Gatunek typowy

Opis

Cerithium bisertum Koken,1889. Carnian (LateTriassic), Italy.
Protoconch hyperstrophic, diverging more than 100° from teleoconch axis, smooth or, in some species with adapical and abapical, axial folds. Teleoconch slender to broadly cone−shaped. First teleoconch whorl with two spiral ribs of which abapical one usually  distinctly angulating whorls. Number of spiral ribs stable during ontogeny or increasing to three. Spiral ribs crossed by weaker axial ribs, threads or enhanced growth lines, at rib intersections usually without nodes.  

Synonimy

Zasięg czasowy

Late Triassic to Early Cretaceous.

Literatura

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