The king of the Jurassic before T. rex
Allosaurus was the dominant large predator of its time, millions of years before Tyrannosaurus evolved. It possessed a lightweight but powerful skull with large serrated teeth that were continuously replaced, and unusually strong forearms for a theropod — allowing it to grasp struggling prey. Bonebed evidence suggests it may have hunted in loose groups or at least scavenged together on large sauropod carcasses.
Its unique jaw joint may have allowed it to open its mouth extremely wide, similar to modern Komodo dragons. It preyed primarily on Stegosaurus and young sauropods in the Morrison Formation.
- • Serrated teeth up to 10 cm long that were shed and replaced regularly.
- • Powerful three-fingered hands with large claws for holding prey.
- • One of the most common large theropods in the Morrison Formation.
- • Possibly hunted in groups based on mass death assemblages.
Allosaurus ambush
An intense 8-second Jurassic action reconstruction of Allosaurus ambushing a young Stegosaurus on an open plain.
Gallery
Habitat
Open woodlands and floodplains of the Morrison Formation in western North America. Home to Stegosaurus and Brachiosaurus.