Tarbosaurus

Tarbosaurus (/ˌtɑːrbəˈsɔːrəs/ TAR-bə-SAWR-əs; meaning "alarming lizard") is a genus of tyrannosaurid theropod dinosaur that flourished in Asia about 70 million years ago, at 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 see this species as an Asian representative of the North American genus Tyrannosaurus; this would make the genus Tarbosaurus redundant. Tarbosaurus and Tyrannosaurus, if not synonymous, are considered to be at least closely related genera. 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 up to five tonnes and equipped with about sixty large 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, probably preying on other large dinosaurs like the hadrosaur Saurolophus or the sauropod Nemegtosaurus. Tarbosaurus is represented by dozens of fossil specimens, including several complete skulls and skeletons. These remains have allowed scientific studies focusing on its phylogeny, skull mechanics, and brain structure.

Tarbosaurus
Temporal range: Late Cretaceous, 70 Ma
Possible Campanian record[1]
Dinosaurium, Tarbosaurus bataar 5
Skeleton on exhibit in Dinosaurium, Prague
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Clade: Dinosauria
Order: Saurischia
Suborder: Theropoda
Superfamily: Tyrannosauroidea
Family: Tyrannosauridae
Subfamily: Tyrannosaurinae
Genus: Tarbosaurus
Maleev, 1955
Species:
T. bataar
Binomial name
Tarbosaurus bataar
(Maleev, 1955)
[originally Tyrannosaurus]
Synonyms

Description

Tarboscale
Size comparison of specimens representing various growth stages

Although slightly smaller than Tyrannosaurus, Tarbosaurus was one of the largest tyrannosaurids. The largest known individuals were between 10 and 12 m (33 and 39 ft) long.[2] The mass of a fully grown individual is considered comparable to or slightly smaller than Tyrannosaurus, often estimated to be around 4–5 metric tons.[3][4]

The largest known Tarbosaurus skull is more than 1.3 m (4.3 ft) long, larger than all other tyrannosaurids except Tyrannosaurus.[5] 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 58 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.[6]

Tarbosaurus Steveoc86
Restoration of an adult and subadult Tarbosaurus next to a human

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 forelimbs, proportionably to body size the smallest of all members of the family. The hands had two clawed digits each, with an additional unclawed third metacarpal found in some specimens, similar to closely related genera. Holtz has suggested that Tarbosaurus also has a theropod reduction of fingers IV-I "developed further" than in other tyrannosaurids,[7] as the second metacarpal in the Tarbosaurus specimens he studied is less than twice the length of the first metacarpal (other tyrannosaurids have a second metacarpal about twice the length of the first metacarpal). Also, the third metacarpal in Tarbosaurus is proportionally shorter than in other tyrannosaurids; in other tyrannosaurids (like Albertosaurus and Daspletosaurus), the third metacarpal is often longer than the first metacarpal, while in the Tarbosaurus specimens studied by Holtz, the third metacarpal is shorter than the first.[5]

In contrast to the forelimbs, 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.[2][5]

Discovery and naming

Tarbosaurus skull
Holotype skull PIN 551-1, Museum of Paleontology, Moscow

In 1946, a joint Soviet-Mongolian expedition to the Gobi Desert in the Mongolian Ömnögovi Province turned up a large theropod skull and some vertebrae in the Nemegt Formation. In 1955, Evgeny Maleev, a Soviet paleontologist, made this specimen the holotype (PIN 551-1) of a new species, which he called Tyrannosaurus bataar.[8] The specific name is a misspelling of the Mongolian баатар/baatar ("hero").[6] In the same year, Maleev also described and named three new theropod skulls, each associated with skeletal remains discovered by the same expedition in 1948 and 1949. The first of these (PIN 551-2) was named Tarbosaurus efremovi, a new generic name composed of the Ancient Greek τάρβος/tarbos ("terror", "alarm", "awe", or "reverence") and σαυρος/sauros ("lizard"),[9] and the species named after Ivan Yefremov, a Russian paleontologist and science fiction author. The other two (PIN 553-1 and PIN 552-2) were also named as new species and assigned to the North American genus Gorgosaurus (G. lancinator and G. novojilovi, respectively). All three of these latter specimens are smaller than the first.[2]

TarbosaurusP1050352
Cast of specimen PIN 553-1, holotype of Gorgosaurus lancinator, in death pose

A 1965 paper by A.K. Rozhdestvensky recognized all of Maleev's specimens as different growth stages of the same species, which he believed to be distinct from the North American Tyrannosaurus. He created a new combination, Tarbosaurus bataar, to include all the specimens described in 1955 as well as newer material.[10] Later authors, including Maleev himself,[11] agreed with Rozhdestvensky's analysis, although some used the name Tarbosaurus efremovi rather than T. bataar.[12] American paleontologist Kenneth Carpenter re-examined the material in 1992. He concluded that it belonged to the genus Tyrannosaurus, as originally published by Maleev, and lumped all the specimens into the species Tyrannosaurus bataar except the remains that Maleev had named Gorgosaurus novojilovi. Carpenter thought this specimen represented a separate, smaller genus of tyrannosaurid, which he called Maleevosaurus novojilovi.[13] George Olshevsky created the new generic name Jenghizkhan (after Genghis Khan) for Tyrannosaurus bataar in 1995, while also recognizing Tarbosaurus efremovi and Maleevosaurus novojilovi, for a total of three distinct, contemporaneous genera from the Nemegt Formation.[14] A 1999 study subsequently reclassified Maleevosaurus as a juvenile Tarbosaurus.[15] All research published since 1999 recognizes only a single species, which is either called Tarbosaurus bataar[5][16][17] or Tyrannosaurus bataar.[18]

U.S. Immigration and Customs Enforcement (ICE) officials return a Tarbosaurus bataar skeleton to the government of Mongolia during a repatriation ceremony May 6, 2013, at a Manhattan hotel in New York 130506-H-ZZ999-007
Poached specimen repatriated to Mongolia from the US in 2013

After the original Russian-Mongolian expeditions in the 1940s, Polish-Mongolian joint expeditions to the Gobi Desert began in 1963 and continued until 1971, recovering many new fossils, including new specimens of Tarbosaurus from the Nemegt Formation.[6] Expeditions involving Japanese and Mongolian scientists between 1993 and 1998,[19] as well as private expeditions hosted by Canadian paleontologist Phil Currie around the turn of the 21st century, discovered and collected further Tarbosaurus material.[20][21] More than 30 specimens are known, including more than 15 skulls and several complete postcranial skeletons.[5]

