Phylum: Mollusca
Class: Cephalopoda
Order: Orthocerida
Family: Orthoceratidae M’Coy, 1844
Cincinnatian Genera: Pleurorthoceras, Richmondoceras

Geologic Range
Lower Ordovician – Upper Triassic

Common Paleoecology
Orthoceratidae is an extinct family of nektonic carnivores

Description of the Family

  • Smooth or elaborately ornamented
  • Subcircular in cross section
  • Central or subcentral siphuncle
  • Siphuncle free of endosiphuncular deposits

Published Descriptions

Treatise on Invertebrate Paleontology, Part K (1964):

  • Smooth or elaborately ornamented, generally subcircular in cross section and with central or subcentral siphuncle that is typically free of endosiphuncular deposits.