Bittium digitatum ( Zhizhchenko, 1934 )

Bittium digitatum ( Zhizhchenko, 1934) View in CoL

Figs 10A–D View FIGURE 10

Bittium scabrum Olivi— Schwetz 1912: 320 View in CoL [non Olivi, 1792].

Cer [ithium]. scabrum Olivi var. comitatensis Font.— Schwetz 1912: 320 [non Cerithium comitatensis Fontannes, 1880 ].

Cerithium (Bittium) scabrum Olivi—Davitashvili 1932: 38 , pl. 4, figs 5–7 [non Bittium scabrum (Olivi, 1792) ].

* Cerithium digitatum View in CoL sp. nov. — Zhizhchenko 1934: 63, pl. 9, figs 26–28.

Bittium digitatum Zhizhchenko— Zhizhchenko 1936: 210 View in CoL , 300, pl. 20, figs 17, 19–22 [non fig. 18 = Bittium tulskajense Iljina, 1993 View in CoL ].

Bittium digitatum Zhizhchenko— Volkova 1955: 49 View in CoL , pl. 22, figs 8–9.

Bittium digitatum Zhizhchenko— Zhizhchenko 1959: 252 View in CoL , pl. 16, figs 1–6.

Bittium digitatum Zhizhchenko— Strachimirov 1960a: 287 View in CoL , pl. 59, figs 41–44.

Bittium (Bittium) digitatum (Zhizhchenko) View in CoL — Manolov 1960: 306, pl. 2, figs 26–30.

Bittium digitatum Zhizhchenko— Pčelincev & Korobkov 1960: 312 View in CoL , pl. 19, figs 16–17.

Bittium digitatum ( Zhizhchenko 1934) View in CoL — Zelinskaya et al. 1968: 162, pl. 40, figs 1–2.

Bittium digitatum Zhizhchenko, 1936 View in CoL — Volkova 1974: 90, pl. 11, figs 8–9.

Bittium (Bittium) digitatum ( Zhizhchenko, 1934) View in CoL — Iljina 1993: 68, pl. 8, figs 13–15.

Bittium digitatum (Zhizh.) View in CoL — Goncharova et al. 2014: 251, pl. 4, fig. 12.

Cerithium scabrum View in CoL — Vorobyev 2014: pl. 13.1.2, fig. j.

Turbonilla (Turbonilla) facki Koenen, 1882 View in CoL — Ilgar 2015: 69, text fig. 5(A), fig. 18 [non Turbonilla facki von Koenen, 1882 View in CoL ].

Bittium digitatum ( Zhizhchenko, 1936) View in CoL — Ilgar 2015: 69, text fig. 5(A), fig. 21.

Bittium digitatum (Zhizhchenko) View in CoL — Guzhov 2015: 84.

Bittium digitatum ( Zhizhchenko, 1934) View in CoL — Guzhov 2022: 1101, pl. 2, figs 12–16, pl. 3, figs 1–6.

Type material. Lectotype, TSNIGR 168/11330, former number 42159), SL: 14 mm, MD: 4.3 mm, early Chokrakian of Cape Tarkhan (Crimea), illustrated in Zhizhchenko (1936, pl. 20, fig. 21), Figs 10A View FIGURE 10 1 –A View FIGURE 1 2 View FIGURE 2 . Zhizhchenko (1934) did not designate a holotype. In Zhizhchenko (1936) he illustrated one of the syntypes and designated it as ‘holotype’. Because a subsequent designation of a holotype is not possible, this specimen became a lectotype. Paralectotypes: TSNIGR 166/11330, illustrated in Zhizhchenko (1936, pl.20, fig.19); TSNIGR 167/11330, illustrated in Zhizhchenko (1936, pl. 20, fig. 20). Note that the specimen illustrated in Zhizhchenko (1936, pl. 20, fig. 18, TSNIGR 165/11330), represents Bittium tulskajense Iljina, 1993 . All specimens from Cape Tarkhan (Crimea), early Chokrakian, Middle Miocene.

