Gatunek typowy
Orthis subcarinata Hall, 1857: Early Devonian, Lochkovian; Tennessee, USA

Opis

Valves subcircular and ventribiconvex; ventral interior with short subpentagonal muscle field bisected by wide median ridge; dorsal interior with swollen, lobate myophore lacking well-developed shaft and brachiophores expanded medianly; deep sockets excavated into valve floor; fulcral plates rare.

Synonimy

Zasięg czasowy

Early Silurian (Llandovery) to Mid Devonian (Eifelian); cosmopolitan.

Literatura