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The cryptocleidoid plesiosaur Tatenectes laramiensis, new genus, is described from the Redwater Shale Member of the Sundance Formation, Narrona County, Wyoming. The holotype of this species was a partial skeleton that has since been lost. A neotype is designated that preserves the same elements present in the holotype. A second specimen is referred to the taxon, and this specimen includes cranial material. The preserved cranial elements are the left squamosal, a partial right frontal, several isolated teeth, the parasphenoid, and large portions of the left and right pterygoids. The skull shares many traits with that of Kimmerosaurus, a cryptocleidoid plesiosaur from the Kimmeridge Clay of England. However, the palate is derived, and resembles those of the poorly-understood cimoliasaurid plesiosaurs of the Creoceno of the southern hemisphere. This similarity is established via comparison with the skull of an undescribed taxoo from late Jurassic of Cuba. The cryptocleidoid plesiosaurs underwent an extensive radiation in the Late Jurassic, and more research attention is needed, beginning with additional preparation and collection of Tatenectes.


This article first appeared in the July 2003 issue of Paludicola, the member magazine of the Rochester Institute of Vertebrate Paleontology, and is reprinted with permission.

©2003 by the Rochester Institute of Vertebrate Paleontology