Cheiloceratidae is a family of

ammonoid 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 cuttlefish) ...

cephalopods included in the goniatitid suborder

Tornoceratina Tornoceratina is one of two suborders included in the Goniatitida, characterized by generally involute, subdiscoidal shells and by sutures in which the ventral ones are undivided. Sutural lobes increase in number during the course of life of th ...

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 A treatise is a formal and systematic written discourse on some subject, generally longer and treating it in greater depth than an essay, and more concerned with investigating or exposing the principles of the subject and its conclusions."Treat ...

Part L, the other being 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 l ...

.A.K Miller, W.M Furnish, and O.H. Schindewolf, 1957. Paleozoic Ammonoidea. Treatise on Invertebrate Paleontology, Part L, Mollusca 4. Geological Soc. of America and Univ. Kansas Press. 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.Saunders, Ward, & Nickolaeva 1993, Evolution of Complexity in Paleozoic Ammonoid Sutures, Supplementary Materia

/ref> but includes '' Dimeroceras'', the basis for the Dimeroceratidae and ultimately the Dimeroceratoidea. The other three are Raymondiceratinae, Sporadoceratinae, and Immatoceratinae. Immatoceratinae includes '' Prionoceras'', the basis for the Prionocerataceae of Korn (2006).The Paleobiology Database
10/21/09 The Russian Osnovy Paleontologii, by Bogoslovsky ''et al'',
10/21/09 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 Dr. Dieter Korn (born 1958)Eugene V. Coan, Alan R. Kabat & Richard E. Petit (15 February) 2009American Malacological Society. 830 pp. + 32 pp. (Annex of Collations). is a German scientist and paleontologist specializing in research on ammonites and ...

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

References

Goniatitida families Prionocerataceae Late Devonian first appearances Late Devonian animals Guadalupian extinctions {{Goniatitida-stub