Polycotylus was a plesiosaur, a type of marine reptile. It was not a dinosaur, though it coexisted with many dinosaurs.
All these Polycotylus pictures were collected from the internet. Enjoy and explore:
- S. W. Williston. 1905. A new armored dinosaur from the Upper Cretaceous of Wyoming. Science 22(564):503
- R. Zangerl. 1953. The vertebrate fauna of the Selma Formation of Alabama. Part III. The turtles of the family Protostegidae. Fieldiana: Geology Memoirs 3(3):63-133
- H.-E. Sauvage. 1873. Notes sur les reptiles fossiles. Bulletin de la Société Géologique de France, série 3 1:365-386