TARBOSAURUS

Nine years after especially fruitful expeditions by the Russian Acadamy of Sciences to Mongolia in 1946 and 1948-1949, Evgeny Maleev coined a new species of Tyrannosaurus—Tyrannosaurus bataar, and later the same year named Tarbosaurus efremovi and added two new species to Gorgosaurus—Gorgosaurus lancinator and Gorgosaurus novojilovi. In 1965, Rozhdestvensky recognized the entire haul as growth stages of the same species and rolled them all into one neat package, combining the only one of Maleev's quartet that had its own generic name with his initial epithet, thus creating Tarbosaurus bataar. Then a relatively peaceful 27 years followed, after which a long series of naming nonsense was heaped upon its almost Tyrannosaurus rex-sized shoulders.

Ken Carpenter moved all but Gorgosaurus novojilovi (which he renamed Maleevosaurus) back to Tyrannosaurus bataar in 1992, then George Olshevsky renamed Tyrannosaurus bataar into Jenghizkhan whilst plucking Tarbosaurus efremovi back from the brink of obscurity in 1995. In the meantime, Zhiming Dong had coined "Shanshanosaurus" for IVPP V4878 which Greg Paul assigned to Aublysodon in 1988, and Albertosaurus periculosis, Tyrannosaurus luanchuanensis, Tyrannosaurus turpanensis and Chingkankousaurus fragilis had all been named based on nothing more than Mongolian teeth or bone fragment. Gosh darn it, they are all specimens of Tarbosaurus bataar which now, unsurprisingly, accounts for the highest percentage of all fossils collected from Mongolia's Nemegt Formation.

Compared to Tyrannosaurus rex, Tarbosaurus is somewhat smaller but has a few more teeth. Its head is similarly high but not as wide, and it probably lacked the binocular vision of T.rex as the rear of its skull hadn't expanded to allow for fully forward-pointing eyes. Its forelimbs were proportionately small, even by tyrant lizard standards, and each hand had two clawed fingers while some specimens also had a third, unclawed stump. Features of its jaws sets Tarbosaurus apart from all but one of its brethren—Alioramus, and even that has been accused of being a juvenile Tarbosaurus in the past. However, Alioramus is more slender by comparison, with a higher tooth count still, and has a distinct row of crests running up its long and shallow snout.