Timeline of tyrannosaur research

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Skeletal mount of the Tyrannosaurus holotype. Tyrannosaurus Rex Holotype.jpg
Skeletal mount of the Tyrannosaurus holotype.

This timeline of tyrannosaur research is a chronological listing of events in the history of paleontology focused on the tyrannosaurs, a group of predatory theropod dinosaurs that began as small, long-armed bird-like creatures with elaborate cranial ornamentation but achieved apex predator status during the Late Cretaceous as their arms shrank and body size expanded. Although formally trained scientists did not begin to study tyrannosaur fossils until the mid-19th century, these remains may have been discovered by Native Americans and interpreted through a mythological lens. The Montana Crow tradition about thunder birds with two claws on their feet may have been inspired by isolated tyrannosaurid forelimbs found locally. [1] Other legends possibly inspired by tyrannosaur remains include Cheyenne stories about a mythical creature called the Ahke, [2] and Delaware stories about smoking the bones of ancient monsters to have wishes granted. [3]


Tyrannosaur remains were among the first dinosaur fossils collected in the United States. The first of these was named Deinodon horridus by Joseph Leidy. However, as this species was based only on teeth the name would fall into disuse. [4] Soon after, Edward Drinker Cope described Laelaps aquilunguis from a partial skeleton in New Jersey. Its discovery heralded the realization that carnivorous dinosaurs were bipeds, unlike the lizardlike megalosaurs sculpted for the Crystal Palace. [5] Laelaps was also among the first dinosaurs to be portrayed artistically as a vigorous, active animal, presaging the Dinosaur Renaissance by decades. [6] Later in the century, Cope's hated rival Othniel Charles Marsh would discover that the name Laelaps had already been given to a parasitic mite, and would rename the dinosaur Dryptosaurus . [7]

Early in the 20th century, Tyrannosaurus itself was discovered by Barnum Brown and named by Henry Fairfield Osborn, who would recognize it as a representative of a distinct family of dinosaurs he called the Tyrannosauridae. [8] Tyrannosaur taxonomy would be controversial for many decades afterward. One controversy centered around the use of the name Tyrannosauridae for this family, as the name "Deinodontidae" had already been proposed. The name Tyrannosauridae came out victorious following arguments put forth by Dale Russell in 1970. [9] The other major controversy regarding tyrannosaur taxonomy was the family's evolutionary relationships. Early in the history of paleontology, it was assumed that the large carnivorous dinosaurs were all part of one evolutionary lineage ("carnosaurs"), while the small carnivorous dinosaurs were part of a separate lineage (coelurosaurs). Tyrannosaurid anatomy led some early researchers like Matthew, Brown, and Huene, to cast doubt on the validity of this division. However, the traditional carnosaur-coelurosaur division persisted until the early 1990s, when the application of cladistics to tyrannosaur systematics confirmed the doubts of early workers and found tyrannosaurs to be large-bodied coelurosaurs. [10]

Another debate about tyrannosaurs would not be settled until the early 21st century: their diet. Early researchers were so overwhelmed by the massive bulk of Tyrannosaurus that some, like Lawrence Lambe, were skeptical that it was even capable of hunting down live prey and assumed that it lived as a scavenger. This view continued to be advocated into the 1990s by Jack Horner but was shown false by Kenneth Carpenter, who reported the discovery of a partially healed tyrannosaur bite wound on an Edmontosaurus annectens tail vertebra, proving that T. rex at least sometimes pursued living victims. [11]


Bones of Dryptosaurus, originally known as Laelaps. DryptosaurusLaelaps.jpg
Bones of Dryptosaurus , originally known as Laelaps .

19th century

Illustration of the teeth of Deinodon. Deinodon.JPG
Illustration of the teeth of Deinodon .




Inaccurate reconstructions of "Laelaps aquilunguis" and Elasmosaurus (1869). Laelaps-cope.jpg
Inaccurate reconstructions of " Laelaps aquilunguis " and Elasmosaurus (1869).





