paleontologists distinguished dinosaur into saurischian (“lizard-hipped”) and ornithischian (“bird-hipped”) dinosaurs. Saurischian dinosaurs include carnivorous theropods and herbivorous sauropods, while ornithischians account for the remainder of plant eaters, including hadrosaurs, ornithopods and ceratopsians, among others.
Oddly enough, birds evolved from “lizard-hipped,” rather than “bird-hipped,” dinosaurs!