Karsaconulus, Szabó, 2018

Szabó, János, 2018, Gastropods of the Lower Jurassic Hierlatz Limestone Formation, part 4. New eucycloidean, trochoidean, neritimorph, and caenogastropod taxa in the fauna of the Hierlatz Alpe (Hallstatt, Austria), Fragmenta Palaeontologica Hungarica 35, pp. 61-84 : 72-73

Karsaconulus n. gen.

Type species – Karsaconulus robustus n. sp.

Derivation of name – Karsa = first name of the author’s grandson, conulus (Latin) = cone.

Diagnosis – Small, thick-walled shells of biconoidal outline with blunt apex. Basal conoid low and having slightly convex wall. Shells anomphalous. Full-grown shells consisting of about six whorls, being strongly convex initially but changing to almost flat subsequently. Suture deeply impressed on early shell but altering into almost flush on later whorls. Periphery rounded angular. Columellar lip robust and sitting on thick, wide, periaxial elevation, surrounded by narrow furrow. Inner lip having wide, uneven, mainly concave outer face between sutural part of outer lip and foot of columella; its basal and apertural edges sharp. Aperture orbicular. Remnants of outer lip bearing sharp outer rim; in latest growth stage, last whorl and outer lip region slightly extending abaxially. Ornament of clear spiral threads from second whorl at least for one whorl then obscure spiral lines/striae appearing on next whorls and base. Growth lines prosocline and feebly prosocyrt on whorls, opisthocyrt on base.

Description – See the type species.

Remarks – The appearance of the shells is similar to that of Proconulus Cossmann, 1918 ; however, the peristomal morphology is strongly different. It has a poorly developed parietal lip while Karsaconulus n. gen. has a rather wide parietal lip there with a concave outer face, having sharp edges that continue also along the columellar lip to its widely extended, concave foot, bearing also sharp rims. In the enlarged, concave surface of the foot of columella, Karsaconulus is reminiscent to Discotectus Favre, 1913 but the full morphology of the latter genus links it to Epulotrochidae Gründel, Keupp & Lang, 2017 .

Occurrence – Within Sinemurian to lowermost Pliensbachian (Lower Jurassic) part of the Hierlatz Limestone Formation in Hierlatz Alpe, Hallstatt, Austria.