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Dinosaurs have been around for the last 243 million years.

Nyasasaurus parringtoni is the oldest known dinosaur fossil, right at 243 million years old. It lived in the middle Triassic age in what is now Tanzania.

Arizona’s earliest known dinosaurs also appeared during the Triassic. Dinosaur fossils are found the in area around Holbrook, in the same area and time period as the Petrified Forest was living. The oldest fossils are of Chindesaurus bryansmalli, from 213-210 million years ago.

Later in the Jurassic Era, Allosaurus (below), Stegosaurs, and Anklylosaurs all lived in Arizona.

Dilophosaurus, a 30 foot long Cretaceous predator, was first found in Arizona. It had a pair of crests along the top of it’s head.

The Cretaceous sauropod Sonorasaurus lived in southern Arizona, and has been named the state dinosaur. It grew to over 45 feet long, and was a relative of the Brachiosaurus. Only the partial remains of one individual have been found.

Two dinosaurs that did not live in Arizona are Tyrannosaurus and Triceratops. Both are not found this far south in North America.