Key Vocabulary
Learn about dinosaurs, the popular reptile rulers of the old earth. Their history, their rise and the fall.
Learn about dinosaurs, the popular reptile rulers of the old earth. Their history, their rise and the fall.
Dinosaur means terrible lizards. They are a varied group of archosaur reptiles. They were the dominant land animals of the Mesozoic era. Over 500 different classifications of dinosaurs are known. Fossils of dinosaurs have been found on every continent. There are still frequent new discoveries. Dinosaurs appeared in the Upper Triassic, about 230 million years ago. The earliest date of a dinosaur fossil is that of Utahraptor. By the early Jurassic they were the top land vertebrates. They dominated most environments on land. Continued until the sudden “Cretaceous-Tertiary” extinction event 66 million years ago.