Adacna minima

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 : 36-37

Adacna minima Ostroumov, 1907

*1907 Adacna minima Ostroumov: 23, text fig., pl. 4, figs 1-5.

1952 Adacna (Adacna) vitrea var. minima (Ostroumoff, 1907). - Zhadin: 353.

1967 Hypanis minima ostroumovi Logvinenko and Starobogatov: 233.

1969 Hypanis minima ostroumovi Logv. et Star. - Logvinenko and Starobogatov: 338, fig. 354(3).

1973 Hypanis minima ostroumovi Logvinenko et Starobogatov, 1968. - Grossu: 146, text fig. 31.

?1974 Hypanis minima sidorovi Starobogatov: 246, fig. 213.

2003 Hypanis minima minima (Ostroumov, 1907). - Andreeva and Andreev: 88, fig. 5.1(3, 4).

?2009 Hypania [sic] minima (Ostroumoff, 1907). - Filippov and Riedel: 75, fig. 4s, t.

2013 Adacna minima ostroumovi (Logvinenko et Starobogatov, 1967). - Kijashko in Bogutskaya et al.: 378, fig. 146.

2016 Adacna (Adacna) minima minima (Ostroumov, 1907). - Vinarski and Kantor: 64.

2016 Adacna (Adacna) minima ostroumovi Logvinenko et Starobogatov, 1967. - Vinarski and Kantor: 64.

Status. Pontocaspian species, endemic to Caspian Sea and Aral Sea; likely disappeared from the latter.

Type locality. The northern Caspian Sea and the Aral Sea ( Vinarski and Kantor 2016).

Distribution. Aral Sea (probably extinct there; Andreeva and Andreev 2003), Caspian Sea.

Taxonomic notes. Graf and Cummings (2018) consider this species as a synonym of A. vitrea , but Kijashko in Bogutskaya et al. (2013) regards it as a valid species. The latter considers A. minima minima from the Aral Sea and A. minima ostroumovi syn. n. from the Caspian Sea as distinct geographical subspecies. The likely disappear ance of the species from the Aral Sea makes a molecular assessment of their distinctness very difficult and given the lack of other arguments we synonymise both. Furthermore, we are uncertain about the status of the subspecies Hypanis minima sidorovi Starobogatov, 1974 from the western Aral Sea. Without further data we assume it concerns a form that falls within the wide morphological variation of A. minima . We moreover are very uncertain as to the status of Hypanis minima from Holocene deposits of Aral Sea as illustrated by Filippov and Riedel (2009, fig. 4s, t). The juvenile specimen has relatively strong cardinal teeth, onset of clear ribs, and a general shape that more resembles Monodacna caspia .

Remarks. The species has been recorded mostly from the middle and southern Caspian Sea and more rarely from the eastern areas in the northern Caspian Sea down to 35 m water depth ( Logvinenko and Starobogatov 1969) as well as from the Aral Sea from where it may have disappeared.

Conservation status. Not assessed.