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Description
Tarbosaurus bataar was a species of very large Tyrannosaurid theropod dinosaur that was originally described as a species of the pre existing genus Tyrannosaurus, of which it is sister taxon. It lived in what today is Mongolia (Nemegt formation) , at the late Cretaceous period (Maastrichtian epoch), 68 myA. After that several other Nemegt Tyrannosaurid specimens were described and given their own generic names; but were later discovered to be growth stages of the same taxon.

Theese diagrams are mostly based on the specimen PIN 551-2, which was one of theese specimens that was originally described as it's own genus; Tarbosaurus efremovi (Maleev 1955b). It consists of a mostly complete specimen leaving aside the posterior caudal vertebrae; although not all of it's bones are ilustrated in Maleev 1974; thus other specimens had to be used to portray the look of the bones.In the case of ZPAL MgD 107/2, ilustrations of the skull and the limb bones were used in order to adapt the skeleton to it's appereance; even if most of the material is still undescribed. It is scaled to the measurements reported in the scientific literature; as the 122 cm skull, the 112 cm femora, and the 28.5 cm humerus.

The skull of PIN 551-3 is usually attributted to PIN 551-2 by some authors but this is not correct as PIN 551-2 preserves it's own skull material (as reflected in Maleev 1974) that suggest a smaller skull than PIN 551-3, mainly going by the size of the lower jaw; which is described and ilustrated, and therefore the animal ends up big headed but not as big headed as in other restorations like that of Paul. This is corroborated by the proportions that ZPAL MgD 107/2 seems to have, going by the measurements that are reported in the literature and photographs of the specimen.

PIN 551-2 doesn't represent the maximum size the taxon can archieve; but it was chosen as a base for most of the bones because of it being the best documented well preserved specimen in the literature. There are reports of remains between a 15% and a 24% larger than the corresponding bones in PIN 551-2, like those of the original Tyrannosaurus bataar holotype (PIN 551-1) or ZPAL MgD 107/2, between others, meaning the taxon could archieve between 10-11 meters in length. As ilustrated here; ZPAL MgD 107/2 would reach just about 10 m, and PIN 551-1 would be the largest specimen described so far according to the impressive size of the cranial material, the largest yet reported of the species.

Tarbosaurus is completely known by a lot of specimens (>30) that include cranial and postcranial material of various ontogenic stages; from very young to adult. (Raptorex kriengsteni ,Shanshanosaurus hyoyanensis, Gorgosaurus novojilovi, Gorgosaurus lancinator, and Tarbosaurus efremovi are all T.bataar synonims).

The original designation; Tyrannosaurus bataar; is defended as more accurate by several experts; like Thomas Carr or Kenneth Carpenter. Tarbosaurus bataar was erected as a combination of the original designation and the more recent (and synonimous) taxon Tarbosaurus efremovi; as Rozhdestvensky (1965) considered the differences between the two taxa to justify the generic separation.

References:
Maleev, Evgeny A. (1955). «Giant carnivorous dinosaurs of Mongolia». Doklady, Academy of Sciences USSR 104(4): 634-637.
Rozhdestvensky, Anatoly K. (1965). «Growth changes in Asian dinosaurs and some problems of their taxonomy». Paleontological Journal 3: 95-109.
Maleev, Evgeny A. (1974). «Gigantic carnosaurs of the family Tyrannosauridae». The Joint Soviet-Mongolian Paleontological Expedition Transactions 1: 132-191.
Carpenter, Ken. (1992). «Tyrannosaurids (Dinosauria) of Asia and North America». En Mateer, Niall J.; and Chen Peiji (eds.). Aspects of Nonmarine Cretaceous Geology. Beijing: China Ocean Press. pp. 250-268.
J.H.Hurum, K.Sabath (2003)Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared.

Description
Tarbosaurus bataar was a species of very large Tyrannosaurid theropod dinosaur that was originally described as a species of the pre existing genus Tyrannosaurus, of which it is sister taxon. It lived in what today is Mongolia (Nemegt formation) , at the late Cretaceous period (Maastrichtian epoch), 68 myA. After that several other Nemegt Tyrannosaurid specimens were described and given their own generic names; but were later discovered to be growth stages of the same taxon.

Theese diagrams are mostly based on the specimen PIN 551-2, which was one of theese specimens that was originally described as it's own genus; Tarbosaurus efremovi (Maleev 1955b). It consists of a mostly complete specimen leaving aside the posterior caudal vertebrae; although not all of it's bones are ilustrated in Maleev 1974; thus other specimens had to be used to portray the look of the bones.In the case of ZPAL MgD 107/2, ilustrations of the skull and the limb bones were used in order to adapt the skeleton to it's appereance; even if most of the material is still undescribed. It is scaled to the measurements reported in the scientific literature; as the 122 cm skull, the 112 cm femora, and the 28.5 cm humerus.

The skull of PIN 551-3 is usually attributted to PIN 551-2 by some authors but this is not correct as PIN 551-2 preserves it's own skull material (as reflected in Maleev 1974) that suggest a smaller skull than PIN 551-3, mainly going by the size of the lower jaw; which is described and ilustrated, and therefore the animal ends up big headed but not as big headed as in other restorations like that of Paul. This is corroborated by the proportions that ZPAL MgD 107/2 seems to have, going by the measurements that are reported in the literature and photographs of the specimen.

PIN 551-2 doesn't represent the maximum size the taxon can archieve; but it was chosen as a base for most of the bones because of it being the best documented well preserved specimen in the literature. There are reports of remains between a 15% and a 24% larger than the corresponding bones in PIN 551-2, like those of the original Tyrannosaurus bataar holotype (PIN 551-1) or ZPAL MgD 107/2, between others, meaning the taxon could archieve between 10-11 meters in length. As ilustrated here; ZPAL MgD 107/2 would reach just about 10 m, and PIN 551-1 would be the largest specimen described so far according to the impressive size of the cranial material, the largest yet reported of the species.

Tarbosaurus is completely known by a lot of specimens (>30) that include cranial and postcranial material of various ontogenic stages; from very young to adult. (Raptorex kriengsteni ,Shanshanosaurus hyoyanensis, Gorgosaurus novojilovi, Gorgosaurus lancinator, and Tarbosaurus efremovi are all T.bataar synonims).

The original designation; Tyrannosaurus bataar; is defended as more accurate by several experts; like Thomas Carr or Kenneth Carpenter. Tarbosaurus bataar was erected as a combination of the original designation and the more recent (and synonimous) taxon Tarbosaurus efremovi; as Rozhdestvensky (1965) considered the differences between the two taxa to justify the generic separation.

References:
Maleev, Evgeny A. (1955). «Giant carnivorous dinosaurs of Mongolia». Doklady, Academy of Sciences USSR 104(4): 634-637.
Rozhdestvensky, Anatoly K. (1965). «Growth changes in Asian dinosaurs and some problems of their taxonomy». Paleontological Journal 3: 95-109.
Maleev, Evgeny A. (1974). «Gigantic carnosaurs of the family Tyrannosauridae». The Joint Soviet-Mongolian Paleontological Expedition Transactions 1: 132-191.
Carpenter, Ken. (1992). «Tyrannosaurids (Dinosauria) of Asia and North America». En Mateer, Niall J.; and Chen Peiji (eds.). Aspects of Nonmarine Cretaceous Geology. Beijing: China Ocean Press. pp. 250-268.
J.H.Hurum, K.Sabath (2003)Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared.