Mosasaur

Mosasaurs Temporal range: Late Cretaceous, 94–66 Ma PreꞒ Ꞓ O S D C P T J K Pg N [1]
Mounted skeleton of a russellosaurine (Plesioplatecarpus planifrons)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Clade:	†Mosasauria
Superfamily:	†Mosasauroidea
Family:	†Mosasauridae Gervais, 1853
Subgroups
†Mosasaurinae †Halisaurinae †Russellosaurina †Tethysaurinae †Tylosaurinae †Plioplatecarpinae †Yaguarasaurinae

Mosasaurs (from Latin Mosa meaning the 'Meuse', and Greek σαύρος sauros meaning 'lizard') are an extinct group of large aquatic reptiles within the family Mosasauridae that lived during the Late Cretaceous. Their first fossil remains were discovered in a limestone quarry at Maastricht on the Meuse in 1764. They belong to the order Squamata, which includes lizards and snakes.

During the last 20 million years of the Cretaceous period (Turonian–Maastrichtian ages), with the extinction of the ichthyosaurs and pliosaurs, mosasaurids became the dominant marine predators. They themselves became extinct as a result of the K-Pg event at the end of the Cretaceous period, about 66 million years ago.