Illustration of the type specimen (AMNH 3982) of Manospondylus gigas Manospondylus.jpg
Illustration of the type specimen (AMNH 3982) of Manospondylus gigas






Leaping Laelaps by Charles R. Knight, 1896. Laelaps-Charles Knight-1897.jpg
Leaping Laelaps by Charles R. Knight, 1896.



20th century

Skeletal reconstruction of T. rex from the original description. Tyrannosaurus skeleton.jpg
Skeletal reconstruction of T. rex from the original description.






Skeleton of Gorgosaurus libratus. Gorgosaurus skeleton AMNH 5428.jpg
Skeleton of Gorgosaurus libratus .




Type specimen of Gorgosaurus sternbergi, now recognized as a juvenile Gorgosaurus libratus. Sharp naturalhistory1920 deinodon.jpg
Type specimen of Gorgosaurus sternbergi, now recognized as a juvenile Gorgosaurus libratus .


Foot of Alectrosaurus olseni. Alectrosaurm olseni.jpg
Foot of Alectrosaurus olseni .








Holotype skull of "Gorgosaurus" (now Nanotyrannus) lancensis. CMNH Nanotyrannus Skull.jpg
Holotype skull of "Gorgosaurus" (now Nanotyrannus ) lancensis.



Holotype skull of Tarbosaurus bataar PIN 551-1, Museum of Paleontology, Moscow. Tarbosaurus holotype skull.jpg
Holotype skull of Tarbosaurus bataar PIN 551-1, Museum of Paleontology, Moscow.







Artist's restoration of Daspletosaurus torosus. Daspletosaurus torDB.jpg
Artist's restoration of Daspletosaurus torosus .



Skeletal mount of Alioramus remotus. Texas Alioramus.jpg
Skeletal mount of Alioramus remotus .







A juvenile Tarbosaurus. Tarbosaurus specimen MPC-D 100 7.jpg
A juvenile Tarbosaurus .



Holotype skull of Nanotyrannus lancensis. CMNH Nanotyrannus Skull.jpg
Holotype skull of Nanotyrannus lancensis .





Tyrannosaurs had long been classified with carnosaurs like Allosaurus (pictured). In the 1990s, this consensus began to change. Allosaurus SDNHM.jpg
Tyrannosaurs had long been classified with carnosaurs like Allosaurus (pictured). In the 1990s, this consensus began to change.


Paleontologists like Abler studied tyrannosaur tooth biomechanics (Tyrannosaurus teeth pictured) in the early 1990s. B-rex teeth.jpg
Paleontologists like Abler studied tyrannosaur tooth biomechanics (Tyrannosaurus teeth pictured) in the early 1990s.





Lockley and Hunt reported a possible T. rex footprint in 1994. Philmont Scout Ranch Tyrannosaurus footprint.jpg
Lockley and Hunt reported a possible T. rex footprint in 1994.


The known skeletal elements of Bagaraatan ostromi. Bagaraatan outline.jpg
The known skeletal elements of Bagaraatan ostromi .




Skeletal mount of Santanaraptor placidus. Santanaraptor.jpg
Skeletal mount of Santanaraptor placidus .


21st century


Edmontosaurus annectens tail vertebrae have been preserved with partially healed T. rex bite marks. DMNS Edmontosaurus.png
Edmontosaurus annectens tail vertebrae have been preserved with partially healed T. rex bite marks.


Known skeletal elements of Eotyrannus lengi. Eotyrannus remains 01.png
Known skeletal elements of Eotyrannus lengi .


Diagram of T. rex forelimb anatomy. Tyrannosaur arm 104.JPG
Diagram of T. rex forelimb anatomy.

Thomas R. Holtz, Jr. published a cladistic analysis of the Tyrannosauridae. [26] Holtz defined the Tyrannosauridae in his analysis as "all descendants of the most recent common ancestor of Tyrannosaurus and Aublysodon." [10] He concluded that the Tyrannosauridae had two subfamilies, a more primitive Aublysodontinae and the tyrannosaurinae. [26] He defined the former as "Aublysodon and all taxa sharing a more recent common ancestor with it than with Tyrannosaurus." [27]

Jaws and teeth of Gorgosaurus. Drumheller 150 cropped.jpg
Jaws and teeth of Gorgosaurus .

