Ovilia, Jousseaume, 1887

Harzhauser, Mathias & Landau, Bernard, 2012, A revision of the Neogene Cancellariid Gastropods of the Paratethys Sea 3472, Zootaxa 3472, pp. 1-71 : 34

Ovilia ? sp.

Figs 7E 1–E 2

Illustrated material. Figs 7H 1–H 2: Mörtersdorf ( Austria), height: 30 mm, width: 26 mm, private collection Anton and Thomas Breitenberger (Bad Vöslau and Pottenstein, Austria).

Description. Globular shell with low, gradate spire and large, convex last whorl. A shoulder appears already on early whorls and separates a flat sutural shelf from the flanks. Sculpture consisting of 13 low fold-like axial ribs overrun by about ten flattened spiral cords, with broad, horizontally elongate nodes developed at the intersections. These are most prominent along the shoulder. Up to three wavy secondary spiral threads are intercalated between the adapical five primary cords, whilst only one (or no) threads are intercalated between the cords on the base. Aperture and base obscured by sediment.

Discussion. Only a single specimen is available and the aperture is unknown. Therefore, even the generic assignment remains doubtful. Although some specimens of the Early Miocene Ovilia doliolaris have tendencies to develop rugose spiral ribs, as evident from the illustration in Basterot (1825), none displays such a conspicuous sculpture. The weak suture of the Austrian shell allows a clear separation from the O doliolaris group and the newly described O. breitenbergerorum , which occurs at the same locality.

A second group of species, which we provisionally include in the genus Ovilia , have axial sculpture, albeit weak, much less conspicuous spiral cords and a less deeply canaliculate suture. This group is characterised by O. excassidea ( Sacco, 1894) in the Miocene and O. cassidea ( Brocchi, 1814) and O. andaluciensis Landau, 1984 in the Pliocene. The Austrian shell resembles O. excassidea in outline and suture type and might represent an ancestral form of this Middle Miocene species. The sculpture of both species is also comparable. Differences are the blunt nodes and densely spaced spiral ribs of the Early Miocene Austrian shell, as opposed to the much narrower spiral cords of O. excassidea , and the poorly defined axial ribs, whilst O. excassidea has a distinct axial sculpture.

Distribution. A rare species, which is only known from the Paratethys Sea.

Paratethys —Eggenburgian (Early Burdigalian): Bohemian Massif ( Austria: Mörtersdorf).