Tarbosaurus

 The Tarbosaurus was discovered 1946, in the Gobi  Desert. Tarbosaurus was originally thought to be a Tyrannosaurus Rex, so they called it, Tyrannosaurus Bataar in 1955. But soon they realized it was a new dinosaur, and corrected it to Tarbosaurus Bataar.

http://www.nhm.ac.uk/discover/dino-directory/tarbosaurus.html