Evidence that the famous T. rex might not have been a North American native has emerged through research conducted by paleontologists Stephen Brusatte University of Edinburgh in Scotland and Thomas Carr from Carthage College in Wisconsin. This new study was published February 2, 2016, in the online journal Scientific Reports and concerns the classification and family relationships of the tyrannosauroid dinosaurs. Altogether, 28 tyrannosauroids were used in the research.
One of the main bits of evidence the study gathered was the idea that not only were the tyrannosaurs spread around the Northern Hemisphere long before the continents split apart but that Tyrannosaurus itself did not evolve in North America. Rather, it or members of its family may have crossed to America via a temporary land connection with Asia during the Late Cretaceous.
Brusatte mentions that many of T. rex's closest family members are indeed Asian. These include the similarly large and robust tyrannosaurs Tarbosaurus and Zhuchengtyrannus from Mongolia and China respectively. Brusatte and Carr's study thus contradicts the idea that Tyrannosaurus' ancestors emerged in North America and kept evolving to get to T. rex's proportions.