Didacna praetrigonoides

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 : 44

Didacna praetrigonoides Nalivkin & Anisimov, 1914

*1914 Didacna praetrigonoides Nalivkin & Anisimov: 5-6, 16-17, pl. 1, figs 1, 2.

1932a Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Bogachev: pl. 2, fig. 1.

1932b Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Bogachev: 42, pl. 4, figs 1-8, pl. 5, fig. 8.

1948 Didacna praetrigonoides Nal. - Fedorov: pl. 2, figs 10-13.

1953 Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Fedorov: 128, pl. 18, figs 1-6, pl. 19, figs 1-6.

1958 Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Nevesskaja: 17-20, pl. 1, figs 1-14.

1969 Didacna trigonoides praetrigonoides Nal. & Anis. - Logvinenko and Starobogatov: 324, fig. 343(2).

1969 Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Vekilov: 120-128, pl. 22, figs 1-9.

1973 Didacna trigonoides praetrigonoides Nalivkin & Anisimov, 1915. - Grossu: 129, text fig. 5.

1983 Didacna praetrigonoides praetrigonoides Nalivkin & Anisimov, 1914. - Popov: 195, pl. 15, figs 1, 2.

1988 Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Yanina and Svitoch: pl. 8, figs 4-7.

2005 Didacna praetrigonoides Nalivkin & Anisimov, 1914. - Yanina: 241, pl. 14, figs 1, 2.

2007 Didacna praetrigonoides praetrigonoides Nalivkin & Anisimov, 1914. - Nevesskaja: 927, pl. 19, figs 9, 10.

Status. Pontocaspian species, endemic to Caspian Sea. Possibly extinct.

Type locality. Apsheron Peninsula, Azerbaijan, Quaternary.

Distribution. Caspian Sea. Logvinenko and Starobogatov (1969) reported the species from the southern Caspian Sea Basin and the southern part of the middle Caspian Sea Basin down to 60 m water depth. The species has been collected from Holocene deposits and beach occurrences the western part of the middle Caspian Sea Basin as well (FW, pers. obs.). The species is reportedly extinct, not mentioned in Kijashko in Bogutskaya et al. (2013).

Remarks. The first appearance of Didacna praetrigonoides is in lower Khvalynian deposits, it became widespread during the late Khvalynian and was rare during the Novocaspian.

Conservation status. Not assessed. Didacna praetrigonoides has been reported to occur 'rarely in the modern Caspian Sea’ ( Nevesskaja 2007: 927), but material from recent assemblages has not been found.