A carnivorous dinosaur from the Cretaceous period, the Spinosaurus, or spined lizard, was a bipedal and carried a distinctive sail on its back - created by long extensions to its vertebrae. It would have had large, robust forelimbs bearing three-fingered hands, with an enlarged claw on the first digit. Evidence suggests that it was highly semiaquatic, and lived both on land and in water much like modern crocodilians do, and hunted both terrestrial and aquatic prey.