Spinosaurus
100 million years ago, the Sahara Desert was wet.  Animals included the pterosaur Alanqa, types of giant crocodiles, and theropod predators the size of T. rex.  The largest predator was Spinosaurus.  In the past, it was thought that Spinosaurus aegyptiacus was bipedal. By 2014, scientists believed that Spinosaurus aegyptiacus was quadrupedal because it is front-heavy. If Spinosaurus aegyptiacus were to walk on two legs, it would topple.  Scientists believe that Spinosaurus probably walked on its knuckles.  Spinosaurus's legs were short, and its jaws were good at catching slippery prey, like fish. Spinosaurus spent most of its time in the water and it was a semi-aquatic dinosaur.