Hierlatzella, 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 : 79-81

Hierlatzella n. gen.

Type species – Hierlatzella arcana n. sp.

Derivation of name – From the name of the type locality with - ella, diminutive suffix.

Diagnosis – Small, pupiform, thin-walled shell of low turriculate spire. Early whorls low and flat with flush suture. Last whorl downward extended and having shallow subsutural concavity. Periphery rounded angular, base convex. Peristome not fully known, disrupted or very thin at parietal region, and having simple outer lip. Axial lip composite but not fully known, seemingly tubular and corresponding to terminal part of rather thick columella, bearing narrow, conispiral umbilicus inside.

Remarks – In the lack of the earliest shell parts, the family attribution remains somewhat uncertain. However, similar simple shelled, slightly pupiform, poorly ornamented, umbilicate, Mesozoic gastropod genera are collected within Coelostylinidae . Because of the few shell characters, some genera of this family are hardly distinguishable (see e.g. case of Coelostylina and Omphaloptycha in NÜTZEL & ERWIN 2004). From these, Spirochrysalis Kittl, 1894 and some Coelostylina Kittl, 1894 species are most similar to Hierlatzella n. gen. but both differ in the lack of the heavy columella, containing the narrow, spiral umbilicus. Spirochrysalis differs also in its peculiar ornament, the spiral threads on the internal basal wall of the whorls. Hierlatzella seems to have also a short inner fold within the last whorl on its abaxial/palatal wall. It is unknown whether the umbilicus is open at the last peristome or closed like in Spirochrysalis .

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