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 one of the most complete "Tyrannosaurus rex" skeletons ever found (56.6% complete) From 2003–2005, Thomas was excavated by NHMLA paleontologists in southeastern Montana. At 17 years old, 34 feet long and nearly 7,000 pounds, it is estimated to be a 70% complete specimen. Thomas is mounted in a "growth series" with the youngest known "Tyrannosaurus rex" fossil, a two-year old, long specimen, and a 13-year old, long juvenile specimen. This fossil is one one of the geologically youngest "T. rex" specimens known, discovered very near the Cretaceous/Tertiary boundary. In 2013, a team of paleontologists from the Naturalis Biodiversity Center (Leiden,