The Mosasaurus was a giant marine reptile, which dominated ancient oceans with its fearsome jaws and massive body. Mosasaurus (/ ˌmoʊzəˈsɔːrəs /; "lizard of the Meuse River ") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The genus was one of the first Mesozoic marine reptiles known to science—the first fossils of Mosasaurus were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, and ... Learn about the rise, diversity and extinction of the mosasaurs, the apex predators of the Cretaceous oceans. Discover their evolution, anatomy, behaviour and fossil record from this comprehensive article. Fossil shell of ammonite Placenticeras whitfieldi showing punctures caused by the bite of a mosasaur , Peabody Museum of Natural History, Yale A tooth from a mosasaur Mosasaurs had double-hinged jaws and flexible skulls (much like those of snakes), which enabled them to gulp down their prey almost whole. A skeleton of Tylosaurus proriger from South Dakota included remains of the flightless diving seabird Hesperornis, a marine bony fish, a possible shark, and another, smaller mosasaur ...
