Didacna eichwaldi

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 : 41-42

Didacna eichwaldi (Krynicki, 1837)

Fig. 3b

°1829 C. [ardium] crassum Eichwald: 283 [non Cardium crassum Gmelin, 1791].

*1837 Cardium Eichwaldi Krynicki: 61 [nom. nov. pro C. crassum Eichwald, 1829, non Gmelin, 1791].

1841 Didacna crassa . - Eichwald: 273, pl. 39, fig. 6a, b.

1876 Cardium crassum Eichwald, 1829. - Grimm: 136-138, pl. 6, fig. 3.

1905 Didacna crassa (Eichwald, 1829). - Ostroumov: 15, 69, pl. 2(A).

1932 Didacna aff. crassa (Eichwald, 1829). - Bogachev: 27, pl. 2, figs 11-14.

1952 Didacna crassa Eichwald, 1841. - Zhadin: 349, fig. 325.

1953 Didacna crassa (Eichwald, 1829). - Fedorov: 130, pl. 20, figs 8, 9, 12, 13.

1958 Didacna crassa crassa Eichwald, 1829. - Nevesskaja: 39-40, pl. 7, figs 8, 9.

1969 Didacna crassa (Eichwald, 1829). - Vekilov: 134-139, pl. 24, figs 1-6, pl. 27, figs 1, 2.

1988 Didacna crassa crassa (Eichwald, 1829). - Yanina and Svitoch: pl. 12, figs 8, 9, pl. 13, figs 1-5.

2005 Didacna crassa (Eichwald, 1829). - Yanina: 242, pl. 14, figs 3-6.

2007 Didacna crassa (Eichwald, 1829). - Nevesskaja: 939-940, pl. 23, figs 1-5.

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

2016 Didacna baeri (Grimm, 1877). - Vinarski and Kantor: 71 [pars, non Grimm, 1877].

Status. Pontocaspian species, endemic to Caspian Sea.

Type locality. "Caspium mare" (Caspian Sea) (for C. crassum Eichwald, 1829).

Distribution. Caspian Sea. Didacna eichwaldi is known from the middle and southern Caspian Sea basins down to 35 m water depth and cannot tolerate lowered salinities.

Taxonomic notes. In recent works ( 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, we see morphological discontinuities in our extensive material from the northern Caspian Sea Basin that implies that D. eichwaldi with its protruding umbo and shouldered appearance is distinct from D. baeri that is characterised by a rounded umbo (see discussion above under D. baeri ). Despite being in common usage, the name Didacna crassa is invalid as it is a junior homonym of Cardium crassum Gmelin, 1791; Krynicki (1837) introduced Cardium eichwaldi as replacement name.

Conservation status. Not assessed.