Tarbosaurus fossils are only found around the Gobi Desert of Mongolia and China, both of which ban their export, though some specimens have been looted by private collectors.[22] A recent $1 million smuggling deal was uncovered when suspicions were raised about a catalog put out by Heritage Auctions for an event in New York City on May 20, 2012. By Mongolian law, any specimen found in the Gobi Desert was to rest at an appropriate Mongolian institution and there was little reasonable doubt that the Tarbosaurus bataar advertised on the catalog was a stolen one. The president of Mongolia and many paleontologists raised objections to the sale which led to a last-minute investigation that confirmed that it was a specimen that can only be found in the Gobi Desert, rightfully belonging to Mongolia.[23] During the court case (United States v. One Tyrannosaurus Bataar Skeleton), Eric Prokopi, the smuggler, pleaded guilty to illegal smuggling and the dinosaur was returned to Mongolia in 2013, where it is temporarily displayed on Sukhbaatar Square, the center of the city of Ulaanbaatar.[24] Prokopi had sold the dinosaur with a partner and fellow commercial hunter in England, Christopher Moore.[25] The case led to the repatriation of dozens more Mongolian dinosaurs, including several skeletons of Tarbosaurus bataar.[26]

Synonyms

Shanshanosaurus headden
The pieces of IVPP V4878, described as Shanshanosaurus huoyanshanensis

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 in Shanshan County, as a new genus and species, Shanshanosaurus huoyanshanensis.[27] Gregory Paul recognized Shanshanosaurus as a tyrannosaurid in 1988, referring it to the now-defunct genus Aublysodon.[28] 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.[29]

Albertosaurus periculosus, Tyrannosaurus luanchuanensis, Tyrannosaurus turpanensis and Chingkankousaurus fragilis were considered synonyms of Tarbosaurus in the second edition of the Dinosauria, but Chingkankousaurus has been assessed as dubious by Brusatte et al. (2013).[5][30]

Named in 1976 by Sergei Kurzanov, Alioramus is another genus of tyrannosaurid from slightly older sediments in Mongolia.[31] Several analyses have concluded Alioramus was quite closely related to Tarbosaurus.[6][16] 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.[32]

Classification

Tarbosaurus and Tyrannosaurus
Diagram showing the differences between a generalised Tarbosaurus (A) and Tyrannosaurus (B) skull

Tarbosaurus is classified as a theropod in the subfamily Tyrannosaurinae within the family Tyrannosauridae. Other members include Tyrannosaurus and the earlier Daspletosaurus, both from North America,[18] and possibly the Mongolian genus Alioramus.[6][16] Animals in this subfamily are more closely related to Tyrannosaurus than to Albertosaurus and are known for their robust build with proportionally larger skulls and longer femurs than in the other subfamily, the Albertosaurinae.[5]

Tarbosaurus bataar was originally described as a species of Tyrannosaurus,[8] an arrangement that has been supported by some more recent studies.[18][13] Others prefer to keep the genera separate, while still recognizing them as sister taxa.[5] A 2003 cladistic analysis based on skull features instead identified Alioramus as the closest known relative of Tarbosaurus, as the two genera share skull characteristics that are related to stress distribution and that are not found in other tyrannosaurines. If proven, this relationship would argue against Tarbosaurus becoming a synonym for Tyrannosaurus and would suggest that separate tyrannosaurine lineages evolved in Asia and North America.[6][16] The two known specimens of Alioramus, which show juvenile characteristics, are not likely juvenile individuals of Tarbosaurus because of their much higher tooth count (76 to 78 teeth) and their unique row of bony bumps along the top of their snouts.[32]

The discovery of Lythronax argestes, a much earlier tyrannosaurine further reveals the close relationship between Tyrannosaurus and Tarbosaurus, and it was discovered that Lythronax is a sister taxon to a clade consisting of Campanian genus Zhuchengtyrannus, and Maastrichtian genera Tyrannosaurus and Tarbosaurus. Further studies of Lythronax also suggest that the Asian tyrannosauroids were part of one evolutionary radiation.[33]

Tarbosaurus baatar skeleton
Mounted adult skeleton
TARBOSAURUS JUVENIL wiki
Fossils of a juvenile specimen

Below is the cladogram of Tyrannosauridae based on the phylogenetic analysis conducted by Loewen et al. in 2013.[34]

Tyrannosauridae

Gorgosaurus libratus

Albertosaurus sarcophagus

Tyrannosaurinae

Dinosaur Park tyrannosaurid

Daspletosaurus torosus

Daspletosaurus horneri

Teratophoneus curriei

Bistahieversor sealeyi

Lythronax argestes

Tyrannosaurus rex

Tarbosaurus bataar

Zhuchengtyrannus magnus

Paleobiology

Tarbosaurus and Saurolophus by durbed
Artist's impression of Tarbosaurus pursuing Saurolophus.

Like several other large tyrannosaurids, Tarbosaurus is known from relatively abundant and well-preserved fossil material. In fact, one quarter of all fossils collected from the Nemegt Formation belong to Tarbosaurus.[35] Although Tarbosaurus has not been studied as thoroughly as the North American tyrannosaurids,[6] the available material has allowed scientists to draw limited conclusions about its biology.

In 2001, Bruce Rothschild and others published a study examining evidence for stress fractures and tendon avulsions in theropod dinosaurs and the implications for their behavior. Since stress fractures are caused by repeated trauma rather than singular events they are more likely to be caused by regular behavior than other types of injuries. None of the eighteen Tarbosaurus foot bones examined in the study was found to have a stress fracture, but one of the ten examined hand bones was found to have one. Stress fractures in the hands have special behavioral significance compared to those found in the feet since stress fractures there can be obtained while running or during migration. Hand injuries, by contrast, are more likely to be obtained while in contact with struggling prey. The presence of stress fractures and tendon avulsions in general provide evidence for a "very active" predation-based diet rather than obligate scavenging.[36]

In 2012, bite marks on two fragmentary gastralia of the holotype specimen of the large ornithomimosaur Deinocheirus mirificus were reported. The size and shape of the bite marks match the teeth of Tarbosaurus, the largest known predator from the Nemegt Formation. Various types of feeding traces were identified; punctures, gouges, striae, fragmentary teeth, and combinations of the above marks. The bite marks probably represent feeding behavior instead of aggression between the species, and the fact that bite marks were not found elsewhere on the body indicates the predator focused on internal organs. Tarbosaurus bite marks have also been identified on hadrosaur and sauropod fossils, but theropod bite marks on bones of other theropods are very rare in the fossil record.[37]

Skull mechanics

Tarbosaurus skull front
Skull seen from the front

The skull of Tarbosaurus was completely described for the first time in 2003. Scientists noted key differences between Tarbosaurus and the North American tyrannosaurids. Many of these differences are related to the handling of stress by the skull bones during a bite. When the upper jaw bit down on an object, force was transmitted up through the maxilla, the primary tooth-bearing bone of the upper jaw, into surrounding skull bones. In North American tyrannosaurids, this force went from the maxilla into the fused nasal bones on top of the snout, which were firmly connected in the rear to the lacrimal bones by bony struts. These struts locked the two bones together, suggesting that force was then transmitted from the nasals to the lacrimals.[6]

Tarbosaurus lacked these bony struts, and the connection between the nasals and lacrimals was weak. Instead, a backwards projection of the maxilla was massively developed in Tarbosaurus and fit inside a sheath formed from the lacrimal. This projection was a thin, bony plate in North American tyrannosaurids. The large backwards projection suggests that force was transmitted more directly from the maxilla to the lacrimal in Tarbosaurus. The lacrimal was also more firmly anchored to the frontal and prefrontal bones in Tarbosaurus. The well-developed connections between the maxilla, lacrimal, frontal and prefrontal would have made its entire upper jaw more rigid.[6]

Another major difference between Tarbosaurus and its North American relatives was its more rigid mandible (lower jaw). While many theropods, including North American tyrannosaurids, had some degree of flexibility between the bones in the rear of the mandible and the dentary in the front, Tarbosaurus had a locking mechanism formed from a ridge on the surface of the angular, which articulated with a square process on the rear of the dentary.[6]

Some scientists have hypothesized that the more rigid skull of Tarbosaurus was an adaptation to hunting the massive titanosaurid sauropods found in the Nemegt Formation, which did not exist in most of North America during the Late Cretaceous. The differences in skull mechanics also affect tyrannosaurid phylogeny. Tarbosaurus-like articulations between the skull bones are also seen in Alioramus from Mongolia, suggesting that it, and not Tyrannosaurus, is the closest relative of Tarbosaurus. Similarities between Tarbosaurus and Tyrannosaurus might therefore be related to their large size, independently developed through convergent evolution.[6]

Bite force and feeding habits

There is evidence to suggest that Tarbosaurus was both a predator and scavenger, as shown with its fossilized bite marks being found on Saurolophus remains.[38] As for its bite force, it was revealed that Tarbosaurus had a bite force of around 8,000 to 10,000 pounds per force, meaning that it could possibly crush bone like its North American relative, Tyrannosaurus.[39]

Brain structure

Tarbosaurus profile
Side view of a skull and neck

A Tarbosaurus skull found in 1948 by Soviet and Mongolian scientists (PIN 553-1, originally called Gorgosaurus lancinator) included the skull cavity that held the brain. Making a plaster cast, called an endocast, of the inside of this cavity allowed Maleev to make preliminary observations about the shape of a Tarbosaurus brain.[40] A newer polyurethane rubber cast allowed a more detailed study of Tarbosaurus brain structure and function.[41]

The endocranial structure of Tarbosaurus was similar to that of Tyrannosaurus,[42] differing only in the positions of some cranial nerve roots, including the trigeminal and accessory nerves. Tyrannosaurid brains were more similar to those of crocodilians and other reptiles than to birds. The total brain volume for a 12 metres (39 ft) Tarbosaurus is estimated at only 184 cubic centimetres (11.2 cu in).[41]

The large size of the olfactory bulbs, as well as the terminal and olfactory nerves, suggest that Tarbosaurus had a keen sense of smell, as was also the case with Tyrannosaurus. The vomeronasal bulb is large and differentiated from the olfactory bulb, which was initially suggested as being indicative of a well-developed Jacobsen's organ, which was used to detect pheromones. This may imply that Tarbosaurus had complex mating behavior.[41] However, the identification of the vomeronasal bulb has been challenged by other researchers, since they are not present in any living archosaurs.[43]

The auditory nerve was also large, suggesting good hearing, which may have been useful for auditory communication and spatial awareness. The nerve had a well-developed vestibular component as well, which implies a good sense of balance and coordination. In contrast, the nerves and brain structures associated with eyesight were smaller and undeveloped. The midbrain tectum, responsible for visual processing in reptiles, was very small in Tarbosaurus, as were the optic nerve and the oculomotor nerve, which controls eye movement. Unlike Tyrannosaurus, which had forward-facing eyes that provided some degree of binocular vision, Tarbosaurus had a narrower skull more typical of other tyrannosaurids in which the eyes faced primarily sideways. All of this suggests that Tarbosaurus relied more on its senses of smell and hearing than on its eyesight.[41]

Life history

Tarbosaurus juvenile
Fossil of a juvenile specimen

Most specimens of Tarbosaurus represent adult or subadult individuals; juveniles remain very rare. Nevertheless, the 2006 discovery of a juvenile skeleton including a complete, 290-millimetre (0.95 ft) long skull provides information on the life history of this dinosaur. This individual probably was aged 2 to 3 years at the time of death. Compared with adult skulls, the juvenile skull was weakly constructed and the teeth were thin, indicating different food preferences in juveniles and adults that reduced competition between different age groups.[44] Examination of the sclerotic rings in this juvenile Tarbosaurus suggests they may also have been crepuscular or nocturnal hunters. Whether the adult Tarbosaurus were also nocturnal is currently unknown due to lack of fossil evidence.[45]

Skin impressions and footprints

Skin impressions were recovered from a large skeleton at the Bugiin Tsav locality that was previously destroyed by poachers. These impressions show non-overlapping scales with an average diameter of 2.4 millimetres (0.094 in) and pertain to the thoracic region of the individual, although the exact position can not be assessed any longer due to the destruction of the skeleton.[46]

Phil Currie and colleagues (2003) described two footprints from the Nemegt locality that probably pertain to Tarbosaurus. These tracks represents natural casts, which means that only the sandy infill of the tracks and not the tracks itself are preserved. The better preserved tracks feature skin impressions over large areas on and behind the toe impressions that are similar to those discovered in Bugiin Tsav. They also feature vertical parallel slide marks that were left by scales when the foot was pushed into the ground. The track measures 61 centimeters (24 in) in length, thus representing a large individual. The second track, although even larger, was affected by erosion and does not show any detail.[46]

Paleoecology

Nemegt locality
Location of the Nemegt Formation within Mongolia

The vast majority of known Tarbosaurus fossils were recovered from the Nemegt Formation in the Gobi Desert of southern Mongolia. This geologic formation has never been dated radiometrically, but the fauna present in the fossil record indicate it was probably deposited during the early Maastrichtian stage, at the end of the Late Cretaceous[35] about 70 million years ago.[47][48] The Subashi Formation, in which Shanshanosaurus remains were discovered, is also Maastrichtian in age.[49]

