[N] 2006 New Plesiosaur from the Tropic Shale, Utah
Schmeisser, R. (2006) Description of a new species of Plesiosaur from the Upper Cretaceous Tropic Shale, Southern Utah. JVP 26(3) Abstracts pp.121
A closely associated pliosauromorph (short-necked plesiosaur) skeleton was excavated in 2005 from a site in the Upper Cretaceous (Cenomanian-Turonian) Tropic Shale. The site is located within Glen Canyon National Recreation Area and is the first nearly complete individual recovered from this region. The skeleton is remarkably well preserved, although heavily fractured. The specimen consists of a nearly complete skull and jaws, teeth, an incomplete set of vertebrae and ribs, scapulae, coracoids, nearly complete forelimbs, ilia, ischia, pubes, nearly complete hindlimbs, and associated paleogastroliths.
Following preparation and description, the new plesiosaur skeleton can be placed within the family Polycotylidae. Several characters are similar to those seen in other polycotylid plesiosaurs. However, the unique combination of characters found in the new specimen, as well as the presence of several previously unrecognized characters permits the assignment of a new species.
Additionally, several characters are similar to one genus of polycotylid (Dolichorhynchops) while several other characters are similar to another genus of polycotylid (Trinacromerum). This suggests that the new specimen could be an intermediate between the two genera. Therefore, specimens of Dolichorhynchops and Trinacromerum should be reevaluated to determine whether they should be synonymized.