''Tornoceras'' is a strongly involute, subdiscoidal Middle and Upper

Devonian The Devonian ( ) is a period (geology), geologic period and system (stratigraphy), system of the Paleozoic era (geology), era during the Phanerozoic eon (geology), eon, spanning 60.3 million years from the end of the preceding Silurian per ...

goniatite Goniatids, informally goniatites, are ammonoid cephalopods that form the order Goniatitida, derived from the more primitive Agoniatitida during the Middle Devonian some 390 million years ago (around Eifelian stage). Goniatites (goniatitids) su ...

with a suture that forms six to ten lobes. Tornoceras is an extinct genus of cephalopods that shares similarities with the modern pearly nautilus. This genus first appeared during the Devonian Period, which spanned from 416 million to 359 million years ago. The shell is circular and relatively flat, with the final whorl enveloping the previous ones. The sutures between the successive chambers of the shell exhibit a gently rippled pattern. ''

Aulatornoceras ''Aulatornoceras'' is a genus belonging to the subfamily Aulatornoceratinae, a member of the Goniatitida, an extinct order of shelled cephalopods included in the Ammonoidea Ammonoids are extinct, (typically) coiled-shelled cephalopods compri ...

'', '' Protornoceras'', '' Epitornoceras'', '' Lobotornoceras'' are among related genera included in the

Tornoceratidae Tornoceratidae is a family of goniatitid ammonoids from the middle and upper Devonian. The family is included in the suborder Tornoceratina and the superfamily Tornoceratoidea. Tornoceratids are subdiscoidal goniatitids with biconvex growth li ...

. Inclusion however varies from classification to classification.Goniat- Tornoceratidae
/ref>The Paleobiology Database Tornoceratidae
/ref>

References

Tornoceratidae Goniatitida genera Devonian animals of Europe Devonian animals Late Devonian animals Devonian animals of Africa Middle Devonian first appearances Late Devonian genus extinctions {{Goniatitida-stub