Dienoycus
Paleontologist John Ostrom's study of Deinonychus in the late 1960s changed the way scientists thought about dinosaurs. It caused the "dinosaur renaissance" and made scientists argue whether dinosaurs were warm-blooded or cold-blooded. Before this, most people thought dinosaurs were big, slow, and looked and acted like modern reptiles. Ostrom told other scientists that Dienocus had a small body, sleek, horizontal posture, the same kind of spine that flightless birds have, and the large claws on its feet.  All this, said Ostrom, meant Deinonychus was probably very fast and caught its food like a predator.