Life Sciences Commons^™

Cranial Anatomy And Taxonomy Of Dolichorhynchops Bonneri New Combination, A Polycotylid (Sauropterygia: Plesiosauria) From The Pierre Shale Of Wyoming And South Dakota, F. Robin O’Keefe

Biological Sciences Faculty Research

The taxonomic identity of two well-preserved polycotylid plesiosaur skeletons from the Pierre Shale of far northern Wyoming and southern South Dakota has been controversial since their discovery. Originally referred to Dolichorhynchops osborni, the material was almost immediately christened Trinacromerum bonneri Adams 1997; more recently the material has been referred toPolycotylus. Recent preparation of the well-preserved skull of one specimen permits detailed examination of the cranial morphology of this animal for the first time, and allows for its inclusion in a cladistic analysis of the Polycotylidae. This analysis reveals a stable sister-taxon relationship with Dolichorhynchops osborni. However, …