Spec DinoVember 11: Spiny Lizard

Velavenator brasiliensis is a megaraptoran, a member of a group of theropods whose relationships are not well understood. Traditionally believed to be a late-surviving branch of the carnosaur group, they may instead be coelurosaurs, perhaps relatives of early tyrannosaurs. Whatever the case, Velavenator is remarkable for the tall sail-like crest on its back, which is formed from vertebrae nearly six feet long. The whole animal is nearly 40 feet long, and is easily the apex predator of South America at the end of the Cretaceous period. With its crest, it resembles outdated pictures of Spinosaurus, before that dinosaur was known to be aquatic and crocodile-like. Interestingly, the sail is not the only spinosaur-like feature this animal has; it also sports a large hooked claw on each of its hands. However, Velavenator is strictly a land animal, and these claws are used not for fishing but for disemboweling large prey such as sauropods and hadrosaurs. The crest itself serves a function in controlling the animal's temperature. It is a heat sink, allowing it to shed excess heat and preventing it from overheating on the tropical South American plains where it lives-- a necessity for such a large a warm-blooded animal in a hot climate.