Tarbosaurus bataar

Tarbosaurus bataar was the dominant large predator in the river systems preserved by Mongolia’s Nemegt Formation. Like Tyrannosaurus rex, it combined a huge tooth-bearing head, two-fingered forelimbs, powerful hind limbs and a long balancing tail. It was not simply an Asian copy: the adult skull was relatively narrower through the snout and lower cheek, with a distinctive domed nasal region and a differently braced lower jaw. A broad sample of skulls and partial skeletons makes Tarbosaurus one of Asia’s best-known large theropods. Rare juvenile material adds a developmental dimension—the smallest described skull lacked several adult reinforcements, indicating that young and mature animals handled food differently as the head deepened and strengthened.

Its fossils occur between approximately 72 and 68 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

The holotype skull is about 1.22 metres long, with 13 maxillary tooth positions and 15 in the dentary. Adult teeth were thick, slightly recurved and serrated, and were replaced continuously. Compared with Tyrannosaurus, the skull was less abruptly expanded behind the snout; its nasals formed a pronounced dome and were less integrated into the main path transmitting bite stresses through the upper jaw. Interlocking bones made the rear of the lower jaw particularly rigid. The neck was short and muscular, the torso carried over long, sturdy hind limbs, and the tail counterbalanced the head. The tiny arms ended in two functional fingers. Juveniles had a shallower, more lightly built skull without some adult features associated with resisting large feeding forces.

• Deep adult skull with a relatively long, narrow snout
• Domed nasal bones less tightly integrated into the upper-jaw stress path
• Rigid dentary-angular interlock at the rear of the lower jaw
• Large serrated teeth replaced continuously throughout life
• Thirteen maxillary and fourteen to fifteen dentary tooth positions
• Extremely reduced two-fingered forelimbs
• Long, powerful hind limbs supporting obligate bipedal locomotion
• Skull becoming proportionally deeper and more strongly reinforced during growth

An expedition of the USSR Academy of Sciences found skull PIN 551-1 and associated cervical vertebrae at Nemegt in 1946. Evgeny A. Maleev described the specimen in 1955 as Tyrannosaurus bataar; later revisions separated it as Tarbosaurus bataar and combined several other Mongolian tyrannosaur names with the same growth series. Subsequent Soviet-Mongolian, Polish-Mongolian, Mongolian and Japanese expeditions recovered many more individuals. Among the most informative is MPC-D 107/7 from Bugin Tsav, a roughly two- to three-year-old animal with a 290-millimetre skull and much of its skeleton preserved. A 2026 reassessment proposed that the immature types of Raptorex kriegsteini and the Chinese Asiatyrannus xui are also juvenile Tarbosaurus, but that wide-ranging synonymy remains a recent hypothesis rather than an uncontested fact.

Discovery credit: Mongolian Paleontological Expedition of the USSR Academy of Sciences.

Naming authors: Evgeny A. Maleev.

The Nemegt Formation records broad river channels, sandy bars, muddy overbanks and vegetated floodplains in a strongly seasonal but appreciably wetter setting than the older desert deposits beneath it. Fish, turtles and crocodyliforms occupied its waterways. Large herbivores included the hadrosaur Saurolophus, the long-armed Deinocheirus, Therizinosaurus, the sauropods Nemegtosaurus and Opisthocoelicaudia, and several smaller ornithomimosaurs and pachycephalosaurs. The formation accumulated across a large basin over time, so appearing in the same named unit does not prove that every listed animal met at one place or moment.

Tarbosaurus was unquestionably carnivorous, but fossils reveal feeding episodes rather than one fixed hunting style. A nearly complete Saurolophus skeleton preserves concentrated punctures, drag marks and bite-and-drag traces on one humerus. Their placement indicates deliberate access to remaining soft tissues after much of the carcass was already unavailable, strong evidence for scavenging on that individual—not proof that Tarbosaurus only scavenged. Adult skull construction accommodated much greater feeding loads than the shallow skull of juvenile MPC-D 107/7, supporting an age-related shift in prey size or feeding technique. No bonebed, trackway or nest demonstrates pack hunting, social hierarchy or parental care.

• Maleev originally named the holotype Tyrannosaurus bataar; Tarbosaurus became the familiar combination after later revision.
• The holotype’s skull length is almost the same as the Tyrannosaurus skull Maleev compared it with, but it has a longer snout and more tooth positions.
• Juvenile MPC-D 107/7 has a skull only 29 centimetres long yet retains the adult number of jaw sockets.
• A 2025 shape analysis found adult-like deepening and reinforcement across many individual skull bones, while also documenting substantial variation unrelated to size.
• The Museum of Evolution in Warsaw deliberately displays both a modern horizontal mount and an old upright mount to show how dinosaur reconstruction changed.

A research repository is not necessarily a public exhibit. Loan and display status can change, so check with the institution before visiting.

1. 01
   The Paleobiology Database

   Open source
2. 02
   Giant Carnivorous Dinosaurs of Mongolia

   Evgeny A. Maleev · Doklady, Academy of Sciences USSR 104(4) · 1955

   Open source
3. 03
   Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared

   Jørn H. Hurum, Karol Sabath · Acta Palaeontologica Polonica 48(2) · 2003

   Open source
4. 04
   Cranial Osteology of a Juvenile Specimen of Tarbosaurus bataar (Theropoda, Tyrannosauridae) from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia

   Takanobu Tsuihiji, Mahito Watabe, Khishigjav Tsogtbaatar and 7 coauthors · Journal of Vertebrate Paleontology 31(3) · 2011

   Open source
5. 05
   New Information on Scavenging and Selective Feeding Behaviour of Tyrannosaurids

   David W. E. Hone, Mahito Watabe · Acta Palaeontologica Polonica 55(4) · 2010

   Open source
6. 06
   Allometric growth and intraspecific variation of the craniomandibular bones of Tarbosaurus bataar (Theropoda, Tyrannosauridae): a geometric morphometric approach

   Changyu Yun, Rafael Delcourt, Philip J. Currie · Lethaia 58(4) · 2025

   Open source
7. 07
   Taxonomic reassessment of juvenile tyrannosaurine specimens from Asia reveal large biogeographic ranges in tyrannosaurids

   Gorm Skouboe Raun, Colton Chase Coppock, Demchig Badamgarav and 2 coauthors · Cretaceous Research 186, 106412 · 2026

   Open source
8. 08
   Dinosaurs: Tarbosaurus bataar

   Australian Museum

   Open source
9. 09
   Permanent exhibition: Tarbosaurus skeletal mounts

   Museum of Evolution, Polish Academy of Sciences

   Open source
10. 10
    Best exhibits: Tarbosaurus bataar

    National Museum of Natural History, Mongolia

    Open source