Gatunek typowy
Costazygia biltzi Gründel, 1999. Callovian (Mid Jurassic), Hohendorf, Germany.

Opis

Short and rather broad shell, with only few (6–7) whorls. Protoconch of about four whorls with rounded apex, early whorls almost planispiral. Protoconch ornamented by subsutural row of nodes. Nodes changing abapically into axial riblets. Sculpture of teleoconch consisting of numerous weak spiral and, in some cases, axial ribs. Growth lines parasigmoidal. Aperture without callus, but abapically with short, broad channel.

Synonimy

Zasięg czasowy

Bathonian (Mid Jurassic) to Valanginian (Early Cretaceous).

Literatura

Gründel, J. 1999f. Zygopleuroidea (Gastropoda) aus dem Lias ind Dogger Deutschlands und Nordwestpolens. Paläontologische Zeitschrift 73, 247–259.

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