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 of the specimen. While Sereno had claimed that the vertebrae of "Raptorex" were nearly fused, and that the bone histology of the specimen indicated it was a subadult about six years old, Fowler and colleagues argued that Sereno and his team had misinterpreted the growth stage data, and found that the specimen was actually a young juvenile only about three years old. They also found fault with the Sereno team's interpretation of the specimen's age. Fowler and colleagues showed that the fish bone which Sereno had identified as "Lycoptera" without comment is actually very different in shape and much larger