Mosasaurus

Mosasaurus was a large marine predator from the North American seas of the Late Cretaceous, about 66 mya. Despite its appearance and coexisting with dinosaurs, it’s not a member of the dinosaur family. Instead, it’s a huge aquatic lizard, most closely related to monitor lizards such as Komodo Dragons. It reached 50 feet in length and weighed over 10 tons. An apex predator of its ecosystem, it only competed with members of its own species and its close relatives such as Tylosaurus.