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Raptorex October 2010 an online "Nature News" report (not peer-reviewed) challenged the provenance and classification of "Raptorex" as a basal tyrannosauroid. Peter Larson, president of the Black Hills Institute of Geological Research, Inc., a private fossil excavation and supply company, inspected the fossil and told "Nature" that he concluded it was a juvenile "Tarbosaurus". Because the specimen was donated by a collector without detailed provenance information, Larson doubted the assigned age, which was based only on the "Lycoptera" vertebra and mollusk shell found alongside the dinosaur fossil. Larson speculated that the fossil could have come from beds in Mongolia that yield