Mosasaur
Mosasaurs (from Latin "Mosa" meaning the 'Meuse river', and Greek σαύρος "sauros" meaning 'lizard') are an extinct group of large marine reptiles containing 38 genera in total. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. Mosasaurs probably evolved from an extinct group of aquatic lizards known as aigialosaurs in the Early Cretaceous. During the last 20 million years of the Cretaceous period (Turonian-Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurs became the dominant marine predators. They became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.
Ghost Ranch
200 million years ago Ghost Ranch and the American Southwest were located close to the equator, and had a warm, monsoon-like climate with heavy seasonal precipitation. Ghost Ranch includes a famous palaeontological site preserving Triassic dinosaurs. Fossil bones were found here as early as 1885. In 1947 the palaeontologist Edwin H. Colbert documented the discovery of over a thousand well-preserved fossilized skeletons of a small Triassic dinosaur called "Coelophysis" in a quarry here. In 2007, fossil remains of "Dromomeron romeri", one of the archaic group of animals recognized as basal dinosauromorphs, were found in the Hayden Quarry. In April 2010, a team of scientists led by Hans-Dieter Sues of the Smithsonian Institution reported the discovery of "Daemonosaurus chauliodus", a basal theropod species, at Ghost Ranch. "Daemonosaurus" lived approximately 205 million years ago, during a transitional period between the oldest known dinosaurs such as "Herrerasaurus", which existed during the Late Triassic period in what is now known as Argentina and Brazil, and the more advanced theropod dinosaurs.