Gatunek typowy
Trizonoceras lepidum Girty, 1909

Opis

shell subdiscoidal to thickly discoidal, completely involute, sublenticular in cross section; surface with sinuous growth lines forming lateral and ventral sinuses and ventrolateral salient, crossed by fine longitudinal lirae in some species; suture with ventral lobe divided by a moderately deep median saddle, each division and first lateral lobe with single notch or subsidiary saddle at or near apicad end; umbilical lobe poorly developed, short, generally rounded; lobes of internal suture rather narrow, undivided.

Synonimy
Currieoceras Manger, 1988

Zasięg czasowy

Carboniferous; Visean - Moscovian 

Literatura

Gordon, McKenzie, Jr. 1965. Carboniferous Cephalopods of Arkansas. Professional Papers, U.S. Geological Survey 460: 1-322, fig.1-96, pl.1-32; Washington.