Topic summary
Tarbosaurus bataar
Extracted from the Wikipedia article Tarbosaurus.
Classification
Tarbosaurus bataar was originally described as a species of Tyrannosaurus, an arrangement that has been supported by some more recent studies. Others prefer to keep the genera separate, while still recognizing them as sister taxa. A 2003 cladistic analysis based on skull features instead identified Alioramus as the closest known relative of Tarbosaurus, as the two genera share skull characteristics that are related to stress distribution and are not found in other tyrannosaurines. If proven, this relationship would argue against Tarbosaurus being a synonym of Tyrannosaurus and would suggest that separate tyrannosaurine lineages evolved convergently in Asia and North America. The two known specimens of Alioramus, which show juvenile characteristics, are not likely juvenile individuals of Tarbosaurus because of their much higher tooth count (76 to 78 teeth) and their unique row of bony bumps along the top of their snouts.