A. amplexus was named by Gregory S. Paul for giant Morrison allosaur remain , and included in his conception Saurophagus maximus ( later Saurophaganax ) . A. amplexus was originally coined by Cope in 1878 as the type species of his new genus Epanterias , and is based on what is now AMNH 5767 , parts of three vertebrae , a coracoid , and a metatarsal . Following Paul 's work , this species have been accepted as a synonym of A. fragilis .