Collignoniceras

Collignoniceras
Scientific classification
Kingdom:	Animalia
Phylum:	Mollusca
Class:	Cephalopoda
Subclass:	Ammonoidea
Order:	Ammonitida
Family:	Collignoniceratidae
Subfamily:	Collignoniceratinae
Genus:	Collignoniceras Mantell, 1822

Collignociceras is an evolute, strongly ribbed and tuberculate ammonoid from the Upper Cretaceous of the western United States and Europe belonging to the ammonite family Collignoniceratidae. The type is Ammonites woollgari, named by Mantell in 1822 for specimens from Sussex, England.

Wright (1957, P. L426 in the Treatise) gave the following description for Collignoniceras: Compressed in early stages, with rounded or high and clavate siphonal tubercles tending to form serrate keel; with straight or slightly sinuous ribs and weak umbilical and strong ventrolateral tubercles; later whorls tend to be squarer in section with exaggerated ventrolateral tubercles which may absort even the umbilile tubercle.

Two subspecies are known from the Turonian (lower Upper Cretaceous) of western North America, C. woollgari wooolgari and C. woollgari regulari. C.w. woollgari has been found with Mammites depressus at the top of the lower shale tongue and lowermost overlying Tres Hermanos sandstone member of the Mancos Shale in New Mexico; in a shale bed at the top of the Greenhorn Formation in Colorado, and alone in sandstone and shale in the upper Frontier Formation in Wyoming. The slightly younger C. w. regulari is known from the lower Carlile Shale, which overlies the Greenhorn. It has been found in U.S. western interior from as far west as northern Arizona and eastern Utah and from New Mexico to Montana.

References

• Arkell et al., 1957, Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L. Geological Soc. of America, Univ of Kansas Press. R.C. Moore, (Ed)
• W. A. Cobban and Hook, S. C. 1979, Collignoniceras woollgari wooollgari (Mantell) ammonite fauna from Upper Cretaceous of Western Interior, United States. Memoir 37, New Mexico Bureau of Mines&Mineral Resources, Socorro NM.