using the front flippers to generate most of the thrust and the back flippers to maneuver

such as large marine reptiles and sharks

in deposits that were ancient lakes and rivers

but rather a distant relative that lived long before dinosaurs appeared

Allosaurus fragilis Tylosaurus using the front flippers toAllosaurus (A. fragilis, 'Different lizard') was the most common predatory theropod of the Kimmeridgian and Tithionian Age of the Upper Jurassic and the most dangerous as well. The Allosaurus had a large and robust head with serrated, sharp and curved teeth of between 5 10 cm, which allowed it to tear the flesh of its prey. It also had muscular arms with three fingers with claws up to 15 cm long, which helped it hold onto its prey. Its tail was long