Gatunek typowy
Tyersella typica Philip, 1962; Victoria, Australia; Siluro-Devonian boundary

Opis

Valves subcircular and ventribiconvex; ventral interior with divergent dental plates and median ridge; dorsal interior with petaloid muscle scar having elevated margins; deep sockets excavated into valve floor; absent of fulcral plates.

Synonimy

Zasięg czasowy

Mid Silurian (Wenlock) to Mid Devonian (Givetian); cosmopolitan.

Literatura