Saurophaganax

Saurophaganax ("lizard-eating master") is a genus of allosaurid dinosaur from the Morrison Formation of Upper Jurassic in Oklahoma. It lived about 151 million years ago). 
"Saurophaganax" was a very large Morrison allosaurid. The maximum size of "S. maximus" has been estimated at anywhere from to in length, and around in weight. This means it was perhaps similar in size to "Tyrannosaurus" or "Carcharodontosaurus".
Some paleontologists think it is a species of "Allosaurus" ("Allosaurus maximus"). It has also been described as a separate genus. The most recent review of basal tetanurans accepted "Saurophaganax" as a distinct genus. New possible "Saurophaganax" material from New Mexico may clear up the status of the genus.