Clathrocaspia knipowitschii aluschtensis ( Golikov & Starobogatov, 1966 )

Anistratenko, Vitaliy V., Neubauer, Thomas A., Anistratenko, Olga Yu., Kijashko, Pavel V. & Wesselingh, Frank P., 2021, A revision of the Pontocaspian gastropods of the subfamily Caspiinae (Caenogastropoda: Hydrobiidae), Zootaxa 4933 (2), pp. 151-197 : 178

† Clathrocaspia knipowitschii aluschtensis ( Golikov & Starobogatov, 1966) comb. n.

Fig. 13e

Pyrgula (Caspia) gmelini [sic] aluschtensis subsp. n.— Golikov & Starobogatov 1966: 354, fig. 1(8).

C. [aspia] gmelini [sic] aluschtensis ( Golikov et Starobogatov, 1966)— Golikov & Starobogatov 1972: 100, pl. 2, fig. 19. C. [aspia] (Cl. [athrocaspia]) makarovi aluschtensis (Gol. et St.)— Alexenko & Starobogatov 1987: 32–33, 37.

Type material. Holotype ( ZIN 4438 /1) and 18 paratypes ( ZIN 4439 /2–4443/6). Collected by S.A. Zernov in 15/08– 15/09/1909, steamship “Meotida”.

Type locality. Black Sea, offshore of Crimea near Alushta ( Table 1 , locality 29). The material comes from phaseoline silts, which typically contain reworked Neoeuxinian (Late Pleistocene) shells ( Wesselingh et al. 2019). The preservation of the type material is typical for this kind of reworked material (pers. obs. F.P.W. 06/2020). Likely, the subspecies is an extinct Late Pleistocene lineage of C. knipowitschii .

Other material. None.

Description. Slender shell with five low convex whorls. Shell surface poorly preserved, only traces of reticulate sculpture are visible. Aperture ovoid, adjoined, leaving no umbilicus. Base steep.

Remarks. Originally this taxon was described as the Black Sea’s fossil subspecies of Clathrocaspia gmelinii , but later Alexenko & Starobogatov (1987) considered it to belong as subspecies in Clathrocaspia makarovi , based on the co-occurrence of that species in the Azov-Black Sea Basin. Kantor & Sysoev (2006: 88) went a step further and listed aluschtensis as a synonym of makarovi . The holotype ( Fig. 13e ), which is illustrated here for the first time, indeed shows a close resemblance to the type of Clathrocaspia makarovi (= knipowitschii ; Fig. 13f ) but differs by a slightly more slender shell and more flattened whorls. Given the differences in morphology and stratigraphy, we consider aluschtensis as an extinct subspecies of C. knipowitschii that inhabited the Black Sea during the Holocene.

Distribution. Known only from the type locality/stratum.

Figures

FIGURE 13. Clathrocaspia knipowitschii (Makarov, 1938) from the Black Sea Basin. (a, b) Neotype, locality 30b (IZAN 522/1). (c, d) Specimen from locality 30b (IZAN 522/2). (e) C. knipowitschii aluschtensis (Golikov & Starobogatov, 1966), holotype, locality 29 (ZIN 4438/1). (f) Holotype of Pyrgula makarovi, locality 31 (ZIN 4492/1). (g, l, u) Specimen from Holocene deposits, locality 32 (IZAN, no number). (h, m) Specimen from same locality (IZAN, no number). (i, n) Paratype of C. brotzkajae from same locality (IZAN, no number). (j, k) Specimen from locality 30c (UGSB 25234). (o, s, t) Specimen identified as C. makarovi by Anistratenko (2013) from locality 30c (UGSB 25236). (p–r) Specimen from locality 30c (UGSB 25235). Scale bars = 1 mm (a–j, l–o), 500 μm (k), 100 μm (p–t), 50 μm (u).