Nothosaurus (name meaning "False Reptile") is a genus of sauropterygian reptile that originated during the Triassic period in what is now Europe, Asia, and Africa. A marine reptile measuring 4 meters long and with forward-pointed teeth to make it easier to catch fish, Nothosaurus was an ancestor of the group of marine reptiles known as the plesiosaurs of the Jurassic and Cretaceous.
In the Series 2 episode "New Blood II: Marine Reptiles", a pair of Nothosaurus were brought to the park from Late Triassic Arizona, 220 million years ago. They reside in the Primeval Aquarium Enclosure.