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.
Coloradisaurus
Coloradisaurus (meaning "Colorados [from Los Colorados Formation] lizard") is a genus of massospondylid sauropodomorph dinosaur. It lived during the Late Triassic period (Norian to Rhaetian stages) in what is now La Rioja Province, Argentina. It is known from the holotype PVL 5904, nearly complete skull. It was discovered and collected from the upper section of the Los Colorados Formation. Originally named "Coloradia" by Jose F. Bonaparte in 1978, this name had already been assigned to a moth, and so the animal was renamed. The genus was first named by David Lambert in 1983 and the type species is "Coloradisaurus brevis". It may in fact be an adult specimen of "Mussaurus". Cladistic analyses by Yates (2007), Yates "et al." (2010, 2011) and Novas "et al." (2011) found that "Coloradisaurus" is basal to the "Glacialisaurus"-"Lufengosaurus" clade within Massospondylidae.