Mosasaurus is a species of extinct group of aquatic scaly reptiles. It lived approximately 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. Mosasaurus is one of the largest aquatic creatures. Mosasaurs lived in the open ocean and deep coastal waters and preferred to hunt very large or well-protected prey, mosasaurus teeth were well adapted to cut and crush, and massive jaw muscles provided tremendous bite force.