Illustrated material. PIN 5794 View Materials /34, SL: 15 mm, MD: 4.6 mm, Belaya River ( Russia), Figs 10B View FIGURE 10 1 –B View FIGURE 1 2 View FIGURE 2 . PIN 5794 View Materials /33, SL: 13.3 mm, MD: 4.2 mm, Belaya River ( Russia), Figs 10C View FIGURE 10 1 –C View FIGURE 1 2 View FIGURE 2 . PIN 5904 View Materials /12, SL: 5 mm, ravine Semikolennyi ( Russia), Fig. 10D View FIGURE 10 . PIN 5794 View Materials /31, ravine Semikolennyi ( Russia), Figs 10E View FIGURE 10 1 –E View FIGURE 1 2 View FIGURE 2 . PIN 5794 View Materials / 30, ravine Semikolennyi ( Russia), Fig. 10F View FIGURE 10 . PIN 5904 View Materials /14, ravine Semikolennyi ( Russia), Fig. 10G View FIGURE 10 .

Revised description. Large, moderately slender regularly conical shell of up to 16 teleoconch whorls, attaining 17–19 mm in height; apical angle ~20°. Protoconch of 3.3 whorls (dp = ~320 μm), with numerous spiral rows of microscopical pustules, after first whorl alternating with spiral threads below mid-whorl. Last protoconch whorl with marked shoulder above mid-whorl, ends with sinusigera. First three teleoconch whorls bicarinate with three smooth primary spiral cords. Third primary cord at abapical suture, partly covered by subsequent whorl. Third to sixth teleoconch whorls weakly convex with three spiral cords with wide spaced tubercles. First secondary cord appears in the middle between adapical suture and upper primary cord at around third to fourth teleoconch whorls. Next secondary cord appears along adapical suture little later, and fifth secondary appears as thin thread between two earlier secondary cords on penultimate or last whorls. Microsculpture of numerous spiral rows of pustules in interspaces; spiral cords with tiny pits. Later whorls subcylindrical with narrow, incised suture, bearing finely cancellate sculpture, with close-set rounded tubercles (up to 30 per whorl) developed at intersections. Last whorl weakly convex, strongly constricted, attaining 33–35% of total height. Base with two prominent peribasal spiral cords and up to three weaker spiral cords over fasciole. Aperture wide, ovate. Columella excavated. Columellar callus forming narrow thickened rim, sharply delimited from base. Anal canal weakly incised. Outer lip thin. Siphonal canal very short, wide, slightly deflected to the left.

Discussion. This species is characterized by its regular conical outline and somewhat cancellate sculpture with tubercles developed at the intersections so close-set as to be almost beaded. It differs from Bittium tani sp. nov. and B. deforme ( Eichwald, 1829) by its regular conical outline and more numerous but lower teleoconch whorls. Bittium digitatum ( Zhizhchenko, 1934) derived from B. tulskajense Iljina, 1993 during the early Chokrakian ( Guzhov 2022). For a detailed discussion and additional pictures see Guzhov (2022).

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

Distribution. Endemic to the early Chokrakian of the Eastern Paratethys Sea.

Eastern Paratethys. Early Chokrakian (Middle Miocene): Turkey: Cape Bayram, Cape Carta, Ordu, Sinop (Sinop District) ( Goncharova et al. 2014; Guzhov, 2022; hoc opus); Bulgaria: Varna district (Strachimirov 1960); Crimea: Bondarenkovo, Chekur-Koyash, Chokrak Lake, Malyi Kamyshlak and Skelya sections, Cape Tarkhan, Yuzmyak place near Leninskoe, Cape Zyuk (Crimea); Ciscaucasia : Belaya, ravine Semikolennyi (Adygea), Bol’shoi Zelenchuk river (Karachay-Cherkessia), Kievskoe, Otradnaya, Rubaily rocks, Shpil’ Mountain (Krasnodar Krai), Mountain Bryk, Podgornoe, Sultan, Vorovskolesskoe (Stavropol Krai, Russia); Transcaucasia : Dzhgali, Kvezani, Badzhi ( Georgia); Tkvarcheli (Abkhazia); Transcaspian Region: Chelyungkyr Plateau, Geokoba Mountain Ridge ( Turkmenistan), Balniyaz place (Garabogazköl Bay), former Sartas (now in the limits of Garabogaz) ( Turkmenistan) ( Andrussow 1911; Zhizhchenko 1959; Volkova 1974; Iljina 1993; Vorobyev 2014; Guzhov 2022).