Tarbosaurus is found chiefly in the Nemegt Formation, whose sediments preserve large river channels and soil deposits that indicate a far more humid climate than those suggested by the underlying Barun Goyot and Djadochta Formations. However, caliche deposits indicate at least periodic droughts. Sediment was deposited in the channels and floodplains of large rivers. The rock facies of this formation suggest the presence of mudflats, and shallow lakes. Sediments also indicate that there existed a rich habitat, offering diverse food in abundant amounts that could sustain massive Cretaceous dinosaurs.[50] Fossils of an unidentified tyrannosaur from the older Djadochta Formation, which closely resemble those of Tarbosaurus, may indicate that it also lived at an earlier time and in a more arid ecosystem than that of the Nemegt.[1]

TarbosaurusDB
Restoration of Tarbosaurus in Late Cretaceous Mongolian environment

Occasional mollusk fossils are found, as well as a variety of other aquatic animals like fish and turtles.[35] Crocodilians included several species of Shamosuchus, a genus with teeth adapted for crushing shells.[51] Mammal fossils are exceedingly rare in the Nemegt Formation, but many birds have been found, including the enantiornithine Gurilynia and the hesperornithiform Judinornis, as well as Teviornis, an early representative of the still-existing Anseriformes (waterfowl). Scientists have described many dinosaurs from the Nemegt Formation, including the ankylosaurid Saichania, and pachycephalosaur Prenocephale.[35] By far the largest predator known from the formation, adult Tarbosaurus most likely preyed upon large hadrosaurs such as Saurolophus and Barsboldia, or sauropods such as Nemegtosaurus, and Opisthocoelicaudia.[6] Adults would have received little competition from small theropods such as the small tyrannosaurid Alioramus, troodontids (Borogovia, Tochisaurus, Zanabazar), oviraptorosaurs (Elmisaurus, Nemegtomaia, Rinchenia) or Bagaraatan, sometimes considered a basal tyrannosauroid. Other theropods, like the gigantic Therizinosaurus, might have been herbivorous, and ornithomimosaurs such as Anserimimus, Gallimimus, and gigantic Deinocheirus might have been omnivores that only took small prey and were therefore no competition for Tarbosaurus. However, as in other large tyrannosaurids as well as modern Komodo dragons, juveniles and subadult Tarbosaurus would have filled niches between the massive adults and these smaller theropods.[5]