He observed that these dinosaurs were distinguished by their unserrated premaxillary teeth. [26] The Tyrannosaurinae he defined as "Tyrannosaurus and all taxa sharing a more recent common ancestor with it than with Aublysodon." [27]

Holtz considered these definitions only tentative due to the scant remains representing most taxa in the Aublysodontinae. [28] Holtz also noted that the lack of serrations on aublyodontines' premaxillary teeth could have been caused by tooth wear in life, postmortem abrasion, or digestion. [29] Alternatively "Aublysodontine"-type teeth could be from an ontogenetic stage or sexual morph of another kind of tyrannosaur. [29] Holtz also expressed the taxonomic opinion that Nanotyrannus lancensis was a juvenile T. rex. [10] The results of his phylogenetic analysis of the Tyrannosauridae are reproduced below:


Skeletal mount of Appalachiosaurus. Appalachiosaurus.jpg
Skeletal mount of Appalachiosaurus .




Artist's restoration of Guanlong. Guanlong wucaii head.jpg
Artist's restoration of Guanlong .




Artist's restoration of Xiongguanlong. Xiongguanlong NT.jpg
Artist's restoration of Xiongguanlong .



Artist's restoration of Yutyrannus. Feathered tyrant by pilsator-d4vbemk.jpg
Artist's restoration of Yutyrannus .



Artist's restoration of Nanuqsaurus. Nanuqsaurus.png
Artist's restoration of Nanuqsaurus .
Artist's restoration of Moros intrepidus. Moros intrepidus reconstruction.png
Artist's restoration of Moros intrepidus .









