Clathrocaspia pallasii

Anistratenko, Vitaliy V., Sitnikova, Tatiana Ya. & Anistratenko, Olga Yu., 2021, Holotypes for three Caspian gastropods of the family Hydrobiidae tracked down description and taxonomic interpretations, Zootaxa 5027 (3), pp. 408-416 : 412-413

Clathrocaspia pallasii (Clessin & W. Dybowski in W. Dybowski, 1887)

Fig. 2e–r

Caspia Pallasii nob.—Clessin & W. Dybowski in W. Dybowski 1887: 37.

Caspia Pallasii n. sp. —W. Dybowski 1888: 79, pl. 3, fig. 3a, b.

Clathrocaspia pallasi [sic] (Dyb.)—Kolesnikov 1947: 108, 111.

Pyrgula (Caspia) pallasii (Cless. & W. Dyb.) — Logvinenko & Starobogatov 1969: 378, fig. 367(5).

Pyrgula (Caspia) sowinskyi Logv. et Star. sp. n. — Logvinenko & Starobogatov 1969: 378, fig. 367(4). [partim, without figure] Pyrgula pallasii (Clessin et W. Dybowski in W. Dybowski, 1888)— Kantor & Sysoev 2006: 101–102, pl. 45, fig. N.

Pyrgula sowinskyi Logvinenko et Starobogatov, 1968 — Kantor & Sysoev 2006: 104 [partim, without figure]

Clathrocaspia pallasii (Clessin & Dybowski in Dybowski, 1887)— Wesselingh et al. 2019: 72 .

Caspia (Clathrocaspia) pallasii Clessin & W. Dybowski in W. Dybowski, 1887 — Anistratenko et al. 2019: 40, fig. 2J–P. Clathrocaspia pallasii (Clessin & Dybowski in Dybowski, 1887)— Anistratenko et al. 2021: 179–180, fig. 12a–h, m–p, r, s.

Type material. Lectotype ( ZB-M W.Dyb. 104) and 67 paralectotypes ( ZB-M W.Dyb. 5, 74, 104 and 105) (designated by Anistratenko et al. 2019).

Type locality. “Kaspi-See” (Caspian Sea, without further details; Table 1, locality 26).

Other material. It was shown that part of the type material of Pyrgula sowinskyi belongs to C. pallasii ( Anistratenko et al. 2021) . The holotype of Pyrgula sowinskyi is rediscovered in ZIN collection ( ZIN 1/533-2021); it derives from the lot, labeled “49/1957” ( Fig. 1 , Tab. 1, locality 17), collected by B.M. Logvinenko off Cheleken Peninsula, Turkmenistan on 4 August 1957 from 56 m depth. Further over 500 paratypes are stored in 15 separate tubes ( ZIN 2/533-2021–16/533-2021), labels only marked with station number and year of collection; these were collected in various parts of the Middle ( Fig. 1 , Tab. 1, localities 4, 9, 34, 35, 36) and South (localities 14, 16, 17, 20, 24, 37, 41) Caspian Sea between 13 June 1956 and 9 August 1957.

Remarks. A certain variability in shell elongation, whorl convexity and sculpture expression is evident among the type series ( Fig. 2e–h ). The typical features of C. pallasii are the slender elongate shell, the low convexity of the whorl profile and the large, bulbous protoconch, which distinguish the species from C. isseli and C. gmelinii . The holotype of Pyrgula sowinskyi is rediscovered and reported here for the first time ( Fig. 2k, l ); it shows typical features of the type specimens of C. pallasii , which confirms their conspecifity with the latter name having nomenclatural priority. A similar decision ( P. sowinskyi is a junior synonym of C. pallasii ) was suggested earlier based on morphology of shells from Starobogatov’s collection considered as the paratype of P. sowinskyi ( Fig. 2m, n ).

Distribution. Endemic to the Caspian Sea, empty shells of this species are reported from many localities in the Middle and South Basins from water depths between 50 and 150 m, although it is mentioned also from 311–870 m (see Anistratenko et al. 2021).

Figures

FIGURE 1. Geographic overview of the study area, with the indication of sampling points and places mentioned in the text (modified from Wesselingh et al. 2019). See Table 1 for details.

FIGURE 2. (a, b) Clathrocaspia isseli (Logvinenko & Starobogatov, 1969), holotype, locality 16 (ZIN 1/532-2021). (c, d) C. isseli, paratype, locality 21 (ZIN 12/532-2021). (e, f) C. pallasii (Clessin & Dybowski in Dybowski, 1887), lectotype, locality 26 (ZB-M W.Dyb. 104). (g, h) C. pallasii, paralectotype, locality 26 (ZB-M W.Dyb. 104). (i, j) C. pallasii, paratype of C. isseli, locality 14 (ZIN 11/532-2021). (k, l) C. pallasii, holotype of Pyrgula sowinskyi Logvinenko & Starobogatov, 1969, locality 17 (ZIN 1/533-2021). (m, n) C. pallasii, paratype of P. sowinskyi, locality 24 (ZIN 12/533-2021). (o–r) C. pallasii, two paratypes of C. isseli, locality 15 (ZIN 4/532-2021). Images c–j, m, n reproduced after Anistratenko et al. 2021. Scale bar = 1 mm.