See also

References

  1. ^ a b Mortimer, M (2004). "Tyrannosauroidea". The Theropod Database. Archived from the original on 2013-09-29. Retrieved 2007-08-21.
  2. ^ a b c Maleev, E. A. (1955). translated by F. J. Alcock. "New carnivorous dinosaurs from the Upper Cretaceous of Mongolia" (PDF). Doklady Akademii Nauk SSSR. 104 (5): 779–783.
  3. ^ Paul, G.S., 2010, The Princeton Field Guide to Dinosaurs, Princeton University Press.
  4. ^ Valkenburgh, B.; Molnar, R. E. (2002). "Dinosaurian and mammalian predators compared". Paleobiology. 28 (4): 527–543. doi:10.1666/0094-8373(2002)028<0527:DAMPC>2.0.CO;2. ISSN 0094-8373.
  5. ^ a b c d e f g h i Holtz, Thomas R., Jr. (2004). "Tyrannosauroidea". In Weishampel, David B.; Dodson, Peter; Osmólska, Halszka. The Dinosauria (Second ed.). Berkeley: University of California Press. p. 124. ISBN 978-0-520-24209-8.
  6. ^ a b c d e f g h i j k l Hurum, Jørn H.; Sabath, Karol (2003). "Giant theropod dinosaurs from Asia and North America: Skulls of Tarbosaurus bataar and Tyrannosaurus rex compared" (PDF). Acta Palaeontologica Polonica. 48 (2): 161–190.
  7. ^ Carpenter K, Tanke D.H. & Skrepnick M.W. (2001), Mesozoic Vertebrate Life (Indiana University Press, ISBN 0-253-33907-3), p. 71.
  8. ^ a b Maleev, Evgeny A. (1955). "Giant carnivorous dinosaurs of Mongolia". Doklady Akademii Nauk SSSR. 104 (4): 634–637.
  9. ^ Liddell, Henry G.; Scott, Robert (1980). Greek–English Lexicon (Abridged ed.). Oxford: Oxford University Press. ISBN 978-0-19-910207-5.
  10. ^ Rozhdestvensky, Anatoly K. (1965). "Growth changes in Asian dinosaurs and some problems of their taxonomy". Paleontological Journal. 3: 95–109.
  11. ^ Maleev, Evgeny A. (1974). "Gigantic carnosaurs of the family Tyrannosauridae". The Joint Soviet-Mongolian Paleontological Expedition Transactions. 1: 132–191.
  12. ^ Barsbold, Rinchen (1983). "Carnivorous dinosaurs from the Cretaceous of Mongolia". The Joint Soviet-Mongolian Paleontological Expedition Transactions. 19: 5–119.
  13. ^ a b Carpenter, Ken. (1992). "Tyrannosaurids (Dinosauria) of Asia and North America". In Mateer, Niall J.; Peiji, Chen. Aspects of Nonmarine Cretaceous Geology. Beijing: China Ocean Press. pp. 250–268.
  14. ^ Olshevsky, George; Ford, Tracy L. (1995). "The origin and evolution of the tyrannosaurids, part 1". Dinosaur Frontline (in Japanese). 9: 92–119.
  15. ^ Carr, Thomas D. (1999). "Craniofacial ontogeny in Tyrannosauridae (Dinosauria, Coelurosauria)". Journal of Vertebrate Paleontology. 19 (3): 497–520. doi:10.1080/02724634.1999.10011161.
  16. ^ a b c d Currie, Philip J.; Hurum, Jørn H.; Sabath, Karol (2003). "Skull structure and evolution in tyrannosaurid phylogeny" (PDF). Acta Palaeontologica Polonica. 48 (2): 227–234.
  17. ^ Xu Xing; Norell, Mark A.; Kuang Xuewen; Wang Xiaolin; Zhao Qi; Jia Chengkai (2004). "Basal tyrannosauroids from China and evidence for protofeathers in tyrannosauroids". Nature. 431 (7009): 680–684. Bibcode:2004Natur.431..680X. doi:10.1038/nature02855. PMID 15470426.
  18. ^ a b c Carr, Thomas D.; Williamson, Thomas E.; Schwimmer, David R. (2005). "A new genus and species of tyrannosauroid from the Late Cretaceous (middle Campanian) Demopolis Formation of Alabama". Journal of Vertebrate Paleontology. 25 (1): 119–143. doi:10.1671/0272-4634(2005)025[0119:ANGASO]2.0.CO;2.
  19. ^ Watabe, Masato; Suzuki, Shigeru (2000). "Cretaceous fossil localities and a list of fossils collected by the Hayashibara Museum of Natural Sciences and Mongolian Paleontological Center Joint Paleontological Expedition (JMJPE) from 1993 through 1998". Hayashibara Museum of Natural Sciences Research Bulletin. 1: 99–108.
  20. ^ Currie, Philip J. (2001). "Nomadic Expeditions, Inc., report of fieldwork in Mongolia, September 2000.". Alberta Palaeontological Society, Fifth Annual Symposium, Abstract Volume. Calgary: Mount Royal College. pp. 12–16.
  21. ^ Currie, Philip J. (2002). "Report on fieldwork in Mongolia, September 2001.". Alberta Palaeontological Society, Sixth Annual Symposium, 'Fossils 2002,' Abstract Volume. Calgary: Mount Royal College. pp. 8–12.
  22. ^ Switek, Brian (19 May 2012). "Stop the Tarbosaurus Auction!". Wired.
  23. ^ Switek, Brian. "The Million Dollar Dinosaur Scandal". Slate.com. Retrieved 21 August 2013.
  24. ^ Parry, Wynne (May 7, 2013). "Mongolia gets stolen dinosaur back". Mother Nature Network. Retrieved 21 August 2013.
  25. ^ Williams, Paige (January 28, 2013). "Bones of Contention". The New Yorker. Retrieved 2017-09-09.
  26. ^ Williams, Paige (June 7, 2014). "The Black Market for Dinosaurs". The New Yorker. Retrieved 2017-09-09.
  27. ^ Dong Zhiming (1977). "On the dinosaurian remains from Turpan, Xinjiang". Vertebrata PalAsiatica (in Chinese). 15: 59–66.
  28. ^ Paul, Gregory S. (1988). Predatory Dinosaurs of the World. New York: Simon & Schuster. p. 464.
  29. ^ Currie, Philip J.; Dong Zhiming (2001). "New information on Shanshanosaurus huoyanshanensis, a juvenile tyrannosaurid (Theropoda, Dinosauria) from the Late Cretaceous of China". Canadian Journal of Earth Sciences. 38 (12): 1729–1737. Bibcode:2001CaJES..38.1729C. doi:10.1139/cjes-38-12-1729.
  30. ^ Brusatte, Hone and Xu, 2013. Phylogenetic revision of Chingkankousaurus fragilis, a forgotten tyrannosauroid from the Late Cretaceous of China. in Parrish, Molnar, Currie and Koppelhus (eds.). Tyrannosaurid Paleobiology. Indiana University Press. 1-13.
  31. ^ Kurzanov, Sergei M. (1976). "A new Late Cretaceous carnosaur from Nogon−Tsav, Mongolia". The Joint Soviet-Mongolian Paleontological Expedition Transactions (in Russian). 3: 93–104.
  32. ^ a b Currie, Philip J. (2003). "Cranial anatomy of tyrannosaurids from the Late Cretaceous of Alberta" (PDF). Acta Palaeontologica Polonica. 48 (2): 191–226. Archived from the original (PDF) on 2007-06-21.
  33. ^ Loewen, Mark A; Irmis, Randall B; Sertich, Joseph J. W; Currie, Philip J; Sampson, Scott D (2013-11-06). "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". PLOS ONE. 8 (11): e79420. doi:10.1371/journal.pone.0079420. PMID 24223179. Retrieved 2017-06-06.
  34. ^ Loewen, M. A.; Irmis, R. B.; Sertich, J. J. W.; Currie, P. J.; Sampson, S. D. (2013). Evans, David C., ed. "Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans". PLoS ONE. 8 (11): e79420. Bibcode:2013PLoSO...879420L. doi:10.1371/journal.pone.0079420. PMC 3819173. PMID 24223179.
  35. ^ a b c d Jerzykiewicz, Tomasz; Russell, Dale A. (1991). "Late Mesozoic stratigraphy and vertebrates of the Gobi Basin". Cretaceous Research. 12 (4): 345–377. doi:10.1016/0195-6671(91)90015-5.
  36. ^ Rothschild, B., Tanke, D. H., and Ford, T. L., 2001, Theropod stress fractures and tendon avulsions as a clue to activity: In: Mesozoic Vertebrate Life, edited by Tanke, D. H., and Carpenter, K., Indiana University Press, p. 331-336.
  37. ^ Bell, P. R.; Currie, P. J.; Lee, Y. N. (2012). "Tyrannosaur feeding traces on Deinocheirus (Theropoda:?Ornithomimosauria) remains from the Nemegt Formation (Late Cretaceous), Mongolia". Cretaceous Research. 37: 186–190. doi:10.1016/j.cretres.2012.03.018.
  38. ^ Switek, Brian. "Tarbosaurus: A Predator and a Scavenger With a Delicate Bite". Smithsonian Magazine. Retrieved 11 November 2018.
  39. ^ Therrien, Francois; Henderson, Donald M.; Ruff, Christopher B. (January 2005). "Bite me: Biomechanical models of theropod mandibles and implications for feeding behavior". Indiana University Press: 179–237. Retrieved 11 November 2018.
  40. ^ Maleev, Evgeny A. (1965). "On the brain of carnivorous dinosaurs". Paleontological Journal (in Russian). 2: 141–143.
  41. ^ a b c d Saveliev, Sergei V.; Alifanov, Vladimir R. (2005). "A new study of the brain of the predatory dinosaur Tarbosaurus bataar (Theropoda, Tyrannosauridae)". Paleontological Journal. 41 (3): 281–289. doi:10.1134/S0031030107030070.
  42. ^ Brochu, Christopher A. (2000). "A digitally-rendered endocast for Tyrannosaurus rex". Journal of Vertebrate Paleontology. 20 (1): 1–6. doi:10.1671/0272-4634(2000)020[0001:ADREFT]2.0.CO;2.
  43. ^ Bever, G.S.; Brusatte, S.L.; Carr, T.D.; Xu, X.; Balanoff, A.M.; Norell, M.A. (2013). "The Braincase Anatomy of the Late Cretaceous Dinosaur Alioramus (Theropoda: Tyrannosauroidea)". Bulletin of the American Museum of Natural History. 376: 1–72. doi:10.1206/810.1.
  44. ^ Tsuihiji, Takanobu; Watabe, Mahito; Tsogtbaatar, Khishigjav; Tsubamoto, Takehisa; Barsbold, Rinchen; Suzuki, Shigeru; Lee, Andrew H.; Ridgely, Ryan C.; Kawahara, Yasuhiro; Witmer, Lawrence M. (2011-05-01). "Cranial Osteology of a Juvenile Specimen of Tarbosaurus bataar (Theropoda, Tyrannosauridae) from the Nemegt Formation (Upper Cretaceous) of Bugin Tsav, Mongolia". Journal of Vertebrate Paleontology. 31 (3): 497–517. doi:10.1080/02724634.2011.557116.
  45. ^ Tsuihiji, Takanobu; Watabe, Mahito; Tsogtbaatar, Khishigjav; Tsubamoto, Takehisa; Barsbold, Rinchen; Suzuki, Shigeru; Lee, Andrew H; Ridgely, Ryan C; Kawahara, Yasuhiro; Witmer, Lawrence M (2011-05-16). "Tiny Tarbosaurus Shows How Tyrants Grew Up | Science | Smithsonian". Journal of Vertebrate Paleontology. 31 (3): 497–517. doi:10.1080/02724634.2011.557116. Retrieved 2017-06-06.
  46. ^ a b Currie, Philip J.; Badamgarav, Demchig; Koppelhus, Eva B. (2003). "The First Late Cretaceous Footprints from the Locality in the Gobi of Mongolia". Ichnos. 10: 1–12. doi:10.1080/10420940390235071.
  47. ^ Sulliban, R.M. (2006). "A taxonomic review of the Pachycephalosauridae (Dinosauria: Ornithischia)." Pp. 347-366 in Lucas, S.G. and Sullivan, R.M. (eds.), Late Cretaceous vertebrates from the Western Interior. New Mexico Museum of Natural History and Science Bulletin 3.
  48. ^ Gradstein, Felix M.; Ogg, James G.; and Smith, Alan G. (2005). A Geologic Time Scale 2004. Cambridge: Cambridge University Press. pp. 500pp. ISBN 978-0-521-78142-8.
  49. ^ Shen, Y.B.; Mateer, Niall J. (1992). "An outline of the Cretaceous System in northern Xinjiang, western China". In Mateer, Niall J.; Peiji, Chen. Aspects of Nonmarine Cretaceous Geology. Beijing: China Ocean Press. pp. 49–77.
  50. ^ Novacek, M. (1996). Dinosaurs of the Flaming Cliffs. Bantam Doubleday Dell Publishing Group Inc. New York, New York. ISBN 978-0-385-47775-8
  51. ^ Efimov, Mikhail B. (1983). "Revision of the fossil crocodiles of Mongolia". The Joint Soviet-Mongolian Paleontological Expedition Transactions (in Russian). 24: 76–95.

