tylosaurus was a large mosasaurus inhabiting the late cretaceous sea's , it was one the largest known predators with larger species reaching around the same size as later mosasaurus hoffmannii from the maastrichtian age with lengths upto 40ft -46ft . hainosaurus from europe likely belong to the dame genus.

tylosaurus remains are largely from north america where it inhabited thewestern interior sea way . tylosaurs stomach remains have been found with fish and other smaller marine reptiles the were likely oporttunist predators feeding on large array of pray . a number of large predators shared the sea with tylosaur the large shark's such as cretoxyrhina or ginsu shark could have competed with it while the large pliosaur elasmosaurus may have taken smaller pray to its body size. fully grown tylosaurs were likely the apex predator of their ecosystem .