This is a very large type of Plesiosaur. It lived during part of the late Cretaceous era about 65 million years ago. They were very graceful swimmers and had extremely longnecks to catch fish with; Elasmosaurus lived around the world from N. America to Asia, there were several Elasmosaurids such the Thalassomodon, Goniosaurus, Aphrosaurus and Futabasaurus. It was first described by Edward Drinker Cope in 1868 that was discovered and collected by Dr. Theophilus Turner, in Kansas, USA.It was thought to be the largest plesiosaur until the discovery of Mauisaurus