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1955 in paleontology

Paleontology or palaeontology (from Greek: paleo, "ancient"; ontos, "being"; and logos, "knowledge") is the study of prehistoric life forms on Earth through the examination of plant and animal fossils. This includes the study of body fossils, tracks (ichnites), burrows, cast-off parts, fossilised feces (coprolites), palynomorphs and chemical residues. Because humans have encountered fossils for millennia, paleontology has a long history both before and after becoming formalized as a science. This article records significant discoveries and events related to paleontology that occurred or were published in the year 1955.

Adasaurus

Adasaurus ( AH-də-SAWR-əs; "Ada's lizard") is a dromaeosaurid theropod dinosaur from the Late Cretaceous Period of Central Asia. It was a small bipedal carnivore with a sickle-shaped claw on the second toe of each hind foot, and was perhaps 1.8 m (5.9 ft) long. The genus name Adasaurus is taken from Ada, an evil spirit in the mythology of Mongolia, and the Greek word sauros meaning 'lizard'. The species name, for the single species, (A. mongoliensis), refers to the country of origin. Adasaurus was named and described in 1983 by Mongolian paleontologist Rinchen Barsbold.

Adasaurus is a member of Dromaeosauridae, a group that is closely related to living birds. Other dromaeosaurids include Deinonychus, Velociraptor, Microraptor, and Buitreraptor. The relationships of Adasaurus are poorly understood. Traditionally, Adasaurus is assigned to the Dromaeosaurinae, which includes heavily built animals such as Dromaeosaurus and Utahraptor but several recent studies have suggested that it may be a member of the Velociraptorinae instead.Two specimens of Adasaurus have been found, both from the Nemegt Formation in the Gobi Desert of southern Mongolia. The holotype, IGM 100/20, is an incomplete skeleton with partial skull, including the vertebral column except the back of the tail, all three bones of the pelvis, the shoulder girdle and the hindlimbs. The second specimen, the paratype IGM 100/51 also described in the original paper, consists of the back end of another skeleton, including the hindlimbs. Both specimens are currently in the collection of the Mongolian Geological Institute in Ulaanbaatar, Mongolia.

The age of the Nemegt is not known for certain, but it is commonly thought to belong to the Maastrichtian stage of the Late Cretaceous Period., and Adasaurus would therefore have lived between 72 and 66 million years ago. Other dinosaurs found in this formation include the tyrannosaur Tarbosaurus, the ornithomimid Anserimimus, the troodontid Zanabazar, and the hadrosaur Saurolophus.

Albertosaurinae

Albertosaurines, or dinosaurs of the subfamily Albertosaurinae, lived in the Late Cretaceous of United States and Canada. The subfamily was first used by Philip J. Currie, Jørn H. Hurum and Karol Sabath as a group of tyrannosaurid dinosaurs. It was originally defined as "(Albertosaurus + Gorgosaurus)", including only the two genera. The group is sister clade to Tyrannosaurinae. In 2007, it was found that the group also contained Maleevosaurus, often synonymized with Tarbosaurus. However, this classification has not been accepted, and Maleevosaurus is still considered a juvenile Tarbosaurus or Tyrannosaurus. Clevenger T. M. McLain found in an abstract, that Alioramus, commonly used as a derived tyrannosauroid, was an albertosaurine, or the sister taxon to the group.

Alioramus

Alioramus (; meaning 'different branch') is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. The type species, A. remotus, is known from a partial skull and three foot bones recovered from Mongolian sediments which were deposited in a humid floodplain about 70 million years ago. These remains were named and described by Soviet paleontologist Sergei Kurzanov in 1976. A second species, A. altai, known from a much more complete skeleton, was named and described by Stephen L. Brusatte and colleagues in 2009. Its relationships to other tyrannosaurid genera are unclear, with some evidence supporting a hypothesis that Alioramus is closely related to the contemporary species Tarbosaurus bataar.

Alioramus were bipedal like all known theropods, and their sharp teeth indicate that they were carnivores. Known specimens were smaller than other tyrannosaurids like Tarbosaurus bataar and Tyrannosaurus rex, but their adult size is difficult to estimate since both Alioramus species are known only from juvenile or sub-adult remains. The recent discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaur. The genus Alioramus is characterized by a row of five bony crests along the top of the snout, a greater number of teeth than any other genus of tyrannosaurid, and a lower skull than most other tyrannosaurids.

