Gatunek typowy

Opis

Type species: Hayamia rex Kase in Kase & Maeda, 1980; Late Cretaceous, Japan
Diagnosis: Large-sized and relatively thin-shelled conch with its height almost equal to width and more or less protruded spire. Surface sculptured by numerous and more or less irregularly spaced spiral threads, in some species also by costellae. Inner lip long narrow and concave without a notch behind. No parietal tubercle. Operculum of naticopsid type, elliptical, lacking a quadrangular process at adaxial edge.

Synonimy

Zasięg czasowy

Jurassic to Cretaceous.

Literatura

Kase, T. & Maeda, H. 1980. Early Cretaceous Gastropoda from the Choshi District, Chiba Prefecture, Central Japan. Transactions and Proceedings of the Palaeontological Society of Japan,118, 291–324.