Olegia, Harzhauser & Landau & Janssen, 2022

Harzhauser, Mathias, Landau, Bernard & Janssen, Ronald, 2022, The Clavatulidae (Gastropoda, Conoidea) of the Miocene Paratethys Sea with considerations on fossil and extant Clavatulidae genera, Zootaxa 5123 (1), pp. 1-172 : 76-78

Genus Olegia nov. gen.

Type species. Olegia mandici nov. sp.; middle Miocene (Sarmatian, Serravallian), Central Paratethys Sea, Croatia .

Etymology. In honor of Oleg Mandic, paleontologist at the NHMW, in recognition of his contributions on the history of the Paratethys Sea.

Diagnosis. Small to medium-sized, solid, slender to moderately slender fusiform with conical spire. Early teleoconch whorls with bipartite sculpture of prominent, smooth subsutural spiral cord and coarsely tuberculate suprasutural cord, mid-whorl concave with comma-shaped riblets representing anal sinus. Sculpture on later whorls consisting of two adsutural rows of beads. Last whorl with tuberculate subsutural collar. Concave subsutural ramp. Cords of alternate strength below shoulder, made tuberculate by axial ribs. Siphonal canal short to moderately short.

Description. Shell small to medium-sized, solid, slender to moderately slender fusiform with conical spire. Early teleoconch whorls with bipartite sculpture of prominent, smooth subsutural spiral cord and coarsely tuberculate suprasutural cord, mid-whorl concave with comma-shaped riblets representing anal sinus. On mid- and later whorls adsutural cords tubercular, tubercles rounded or slightly pointed. Mid-whorl distinctly concave, smooth, except for comma-shaped riblets representing anal sinus. Last whorl ~65% of total height, with tuberculate subsutural collar, concave subsutural ramp. Shoulder moderate to well developed. Cords of alternate strength below shoulder made tuberculate by axial ribs that develop only below shoulder. Base delimited by tubercular peribasal cord, weakly constricted. Siphonal fasciole poorly developed. Aperture moderately wide, ovate. Outer lip not thickened, smooth within. Anal sinus moderately wide, moderately deep to deep, asymmetrically U-shaped. Siphonal canal moderately short, strongly deflected to the left with shallow notch at tip. Columellar and parietal callus thickened, sharply delimited, forming broad callus rim.

Stratigraphic and geographic range. Early to late Miocene (Karpatian to Sarmatian, late Burdigalian to Tortonian).Central Paratethys Sea: Poland, Ukraine, Austria, Slovakia, the Czech Republic, Bosnia and Herzegovina, Croatia, Moldova, Bulgaria, Romania. Proto-Mediterranean Sea: Italy (Tortonian).

Included species. Central Paratethys Sea: Pleurotoma (Clavatula) agathae Hoernes & Auinger, 1891 , Pleurotoma (Clavatula) brigittae Hoernes & Auinger, 1891 , Pleurotoma doderleini, Hörnes 1854 , Pleurotoma (Clavatula) dorotheae Hoernes & Auinger, 1891 , Pleurotoma rumana Simionescu & Barbu, 1940 , Olegia mandici nov. sp., Clavatula schreibersi szokolyensis Strausz, 1960 , Pleurotoma winterlingensis Quenstedt, 1884 .

Proto-Mediterranean Sea: Clavatula aradasi Bellardi, 1877 , Clavatula baccifera Bellardi, 1877 , Clavatula consularis Bellardi, 1877 , Clavatula stazzanensis Bellardi, 1877 .

Discussion. Olegia differs from Clavatula in its small fusiform shape, the comma-shaped axial riblets on early teleoconch whorls and by the beaded spiral cords of more or less equal size on the last whorl. Moreover, the shoulder of Olegia is rounded and distinctly less prominent. A separation from Megaclavatula nov. gen. is based on the very different early teleoconch sculpture, which is tripartite in Megaclavatula . In addition, Megaclavatula is larger, has a more constricted base, lacks ribs below the shoulder, lacks beaded basal and peribasal cords and has a longer siphonal fasciole. Granulatocincta nov. gen. is distinguished by its tripartite early whorl sculpture and characteristic sculpture of close-set granulose spiral cords on later whorls.

Olegia is rarely reported from the Karpatian and Badenian but survived the Badenian-Sarmatian Extinction Event ( Harzhauser & Piller 2007) and radiated thereafter. It became the most common Clavatulidae genus in the Sarmatian Paratethys Sea. In the Proto-Mediterranean Sea the genus is represented by Olegia consularis ( Bellardi, 1877) as described by Venzo & Pelosio (1963) from the Tortonian of Vigoleno ( Italy) and by O. aradasi ( Bellardi, 1877) and O. stazzanensis ( Bellardi, 1877) (see Ferrero Mortara et al. 1981, pl. 14, figs 10–11).

Paleoecology. Typically found in inner neritic settings with sandy bottoms (own data).