Bellatara ankaraensis, Islamoğğlu & Dominio & Kowalke, 2011

Islamoğğlu, Yeşşim, Dominio, Stefano & Kowalke, Thorsten, 2011, Early Eocene Caenogastropods (Mollusca, Gastropoda) from Haymana-Polatl Basin, Central Anatolia (Turkey): taxonomy and palaeoecology, Geodiversitas 33 (2), pp. 303-330 : 316

Bellatara ankaraensis n. sp. ( Fig. 6G, S )

HOLOTYPE. — MTA-Y. İ.-2007 -45.

PARATYPES. — MTA-Y. İ.-2007 -46 and 47.

ETYMOLOGY. — After the name of Ankara, the capital city of Turkey, the nearest city to the locality.

OTHER MATERIAL EXAMINED. — 73 other non-type specimens (MTA-Y. İ.-2007 -48 to 50).

TYPE LOCALITY AND HORIZON. — Grey siltstone-mudstone, KIrkkavak Formation (Macunköy: sample G1, G2, G3, G4).

DIAGNOSIS. — Medium-sized, up to 3.5 cm in height, turriculate shell of up to ten whorls; the spire is slender and conical; the spire whorls are flat, with two spiral rows of rounded nodes, the suture line is deep and grooved producing a stepped spire; the last whorl has 4 or 5 thick, rounded and projecting spines, increasing in thickness towards adapertural part of the whols, 5 or 6 thin and sharp spiral bands producing a slightly angulated outline of the base of the body whorl, aperture is oblique ovoidal with deeply incised and elongated anal siphonal canal, columellar lip folded, outer lip is sharp.

REMARKS

Bellatara ankaraensis n. sp. is closely related to B. paleochroma ( Bayan, 1870) (= Cerithium (Bellardia) paleochroma Bayan, 1870 = Cerithium (Bellardia) janus Mayer, 1870 ) from the Eocene of Italy, but differs in the less plump spire whorls with two row nodes ordered one below the other, causing an axial rib like appearance. Moreover, its aperture is more oblique with elongated siphonal canals. Bellatara paleochroma possesses a more slender, flat and slightly concave shell with 6-8 spines in the penultimate and last whorls ( Oppenheim 1896: 182, pl. 15, figs 1-3). Bellatara ankaraensis n. sp. differs distinctly from Eocene B. vellicatum ( Bellardi, 1852) and B. verneulii (Rouault, 1850) by its shorter spire and by the ornamentation. Bellatara vellicatum has a slender shell, ornamented with granules growing towards the last whorl. Bellatara verneulii bears axial sculpture. The Oligocene B. lozoueti Harzhauser, 2004 has an elongated body whorl and irregular, but continuous keel ( Harzhauser 2004: 118, pl. 7, figs 5-7), whereas B. narica ( Vredenburg, 1925) has a sculpture of axial ribs restricted to the last two whorls.

Figures

FIG. 6. — Caenogastropods (deposited in the repositories of the General Directorate of Mineral Research and Exploration, Ankara): A, Cerithium puigcercosensis (Cossmann,1897) n. comb.;B-F, Vicinocerithium cf.subacutum (d’Orbigny,1850); G, S, Bellatara ankaraensis n. sp., holotype;H, I, Tympanotonos turris (Deshayes,1833); J, Cerithium cf.anguloseptum Rauff,1884; K-M, Gantechinobathra vulcani (Brongniart, 1823); P-R, “Crommium” sp. 2. Scale bars: 1 cm.