Didacna baeri

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 : 40

Didacna baeri (Grimm, 1877)

Fig. 3a

*1877 Cardium Baeri Grimm: 51-54, pl. 8, figs 2, 3.

1914 Didacna Baeri (Grimm, 1877). - Nalivkin & Anisimov: 4, pl. 1, figs 4, 5.

1932 Didacna Baeri (Grimm, 1877). - Bogachev: 29, pl. 3, figs 1-7.

1933 Didacna Baeri (Grimm, 1877). - Zhizhchenko: 34, pl. 2, figs 5-8.

1952 Didacna baeri (Grimm, 1877). - Zhadin: 347-348, figs 321, 322.

1953 Didacna baeri (Grimm, 1877). - Fedorov: 129, pl. 20, figs 10, 11.

1968 Didacna baeri (Grimm, 1877). - Gadzhiev: 76-77, pl. 1, figs 1, 2.

1969 Didacna baeri (Grimm). - Logvinenko & Starobogatov: 324, fig. 344(2).

1969 Didacna baeri (Grimm, 1877). - Vekilov: 139-144, pl. 25, figs 1-8.

1973 Didacna baeri Grimm, 1877. - Grossu: 131, text fig. 7.

1983 Didacna baeri (Grimm, 1877). - Popov: 180, pl. 16, figs 20-23.

1988 Didacna baeri (Grimm, 1877). - Yanina & Svitoch: 129, pl. 3, figs 7-13.

2005 Didacna baeri (Grimm, 1877). - Yanina: 242-244, pl. 14, figs 12-15.

2007 Didacna baeri (Grimm, 1877). - Nevesskaja: 940-941, pl. 23, figs 11-17.

2013 Didacna baeri (Grimm, 1877). - Kijashko in Bogutskaya et al.: 352, fig. 136, photo 41 [pars, excluding synonymy of Didacna crassa ].

2016 Didacna baeri (Grimm, 1877). - Vinarski & Kantor: 71 [pars, excluding synonymy of Didacna crassa ].

Status. Pontocaspian species, endemic to Caspian Sea.

Type locality. Caspian Sea, offshore Turkmenistan, station 132, 40°32'N, 52°23'E.

Distribution. Logvinenko and Starobogatov (1969) reported Didacna baeri from the southern basin (mostly on the eastern side) and from the middle basin down to 60 m water depth.

Taxonomic notes. In recent works (e.g., Kijashko in Bogutskaya et al. 2013), the species Didacna crassa (Eichwald, 1829) [= D. eichwaldi (Krynicki, 1837)] has been considered a synonym of D. baeri . However, both species can be distinguished. Didacna baeri has a less extended, more roundish shell, a less developed keel, and a low top with less projecting beak and in general more ribs than D. eichwaldi (Fig. 3). Didacna baeri occurred for the first time in the Novocaspian transgressive deposits whereas D. crassa already occurred in the late Khvalynian (Late Pleistocene). Both became very common during the Novocaspian.

Conservation status. Not assessed.