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
Raptorex the Nemegt Formation; according to the authors, this implies that the vertebra found with the holotype specimen of "Raptorex kriegsteini" – and by extension the holotype of "R. kriegsteini" itself – most likely come from the Nemegt Formation and are Late Cretaceous in age. "Raptorex" has been interpreted as a tyrannosaurid, tyrannosauroid and a synonym of "Tarbosaurus". It is currently placed as a basal tyrannosauroid more derived than "Bagaraatan" but more basal than "Dryptosaurus". Below is a cladogram placing "Raptorex" as a basal tyrannosauroid. It was published by Loewen "et al." in 2013 on PLoS ONE. Raptorex Raptorex is a