Cerithium cf. anguloseptum Rauff, 1885

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 : 314

Cerithium cf. anguloseptum Rauff, 1885 ( Fig. 6J )

Cerithium anguloseptum Rauff, 1885: 31 , pl. 11, figs 17, 23, 24, 26, 29, 30. — Oppenheim 1896: 185-187; pl. 15, figs 5, 6.

MATERIAL EXAMINED. — One specimen hosted in the NHMV (2008z0310/0012).

LOCALITY AND HORIZON. — Grey siltstone, KIrkkavak Formation (Macunköy: sample G2).

PALAEOGEOGRAPHIC DISTRIBUTION. — Monte Postale ( Italy): Ypresian ( Oppenheim 1896).

DESCRIPTION

Medium-sized shell of up to nine whorls ornamented with a prominent, opisthocline, thick and rounded axial ribs crossed by 3-5 fine spiral threads. The intersections of axial ribs and spiral threads form tubercules growing up to the last whorl. Suture line is deep. The last whorl is inflated.The spiral threads are dominant at the base. Aperture is elongated oval.

REMARKS

The identity of the only specimen of Cerithium anguloseptum from the Eocene of Monte Postale is uncertain, due to its wider apical angle (40°; Cerithium anguloseptum has a 30° angle) and more inflated body whorl and thicker perpendicular axial ribs. Cerithium (Thericium) depereti Doncieux, 1908 from the early Eocene of the Corbières, France ( Doncieux 1908: 116, pl. 7, fig. 1a-c; Plaziat 1970: 28, pl. 14, fig. 11) differs by its more plump shell having flat whorls with perpendicular, thicker and closer axial ribs. Our specimen has curved apical whorls, a variable feature of cerithioids which inhabit brackish environments ( Plaziat 1977).

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.