Doridoidea

Malcolm Edmunds

Abstract. Descriptions are given of Onchidoris depressa (Alder & Hancock 1842) and Aegires punctilucens (d’Orbigny 1837) from Ghana belonging to the families Onchidorididae and Aegiridae respectively, both of which are widespread in temperate waters of the North-east Atlantic, together with brief descriptions of six further species of doridoid nudibranchs which are insufficiently documented to justify their being formally described and named. Fifty-three species of dorididoid nudibranchs have been recorded from Ghana, the most biodiverse site being the shallow 10 m deep offshore reef. It is estimated that a more intensive study might have yielded more than 70 species, but this is far fewer than can be found in the tropical Indo-Pacific region, probably because West Africa experiences a cold water current and lacks coral reefs. Thirty-one of the 53 species are currently only known from Ghana, probably because west African nudibranchs are so poorly known. Others also occur elsewhere in the Gulf of Guinea, Angola, the Azores, Canaries, Madeira, the Mediterranean and even northern Europe. There are 7 amphiatlantic species and 4 recorded from the Indo-Pacific, these latter probably being transported by boats.

Key words. Doridoidea, Onchidoris, Aegires, ecology, biodiversity

Date of publication. November 2013

 

Spurilla dakariensis Pruvot-Fol 1953 (Mollusca: Opisthobranchia: Aeolidoidea), a valid species of Berghia Trinchese 1877 from Senegal, West Africa

Manuel Caballer & Jesús Ortea

Abstract. Spurilla dakariensis Pruvot-Fol 1953, a poorly known species from west Africa, is redescribed based on a specimen collected alive in Gorée Bay, Senegal, during the campaign Dakar'09. A neotype is designated and new data are provided on the colouration and the external and the internal anatomy. The characters observed suggest that S. dakariensis is indeed a valid species of the genus Berghia Trinchese 1877, thus, a new combination for this taxon is proposed: Berghia dakariensis new combination.

Key words. Mollusca, Berghia dakariensis, new combination, redescription, Senegal

Date of publication. November 2013

 

The many tails of Akera bullata Müller 1776 (Gastropoda: Aplysiomorpha)

J. C. A. Craik

Abstract. The original description of the opisthobranch gastropod Akera bullata mentions a tail-like trailing “pallial filament”. Several other early descriptions illustrate this structure, as do a recent field guide and other authoritative works. However, this filament is absent from (at least some) British and Irish populations. In a population in west Scotland there is no such structure, but many individuals have “tails” of two kinds—trails of mucus containing pseudofaeces, or filamentous algae growing on the shell. Using the latter as an example, I tentatively propose that the “pallial filament” of early authors was not a genuine body part but another organism, possibly a hydroid coelenterate, growing on the shell. This needs verification by examination of Akera with a filament like that described by early authors. However, there seem to have been no first-hand descriptions of animals with this structure since Tchang-Si (1931).

Key words. Akera bullata, commensal, algae, filament, mucus, pseudofaeces

Date of publication. November 2013

 

On the discovery of a new Volutopsius (Gastropoda, Buccinidae) from the north-eastern Atlantic Ocean

Koen Fraussen, David W. McKay & Jim Drewery

Abstract. During an ongoing research programme to investigate fishing grounds on and around the Rockall Plateau and along the continental slope to the west of Scotland the scientific staff on board of R/V Scotia collected a number of Mollusca as a by-catch, among them several Buccinidae. Two of the larger species deserve more attention: Beringius bogasoni Warén & Smith 2006 and specimens of an unknown Volutopsius. The latter can be distinguished from Volutopsius norwegicus (Gmelin 1791) by the spiral sculpture and is added to the British Fauna as Volutopsius scotiae sp. nov.

Key words. Atlantic, Rockall, Buccinidae, Beringius, Volutopsius, new taxon

New taxon. Volutopsius scotiae Fraussen, McKay & Drewery, 2013

Date of publication. November 2013

 

Mitromorpha (Mitrolumna) diaoyuensis n. sp. (Prosobranchia: Conidae), a new species from the Diaoyu (Senkaku) Islands, East China Sea

Constantine Mifsud

Abstract. A new species of Mitromorpha Carpenter 1865, subgenus Mitrolumna Bucquoy, Dautzenberg & Dollfus 1883 is described from the circalittoral of the East China Sea for the first time.

