Encyclopedia of Dinosaurs and Prehistoric Life Standards

• Allosaurus — A genus of large bipedal theropod dinosaur, carnivorous, that lived during the Late Jurassic period (approximately 155 to 145 million years ago), operating as the apex predator in what is now North America (Morrison Formation). It was characterized by a massive skull equipped with dozens of sharp, serrated teeth, short but powerful forelimbs ending in three fingers with large claws, and a long, heavy tail used for balance.