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Mesosaurus provided evidence for the theory of continental drift based on the fact that its remains were found in two widely separated regions, one in southern Africa and the other in eastern South America. Because it was a coastal animal and could not have crossed the Atlantic Ocean, its presence indicates that the two continents were once joined together. Mesosaurus was one of the first reptiles to return to the water after the early tetrapods had come to the land in the Late Devonian. It lived in shallow water environments adjoining coastlines and fed on small crustaceans and other prey with jaws that were long and filled with thin, pointed teeth. It measured about 3 feet (1 m) in length, had webbed feet, a streamlined body, and a long tail that may have supported a fin. It probably propelled itself through the water with its hind feet and tail. The nostrils of the animal were located on top of its head, allowing it to come to the surface and breathe much like a modern crocodile. The mesosaur may have been able to move onto land for short periods of time by pushing itself in a manner similar to the way that female sea turtles move onto the beach to lay their eggs.