Bittium orientale ( Andrussow, 1911 )

Bittium orientale ( Andrussow, 1911)

Figs 17A–H View FIGURE 17

* Cerithium orientale View in CoL sp. nov. — Andrussow 1911: 75, text-fig. 50, fig. 26.

Cerithium orientale Andr.— Uspenskaya 1927: 639 View in CoL , pl. 34, figs 24–27.

Cerithium orientalis [sic] Andrus.— Davidaschvili 1932: 39, pl. 4, figs 15–19.

Potamides orientalis [sic] Andrussov— Zhizhchenko 1936: 208, pl. 21, figs 6–10.

Potamides orientalis [sic] Andrussov— Strachimirov 1953: 70, pl. 16, figs 10–13.

Potamides orientalis [sic] Andrussov— Zhizhchenko 1959: 251, pl. 16, figs 7–12.

Potamides orientalis [sic] Andrussov 1911— Strachimirov 1960a: 286, pl. 59, figs 25–26.

Newtoniella dertobicarinata var. agibelica Zhizhchenko 1936 — Strachimirov 1960a: 287, pl. 59, figs 27–30 [non Zhizhchenko 1936]

Potamides orientalis [sic] (Andrussov, 1911)— Zelinskaya et al. 1968: 160, pl. 39, fig. 19.

Cerithium View in CoL (?) orientale Andrussov, 1911 View in CoL — Iljina 1993: 81, pl. 10, figs 13–15.

C. (?) orientale Andrussov— Iljina, 2004: 621 View in CoL .

Bittium moesiense Jekelius, 1944 — Bandel 2006: 72, pl. 5, figs 7–8 [non Bittium moesiense Jekelius, 1944 (= Bittium konkense Sokolov, 1899 )].

Cerithium orientale Andrussow— Guzhov 2015: 84 View in CoL .

Cerithium orientale Andrussow, 1911 View in CoL — Guzhov 2022: 1.

Type material. Lectotype TSNIGR 12 /11285, figured in Andrussow 1911: pl. 50, fig. 26; SL: 9.4 mm, MD: 4 mm, Cape Tarkhan (Crimea), Middle Miocene, early Chokrakian , Figs 17A View FIGURE 17 1 –A View FIGURE 1 2 View FIGURE 2 .

Illustrated material. PIN 5904/36, SL: 11.2 mm, MD: 4.3 mm, Belaya River ( Russia), early Chokrakian, Fig. 17B View FIGURE 17 . PIN 5904/37, SL: 10.4 mm, MD: 3.8 mm, Belaya River ( Russia), early Chokrakian, Figs 17C View FIGURE 17 1 –C View FIGURE 1 2 View FIGURE 2 . PIN 5904/38, SL: 11.6 mm, MD: 4.4 mm, Belaya River ( Russia), early Chokrakian, Fig. 17D View FIGURE 17 . PIN 5904/39, SL: 13 mm, MD: 4.9 mm, Belaya River ( Russia), early Chokrakian, Figs 17E View FIGURE 17 1 –E View FIGURE 1 2 View FIGURE 2 . PIN 5904/40, SL: 7.7 mm, MD: 2.9 mm, Khadyzhensk ( Russia), early Chokrakian, Figs 17F View FIGURE 17 1 –F View FIGURE 1 2 View FIGURE 2 . PIN 5904/41, SL: 9.1 mm, MD: 3.5 mm, Belaya River ( Russia), early Chokrakian, Figs 17G View FIGURE 17 1 –G View FIGURE 1 3 View FIGURE 3 . PIN 5904/42, Belaya River ( Russia), Middle Miocene, lower Chokrakian, Figs H 1 –H View FIGURE 1 2 View FIGURE 2 .

Revised description. Large, moderately stocky, conical shell of up to ten teleoconch whorls, attaining 12 mm in height; apical angle 20–37°. Protoconch of two and half whorls terminating with sinusigera (dp = ~260 μm). Teleoconch whorl profile angled below mid-whorl, with very broad, often slightly concave subsutural ramp; weakly convex below. Suture becoming more superficial during ontogeny, almost linear. First teleoconch whorls with two spiral cords at mid-whorl, and third only partially visible cord at abapical suture. Secondary sculpture of single delicate subsutural cord appearing on second to third whorls, fading after three to four whorls. Subsequent teleoconch whorls with two prominent close-set spiral cords, the adapical cord placed near mid-whorl, bearing spirally elongated, weakly pointed tubercles at intersections with axial ribs. Axial ribs subobsolete, 9–12 per whorl, quickly weakening above and below beads. Microsculpture of very thin and dense spiral striae in spiral interspaces, often weakly tuberculate; spiral cords with numerous tiny pits. Last whorl low, convex, slightly angled on periphery, attaining 41–47% of total height. Base strongly constricted, convex, bearing two widely spaced peribasal cords; additional spiral cords on base varying from three regularly spaced, prominent cords to two to four thin spiral threads. Columella excavated. Columellar callus forming thin, narrow rim. Anal canal weakly marked, narrow. Outer lip thin. Siphonal canal very short and wide. Gerontic stage on last third of last whorl expressed by increasing number of close-set tubercular axial ribs.

Discussion. Bittium orientale ( Andrussow, 1911) is characterized by its bicarinate outline. It was placed in Cerithium by most authors, but the character of protoconch and sculpture of the early teleoconch whorls suggests a relation with several endemic Bittium species of the Eastern Paratethys, such as early Chokrakian Bittium agibelicum ( Zhizhchenko, 1936) , B. nabokovorum nom. nov., and the early Maeotian B. badzoshviliae sp. nov. Bittium orientale differs from B. agibelicum in its broader, generally larger shell and the narrower subsutural ramp; it differs from B. nabokovorum in its much larger and massive shell and scattered beads. Occasionally, specimens with three or four tuberculate spiral cords may occur. These cords form either as adapical secondary cord and/or when the suprasutural cord moves above the suture. A reworked shell with two adapical secondary cords from Khadyzhensk ( Russia) ( Fig. 17F View FIGURE 17 ) may represent an archaic specimen or an ancestor of B. orientale .

Bandel (2006) illustrated a juvenile specimen with well-preserved protoconch as Bittium moesiense Jekelius, 1944 from Bulganak (Crimea) without stratigraphic information. Most probably, he referred to Gulf Bulganak, which is known for the Chokrakian sections Malyi Kamyshlak and Skelya. The early teleoconch features agree with those of B. orientale .

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

Distribution. Early Chokrakian of the Eastern Paratethys.

Eastern Paratethys. Early Chokrakian (Middle Miocene): Bulgaria: Samotino, Varna ( Strachimirov 1960a); Crimea: Lake Chokrak, Malyi Kamyshlak, Skelya, Mramornaya gully (Sevastopol), Cape Tarkhan, Yuzmyak, Cape Zyuk ( Zhizhchenko 1936, hoc opus); Ciscaucasia : Belaya River (= Tul’skii), ravine Semikolennyi (Adygea), Khadyzhensk, Novourupskii, rocks Rubaily (Krasnodar Krai), Yaman-Dzhalga (Stavropol Krai, Russia) ( Iljina 1993; hoc opus); Transcaucasia : Dzhgali, Gorisa, Kvezani ( Georgia), Ajivan Mountain Ridge ( Azerbaijan) ( Iljina 1993); Transcaspian Region: Balniyaz, well Belek, Geokoba Mountain Ridge ( Turkmenistan) ( Iljina 1993).