Specimen ZPAL Ga.9/29 from the Late Callovian (Mid Jurassic) of from Łuków (block in glacial drift) in lateral views, uppermost, broken spine marked by dashed line.

Diagnoza

Early teleoconch with two spiral ribs. On second whorl of teleoconch upper rib transforming into keel composed of three subordinate spiral ribs and fine axial riblets. Lower rib increasingly weaker  during  ontogeny. Teleoconch whorls angulated at spiral keel. Axial  ornamentation consisting of strongly opisthocline growth lines at early whorls and weak spiral striae later in ontogeny. Body whorl demarcated from the base by second spiral keel. Two keels extended into spine-like processes of outer lip at the adult shell peristome. Anterior canal extended into spine-like process, curved anteriorly.

Porównanie

The type material is Bathonian in age. Later authors reported the species to be from the Callovian and/ or Oxfordian. The older findings classified as D. nudispira may be in fact D. cochleata and thus closer to the type material. The Callovian–Oxfordian shells may represent another species.

Autekologia

Występowanie geograficzne

Europe; in Poland Łuków 

Zasięg czasowy

Late Jurassic; in Poland only Callovian.

Materiały muzealne

Material from Europe and over 100 shells from Łuków(ZPAL).

Literatura

Gründel, J. 2001. Nerithimorpha und weitere Caenogastropoda (Gastropoda) aus dem  Dogger Norddeutschlands und desnordwestlischen Polens. Berliner Geowissenschaftliche Abhandlungen, Reihe E36, 45–99.

Kaim, A. 2004. The evolution of conch ontogeny in Mesozoic open sea gastropods. Palaeontologia Polonica 62, 3–183.

Quenstedt, F.A. 1858. Der Jura. 842 pp. Laupp and Siebeck, Tübingen.