Vicinocerithium Wood, 1910

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 : 321

Genus Vicinocerithium Wood, 1910

TYPE SPECIES. — Vicinocerithium bouei ( Deshayes, 1824) . Europe, Eocene.

Vicinocerithium cf. subacutum (d’Orbigny, 1850) ( Fig. 6 B-F)

Cerithium subacutum d’Orbigny, 1850: 318 , no. 385.

Batillaria subacuta – Erünal 1942: 128, figs 11, 12. — Stchépinsky 1946: 55, pl. 22, figs 19, 20.

Vicinocerithium subacutum – Pacaud 2007: 32.

MATERIAL EXAMINED. — 12 specimens ( MTA-Y. İ.-2007 -28 to 33).

LOCALITY AND HORIZON. — Grey siltstone-mudstone, KIrkkavak Formation (Macunköy: samples G1, G2).

PALAEOGEOGRAPHIC DISTRIBUTION. — Paris Basin ( France); NW Turkey (Gündüzler/ Kocaeli, Sünnet/ Bolu): Late Ypresian ( Stchépinsky 1946); Hampshire ( England): Ypresian ( Jeffery & Tracey 1997).

DESCRIPTION

Medium-sized, slender shells with more than seven flat whorls, incised, deep sutures. The sculpture of the whorls consists of spiral threads and projecting tubercules. Adapical part of each whorl comprises more than half part of the whorl and includes two granulate rows. Towards the last whorl, the length and width of the granules increase causing a slight angulation in the median line of the whorls as short spines between 9-10 in number. Abapical part of the whorls include only prominent up to four spiral threads. The granule rows of the whorls tied up with spiral threads being not dominant. The shell is decorated fine oblique, prosocline growth lines. Last whorl appears to be inflated. It’s spines are strongly projecting. The posterior side of the base is characterized by at least 5 thick spiral threads. Aperture is typical cerithioid, oblique ovoidal siphonostome.

REMARKS

The specimens were compared to the very similar species Batillaria subacuta from Cuisian of Paris Basin and Batillaria praesubacuta Doncieux, 1908 from Sparnacian of Corbières Basin of France, as represented in the collections of the MNHN. The most distinctive features between these two species is that Batillaria praesubacuta has a more narrow and slender shell lacking the prominent spiral threads ( Doncieux 1908). Compared to Batillaria subacuta (MNHN.F.J02530; Cuise, La Motte, Oise, France), our samples have a thicker shell and more spiral threads (up to four) in the spire whorls. Our smaller specimens display only small granules, whereas the adults have bigger spines in the last whorl. Moreover, some specimens have curved apex which is a known feature of brackish water environments ( Plaziat 1977; Kowalke 2006a: south Mediterranean Quaternary). Compared to syntypes (syntypes of Doncieux hosted at the MNHN) of Batillaria praesubacuta (MNHN.F.R64133; Fabrezan, Aude, France), no spiral cords are observed on the slender shells of Batillaria praesubacuta . Only few specimens from the collections from the Corbières Basin (Collection Courtessole- Griffe; MNHN 1989-3) were characterized by a sculptural pattern of fine spiral threads. Another similar species is Batillaria fauvergei Doncieux, 1908 from Sparnacian of Corbières Basin (Collection Courtessole-Griffe, MNHN; ruinean de Perlinge, Caunettes-en-Val, France). But it differs from V. subacuta (d’Orbigny, 1850) by having one row of small rounded nodes.

The investigated specimens have sculptural pattern suggesting a relationship with Batillaria subacuta . Ornamentation is formed by spiral bands and sharp spinous tubercules. The species is provisionally placed in genus Vicinocerithium Wood, 1910 which was described as a subgenus of Batillaria by Wenz (1938). Given the distinct differences between Batillaria and Vicinocerithium , this species is proposed in a separate genus Vicinocerithium Wood, 1910 of the family Batillariidae (Lozouet pers. corresp. 2005). Thus, usage of Vicinocerithium cf. subacutum (d’Orbigny, 1850) is appropriated.

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.