Chindesaurus was one of the earliest dinosaurs in North America and it was first discovered in Triassic rocks at Petrified Forest National Park. This large dog-sized dinosaur was first thought to be an ancestor of the huge long-necked dinosaurs found in the Jurassic but is now recognized as a bipedal early meat-eating dinosaur. Chindesaurus and closely-related dinosaurs are found in Arizona, New Mexico, and Utah.