''Pseudosirenites'' is a genus of Upper Triassic ammonites belonging to the

ceratitid Ceratitida is an order that contains almost all ammonoid cephalopod genera from the Triassic as well as ancestral forms from the Upper Permian, the exception being the phylloceratids which gave rise to the great diversity of post Triassic ammoni ...

family

Trachyceratidae The Trachyceratidae is an extinct family of ceratitid ammonoid cephalopods. The Trachyceratidae makes up part of the superfamily Trachyceratoidea along with such families as the Buchitidae, Distichitidae, Dronovitidae and Noridiscitidae. ...

, like ''

Sirenites ''Sirenites'' is a genus 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 ...

'', but with a narrow outer rim (venter) that has a nodose keel on either side.

References

* Arkell, et al., Mesozoic Ammonoidea, '

Treatise on Invertebrate Paleontology The ''Treatise on Invertebrate Paleontology'' (or ''TIP'') 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 co ...

, Part L, Mollusca 4, Geological Society of America. 1957. Trachyceratidae Triassic ammonites Ceratitida genera Ammonites of North America {{Ceratitida-stub