Tyrannosaurus rex, also known as Tyrannosaurus rex, is a type of theropod dinosaur and the most representative large theropod dinosaur. Tyrannosaurus rex once roamed an island continent called Laramidia (now located on the eastern foothills of the Rocky Mountains in western North America). The distribution range of tyrannosaurs is wider than other members of the tyrannosauridae family. Its fossils were discovered in various strata of the Late Cretaceous Maastrichtian stage (approximately 68 to 66 million years ago). Tyrannosaurus is the last known member of the Tyrannosauridae family before the Cretaceous Paleogene extinction event, and is also one of the latest non avian dinosaurs to go extinct. Tyrannosaurus rex is currently the heaviest known carnivorous dinosaur.