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
Specimens of Tyrannosaurus specimen which can be attributed to "Tyrannosaurus rex" consists of two partial vertebrae (one of which has been lost) found by Edward Drinker Cope in 1892. Cope believed that they belonged to an "agathaumid" (ceratopsid) dinosaur, and named them "Manospondylus gigas", meaning "giant porous vertebra" in reference to the numerous openings for blood vessels he found in the bone. The "M. gigas" remains were later identified as those of a theropod rather than a ceratopsid, and H.F. Osborn recognized the similarity between "M. gigas" and "Tyrannosaurus rex" as early as 1917. However, due to the fragmentary nature of the "Manospondylus"