Tarbosaurus bataar, Maleev, 1955

Currie, Philip J., 2003, Cranial anatomy of tyrannosaurid dinosaurs from the Late Cretaceous of Alberta, Canada, Palaeontologica Polonica 48 (2), pp. 191-226 : 225

Tarbosaurus bataar .

— Ta. bataar ( Maleev 1955) is a combination introduced by Rozhdestvensky 1965 (see Hurum and Sabath 2003 for details). Paul (1988), Holtz (1994, 2001), Carr (1999) and others consider Tarbosaurus Maleev, 1955 and Tyrannosaurus Osborn, 1905 to be congeneric, while some researchers ( Paul 1988) even include Daspletosaurus Russell, 1970 within the genus Tyrannosaurus . At least two characters, the locking mechanism of the jaws ( Hurum and Currie 2000) and the length of the arms ( Holtz 2001; Currie 2003), suggest that Tarbosaurus is more derived than either Daspletosaurus or Tyrannosaurus and therefore could not be ancestral to either. The overall picture becomes more complicated when Nanotyrannus and Alioramus are considered, the former possibly being a sister−taxon to Tyrannosaurus , and the latter to Tarbosaurus . Holtz (2001) listed nine characters to distinguish Tyrannosaurus from other tyrannosaurids, including its sister taxon “ Tyrannosaurus ” bataar . This is the highest number of autapomorphies that he presented for any tyrannosaurid species, and argues that there is a considerable amount of difference between T. rex and “ Tyrannosaurus ” bataar . Because there are major differences between these two species, and because there are valid reasons for believing that this animal may be the sister taxon of Daspletosaurus + Tyrannosaurus ( Currie et al. 2003) , there is ample justification for generic distinction of Tarbosaurus .