Raptorex Raptorex Raptorex is a dubious genus of tyrannosaurid dinosaur. Its fossil remains consist of a single juvenile specimen probably uncovered in Mongolia, or possibly northeastern China. The type species is "R. kriegsteini", described in 2009 by Sereno and colleagues. The genus name is derived from Latin ', "robber", and ', "king". The specific name honours Roman Kriegstein, a survivor of the Holocaust, whose son Henry Kriegstein donated the specimen to the University of Chicago for scientific study. While initially considered to have come from the Yixian Formation of China, dated to approximately 125 million years ago during the early Cretaceous
Tyrannosaurus Asian "Tarbosaurus", both of which have occasionally been synonymized with "Tyrannosaurus". Tyrannosaurids were once commonly thought to be descendants of earlier large theropods such as megalosaurs and carnosaurs, although more recently they were reclassified with the generally smaller coelurosaurs. In 1955, Soviet paleontologist Evgeny Maleev named a new species, "Tyrannosaurus bataar", from Mongolia. By 1965, this species had been renamed "Tarbosaurus bataar". Despite the renaming, many phylogenetic analyses have found "Tarbosaurus bataar" to be the sister taxon of "Tyrannosaurus rex", and it has often been considered an Asian species of "Tyrannosaurus". A recent redescription of the skull of "Tarbosaurus bataar"