Pseudohaploceras
Pseudohaploceras is a genus of desmosceratid ammonites from the Early Cretaceous; Valanginian to Albian epochs.[1]
| Pseudohaploceras Temporal range: Early Cretaceous ~ | |
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| Subfamily: | Pizosiinae |
| Genus: | Pseudohaploceras Hyatt, 1900 |
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Description
The genus is distinguished by its moderately involute, slightly to moderately compressed shell with convex sides and regular straight or sinuous constrictions between which are fairly fine, distinct, sharp or rounded branching ribs extending from the umbilical edge and crossing the venter, the outer rim.
Pseudohaploceras is considered an offshoot of early Valdedorsella, which differ in having a more broadly rounded whorl section and generally straight radial constrictions. It is included in the subfamily Pizosiinae.
Distribution
Fossils of Pseudohaploceras have been found in Austria, Bulgaria, China, Colombia (Tibasosa Formation, Santa Rosa de Viterbo and Yuruma and Apón Formations, La Guajira), Egypt, Italy, Japan, Mexico, Serbia and Montenegro, Spain, Tanzania, and the former USSR.[2]
References
- Wright, C. W. with Callomon, J.H. and Howarth, M.K. (1996), Mollusca 4 Revised , Cretaceous Ammonoidea, vol. 4, in Treatise on Invertebrate Paleontology, Part L (Roger L. Kaesler ed.), Boulder, Colorado: The Geological Society of America & Lawrence, Kansas: University of Kansas Press, pp. 73, 72.
- Pseudohaploceras at Fossilworks.org
Further reading
- W.J. Arkell; et al. (1957). R.C. Moore (ed.). Mesozoic Ammonoidea, Treatise on Invertebrate Paleontology Part L. Geological Society of America, University of Kansas Press.