See also


  1. Mayor (2005); "Crow Fossil Collectors," page 276.
  2. 1 2 Mayor (2005); "Cheyenne Fossil Knowledge," pages 211–212.
  3. 1 2 Mayor (2005); "Smoking the Monster's Bone: An Ancient Delaware Fossil Legend," pages 68–69.
  4. Horner (2001); "History of Dinosaur Collecting in Montana," page 44.
  5. For the implications of Dryptosaurus for theropod gait, see Holtz (2004); "Introduction", page 111. For a characterization of the Crystal Palace theropods, see Bakker (2004); page 3.
  6. Brett-Surman (1999); "1897," page 713.
  7. Moore (2014); "1866," page 62.
  8. For the discovery of T. rex, see Horner (2001); "History of Dinosaur Collecting in Montana," page 48. For the erection of the Tyrannosauridae, see Holtz (2004); "Introduction", page 114.
  9. 1 2 3 4 5 6 7 8 Holtz (2004); "Introduction", page 114.
  10. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 Holtz (2004); "Systematics and Evolution", page 127.
  11. 1 2 3 4 5 6 7 8 Holtz (2004); "Paleobiology", pages 134–135.
  12. 1 2 3 4 5 6 7 8 9 10 11 Holtz (2004); "Table 5.1: Tyrannosauroidea", page 114.
  13. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Holtz (2004); "Table 5.1: Tyrannosauroidea", page 112.
  14. 1 2 Holtz (2004); "Introduction", page 111.
  15. Tanke (2010); "Background and Collection History," page 542.
  16. 1 2 3 4 5 6 7 8 9 10 11 12 13 Holtz (2004); "Table 5.1: Tyrannosauroidea", page 113.
  17. "Barnum Brown". Strange Science. 2015-06-14. Retrieved 2017-12-12.
  18. 1 2 3 4 5 6 7 8 9 10 11 12 13 Holtz (2004); "Paleobiology", page 134.
  19. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Holtz (2004); "Paleobiology", page 135.
  20. Chicago Field Museum - All About Sue
  21. Holtz (2004); "Paleobiology", pages 135–136.
  22. Holtz (2004); "Systematics and Evolution", page 133.
  23. Holtz (2004); "Systematics and Evolution", page 128.
  24. 1 2 Carpenter and Smith (2001); "Abstract," page 90.
  25. Carpenter and Smith (2001); "Introduction," page 91.
  26. 1 2 3 Holtz (2001); "Abstract," page 64.
  27. 1 2 Holtz (2001); "Results," page 66.
  28. Holtz (2001); "Results," page 66-67.
  29. 1 2 Holtz (2001); "Results," page. 67.
  30. 1 2 Abler (2001); "Abstract," page 84.
  31. Abler (2001); "Kerf-and-Drill Model," page 86.
  32. Abler (2001); "Kerf-and-Drill Model," pages 86–88.
  33. Abler (2001); "Introduction," page 84.
  34. Jacobsen (2001); "Abstract," page 58.
  35. Jacobsen (2001); "Introduction," page 59.
  36. Jacobsen (2001); "Discussion," page 61.
  37. Jacobsen (2001); "Discussion," page 60.
  38. Rauhut (2003); "Abstract," page 903.
  39. Xu et al. (2004); "Abstract," page 680.
  40. Carr, Williamson, and Schwimmer (2005); "Abstract," page 119.
  41. Carpenter, Miles, and Cloward (2005); "Abstract," page 23.
  42. Xu et al. (2006); "Abstract," page 715.
  43. Sereno et al. (2009); "Abstract," page 418.
  44. Ji, Ji, and Zhang (2009); "Abstract," page 1369.
  45. Carr and Williamson (2010); "Abstract," page 1.
  46. Averianov, Krasnolutskii, and Ivantsov (2010); "Abstract," page 42.
  47. Li et al. (2010); "Abstract," page 183.
  48. Carr et al. (2011); "Abstract," page 241.
  49. Hone et al. (2011); "Abstract," page 495.
  50. Xu et al. (2012); "Abstract," page 92.
  51. Brusatte and Benson (2013); "Abstract," page 47.
  52. Loewen et al. (2013); "Abstract," page 1.
  53. Fiorillo and Tykoski (2014); "Abstract," page 1.
  54. Lü et al. (2014); "Abstract," page 1.
  55. Hill (2015); in passim.
  56. Brusatte et al. (2016); in passim.
  57. Carr, Thomas D.; Varricchio, David J.; Sedlmayr, Jayc C.; Roberts, Eric M.; Moore, Jason R. (2017). "A new tyrannosaur with evidence for anagenesis and crocodile-like facial sensory system". Scientific Reports. 7: 44942. Bibcode:2017NatSR...744942C. doi:10.1038/srep44942. PMC   5372470 . PMID   28358353.
  58. McDonald, A.T.; Wolfe, D.G.; Dooley Jr, A.C. (2018). "A new tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous Menefee Formation of New Mexico". PeerJ. 6: 6:e5749. doi:10.7717/peerj.5749. PMC   6183510 . PMID   30324024.
  59. Zanno, L.E.; Tucker, R.T.; Canoville, A.; Avrahami, H.M.; Gates, T.A.; Makovicky, P.J. (2019). "Diminutive fleet-footed tyrannosauroid narrows the 70-million-year gap in the North American fossil record". Communications Biology. 2 (64): 64. doi:10.1038/s42003-019-0308-7. PMC   6385174 . PMID   30820466.
  60. Martin Kundrát; Xing Xu; Martina Hančová; Andrej Gajdoš; Yu Guo; Defeng Chen (2019). "Evolutionary disparity in the endoneurocranial configuration between small and gigantic tyrannosauroids". Historical Biology: An International Journal of Paleobiology. 32 (5): 620–634. doi:10.1080/08912963.2018.1518442. S2CID   91373963.
  61. Eric Snively; Haley O’Brien; Donald M. Henderson; Heinrich Mallison; Lara A. Surring; Michael E. Burns; Thomas R. Holtz Jr; Anthony P. Russell; Lawrence M. Witmer; Philip J. Currie; Scott A. Hartman; John R. Cotton (2019). "Lower rotational inertia and larger leg muscles indicate more rapid turns in tyrannosaurids than in other large theropods". PeerJ. 7: e6432. doi:10.7717/peerj.6432. PMC   6387760 . PMID   30809441.
  62. Tomoya Hanai; Takanobu Tsuihiji (2019). "Description of tooth ontogeny and replacement patterns in a juvenile Tarbosaurus bataar (Dinosauria: Theropoda) using CT‐scan data". The Anatomical Record. 302 (7): 1210–1225. doi: 10.1002/ar.24014 . PMID   30378771. S2CID   53109996.
  63. Ingmar Werneburg; Borja Esteve-Altava; Joana Bruno; Marta Torres Ladeira; Rui Diogo (2019). "Unique skull network complexity of Tyrannosaurus rex among land vertebrates". Scientific Reports. 9 (1): Article number 1520. Bibcode:2019NatSR...9.1520W. doi:10.1038/s41598-018-37976-8. PMC   6365547 . PMID   30728455.
  64. Joseph E. Peterson; Karsen N. Daus (2019). "Feeding traces attributable to juvenile Tyrannosaurus rex offer insight into ontogenetic dietary trends". PeerJ. 7: e6573. doi:10.7717/peerj.6573. PMC   6404657 . PMID   30863686.
  65. W. Scott Persons IV; Philip J. Currie; Gregory M. Erickson (2019). "An older and exceptionally large adult specimen of Tyrannosaurus rex". The Anatomical Record. 303 (4): 656–672. doi: 10.1002/ar.24118 . PMID   30897281.
  66. "Tiny "Coyote of the Cretaceous" Fills a Gap in the Tyrannosaur Tree". PBS.
  67. Voris, Jared T.; Zelenitsky, Darla K.; Therrien, François; Currie, Philip J. (2019-11-28). "Reassessment of a juvenile Daspletosaurus from the Late Cretaceous of Alberta, Canada with implications for the identification of immature tyrannosaurids". Scientific Reports. 9 (1): 17801. Bibcode:2019NatSR...917801V. doi:10.1038/s41598-019-53591-7. ISSN   2045-2322. PMC   6882908 . PMID   31780682.
  68. Wu Xiao-chun; Shi Jian-Ru; Dong Li-Yang; Thomas D. Carr; Yi Jian; Xu Shi-Chao (2019). "A new tyrannosauroid from the Upper Cretaceous of Shanxi, China". Cretaceous Research. 108: Article 104357. doi:10.1016/j.cretres.2019.104357. S2CID   214354354.
  69. Voris, Jared T.; Therrien, Francois; Zelenitzky, Darla K.; Brown, Caleb M. (2020). "A new tyrannosaurine (Theropoda:Tyrannosauridae) from the Campanian Foremost Formation of Alberta, Canada, provides insight into the evolution and biogeography of tyrannosaurids". Cretaceous Research. 110: 104388. doi:10.1016/j.cretres.2020.104388. S2CID   213838772.

