Revueltosaurus Characteristics

Only fossil teeth of Revueltosaurus have been found in New Mexico and Arizona, USA. Revueltosaurus was originally described as an ornithischian dinosaur based on several discoveries of teeth, but was reclassified when a partial skeleton was discovered in 2004.

The newly discovered full skeleton of a Revueltosaurus makes it clear that the teeth are not of a plant-eating dinosaur, but of a herbivorous or perhaps omnivorous crocodilian ancestor living a mostly terrestrial life in the uplands of the Late Triassic. It may have been one source of meat for the developing theropods around the world.

The animal, one of many creatures from the Late Triassic known only from their teeth, was thought to be an ancestor of the plant-eating ornithischian dinosaurs like Stegosaurus and Triceratops, which roamed the world millions of years later in the Jurassic and Cretaceous period. Because the teeth look like those we know from herbivorous ornithischians, people assigned them to the dinosaurs.

Dinosaurs are divided into two main groups, the ornithischians and saurischians, both of which, based on fossil finds, appeared to arise in the Late Triassic, between 225 and 200 million years ago. The early ornithischians were thought to have evolved into animals such as the stegosaurs of the Jurassic and the frilled and duck-billed dinosaurs of the Cretaceous, while the saurischians split into the sauropodomorphs - the long-necked browsers like Brachiosaurus - and the carnivorous theropods, like Tyrannosaurus Rex. Only the theropods survive to the present day as birds.

It is a stunning development because Revueltosaurus is only one of many late Triassic animals known only by their teeth that were thought to be the ancestors of plant-eating dinosaurs. But the fact that the teeth came from an early crocodile, and not from a dinosaur, suggests that many of the animals that roamed North America more than 200 million years ago have been erroneously classified as dinosaurs.

Revueltosaurus was named by K. Padian in 1990