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.
Cochleosaurus
Cochleosaurus ('spoon lizard') is a name of a tetrapod belonging to Temnospondyli, which lived during the late Carboniferous period (Moscovian, about 310 millions years ago). The great abundance of its remains (about 50 specimens) have been found in the Kladno Formation of the Czech Republic, near Nýřany in Central Europe and in the Morien Group of Nova Scotia in North America. It was a creature of medium size, measuring 120-160 centimeters. It is believed that "Cochleosaurus" was a semiaquatic ambush predator, hunting like modern crocodiles. Czech paleontologist Antonin Fritsch named the genus in 1885 in reference to the spoon-shaped processes on the supra-occipital bones at the back of the skull (from Latin "cochlear" "spoon" and Greek "sauros" "lizard").