Laevicaspia kolesnikoviana (Logvinenko & Starobogatov in Golikov & Starobogatov, 1966) Neubauer & Velde & Yanina & Wesselingh, 2018

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

Laevicaspia kolesnikoviana (Logvinenko & Starobogatov in Golikov & Starobogatov, 1966) comb. n. Fig. 10A-E, K, N

Laevicaspia kolesnikoviana *1966 P. [yrgula] (Caspiella) kolesnikoviana Logvinenko et Starobogatov; Golikov & Starobogatov: 357, fig. 2 (8-9).

Laevicaspia kolesnikoviana 1969 Pyrgula [( Caspiella )] Pyrgula kolesnikoviana Logv. et Star. - Logvinenko & Starobogatov: 372, fig. 366 (1).

Laevicaspia kolesnikoviana 2006 Pyrgula kolesnikoviana Logvinenko et Starobogatov in Golikov et Starobogatov, 1966. - Kantor & Sysoev: 100, pl. 47, fig. N.

Laevicaspia kolesnikoviana 2016 Pyrgula kolesnikoviana Logvinenko et Starobogatov in Golikov et Starobogatov, 1966. - Vinarski & Kantor: 239.

Material.

514 specimens ( RGM 1309816 , RGM 1309818 , RGM 1309819 , RGM 1310212 , RGM 1310221 -1310225, LV 201516 ) .

Type material.

Holotype: ZIN 4462/1 .

Type locality.

Caspian Sea, N of Apsheron peninsula, NW from Kamni Dva Brata Island, 40°47'N, 49°42'E, 30 m ( Vinarski and Kantor 2016).

Dimensions.

3.55 × 1.63 mm ( RGM 1309816, Fig. 10A-C, K ); 3.59 × 1.67 mm ( LV 201516, Fig. 10D ); 3.95 × 1.82 mm ( RGM 1309819, Fig. 10E, N ); 3.90 × 1.77 mm ( RGM 1309818); 4.04 × 1.96 mm ( RGM 1310222); 4.49 × 1.99 mm ( RGM 1310223); 3.54 × 1.72 mm ( RGM 1310224).

Description.

Small, slender ovoid, shiny shell with up to 6.9 whorls. Protoconch consists of 1.2 whorls, measuring 355 µm in diameter; nucleus rather long, ca. 130 µm wide; surface finely granulate (maybe due to preservation; traces of finely malleate to irregularly striate pattern occurs on margins of nucleus and initial part); faint striae on last third; P/T boundary distinct. Whorl convexity of teleoconch whorls decreasing: first to second whorl moderately to highly convex, last whorl low to moderately convex. Faint subsutural band appears on later teleoconch whorls in some specimens, sometimes accompanied by weak concavity below. Last whorl attains 50-57% of shell height, passing via broad, regular convexity in to weakly convex base. Aperture ovoid, inclined, closely attached to preceding whorl; in latest ontogeny, shell growth is more abapically directed, resulting in marked thickening at adapical angle. Peristome thin or thickened all around, with parietal margin sometimes slightly expanded; weakly but regularly sinuate in lateral view, with broad adapical indentation and about equally broad and high abapical protrusion. Umbilicus usually closed or very narrow, slit-like. Growth lines weak, prosocline in upper half, orthocline in lower half. In addition, faint spiral furrows appear in some specimens.

Discussion.

Co-occurring Laevicaspia vinarskii sp. n. differs in the consistently lower whorl expansion rate at the same size and the smaller aperture. Laevicaspia kowalewskii (Clessin & W. Dybowski in W. Dybowski, 1887) can be distinguished by its broader and larger shell.

Distribution.

Endemic to the Caspian Sea, reported from depths between 25 and 180 m ( Kolesnikov 1947, Logvinenko and Starobogatov 1969).

Figures

Figure 10. Pyrgulinae. A-C, K Laevicaspia kolesnikoviana (Logvinenko & Starobogatov in Golikov & Starobogatov, 1966), RGM 1309816 D L. kolesnikoviana, LV 201516 E, N L. kolesnikoviana, RGM 1309819 F, G Laevicaspia vinarskii sp. n., holotype, LV 201517 H, O L. vinarskii sp. n., RGM paratype, 1309805 I, J, L, M L. vinarskii sp. n., paratype, RGM 1309821.