Ornithoraptor

Ornithoraptor (name meaning "bird thief") is an extinct species of theropod dinosaur belonging to an extinct family of theropod dinosaurs, Dromaeosaurids. It was one of the first ever large Dromaeosaurid to evolved and the largest of the Jurassic Dromaeosaurids, it was almost the size of a Deinonychus, but was 9 inches shorter and probably weighed 4 pounds less than Deinonychus. This predator lived in the Late Jurassic (about 160-145 million years ago) in what is now North America, where it hunted Camptosaurus, Stegosaurus (sometimes), young sauropods (sometimes), and probably early ankylosaurids that were just evolving at the same time. It could have been responsible for the extinction of the last Stegosauruses and other Stegosaurids of North America. It probably also fed on animals that were smaller than itself. No one knows why Ornithoraptor became extinct, but it is unlikely as it could have been the ancestors of Utahraptors.