Home > Diorama > Dinosaur Explorer > Elasmosaurus The Elasmosaurus (which literally means "thin-plated lizard") was a long-necked marine reptile that lived during the late Cretaceous Period, approximately 65 million years ago. First discovered in 1868 by paleontologist E.D. Cope in Wyoming, this large sea creature measured 46 feet in length, half of which was its neck which contained 75 vertebrae (in comparison, the average human neck contains between 7 - 8 vertebrae). Elasmosaurus, which was carnivorous reptile that fed on fish and other swimming animals, lived in the open ocean, breathed air, and swam with four paddle-like flippers in a manner similar to that of modern turtles. Small stones have often been found inside the stomach region of many of the Elasmosaurus skeletons discovered, which is thought helped them grind up their food as well as acted as ballast to help them dive. One Elasmosaurus can be found in the diorama at Universe of Energy. It is the "snake-like creature" that attacks Ellen in the "tidal pool" scene, and is located to the left of the vehicles.