Bittium nabokovorum Guzhov, 2025

Bittium nabokovorum Guzhov nom. nov.

Figs 16A–E View FIGURE 16

* Bittium binodulosum Guzhov View in CoL , sp. nov. — Guzhov 2022: 25, text-fig. 5, pl. 5, figs 17–19 [non Bittium binodulosum Yokoyama, 1920 View in CoL ].

Type material. Holotype PIN 5794 View Materials /74, SL: 5.3 mm, MD: 2.2 mm, Figs 16A View FIGURE 16 1 –A View FIGURE 1 3 View FIGURE 3 . Paratypes: PIN 5794 View Materials /75, SL: 5.5 mm, MD: 2.4 mm, Figs 16B View FIGURE 16 1 –B View FIGURE 1 2 View FIGURE 2 . PIN 5794 View Materials /79, SL: 6.0 mm, MD: 2.3 mm, Fig. 16C View FIGURE 16 . PIN 5904 View Materials /17, Fig. 16D View FIGURE 16 . PIN 5904 View Materials /18, Fig. 16E View FIGURE 16 . All specimens from Belaya River ( Russia), Middle Miocene, early Chokrakian .

Description. Small, slender conical shell of seven teleoconch whorls, attaining 5.0–6.0 mm in height, apical angle ~27–33°. Protoconch of 2.5 rounded whorls, with sinusigera (dp = ~270 μm), covered by microscopic pustules arranged in spiral rows or irregular. Whorls bicarinate, markedly angled slightly below mid-whorl, with broad, sloping, slightly concave subsutural ramp. Periphery coinciding with adapical primary cord at angulation. Second primary cord slightly weaker. Third narrow spiral cord at abapical suture partially obscured by subsequent whorl. Secondary spiral threads may occur on early teleoconch whorls. Upper two cords overrun 18–23 subobsolete ribs forming spinous tubercles at intersections and vaguely cancellate sculpture between spiral cords. Microsculpture of early teleoconch whorls of rows of tiny pustules in spiral interspaces, becoming obsolete during ontogeny. Last whorl attaining 47–50% of total height. Transition into conical base convex with two prominent peribasal cords and three close-spaced cords over fasciole.Aperture ovate. Columella excavated. Columellar callus forming narrow thin rim, sharply delimited from base. Anal canal indistinct. Outer lip thin. Siphonal canal short and wide.

Discussion. This species was recently established by Guzhov (2022) as Bittium binodulosum but the name is preoccupied by Yokoyama (1920) for a Pleistocene fossil from Japan. Therefore, Bittium nabokovorum nom. nov. is proposed herein as a replacement name in honor of the Eugeny Nabokov and Irina Nabokova, with whose help the study of Neogene strata in Adygea was possible.

Bittium nabokovorum might be an early Chokrakian descendent of the Tarkhanian-Chokrakian Bittium tschokrakense ( Özsayar, 1977) during the early Chokrakian ( Guzhov 2022). For a discussion on this species see Guzhov (2022).

Distribution. Early Chokrakian (Middle Miocene) of the Eastern Paratethys.

Paleoenvironment. Shallow marine, inner neritic based on the associated fauna (own data A.G.).

Eastern Paratethys. Early Chokrakian (Middle Miocene): Turkey: Ordu (Sinop District) (hoc opus); Crimea: Chokrak Lake (Crimea); Ciscaucasia : Belaya River , ravine Semikolennyi (Adygea), Kutais, rocks Rubaily (Krasnodar Krai, Russia) ( Guzhov 2022) .