Allosaurus (AL-oh-SORE-us) Meat eater, 35 feet long, Late Jurassic period. 145 million years ago located in western North America. Allosaurus was the largest meat eater of the Jurassic period. It probably killed or scavenged plant eaters much larger than itself including the giant Brachiosaurus. Scientists found nearly 50 allosaur skeletons and over 10,000 bones in one dig site in Utah.