Several authors (e.g. Paul 1988 a; Carpenter 1992) have synonymized the genus

Tarbosaurus

with Tyrannosaurus, but no detailed comparison of these two taxa has been carried out so far. Pending the revisions of tyrannosaurid interrelationships, currently being worked on independently by P. Currie, C. Brochu, and. Holtz, Tarbosaurus is provisionally regarded as a separate genus here.