The fossil remains of smaller species resembling Allosaurus and dating from the Early Cretaceous of North America, Australia and Japan supports the hypothsis that it survived the mass extinction at the end of the Jurassic, some 144 mya.

When did the Allosaurus become extinct?

There were at least 3 species of Allosaurus at various times in the late Jurassic. By the end of the late Jurassic, Allosaurus went extinct with many of the other dinosaurs during the faunal turnover leading into the Cretaceous.

What caused the Allosaurus to go extinct?

Some of the explanations are that the animals got stuck in the mud, a bog, or a seep, and/or that drought brought the dinosaurs to a waterhole where they died. In 1991, a Swiss team discovered a 95% complete, 26 ft (8 m) long Allosaurus skeleton near Shell, Wyoming.