Ohioceras

Ohioceras is an extinct genus of suborthochonic nautiloids from the Silurian of Ohio belonging to the orthoceroid family Kionoceratidae.

Ohioceras is characterized by a slightly curved longiconic shell with a circular to slightly depressed cross-section. The surface is lined with broad, low, longitudinal ribs separated by distinct shallow grooves. The siphuncle is subcentral, apparently orthochoanitic.