Journal of Conchology 43 (6), October 2020

ISSN 2755-3531


Phylogeny, species-limits and taxonomic revision of Otalini (Helicidae) from North-West Africa

David T. Holyoak, Geraldine A. Holyoak, Benjamín J. Gómez Moliner & Luis J. Chueca

Abstract. The affinities and detailed phylogeny of the tribe Otalini of the Helicidae are elucidated from DNA sequence data, derived from all the recognised genera and most of the NW African species. The genus Theba (Thebini) emerges as the sister group of all Otalini. Eremina is placed here in a separate new tribe Ereminini; it forms a clade sister to the combined Thebini and Otalini. The nine genera recognised within the Otalini are placed in two subtribes, as follows: Cantareusina (new subtribe, for Cantareus, Cornu, Erctella, Rossmaessleria), and Otalina (Maurohelix, Massylaea, Eobania, Otala and Loxana). Other nominal genera based on type species from NW. Africa are synonymised. The first comprehensive modern revisions of species limits in Loxana and Maurohelix are presented, based on studies of genital anatomy and shells from extensive recent collections, mapping of distributions and DNA sequence data. Numerous conchologically distinctive allopatric populations within the expanded concept of Loxana appear to be more realistically regarded as forming far fewer biological species. Hence, this supports reduction of five polytypic genera previously recognised (including Alabastrina and Atlasica) to the single genus Loxana. The habitat preferences of these species are described, their ranges are mapped and evolution and differentiation of their shell characters are discussed. Data supplementary to those from other recent studies are also presented for Rossmaessleria, Massylaea, Eobania and Otala. Massylaea and Eobania are maintained as separate genera based on new molecular and morphological data. One new species is described within Otala, three other species are recognised as valid and additions to that genus (O. juilleti, O. orientalis, O. pallaryi) and the placement of O. hieroglyphicula therein is confirmed. Evolution of the distal genitalia in Helicidae is discussed, revealing several remarkable instances of convergent evolution that had not been reported previously.

Key words. Otalini, Helicidae, Maghreb, DNA, phylogeny, evolution, species limits, genital anatomy, taxonomy, distribution

Date of publication. October 2020


First location of the invasive snail Xerolenta obvia (Menke, 1828) (Stylommatophora, Geomitridae) in the Iberian Peninsula 

Alberto Martínez-Ortí

Abstract. A well-established population of Xerolenta obvia has recently been discovered for the first time in the east of the Iberian Peninsula, specifically in Linares de Mora, a village in Teruel (Aragon, Spain). It is a land snail native to south-eastern Europe, also considered an invasive species in other countries and other continents. Morpho-anatomical studies of the shell and the reproductive system have been carried out, allowing us to confirm its identity. It is compared with the close-related species Cernuella neglecta and Helicella itala. The new location is shown relative to its European distribution, and aspects of its ecology and its status as an invasive species and an intermediate host of parasites are discussed.

Key words. Land mollusc, Xerolenta obvia, invasive species, Aragon, Spain, Iberian Peninsula

Date of publication. October 2020


Discovery of the first recorded live population in the UK of the lagoon spire snail Semisalsa stagnorum (Gmelin, 1791) (Gastropoda: Cochliopidae) with notes on its habitat and conservation 

Martin Willing & Ben Rowson

Abstract. Semisalsa stagnorum is a “hydrobioid” snail that, until 2005, was only known in Britain from dead shells from two sites in England: a Roman and Saxon aged archaeological complex in Bath, Somerset and from modern sediments taken from a brackish lagoon on Farlington Marshes, Hampshire. In 2005 freshly dead shells were discovered in a slightly brackish lagoon on Thorney Island, West Sussex with live animals confirmed there in 2006. Studies between 2005 and 2019 confirmed the restricted distribution of the snail on the ‘island’ (now effectively a peninsula) and allowed data to be gathered on the snail’s autecology and common associates. Sequencing of COI mtDNA confirms the population belongs to Semisalsa and not to any other British hydrobiid species. Comparisons are made with the ecology of similar S. stagnorum populations living in the Netherlands. The conservation of this Critically Endangered snail is discussed, with successional and salinity changes to its habitat being considered as the greatest threats.

