Unable to catch dinosaurs because of teeth with no grooves buitreraptor probably ate insects or small mammals, maybe even eggs. Its feathers were probably used to keep it warm, like the feathers on troodon.
One of the earliest dinosaurs, herrerasaurus was a carnivore witha hip that resembled both lizard hipped dinosaurs and bird hiped dinosaurs. (Saurischians and ornithschians). Its name means Herrera's lizard.