Key words. Conidae, Mitromorphidae, Mitromorpha nov. sp., Diaoyu Islands, East China

New taxon. Mitromorpha (Mitrolumna) diaoyuensisMifsud, 2013

Date of publication. November 2013

 

The genus Daphnellopsis (Gastropoda: Muricidae) in the Recent and Quaternary of the Indo-West Pacific Province

Roland Houart

Abstract. The muricid genus Daphnellopsis Schepman 1913 is revised and maintained in the subfamily Ergalataxinae, waiting for eventual genetic studies. Six species are included, D. fimbriata (Hinds 1843), D. lamellosa Schepman 1913 (type species), D. hypselos Houart 1995 and three new species described herein: D. lozoueti n. sp.; and D. pinedai n. sp., both from the Quaternary (Upper Pleistocene) of Santo, Vanuatu, and D. lochi n. sp. a Recent species of Western Australia. All the species are described or re-described, illustrated and compared with each other, their geographical range is given and illustrated on a map. The protoconchs of five species are illustrated as well as some details of the shells. A jaw is pointed out for the first time in D. fimbriata and is illustrated by scanning electron microscope (SEM) images.

Key words. Gastropoda, Muricidae, Ergalataxinae, Daphnellopsis, Indo-West Pacific

New taxa. Daphnellopsis lozoueti Houart, 2013; Daphnellopsis pinedai Houart, 2013; Daphnellopsis lochi Houart, 2013

Date of publication. November 2013

 

Systematics of the Acanthocardia paucicostata group in the Mediterranean Plio-Pleistocene, with description of a new species (Bivalvia, Cardiidae)

Rafael La Perna & Mauro D’Abramo

Abstract. Three Acanthocardia species, namely A. paucicostata (Sowerby 1841), A. bianconiana (Cocconi 1873) and a new species herein described are particularly similar to each other, sharing some shell characters: shell relatively thin-walled, compared with the congeners, tending to be antero-posteriorly elongate, bearing a low number of radial ribs (15–18). A. paucicostata is an extant species with a stratigraphic distribution ranging back to the Late Miocene at least. A. bianconiana, regarded as a variety or subspecies of A. paucicostata in the past literature, had a Plio-Pleistocene Mediterranean distribution. The new species, A. brunettii n.sp., the smallest Acanthocardia species so far known and with an unusually elongate shape, also had a Plio-Pleistocene distribution. There are evidences that the paucicostata group also had representatives in the Miocene, either in the paleo-Mediterranean or the Paratethys.

Key words. Acanthocardia, Plio-Pleistocene, Mediterranean, systematics, new species

New taxon. Acanthocardia brunettii La Perna & D’Abramo, 2013

Date of publication. November 2013

 

A review of Retinella (Lyrodiscus): the endemic Zonitidae of the Canary Islands

Maria R. Alonso, David T. Holyoak, Geraldine A. Holyoak, Yurena Yanes & Miguel Ibáñez

Abstract. The genital anatomy is described for all five island populations of Retinella (Lyrodiscus) endemic in the Canary Islands, revealing that it is mainly similar to that of the only species studied previously (R. circumsessa). Their shell characters, detailed distribution and habitat preferences are also described and reassessed. Five species are recognised. The population of El Hierro has hitherto been assigned to R. lenis, the species on La Palma, but it is named as a new species here. Descriptions of species from the south-west Alps by Giusti et al. (1986) revealed additional combinations of anatomical and shell characters that made it impossible to identify the limits of subgenera among the European Retinella species. Lyrodiscus was regarded by them as a possible exception to this because of its peculiar shell sculpture. Since our data show that the endemic Canary Islands species assigned to Lyrodiscus from conchological characters are also very similar to each other anatomically, it is useful to retain them together in the same subgeneric group until a phylogenetic study provides an adequate basis for a revised classification. Two additional Lyrodiscus species showing the characteristic shell sculpture are known from fossils in NW. Europe. Hence, it is argued that the species still living in the Canary Islands can most easily be regarded as relicts of a fauna that was widespread in NW. Europe in the Neogene and early Pleistocene. There, they apparently became extinct during the cold conditions of the Late Pleistocene glacial stages, whereas they survived in the milder climates within forest and scrub-covered habitats on the Canary Islands.

