Saurophagnax

Saurophaganax ("lord of lizard-eaters") is a genus of allosaurid theropod from the Morrison formation, from late-Jurassic Oklahoma (late Kimmeridgian age, about 151 million years ago). 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. Saurophaganax is one of the largest Jurassic theropods, it weighed 3.3 short tons, with a length of 12 to 13 meters, making it larger than most known Allosaurus and possibly longer than Tyrannosaurus rex.