Cerastus pseudoena, Neubert & Damme, 2012

Neubert, Eike & Damme, Dirk van, 2012, Palaeogene continental molluscs of Oman, Contributions to Natural History 20, pp. 1-28 : 16-18

Cerastus pseudoena sp. nov.

( Fig. 16 )

Type specimens: Holotype NMBE 5018985 . Type locality: Wadi Darbat , Dhofar, Oman.

Stratum typicum: Paludal biomicritic limestones of the Zalumah Formation.

Age: Late Priabonian.

Material: This species is only represented by the holotype specimen.

Etymology: pseudoena refers to the superficial similarity of this species with the Modern European enid species Ena montana (DRAPARNAUD, 1801) .

Diagnosis: A small species of Cerastidae with a unique formation of aperture, slight ribbing pattern on teleoconch whorls, and partly obscured umbilicus.

Description: Shell slender, turreted; protoconch small, obtuse (not preserved as shell); upper teleoconch whorls elongate conical, last three whorls more rapidly increasing; a fine pattern of axial riblets covering the whorls (only partly preserved, Fig. 16b ); aperture elongate oval, columellar part triangular, broad, peristomial rim slightly reinforced by lip formation, somewhat flared; umbilicus open, partly obscured by triangular columellar shield.

Measurements: Holotype ( Fig. 16 ): H = 13.78 mm; Wh> 8.

Remarks: This new species is placed in the family Cerastidae , because it matches very well the enoid shell form of most of the Modern species in this family. The correct separation between Cerastidae and Enidae is based on several anatomical details ( Mordan 1992). However, all cerastid species recorded from the Arabian peninsula share the shell morphological detail of shells that are ribbed on the upper teleoconch, at least. This holds also true for C. pseudoena sp. nov., which thus supports its affiliation to that family. It is described under the genus Cerastus ALBERS, 1860 , because this genus has a long-lasting history as suggested by its distribution that ranges from Ethiopia via the southwestern Arabian Peninsula to northwestern India. Cerastus girwanensis CONNOLLY, 1941 , a Modern endemic species from the Southwest of Saudi Arabia is shown here ( Fig. 17 ) to facilitate comparison.

Figures

Figs. 16–17: Species of Cerastidae. Fig. 16a: Cerastus pseudoena sp. nov., Wadi Darbat, holotype NMBE 5018985 in frontal view. Fig. 16b: ditto, detail of protoconch and upper teleoconch whorls; detail not to scale. Fig. 17: Cerastus girwanensis CONOLLY, 1941, SMF 311620, Saudi Arabia, Asir province, Wadi al-Sharan S of Bani Sa'ad, 1750 m alt, leg. E. Neubert.