? Turricaspia basalis (Dybowski & Grochmalicki, 1915)

*1915 Micromelania dimidiata var. basalis Dybowski & Grochmalicki: 131, pl. 3, fig. 36a, b.

1969 Pyrgula (Trachycaspia) laticarinata Logvinenko and Starobogatov: 359, fig. 359(3).

2006 Pyrgula basalis basalis (B. Dybowski & J. Grochmalicki, 1915). - Kantor and Sysoev: 97, pl. 46, fig. A.

2006 Pyrgula basalis laticarinata Logvinenko & Starobogatov, 1968. - Kantor and Sysoev: 97, pl. 46, fig. B.

2016 Pyrgula basalis basalis (B. Dybowski & Grochmalicki, 1915). - Vinarski and Kantor: 236.

2016 Pyrgula basalis laticarinata Logvinenko & Starobogatov, 1968. - Vinarski and Kantor: 236.

Status. Pontocaspian species, identity uncertain.

Type locality. Caspian Sea (no details).

Distribution. Middle and southern Caspian Sea (Logvinenko and Starobogatov 1969). This species was mentioned from depths between 200 and 400 m in the South Caspian Basin of Azerbaijan (Mirzoev and Alekperov 2017, who reported the species as T. laticarinata).

Taxonomic notes. The species is characterised by a massive keel near the lower suture.? Turricaspia dimidiata is distinguished based on its more centrally placed keel. This distinction is tentative and only based on comparison of available illustrations; we are aware of the possibility that these differences might not be diagnostic. Moreover, the keel seems to become stronger with increasing water depth (Starobogatov 1968). Pyrgula laticarinata Logvinenko & Starobogatov, 1969, which differs from T. basalis only in the strength of the keels, was considered a junior synonym by Neubauer et al. (2018).

Conservation status. Not assessed.