dynamic and evocative drawing realized after seeing Jurassic Park
micro graphite HB
Fossil range: Late Cretaceous
Tarbosaurus skeleton in University Geology and Palaeontology Museum, Münster, Germany
T. bataar Maleev, 1955 (type)
Maleevosaurus Carpenter, 1992
Jenghizkhan Olshevsky, 1995
Chingkankousaurus? Young, 1958
Tarbosaurus (pronounced /ˌtɑrboʊˈsɔrəs/ TAR-bo-SOR-əs; meaning "terrifying lizard") is a genus of tyrannosaurid theropod dinosaur that flourished in Asia between 70 and 65 million years ago, near the end of the Late Cretaceous Period. Fossils have been recovered in Mongolia with more fragmentary remains found further afield in parts of China. Although many species have been named, modern paleontologists recognize only one, T. bataar, as valid. Some experts contend that this species is actually an Asian representative of the North American genus Tyrannosaurus; if true, this would invalidate the genus Tarbosaurus altogether.
Tarbosaurus and Tyrannosaurus are considered closely related genera, even if they are not synonymous. Alioramus, also from Mongolia, is thought by some authorities to be the closest relative of Tarbosaurus. Like most known tyrannosaurids, Tarbosaurus was a large bipedal predator, weighing more than a ton and equipped with dozens of large, sharp teeth. It had a unique locking mechanism in its lower jaw and the smallest forelimbs relative to body size of all tyrannosaurids, renowned for their disproportionately tiny, two-fingered forelimbs.
Tarbosaurus lived in a humid floodplain criss-crossed by river channels. In this environment, it was an apex predator at the top of the food chain, probably preying on other large dinosaurs like the hadrosaur Saurolophus or the sauropod Nemegtosaurus. Tarbosaurus is very well-represented in the fossil record, known from dozens of specimens, including several complete skulls and skeletons. These remains have allowed scientific studies focusing on its phylogeny, skull mechanics, and brain structure.
Although smaller than Tyrannosaurus, Tarbosaurus was one of the largest tyrannosaurids. The largest known individuals were between 10 and 12 meters (33 to 40 ft) long, each with a head held up to 5 meters (16.5 ft) above the ground. The mass of a fully grown individual has never been published, although it is considered comparable to or slightly smaller than Tyrannosaurus.
The largest known Tarbosaurus skull is more than 1.3 meters (4 ft) long, larger than all other tyrannosaurids except Tyrannosaurus. The skull was tall, like that of Tyrannosaurus, but not as wide, especially towards the rear. The unexpanded rear of the skull meant that Tarbosaurus eyes did not face directly forwards, suggesting that it lacked the binocular vision of Tyrannosaurus. Large fenestrae (openings) in the skull reduced its weight. Between 60 and 64 teeth lined its jaws, slightly more than in Tyrannosaurus but fewer than in smaller tyrannosaurids like Gorgosaurus and Alioramus. Most of its teeth were oval in cross section, although the teeth of the premaxilla at the tip of the upper jaw had a D-shaped cross section. This heterodonty is characteristic of the family. The longest teeth were in the maxilla (upper jaw bone), with crowns up to 85 millimeters (3.3 in) long. In the lower jaw, a ridge on the outer surface of the angular bone articulated with the rear of the dentary bone, creating a locking mechanism unique to Tarbosaurus and Alioramus. Other tyrannosaurids lacked this ridge and had more flexibility in the lower jaw.
Tyrannosaurids varied little in body form, and Tarbosaurus was no exception. The head was supported by an S-shaped neck, while the rest of the vertebral column, including the long tail, was held horizontally. Tarbosaurus had tiny, two-fingered forelimbs, which were smaller relative to its body size than those of any other member of the family. In contrast, the three-toed hindlimbs were long and thick, supporting the body in a bipedal posture. The long, heavy tail served as a counterweight to the head and torso and placed the center of gravity over the hips.
Chinese paleontologists discovered a partial skull and skeleton of a small theropod (IVPP V4878) in the Xinjiang Autonomous Region of China in the mid-1960s. In 1977, Dong Zhiming described this specimen, which was recovered from the Subashi Formation, as a new genus and species, Shanshanosaurus huoyanshanensis. Gregory Paul recognized Shanshanosaurus as a tyrannosaurid in 1988, referring it to the now-defunct genus Aublysodon. Dong and Currie later re-examined the specimen and deemed it to be a juvenile of a larger species of tyrannosaurid. These authors refrained from assigning it to any particular genus but suggested Tarbosaurus as a possibility. Over the years, other Chinese localities have produced tyrannosaurid teeth and fragmentary remains, several of which have been given names. Albertosaurus periculosis, Tyrannosaurus luanchuanensis, Tyrannosaurus turpanensis and Chingkankousaurus fragilis are often considered synonyms of Tarbosaurus.
Named in 1976 by Sergei Kurzanov, Alioramus is another genus of tyrannosaurid from slightly older sediments in Mongolia. Several analyses have concluded Alioramus was quite closely related to Tarbosaurus. It was described as an adult, but its long, low skull is characteristic of a juvenile tyrannosaurid. This led Currie to speculate that Alioramus might represent a juvenile Tarbosaurus, but he noted that the much higher tooth count and row of crests on top of the snout suggested otherwise.[link]