Related Research Articles

<i>Albertosaurus</i> Genus of bipedal predatory dinosaur

Albertosaurus is a genus of large tyrannosaurid theropod dinosaur that lived in northwestern North America during the early to middle Maastrichtian age of the Late Cretaceous period, about 71 million years ago. The type species, A. sarcophagus, was apparently restricted in range to the modern-day Canadian province of Alberta, after which the genus is named, although an indeterminate species has been discovered in the Corral de Enmedio and Packard Formations of Mexico. Scientists disagree on the content of the genus and some recognize Gorgosaurus libratus as a second species.(citation needed)

<i>Tyrannosaurus</i> Genus of Late Cretaceous theropod

Tyrannosaurus is a genus of large theropod dinosaur. The species Tyrannosaurus rex, often called T. rex or colloquially T-Rex, is one of the best represented theropods. It 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.

<span class="mw-page-title-main">Tyrannosauridae</span> Family of dinosaurs

Tyrannosauridae 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.

<i>Tarbosaurus</i> Tyrannosaurid dinosaur genus from Late Cretaceous of Mongolia

Tarbosaurus is a genus of tyrannosaurine theropod dinosaur that lived in Asia about 70 million years ago, during the Maastrichtian age at the end of the Late Cretaceous period, considered to contain a single known species: Tarbosaurus bataar. Fossils have been recovered from the Nemegt Formation of Mongolia, with more fragmentary remains found further afield in the Subashi Formation of China.

