Coilopoceratidae is a family of generally large, proper

ammonites Ammonoids are extinct, (typically) coiled-shelled cephalopods comprising the subclass Ammonoidea. They are more closely related to living octopuses, squid, and cuttlefish (which comprise the clade Coleoidea) than they are to nautiluses (family N ...

with strongly involute shells from the Cretaceous,

Albian The Albian is both an age (geology), age of the geologic timescale and a stage (stratigraphy), stage in the stratigraphic column. It is the youngest or uppermost subdivision of the Early Cretaceous, Early/Lower Cretaceous epoch (geology), Epoch/s ...

Turonian The Turonian is, in the International Commission on Stratigraphy, ICS' geologic timescale, the second age (geology), age in the Late Cretaceous epoch (geology), Epoch, or a stage (stratigraphy), stage in the Upper Cretaceous series (stratigraphy), ...

. Coilopoceratids have variably compressed shells with flattish to broadly rounded sides and narrowly rounded to sharp keel-like venters. Whorl sections are generally lanceolate. The suture is ammonitic with an overall clumpy appearance. The Coilopoceratidae are derived from the

Tissotiidae Tissotiidae is a family of ammonites (Ammonitina) belonging to the Acanthoceratoidea. The Tissotiidae are derived from the Vascoceratidae, another acanthoceratoid family, and gave rise to the Coilopoceratidae. They have been divided into two s ...

by a secondary re-development of an ammonitic suture and of more narrowly compressed shells.

Genera

*'' Coilopoceras'' Hyatt, 1903 (synonym = ''Glebosoceras'' Reyment, 1954) - from north and west Africa, Syria, Baluchistan, and western North America (Colorado, New Mexico, Texas). *'' Herrickiceras'' Cobban & Hook, 1980 - from Western North America, central Africa, and the Middle East. *''

Hoplitoides ''Hoplitoides'' is an ammonite from the Upper Cretaceous, Turonian belonging to the Coilopoceratidae, a family in the Acanthoceratoidea. ''Hoplitoides'' have early whorls which are grooved, then flat, and finally narrowly rounded venters; early ...

'' von Koenen, 1898 – from north and west Africa, Syria, Columbia, Peru, western North America.

References

*
Paleobiology Database Coilopoceratidae entry
Ammonitida families Acanthoceratoidea Turonian first appearances Coniacian extinctions {{Ammonitina-stub