Abeskunus exiguus

Wesselingh, Frank, Poorten, Jan Johan ter, Kijashko, Pavel, Albrecht, Christian, Anistratenko, Olga Yu, Frolov, Pavel, Gándara, Alberto Martinez, Gittenberger, Arjan, Gogaladze, Aleksandre, Mikhail Karpinsky, Popa, Luis, Sands, Arthur F, Vandendorpe, Justine & Wilke, Thomas, 2019, Mollusc species from the Pontocaspian region - an expert opinion list, ZooKeys 827, pp. 31-124 : 95-96

Abeskunus exiguus (Eichwald, 1838)

°1837 Lithoclypus [sic] Caspius m. - Krynicki: 58 (nomen nudum).

*1838 Paludina exigua Eichwald: 152-153.

1863 Bithinia sphaerion Mousson: 409-410.

1874 Lithoglyphus ? Caspius Krynicki. - Martens: 80.

1877 Lithoglyphus caspius Grimm: 82-84, pl. 9, fig. 8.

1977 Pseudamnicola (Abeskunus) brusiniana michelae Tadjalli-Pour: 108, pl. 2, fig. 9.

2016 Pseudamnicola exigua (Eichwald, 1838). - Vinarski and Kantor: 223.

2016 Pseudamnicola sphaerion (Mousson, 1863). - Vinarski and Kantor: 223.

Status. Accepted Pontocaspian species.

Type locality. In fossil (likely Pleistocene) limestone of Dagestan, Russia.

Distribution. Western Caspian Sea, known from northern and southern parts. Records from the eastern Caspian Sea by Logvinenko and Starobogatov (1969) could not be confirmed.

Taxonomic notes. An in-depth study of the literature suggests that the names Paludina exigua , Bithinia sphaerion syn. n., and Lithoglyphus caspius all refer to the same species. The name Lithoglyphus caspius was made available by Martens (1874) by referring to the description and illustration of Eichwald’s species, rendering L. caspius a junior objective synonym of Abeskunus exiguus . All three taxa share the globular shape, short spire, and inflated last whorl. The subspecies Pseudamnicola brusiniana michelae syn. n. from Iranian coasts of the Caspian Sea closely resembles A. exiguus and is herein considered a synonym as well. Abeskunus exiguus differs from A. brusinianus in the highly globular shell with small spire. A revision of the species is currently being prepared.

Conservation status. Not assessed.