<i>Daspletosaurus</i> Genus of tyrannosaurid dinosaur from Late Cretaceous period

Daspletosaurus is a genus of tyrannosaurid dinosaur that lived in Laramidia between about 77 and 75 million years ago, during the Late Cretaceous Period. The genus Daspletosaurus contains three species. Fossils of the earlier type species, D. torosus, have been found in Alberta, and fossils of a later second species, D. wilsoni, and third species, D. horneri, have been found only in Montana. A possible fourth species, also from Alberta, awaits formal identification. The taxon Thanatotheristes has been suggested to represent a species of Daspletosaurus, D. degrootorum, but this has not been widely supported. Daspletosaurus is closely related to the much larger and more recent tyrannosaurid Tyrannosaurus rex. Like most tyrannosaurids, Daspletosaurus was a multi-tonne bipedal predator equipped with dozens of large, sharp teeth. Daspletosaurus had the small forelimbs typical of tyrannosaurids, although they were proportionately longer than in other genera.

<i>Dilong paradoxus</i> Extinct species of dinosaur

Dilong is a genus of basal tyrannosauroid dinosaur. The only species in this genus is Dilong paradoxus. It is from the Lower Cretaceous Yixian Formation near Lujiatun, Beipiao, in the western Liaoning province of China. It lived about 126 million years ago. This theropod discovery was significant as it was one of the first tyrannosauroids with fossil evidence of simple feathers.

<i>Gorgosaurus</i> Genus of tyrannosaur dinosaur

Gorgosaurus is a genus of tyrannosaurid theropod dinosaur that lived in western North America during the Late Cretaceous Period (Campanian), between about 76.6 and 75.1 million years ago. Fossil remains have been found in the Canadian province of Alberta and the U.S. state of Montana. Paleontologists recognize only the type species, G. libratus, although other species have been erroneously referred to the genus.

<span class="mw-page-title-main">Coelurosauria</span> Clade of dinosaurs

Coelurosauria is the clade containing all theropod dinosaurs more closely related to birds than to carnosaurs.

<i>Aublysodon</i> Extinct genus of dinosaurs

Aublysodon is a genus of carnivorous dinosaurs known only from the Judith River Formation in Montana, which has been dated to the late Campanian age of the late Cretaceous period. The only currently recognized species, Aublysodon mirandus, was named by paleontologist Joseph Leidy in 1868. It is sometimes considered dubious now, because the type specimen consists only of an isolated premaxillary (front) tooth. Although this specimen is now lost, similar teeth have been found in many US states, western Canada, and Asia. These teeth almost certainly belong to juvenile tyrannosaurine tyrannosaurids, but most have not been identified to species level. However, it is likely that the type tooth belongs to one of the species in the genus Daspletosaurus, which was present in contemporary formations, and which matches specific details of the original tooth. The synapomorphies alleged to distinguish the Aublysodontinae, especially lack of serrations on premaxillary teeth could have been caused by tooth wear in life, postmortem abrasion, or digestion. Most other "aublysodontine"-type teeth may be from ontogenetic stages or sexual morphs of other tyrannosaurids.

<i>Alectrosaurus</i> Extinct genus of dinosaurs

Alectrosaurus is a genus of tyrannosauroid theropod dinosaur that lived in Asia during the Late Cretaceous period, about some 96 million years ago in what is now the Iren Dabasu Formation.

<i>Alioramus</i> Tyrannosaurid theropod dinosaur genus from the Late Cretaceous period

Alioramus is a genus of tyrannosaurid theropod dinosaurs from the Late Cretaceous period of Asia. It currently contains two species. The type species, A. remotus is known from a partial skull and three foot bones recovered from the Mongolian Nemegt Formation, which was 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 also from the Nemegt Formation, was named and described by Stephen L. Brusatte and colleagues in 2009. Its relationships to other tyrannosaurid genera were at first unclear, with some evidence supporting a hypothesis that Alioramus was closely related to the contemporary species Tarbosaurus bataar. However, the discovery of Qianzhousaurus indicates that it belongs to a distinct branch of tyrannosaurs, namely the tribe Alioramini.

<i>Siamotyrannus</i> Extinct genus of dinosaurs

Siamotyrannus is a genus of theropod dinosaur from the early Cretaceous of Thailand.

