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 or a new genus entirely is still unknown. Other tyrannosaurid fossils found in the same formations as "Tyrannosaurus rex" were originally classified as separate taxa, including "Aublysodon" and "Albertosaurus megagracilis", the latter being named "Dinotyrannus megagracilis" in 1995. These fossils are now universally considered to belong to juvenile "Tyrannosaurus rex". A small but nearly complete skull from Montana, long, may be an exception. This skull was originally classified as a species of "Gorgosaurus" ("G. lancensis") by Charles W. Gilmore in 1946, but was later referred to a new genus, "Nanotyrannus". Opinions remain divided on the validity of "N. lancensis". Many