When I first read Matthew Baron’s new dinosaur study, I actually gasped.
For most of my life, I’ve believed that the dinosaurs fell into two major groups: the lizard-hipped saurischians, which included the meat-eating theropods like Tyrannosaurus and long-necked sauropodomorphs like Brontosaurus1; and the bird-hipped ornithischians, which included horned species like Triceratops and armored ones like Stegosaurus. That’s how dinosaurs have been divided since 1887. It’s what I learned as a kid. It’s what all the textbooks and museums have always said. And according to Baron, a Ph.D. student at the University of Cambridge, it’s wrong.
By thoroughly comparing 74 early dinosaurs and their relatives, Baron has radically redrawn the two major branches of the dinosaur family tree. Defying 130 years of accepted dogma, he splits the saurischians apart, leaving the sauropods in one branch, and placing the theropods with the ornthischians on the other. Put it this way: This is like someone telling you that neither cats nor dogs are what you thought they were, and some of the animals you call “cats” are actually dogs.
“Luckily, most of what we’ve pieced together about dinosaurs—how they fed, breathed, moved, reproduced, grew up, and socialized—will stand unchanged,” says Lindsay Zanno from the North Carolina Museum of Natural Sciences, who was not involved in the study. Still, “these conclusions lead us to question the most basic structure of the entire dinosaur family tree, which we have used as the backbone of our research for over a century. If confirmed by independent studies, the changes will shake dinosaur paleontology to its core.”