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 a clade with fellow Asian tyrannosaurid "Zhuchengtyrannus", with "Lythronax" being their sister taxon. A further study from 2016 by Steve Brusatte, Thomas Carr et al., also indicates "Tyrannosaurus" may have been an immigrant from Asia, as well as a possible descendant of "Tarbosaurus". The study further indicates the possibility that "Tyrannosaurus" may have driven other tyrannosaurids that were native to North America extinct through competition. Other finds in 2006 indicate giant tyrannosaurs may have been present in North America as early as 75 million years ago. Whether or not this specimen belongs to "Tyrannosaurus rex", a new species of "Tyrannosaurus",