Specimen MZ VIII Mg 4238/1 from the Callovian (Mid Jurassic) of  Łuków (block in glacial drift), lateral and apical view.

Diagnoza

Shell relatively broad. Teleoconch ornamented with strong axial ribs (approx. 12–13 per whorl) and one medial keel. At intersections of axial ribs and keel small nodes appearing. Keel getting weaker during ontogeny, almost disappearing on the body whorl. Base well demarcated by angulation of whorl. Teleoconch surface covered by fine, densely packed lirae.

Porównanie

The protoconch of holotype is not well preserved but all Polish specimens have a smooth protoconch 2 so the paratype juvenile shell (SMNS 63302) belongs to another species.

Autekologia

Występowanie geograficzne

Germany and Poland (only in Łuków).

Zasięg czasowy

Callovian.

Materiały muzealne

Material from Germany and ten shells from Łuków, Poland.

Literatura

Gründel, J. 1998a. Archaeo− und Caenogastropoda aus dem Dogger Deutschlands und Nordpolens. Stuttgarter Beiträge zur Naturkunde, Serie B (Geologie und Paläontologie) 260, 1–39.

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