Mosasaurs (from Latin Mosa meaning the 'Meuse river', and Greek σαύρος sauros meaning 'lizard') are large, extinct, marine reptiles. The first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from semiaquatic squamates known as aigialosaurs, which were more similar in appearance to modern-day monitor lizards, in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian), with the extinction of the ichthyosaurs and decline of plesiosaurs, mosasaurs became the dominant marine predators.
Species: Prognathodon sp Age: Late Cretaceous (~70 Million Years) Location: Khourigba, Morocco Description: Complete Tooth, Sharp and well defined