Dimeroceratidae is one of three families in the

Dimeroceratoidea Dimeroceratoidea, formerly Dimerocerataceae, is one of six superfamilies in the goniatitid suborder Tornoceratina which lived During the Devonian. Five families are included, the Dimeroceratidae being the type family. Gonitites, to which they ...

, a goniatid superfamily included in the

Ammonoidea Ammonoids are a group of extinct marine mollusc animals in the subclass Ammonoidea of the class Cephalopoda. These molluscs, commonly referred to as ammonites, are more closely related to living coleoids (i.e., octopuses, squid and cuttle ...

; extinct shelled cephalopods with adorally convex septa and usually narrow ventro-marginal siphuncles. The family Dimeroceratidae was established for the genus '' Dimeroceras'' which was previously included in the Cheiloceratidae in the

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') published by the Geological Society of America and the University of Kansas Press, is a definitive multi-authored work of some 50 volumes, written by more than 300 paleontologists, and co ...

Part L, but differing from the similar subglublar to thickly lenticular ''

Cheiloceras ''Cheiloceras'' is a subglobular to thickly lenticular goniatite with a closed umbilicus from the Upper Devonian and type genus for the Cheiloceratidae. ''Cheiloceras'' is sometimes split into at least three subgenera. ''Cheiloceras (Cheilocer ...

'' in having a large lateral lobe and the umbilical lobe outside the umbilicus. The Dimeroceratidae are derived from the Cheiloceratid genus '' Torleyoceras'' through the ancestral '' Paradimeroceras'' which gave rise to ''Dimeroceras'', (Saunders et al. 1999). Other genera included are ''Paratornoceras'' and '' Acrimeroceras''. Dimeroceratids have been found in the Devonian of China and Australia.

References

* Miller, Furnish, & Schindewolf, 1957. Paleozoic Ammonoidea. Treatise on Invertebrate Paleontology Part L. R.C. Moore (Ed) Geological Society of America. * Saunders, Work, & Nikoleava, 1999. Evolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Materia

Dimeroceratidae-Paleodb
Dimeroceratidae, Goniatitida families Devonian first appearances Devonian extinctions {{Goniatitida-stub