Polycotylus was a plesiosaur, a type of marine reptile. It was not a dinosaur, though it coexisted with many dinosaurs. The first Polycotylus fossil was discovered in 1869.

All the Polycotylus illustrations below were collected from the internet. Enjoy and explore:

Polycotylus was described by the following scientific paper(s):
  • B. A. Schumacher and J. E. Martin. 2016. Polycotylus latipinnis Cope (Plesiosauria, Polycotylidae), a nearly complete skeleton from the Niobrara Formation (Early Campanian) of southwestern South Dakota. Journal of Vertebrate Paleontology 36(1):e1031341:1-15
  • E. D. Cope. 1869. Synopsis of the Extinct Batrachia, Reptilia and Aves of North America. Part I. Transactions of the American Philosophical Society, New Series 14:1-104
  • F. R. O'Keefe and L. M. Chiappe. 2011. Viviparity and K-selected life history in a Mesozoic marine Plesiosaur (Reptilia, Sauropterygia. Science 333(870):870-873