Saurophaganax ("lizard-eater") is a genus of allosaurid dinosaur from the Morrison Formation of Late Jurassic Oklahoma (latest Kimmeridgian age, about 151 million years ago), USA. Some paleontologists consider it to be a species of Allosaurus (A. maximus). Saurophaganax represents a very large Morrison allosaurid characterized by horizontal laminae at the bases of the dorsal neural spines above the transverse processes, and "meat-chopper" chevrons. The maximum size of S. maximus has been estimated at anywhere from 10.5 metres (34 ft) to 13 m (43 ft) in length, and around 3 tonnes (3.0 long tons; 3.3 short tons) in weight.