Journal of Conchology Volume 44, Part 6, November 2023

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An illustrated checklist of the intertidal Bivalvia of the state of Kuwait 
Oliver, P. G., Al-Kandari, M., Behbehani, M. and Dekker, H.

From recent surveys and a review of previous studies a list of 214 species of marine bivalves collected on the shores of Kuwait is presented. For each there are illustrations and citations from past studies. Species are included only if they could be verified from specimens or high-quality images. The absence of species previously recorded, and the unique elements of the bivalve fauna are briefly discussed.

Key words: Northwest Arabian Gulf, Persian Gulf, Mollusca, Taxonomy, Identification.

An overview of the specific diversity in the genus Cystiscus stimpson, 1865 and the description of 27 new Cystiscus species (Muricoidea: Cystiscidae) from the Walters Shoal, southwestern Indian Ocean 
Boyer, F.

The Cystiscus fauna collected on the Walters Shoal by the 2017 MNHN/IRD Expedition is revised on the ground of shell morphology. Twenty-nine different species are recognized, 27 of them being formally described as Cystiscus subcylindricus, sp. nov., C. triplicatus sp. nov., C. herberti sp. nov., C. inflatus sp. nov., C. stimpsoni sp. nov., C. pyriformis sp. nov., C. harpaeformis sp. nov., C. laurae sp. nov., C. robustus sp. nov., C. minimus sp. nov., C. ovoides sp. nov., C. mamillatus sp. nov., C. angustus sp. nov., C. profundus sp. nov., C. granum sp. nov., C. dentiferus sp. nov., C. alatus sp. nov., C. apertus sp. nov., C. contortus sp. nov., C. sinuosus sp. nov., C. pupoides sp. nov., C. lussii sp. nov., C. smithi sp. nov., C. serratus sp. nov., C. lachrymaformis sp. nov., and C. quinqueplicatus sp. nov. Among the 27 described species, 25 of them are only known from their holotype, one paratype from the type station is reported for C. subcylindricus, and two conspecific specimens collected from a non-type station are reported for C. lussii. Eight morphs represented by one or two shells are tentatively ascribed to some of the 27 recognized species. Among the 29 recognized species, 28 of them are found at bathyal levels, and only one of them (C. quinqueplicatus) was collected at a reef level, so the Cystiscus fauna of the Walters Shoal is characterized as bathyal fauna. From the fact that any other Cystiscus assemblage was ever studied from the bathyal of the Indo-Pacific Province, no direct comparison is made with external items, and the Cystiscus species of the Walters Shoal are only compared to each other.

Key words: Cystiscidae, Cystiscus, Walters Shoal, Southwest Indian Ocean, bathyal levels, shell morphology, phenetic disparity, species diversity, twin species.

A new species of Bythinella (Truncatelloidea:Bythinellidae) from Bosnia and Herzegovina 
Falniowski, A., Jaszczyńska, A. and Hofman, S.

A new species of Bythinella from Vrelo Vrioštice spring in Bosnia and Herzegovina is described. The shell, protoconch, radula, female reproductive organs and penis are illustrated and described. Cytochrome oxidase c subunit I (COI) placed the new species as the sister taxon of B. serborientalis Radoman, 1978. Shell biometry (PCA) and COI (genetic distance p = 0.072) clearly confirm the distinctness of the newly described species..

Key words: shell, radula, female reproductive organs, penis, cytochrome oxidase subunit I (COI), molecular phylogeny.

The introduction of Cochlicella acuta and Cochlicella barbara into Britain and the extinction of Xerocrassa geyeri in Cornwall 
Walker, T.

The introduction into Britain of two helicid species, Cochlicella acuta and C. barbara, is discussed in the knowledge that old carbon may have influenced the chronology; modern specimens of C. acuta from Cornish sand dunes gave radiocarbon dates which are 600−800 years old. The introduction of C. acuta is confirmed to the early Bronze Age and it may have been present in the late Neolithic. C. barbara arrived in Cornwall prior to its first observation in the 1960s but, in view of the old carbon problem, a precise date cannot be determined. Xerocrassa geyeri became extinct in most of southern Britain in the early Holocene, but survived at Gwithian in Cornwall for several more millennia, with radiocarbon dating suggesting that it could have been present there until the later part of the early Bronze Age.

Key words: Cochlicella acuta, Cochlicella barbara, Xerocrassa geyeri, mollusc introductions, mollusc extinction, Cornwall, radiocarbon dating, old carbon effect.

Short Communication 
First record for the UK of the non-native dwarf surf clam – Mulinia lateralis (Say, 1822) 
Holmes, A., Jarvis, S. and Delduca, E.

Barry Colville (1930–2023) 
Willing, M. J.