Baatar

The word Baatar (Mongolian: баатар, hero) is part of many names signifying:

PeopleDamdin Sükhbaatar, a Mongolian military leader and revolutionary hero

Mengke Bateer (Mönkhbaatar), a Chinese basketball player from Inner Mongolia

The fictional character Orkhon Baatar in The Palace of Heavenly PleasurePlacesUlaanbaatar (also spelled Ulaan Baatar), the capital of Mongolia

Sükhbaatar Province, an administrative subdivision (Aimag) of MongoliaAnimalsAlbionbaataridae, An extinct mammal family in England

its genera Albionbaatar and Proalbionbaatar

Arginbaataridae, an extinct mammal family in Mongolia

its genus Arginbaatar

Sloanbaataridae, an extinct mammal family in Mongolia

its genera Sloanbaatar, Kamptobaatar, Nessovbaatar

Ctenacodon (Plagiaulacidae), an extinct mammal Ctenacodon brentbaatar in North America

Kryptobaatar (also Gobibaatar, Tugrigbaatar), an extinct mammal in Central Asia

Tarbosaurus, misspelled, the extinct dinosaur Tarbosaurus bataar

Deinocheirus

Deinocheirus ( DY-no-KY-rəs) is a genus of large ornithomimosaur that lived during the Late Cretaceous around 70 million years ago. In 1965, a pair of large arms, shoulder girdles, and a few other bones of a new dinosaur were first discovered in the Nemegt Formation of Mongolia. In 1970, this specimen became the holotype of the only species within the genus, Deinocheirus mirificus; the genus name is Greek for "horrible hand". No further remains were discovered for almost fifty years, and its nature remained a mystery. Two more complete specimens were described in 2014, which shed light on many aspects of the animal. Parts of these new specimens had been looted from Mongolia some years before, but were repatriated in 2014.

Deinocheirus was an unusual ornithomimosaur, the largest of the clade at 11 m (36 ft) long, and weighing 6.4 t (7.1 short tons). Though it was a bulky animal, it had many hollow bones which saved weight. The arms were among the largest of any bipedal dinosaur at 2.4 m (7.9 ft) long, with large, blunt claws on its three-fingered hands. The legs were relatively short, and bore blunt claws. Its vertebrae had tall neural spines that formed a "sail" along its back. The tail ended in pygostyle-like vertebrae, which indicate the presence of a fan of feathers. The skull was 1.024 m (3.36 ft) long, with a wide bill and a deep lower jaw, similar to those of hadrosaurs.

The classification of Deinocheirus was long uncertain, and it was initially placed in the theropod group Carnosauria, but similarities with ornithomimosaurians were soon noted. After more complete remains were found, Deinocheirus was shown to be a primitive ornithomimosaurian, most closely related to the smaller genera Garudimimus and Beishanlong, together forming the family Deinocheiridae. Members of this group were not adapted for speed, unlike other ornithomimosaurs. Deinocheirus is thought to have been omnivorous; its skull shape indicates a diet of plants, fish scales were found in association with one specimen and gastroliths were also present in the stomach region of the specimen. The large claws may have been used for digging and gathering plants. Bite marks on Deinocheirus bones have been attributed to the tyrannosaurid Tarbosaurus.

Evgeny Maleev

Evgeny/Evgenii Aleksandrovich Maleev [1] (Russian: Евгений Александрович Малеев, pronounced [jɪˈvɡenʲɪj ɐlʲɪˈksandrəvʲɪtɕ mɐˈlʲeɪf]; 25 February 1915 – 12 April 1966) was a Soviet paleontologist who named the ankylosaur Talarurus; the theropods Tarbosaurus and Therizinosaurus; and the family Therizinosauridae.

Maleev did research on Tarbosaurus brains by cutting open fossilized braincases with a diamond saw. Modern researchers use computer tomography scans and 3D reconstruction software to visualize the interior of dinosaur endocrania, thus eliminating the need to damage valuable specimens.Two dinosaurs — Maleevus and Maleevosaurus — have been named for Maleev.

Gallery of Paleontology and Comparative Anatomy

The Gallery of Paleontology and Comparative Anatomy (in French, galerie de Paléontologie et d'Anatomie comparée) is a part of the French National Museum of Natural History (Muséum national d'histoire naturelle, MNHN). It is situated in the Jardin des plantes in Paris near the Gare d'Austerlitz.

The Gallery of Comparative Anatomy (occupying the ground floor), holds nearly a thousand skeletons and interprets their organization and classification. The Gallery of Paleontology (occupying the first and second floor) presents a famous collection of fossil vertebrates, fossil invertebrates and fossil plants. Among the most appreciated pieces by the public is worth mentioning a series of dinosaur skeleton casts (Diplodocus, Iguanodon, Allosaurus, Carnotaurus, Tarbosaurus, Unenlagia, Dromaeosaurus, Bambiraptor) but also a Tyrannosaurus skull (cast of specimen AMNH 5027), an authentic skull of Triceratops, an authentic Compsognathus skeleton, and some authentic fossilised skeletons of other extinct animals like Sarcosuchus, Cynthiacetus, Mammuthus meridionalis, Mammuthus primigenius, Megatherium, Thalassocnus, Ursus spelaeus, Panthera leo spelaea, Aepyornis and many others.

Mongolian Natural History Museum

The Mongolian Natural History Museum (Mongolian: Байгалийн түүхийн музей) is a repository and research institution located in Ulaanbaatar, Mongolia. The museum was previously known as the Mongolian National Museum or State Central Museum. This change in name has often led to confusion with Ulaanbaatar's other preeminent museum, the National Museum of Mongolia. Although the two museums are located quite close to one another, they contain very different exhibits. The Mongolian National Museum focuses on the archaeology and history of Mongolia, while the Mongolian Natural History Museum is concerned primarily with the flora, fauna, geology and natural history of the country.

The museum includes Departments of Geology, Geography, Flora and Fauna, Paleontology, and Anthropology encompassing the natural history of Mongolia. The museum's holdings include more than 6000 specimens, 45% of which are on permanent public display.

The museum is particularly well known for its dinosaur and other paleontological exhibits, among which the most notable are a nearly complete skeleton of a late Cretaceous Tarbosaurus tyrannosaurid and broadly contemporaneous nests of Protoceratops eggs.

Raptorex

Raptorex is a dubious genus of tyrannosaurid dinosaur. Its fossil remains consist of a single juvenile specimen probably uncovered in Mongolia, or possibly northeastern China. The type species is R. kriegsteini, described in 2009 by Sereno and colleagues. The genus name is derived from Latin raptor, "robber", and rex, "king". The specific name honours Roman Kriegstein, a survivor of the Holocaust, whose son Henry Kriegstein donated the specimen to the University of Chicago for scientific study.While initially considered to have come from the Yixian Formation of China, dated to approximately 125 million years ago during the early Cretaceous period, later studies showed that such an early date for the fossil are unlikely, and given its extremely close similarity to juvenile tyrannosaurids of the late Cretaceous, it probably came from the Iren Dabasu or similar formation. Because the specimen is a juvenile, and the changes undergone by tyrannosaurids during growth are not yet well understood, many researchers now consider it to be a nomen dubium, because it cannot be confidently paired with an adult skeleton (though it is extremely similar to juvenile Tarbosaurus bataar skeletons of the same size and age).

