Caspiinae B. Dybowski, 1913

Neubauer, Thomas A., Velde, Sabrina van de, Yanina, Tamara & Wesselingh, Frank P., 2018, A late Pleistocene gastropod fauna from the northern Caspian Sea with implications for Pontocaspian gastropod taxonomy, ZooKeys 770, pp. 43-103 : 43

Subfamily Caspiinae B. Dybowski, 1913

Discussion.

The genus Caspia has been widely used for species with small ovoid shells, occasionally with spiral or reticulate teleoconch sculpture. Based on the expression of sculpture, some authors have divided the species among the (sub)genera Caspia s.s., with a single spiral line below the suture, and Clathrocaspia Lindholm, 1930, exposing a reticulate pattern (e.g., Anistratenko and Prisyazhniuk 1992, Anistratenko 2013, Boeters et al. 2015, Büyükmeriç and Wesselingh 2018). Species lacking teleoconch sculpture were grouped under the new taxon Ulskia by Logvinenko and Starobogatov (1969). While those authors considered it a subgenus of Pyrgula , W. Dybowski (1887) originally treated its type species ( Caspia ulskii Clessin & W. Dybowski in W. Dybowski, 1887, see below) as a sculpture-less form of Caspia .

Ulskia ulskii is available in the present material, and we have investigated the type species of Clathrocaspia ( Caspia pallasii Clessin & W. Dybowski in W. Dybowski, 1887) obtained from Holocene deposits of the northern and southern Caspian Sea. However, the type species of Caspia , Caspia baerii Clessin & W. Dybowski in W. Dybowski, 1887, is unknown to us. The original description suggests that it is similar to Ulskia and Clathrocaspia in terms of size and shape, yet to differ in the presence of a single line below to suture, demarcating a narrow subsutural ramp. All three genera are probably closely related, which is also suggested by the similar protoconchs of Ulskia and Clathrocaspia (pers. obs. T.A.N.). Since Ulskia and Clathrocaspia can be easily distinguished based on the presence of sculpture, we propose to treat them as distinct genera. The status of Caspia remains doubtful until the type species is properly re-investigated.

The Caspia - Clathrocaspia - Ulskia species group can be well delimited from the larger, elongate-conical or -ovoid Turricaspia auct. and Pyrgula auct. Moreover, unpublished molecular data suggest that the group is unrelated to Pyrgulinae (T. Wilke, pers. comm. 04/2018). We follow Anistratenko (2013) and Bouchet et al. (2017), who listed the Caspiinae as separate subfamily.