Cheiloceratidae is a family of ammonoid cephalopods included in the goniatitid suborder Tornoceratina

Tornoceratina

Tornoceratatina is one of two suborders of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.-References:...

 in which the suture has 4 to 12 lobes, the ventral one undivided and those in the lateral areas originating as subdivisions of internal and external lateral saddles.

Taxonomy

The taxonomy of the Cheiloceratidae varies according to the perception of different researchers over time and can be considered a work in progress. That presented in the taxobox is simply one of the more recent.

Cheiloceratidae is the larger of two families included in the Cheilocerataceae in the 1957 Treatise

Treatise on Invertebrate Paleontology

The Treatise on Invertebrate Paleontology 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 covering every phylum, class, order, family, and genus of fossil and...

 Part L, the other being the Tornoceratidae

Tornoceratidae

Tornoceratidae is a family of goniatitid ammonoinds from the middle and upper Devonian The family is included in the suborder Tornoceratinaand the superfamily Tornoceratoidea....

. The Cheiloceratidae (M,F,&S) range from the Upper Devonian to the Middle Permian and includes 4 subfamilies. Cheiloceratinae is essentially the Cheiloceratidae of Saunders et al but includes Dimeroceras, the basis for the Dimeroceratidae and ultimately the Dimeroceratoidea. The other three are Raymondiceratinae

Raymondiceratinae

Raymondiceratinae is a subfamily of Upper Devonian cheiloceratid goniatites in which the sutures have 4 distinct lobes and the growth lines are convex. The subfamily includes three genera....

, Sporadoceratinae

Sporadoceratinae

Sporadoceratinae is one of two subfamilies of the Sporadoceratidae family, a member of the Goniatitida order. They are an extinct group of ammonoid, which are shelled cephalopods related to squids, belemnites, octopuses, and cuttlefish, and more distantly to the nautiloids.-References:* accessed...

, and Immatoceratinae. Immatoceratinae includes Prionoceras, the basis for the Prionocerataceae

Prionocerataceae

Prionocerataceae is a superfamily in the goniatitid suborder, Tornoceratatina that was extant during the latter Paleozoic.The inclusive taxonomy of the Prionocerataceae varies according to classification...

 of Korn (2006).

The Russian Osnovy Paleontologii, by Bogoslovsky et al, placed the Cheiloceratidae, in the sense of the Cheiloceratinae of the Treatise, in the superfamily Dimeroceratoidea (ex Dimerocerataceae) which is included in the suborder Tornoceratina. Sister families to the Cheiloceratidae in the Dimeroceratoidea are the Dimeroceratidae, Phenacoceratidae, Prolobitidae, and Sinotitidae.

Saunders et al includes the Cheiloceratidae in the suborder Tornoceratina along with the Maenioceratidae, Tornoceratidae, Sinotitidae, Posttornoceratidae, Sporadoceratidae, and Dimeroceratidae; without the use of a superfamily.

In the more recent taxonomy attributed to Dieter Korn

Dieter Korn

Dr. Dieter Korn is a German scientist and paleontologist specializing in research on ammonites and goniatites. He received his Ph.D. in 1996 from the University of Tübingen and is employed by the Museum für Naturkunde in Berlin, Germany, in the Leibniz Institute for Research on Evolution and...

in 2006 the Cheiloceratidae is included in the Prionocerataceae and includes two subfamilies, the Cheiloceratinae and Nehdenitinae.