The Dinosaur Family Tree Gets A Makeover

About 130 years ago, Harry Govier Seeley, a paleontologist trained in Cambridge, classified dinosaurs into two distinct groups, or clades, based on the shape of their pelvic bones. The “reptile-hipped” saurischians included carnivorous theropods like the Tyrannosaurus Rex (T-Rex), while the “bird-hipped” ornithischians comprised herbivores such as the Stegosaurus and Triceratops. As more dinosaur fossils were discovered, a third group, dubbed sauropodomorphs, was established. In 1887, Seeley concluded that the long-necked herbivorous sauropods, like the Brontosaurus, were related to theropods and classified them as saurischians.