Largest mosasaur

Mosasaurs were prehistoric sea lizards, related to modern-day varanids or monitor lizards. One contender for the largest is Hainosaurus bernardi, which lived during the late Cretaceous Period, 70.6–66 million years ago, and its first-documented fossil remains were found in Belgium. It is believed by most researchers to have attained a total length of up to 15 m (49 ft), although some have downgraded this estimate to 12.2 m (40 ft). Also worth noting is that a related species, Mosasaurus hoffmannii, has recently been estimated by some scientists to attain a total length of up to 18 m (59 ft).

Its fossils have been found in Europe, where it lived during the late Cretaceous Period (99.6-65 million years ago), preying upon fish, molluscs, and other sea reptiles - including other mosasaurs.