How well do you know your dinos? We asked paleontologist Scott Persons, who teaches dinosaur evolution at the University of Alberta, to give us a whirlwind tour of the real Mesozoic World.
Dinosauria: All About the Base
The earliest, or basal, dinosaurs evolved from archosaurs, a branch off the reptile line, more than 230 million years ago — but exactly when remains a question. These dino-pioneers, such as Herrerasaurus, were “fleet-footed carnivores,” Persons says, thanks in part to an evolutionary advance in hip joints: Unlike the sprawling, reptilian stance of other archosaurs, dinosaurs had an erect posture, with their legs under their bodies.
Timespan: ?-230 million years ago (mya)