Key words. Macaronesia, Canary Islands, Retinella, Lyrodiscus, subgenera, Zonitidae, genital anatomy, genital pore, shells, palaeobiogeography, island endemics, Tertiary relicts, Pleistocene fossils

New taxon. Retinella hierroensis Alonso & Ibáñez, 2013

Date of publication. November 2013

 

Taxonomic revision of Leiostracus onager and Leiostracus subtuszonatus (Gastropoda: Pulmonata: Orthalicidae)

Rodrigo Brincalepe Salvador & Daniel Caracanhas Cavallari

Abstract. Leiostracus subtuszonatus (Pilsbry 1899) was originally described as a colour variant of L. onager (Beck 1837). Here we conduct a taxonomic revision of these two species and regard them as separate taxa, distinguished by shell size, colour pattern, whorl convexity and protoconch sculpture. We also define a neotype for each species and offer updated descriptions, diagnosis and geographical ranges.

Key words. Bahia state, Brazil, Leiostracus, Bulimulinae, land snails, Stylommatophora

Date of publication. November 2013

 

Habeas, a new genus of Diplommatinidae from Central Bahia, Brazil (Caenogastropoda), with description of three new species

Luiz Ricardo L. Simone

Abstract. A new genus of Diplommatinidae is described, based on samples collected in cave environment in Bahia state, Brazil. The genus Habeas n. gen. is described based on distinctive characters, such as uniformity of spiral growth, displaced peristome, umbilicus and relative large size. Three new species are also described: Habeas corpus n. sp. (the type species), from Carinhanha (cave environment), is the largest one, with wide opened umbilicus and the peristome located away from the penultimate whorl; Habeas data n.sp., also from caves of Carinhanha, is the medium species and has a weak developed sculpture, peristome attached to penultimate whorl, and the umbilicus only opened in last whorl; Habeas priscus n.sp., from Central, Caatinga vegetation, is the smallest species, and is mainly characterized by the dome-shaped spire. The description of these species shows how many taxa still remain to be discovered in Brazilian caves and Caatinga phytosionomy, and brings additional argumentation for environment preservation.

Key words. Habeas, new genus, Diplommatinidae, cave environment, new species, Caenogastropoda

New taxa. Habeas Simone, 2013; Habeas corpus Simone, 2013; Habeas data Simone, 2013; Habeas priscus Simone, 2013

Date of publication. November 2013

 

Description of a new Pseudobithynia n. sp. (Gastropoda: Bithyniidae) from northwest Turkey 

Deniz Anıl Odabaşı, Ümit Kebapçı & Mehmet Akbulut

Abstract. The family Bithyniidae widely distributed in the Balkans and is represented by two genera in Europe: Bithynia and Pseudobithynia. More recent data about the Bithyniidae shows that the majority of family members are distributed in the Balkans and especially Greece. Seven species of Bithynia but only one of Pseudobithynia is currently known from Turkey. This study is aimed at describing a new species, Pseudobithynia yildirimi n. sp. from the Biga Peninsula in northwestern Turkey. Pseudobithynia yildirimi n. sp. is compared to related taxa in Turkey, as well as in Greece and neighbouring Iran. The penis variability and status of pseudo-maleness in P. yildirimi were also investigated.

Key words. Gastropoda, Bithyniidae, Pseudobithynia yildirimi n. sp., Biga Peninsula, Turkey

New taxon. Pseudobithynia yildirimi Odabaşı, Kebapçı & Akbulut, 2013

Date of publication. November 2013

 

 

Four new species of Streptaxidae from Mfamosing limestone hills in southeastern Nigeria

Christopher Omamoke Oke

Abstract. Four new species of Streptaxidae (Mollusca, Gastropoda Pulmonata) are described from the threatened limestone hills in Mfamosing, Cross River State, southeastern Nigeria. The described species are Costigulella mfamosingi, Gulella odietei, G. ogbeifuni, and G. (Conogulella) egborgei.

Key words. Mollusca, Streptaxidae, Gulella, Costigulella, Conogulella, Nigeria

New taxa. Costigulella mfamosingi Oke, 2013; Gulella odietei Oke, 2013; Gulella ogbeifuni Oke, 2013; Gulella (Conogulella) egborgei Oke, 2013

Date of publication. November 2013

 

A first record of Sphaerium nucleus in Wales [Short Communication]

C. Clifford, G. R. Thomas, R. Taylor & D.W. Forman

Date of publication. November 2013