Saichania

Saichania (Mongolian meaning "beautiful one") is a genus of herbivorous ankylosaurid dinosaur from the Late Cretaceous period of Mongolia and China.

The first fossils of Saichania were found in the early 1970s in Mongolia. In 1977 the type species Saichania chulsanensis was named. The description of this species has been based on limited fossil material; especially the rear of the animal is not well known.

Saichania was over five metres long and weighed over two tonnes. It was more robustly built than other members of the Ankylosauridae. Neck vertebrae, shoulder girdle, ribs and breast bones were fused or firmly connected. Its body was flat and low-slung, standing on four short legs. The forelimbs were very powerful. The head was protected by bulbous armour tiles. It could defend itself against predators like Tarbosaurus with a tail-club. On the torso keeled osteoderms were present. Saichania bit off plants in its desert habitat with a horny beak and processed them in its wide hindgut.

Subashi Formation

The Subashi Formation (Chinese: 苏巴什组)is a late Cretaceous formation from the Xinjiang Autonomous Region of western China. Initially described by Dong Zhiming in 1977, the formation contains remains of Tarbosaurus which were initially described as a separate taxon Shanshanosaurus huoyanshanensis. Remains of a sauropod, likely Nemegtosaurus, and a hadrosaurid, likely Jaxartosaurus, have also been found.

The formation is located in the Flaming Mountains region of Xinjiang, north of the Turpan Depression. It is not far from Lianmuqin Town of Shanshan County,

and is presumably named after the village of Subashi (42°55′11″N 89°44′36″E), which is located some 15 km to the west of Lianmuqin, in Tuyugou Township (吐峪沟乡).

The Dino King

Speckles the Tarbosaurus (점박이: 한반도의 공룡 3D: Jumbagi: Hanbandoui gongryong 3D) is a 2012 3D South Korean computer-generated epic adventure drama film directed by Han Sang-Ho. The film was released under the title The Dino King in the United States. The Dino King was released alongside a documentary that serves as prequel, Tarbosaurus: The Mightiest Ever, and is followed by Dino King 3D: Journey to Fire Mountain, both also being directed by Han Sang-Ho.

The Truth About Killer Dinosaurs

The Truth About Killer Dinosaurs is a two-part BBC documentary, presented by Bill Oddie, in which a group of scientists test out the strength of dinosaur weaponry using biomechanics. The first episode determines the winner of a battle between Tyrannosaurus and Triceratops, and the second compares the strength of an ankylosaur and Velociraptor. The programmes were broadcast on BBC 1 in August and September 2005. In the US, The Truth About Killer Dinosaurs was known as Dinosaur Face-Off.

Tyrannosauridae

Tyrannosauridae (or tyrannosaurids, meaning "tyrant lizards") is a family of coelurosaurian theropod dinosaurs that comprises two subfamilies containing up to thirteen genera, including the eponymous Tyrannosaurus. The exact number of genera is controversial, with some experts recognizing as few as three. All of these animals lived near the end of the Cretaceous Period and their fossils have been found only in North America and Asia.

Although descended from smaller ancestors, tyrannosaurids were almost always the largest predators in their respective ecosystems, putting them at the apex of the food chain. The largest species was Tyrannosaurus rex, one of the largest known land predators, which measured up to 12.3 metres (40 ft) in length and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight. Tyrannosaurids were bipedal carnivores with massive skulls filled with large teeth. Despite their large size, their legs were long and proportioned for fast movement. In contrast, their arms were very small, bearing only two functional digits.

Unlike most other groups of dinosaurs, very complete remains have been discovered for most known tyrannosaurids. This has allowed a variety of research into their biology. Scientific studies have focused on their ontogeny, biomechanics and ecology, among other subjects. Soft tissue has been reported from one specimen of Tyrannosaurus rex.

Tyrannosaurus

Tyrannosaurus is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex (rex meaning "king" in Latin), often called T. rex or colloquially T-Rex, is one of the most well-represented of the large theropods. Tyrannosaurus lived throughout what is now western North America, on what was then an island continent known as Laramidia. Tyrannosaurus had a much wider range than other tyrannosaurids. Fossils are found in a variety of rock formations dating to the Maastrichtian age of the upper Cretaceous Period, 68 to 66 million years ago. It was the last known member of the tyrannosaurids, and among the last non-avian dinosaurs to exist before the Cretaceous–Paleogene extinction event.

Like other tyrannosaurids, Tyrannosaurus was a bipedal carnivore with a massive skull balanced by a long, heavy tail. Relative to its large and powerful hindlimbs, Tyrannosaurus forelimbs were short but unusually powerful for their size and had two clawed digits. The most complete specimen measures up to 12.3 m (40 ft) in length though T. rex could grow to lengths of over 12.3 m (40 ft), up to 3.66 meters (12 ft) tall at the hips, and according to most modern estimates 8.4 metric tons (9.3 short tons) to 14 metric tons (15.4 short tons) in weight. Although other theropods rivaled or exceeded Tyrannosaurus rex in size, it is still among the largest known land predators and is estimated to have exerted the largest bite force among all terrestrial animals. By far the largest carnivore in its environment, Tyrannosaurus rex was most likely an apex predator, preying upon hadrosaurs, armored herbivores like ceratopsians and ankylosaurs, and possibly sauropods. Some experts have suggested the dinosaur was primarily a scavenger. The question of whether Tyrannosaurus was an apex predator or a pure scavenger was among the longest debates in paleontology. Most paleontologists today accept that Tyrannosaurus was both an active predator and a scavenger.

More than 50 specimens of Tyrannosaurus rex have been identified, some of which are nearly complete skeletons. Soft tissue and proteins have been reported in at least one of these specimens. The abundance of fossil material has allowed significant research into many aspects of its biology, including its life history and biomechanics. The feeding habits, physiology and potential speed of Tyrannosaurus rex are a few subjects of debate. Its taxonomy is also controversial, as some scientists consider Tarbosaurus bataar from Asia to be a second Tyrannosaurus species while others maintain Tarbosaurus is a separate genus. Several other genera of North American tyrannosaurids have also been synonymized with Tyrannosaurus.

As the archetypal theropod, Tyrannosaurus is one of the best-known dinosaurs since the 20th century, and has been featured in film, advertising, postal stamps, and many other media.

Zhuchengtyrannus

Zhuchengtyrannus (meaning "Zhucheng tyrant") is a genus of tyrannosaurid theropod dinosaur known from the Late Cretaceous period of Shandong Province, China. It belongs to the tyrannosaurinae subfamily, and contains a single species, Zhuchengtyrannus magnus.

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