<span class="mw-page-title-main">Tyrannosauroidea</span> Extinct superfamily of dinosaurs

Tyrannosauroidea is a superfamily of coelurosaurian theropod dinosaurs that includes the family Tyrannosauridae as well as more basal relatives. Tyrannosauroids lived on the Laurasian supercontinent beginning in the Jurassic Period. By the end of the Cretaceous Period, tyrannosauroids were the dominant large predators in the Northern Hemisphere, culminating in the gigantic Tyrannosaurus. Fossils of tyrannosauroids have been recovered on what are now the continents of North America, Europe and Asia, with fragmentary remains possibly attributable to tyrannosaurs also known from South America and Australia.

<i>Dryptosaurus</i> Extinct genus of reptiles

Dryptosaurus is a genus of basal eotyrannosaurian theropod dinosaur that lived on the island continent of Appalachia approximately 67 million years ago during the end of the Maastrichtian age of the Late Cretaceous period. Dryptosaurus was a large, bipedal, ground-dwelling carnivore that could grow up to 7.5 metres (25 ft) long and weigh up to 1.5 metric tons. Although it is now largely unknown outside of academic circles, the famous 1897 painting of the genus by Charles R. Knight made Dryptosaurus one of the more widely known dinosaurs of its time, in spite of its poor fossil record. First described by Edward Drinker Cope in 1866 and later renamed by Othniel Charles Marsh in 1877, Dryptosaurus is among the very first theropod dinosaurs ever known to science.

<i>Deinodon</i> Extinct genus of dinosaurs

Deinodon is a dubious tyrannosaurid dinosaur genus containing a single species, Deinodon horridus. D. horridus is known only from a set of teeth found in the Late Cretaceous Judith River Formation of Montana and named by paleontologist Joseph Leidy in 1856. These were the first tyrannosaurid remains to be described and had been collected by Ferdinand Vandeveer Hayden. The teeth of Deinodon were slightly heterodont, and the holotype of Aublysodon can probably be assigned to Deinodon.

<span class="mw-page-title-main">Tyrannosaurinae</span> Extinct subfamily of dinosaurs

Tyrannosaurinae is one of the two extinct subfamilies of Tyrannosauridae, a family of coelurosaurian theropods that consists of at least three tribes and several genera. All fossils of these genera have been found in the Late Cretaceous deposits of western North America and east Asia. Compared to the related subfamily Albertosaurinae, tyrannosaurines overall are more robust and larger though the alioramins were gracile by comparison. This subfamily also includes the oldest known tyrannosaurid genus Lythronax as well as the youngest and most famous member of the group, Tyrannosaurus rex.

<span class="mw-page-title-main">Albertosaurinae</span> Extinct subfamily of dinosaurs

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 the 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.

<i>Bistahieversor</i> Extinct genus of dinosaurs

Bistahieversor, also known as the "Bisti Beast", is a genus of basal eutyrannosaurian theropod dinosaur. The genus contains only a single known species, B. sealeyi, described in 2010, from the Late Cretaceous of New Mexico. The holotype and a juvenile were found in the Hunter Wash Member of the Kirtland Formation, while other specimens came from the underlying Fossil Forest member of the Fruitland Formation. This dates Bistahieversor approximately 75.5 to 74.5 million years ago during the Campanian age, found in sediments spanning a million years.

<i>Lythronax</i> Genus of tyrannosaurid dinosaur from the Late Cretaceous period

Lythronax is a genus of tyrannosaurid dinosaur that lived in North America around 81.9-81.5 million years ago during the Late Cretaceous period. The only known specimen was discovered in Utah in the Wahweap Formation of the Grand Staircase–Escalante National Monument in 2009, and it consists of a partial skull and skeleton. In 2013, it became the basis of the new genus and species Lythronax argestes; the generic name Lythronax means "gore king", and the specific name argestes originates from the Greek poet Homer's name for the wind from the southwest, in reference to the specimen's geographic provenance in North America.

<i>Timurlengia</i> Extinct genus of dinosaurs

Timurlengia is an extinct genus of tyrannosauroid theropod dinosaur found in Uzbekistan, in the Bissekty Formation in the Kyzylkum Desert, hailing from the Turonian age of the early Late Cretaceous. The type species is Timurlengia euotica.