Key words. Semisalsa stagnorum, Heleobia stagnorum, brackish water, saline lagoons, sea levels, Chichester Harbour, conservation

Date of publication. October 2020


First record of Diaphera Albers, 1850 (Gastropoda: Eupulmonata: Diapheridae) from China

Zhe-Yu Chen & Barna Páll-Gergely

Abstract. Diaphera lini n. sp. [林氏扭钻螺] is described from Guangxi Province, which represents the first record of Diaphera Albers, 1850 in China. The new species differs from the most similar, and geographically closely occurring Diaphera densecostulata by the larger, strongly ribbed shell, longer detached part of the last whorl, more conspicuously distinct sinulus, blunter upper palatal tooth and longer columellar lamella.

Key words. Taxonomy, systematics, shell, new species

New taxon. Diaphera lini Chen & Páll-Gergely, 2020

Date of publication. October 2020


Shells of Papilloderma Wiktor, Martín and Castillejo, 1990 (Gastropoda, Eupulmonata, Papillodermatoidea) found in caves reveal an unknown dwarf hypogean species

Carlos E. Prieto, Sergio Quiñonero-Salgado, Jesús Ruiz-Cobo & Álvaro Alonso

Abstract. The slug Papilloderma altonagai Wiktor, Martín & Castillejo, 1990 was described from an adult from the Sanctuary of Covadonga (Asturias, Spain) and a juvenile from Puerto de Alisas (in neighbouring Cantabria), but it was never recorded again outside the first site, an anthropogenic environment. New data, based on limacellae recovered by sieving of gravitational sediments from fossil caves, provides the first records contributed after the initial description. The records confirm and expand the distribution in the eastern area (Cantabria, in the northern foothills of the Valnera massif) and validate the usage of Papilloderma shells as indicators of their presence. The morphological analysis of limacellae suggests that there are two closely related taxa in the eastern area, a large endogean species corresponding to P. altonagai, and a much smaller unknown species living in the epikarst environment. A recent new record for the Sierra de Cuera (Asturias) also expands the western range out from Picos de Europa.

Key words. Epikarst, dwarfed slug, sympatry, morphometry, limacellae

Date of publication. October 2020


A new species of Meretrix from the Arabian Sea (Mollusca: Bivalvia)

Xiaoxuan Wang, Lingfeng Kong, Chloè Martin, Qi Li, & Akihiko Matsukuma

Abstract. A new, economically important venerid species, Meretrix marisarabicum n. sp., from the estuaries of Karachi, Pakistan is described based on shell morphology and DNA phylogeny. This new species can be distinguished from other Meretrix species based on overall shell shape and the form of the pallial sinus; it has large, antero-posteriorly elongate oval shells with a very shallow pallial sinus. Although a number of shells of this species were also collected at archaeological sites in the Sultanate of Oman, where it was dated to Neolithic times between 5500 and 4000 BC, no live specimens have been found there. This absence is probably related to environmental changes of the Oman littoral during the Holocene Climate Optimum.

Key words. Meretrix, new species, Arabian sea, COI

New taxon. Meretrix marisarabicum Martin & Matsukuma in Wang et al., 2020

Date of publication. October 2020


Theora lubrica Gould, 1861 (Bivalvia: Semelidae), new to the UK, with notes on associated non-native species, and an earlier date of introduction for Arcuatula senhousia (Bivalvia: Mytilidae) to the UK

Tim M. Worsfold, Nicola Pennisi & Christopher W. Ashelby

Abstract. The non-native bivalve Theora lubrica was recorded for the first time for the U.K. in April 2018, from Lake Lothing (Oulton Broad), Lowestoft, Suffolk. This represents the most northerly European record to date for the species. Several other non-native or cryptogenic species were recorded from the same location; in particular, the most northerly European locality of the tubeworm Hydroides ezoensis was confirmed. Theora lubrica has also been found in the vicinity of Southampton Water and the earliest known U.K. records (May 2011) of the non-native mussel Arcuatula senhousia, from the same area, are documented here.

Key words. Non-native species, window shell, Asian semele, Asian date mussel

Date of publication. October 2020


Southernmost record of Sinum cymba (Menke, 1828) (Gastropoda: Naticidae)

Nicolás O. Zambrano, Juan Antonio Aliaga & Juan Francisco Araya

Date of publication. October 2020


An unusual habitat for Vertigo angustior Jeffreys 1830 in northern France [Short Communication]

Xavier Cucherat & David Bécu

Date of publication. October 2020