Mesosaurus ("middle lizard") is an extinct genus of reptile from the early Permian Period (298.9–252.2 million years ago) of southern Africa and South America. Along w/Brazilosaurus and Stereosternum, it is a member of the family Mesosauridae and the order Mesosauria. Mesosaurus was long thought to have been one of the first marine reptiles, although new data suggests that at least those of Uruguay inhabited a hypersaline water body, rather than a typical marine environment. In any case, it had many adaptations to a fully aquatic lifestyle. Mesosaurus was one of the first reptiles to return to the water after early tetrapods came to land in the Late Devonian or later in the Paleozoic. It was around 3.3' in length, w/webbed feet, a streamlined body, and a long tail that may have supported a fin. It likely propelled itself through the water w/its long hind legs and flexible tail. Its body was also flexible and could easily move sideways, but it had heavily thickened ribs, which would have prevented it from twisting its body. Mesosaurus had a small skull w/long jaws. The nostrils were located at the top, allowing the creature to breathe w/only the upper side of its head breaking the surface, in a similar manner to a modern crocodile. The teeth were originally thought to have been straining devices for the filter feeding of planktonic organisms. However, newly examined remains of Mesosaurus show that it had fewer teeth, and that the dentition was suitable for catching small prey such as crustaceans and small fish. Offered here is a 5-5/8x25-3/8" specimen plate w/wooden board attached on back for display purposes. Mesosaurus brasiliensis specimen measures 22.5" long (tail is curled, not straight) and comes from South America. Stunningly preserved, the tiny bones of the feet are clearly visible as are a few of the creature's fine teeth. If one looks closely, the partial boney remains of the Mesosaur's last meal are still visible where the stomach once was. Specimen has some minor scattered restoration, most notable to tip of tail and on a few ribs. Still makes for a great prehistoric fossil display. From the Robert M. Overstreet Collection and comes with COA.