Timeline of tyrannosaur research

Source: Wikipedia, the free encyclopedia.

Skeletal mount of the Tyrannosaurus holotype.

This timeline of tyrannosaur research is a chronological listing of events in the

Delaware stories about smoking the bones of ancient monsters to have wishes granted.[3]

Tyrannosaur remains were among the first dinosaur

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

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

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]

Prescientific

Laelaps
.

19th century

Illustration of the teeth of Deinodon.

1850s

1856

  • Deinodon horridus.[12]

1860s

(1869).

1865

  • Leidy described the new genus and species
    Tomodon horrificus.[12]

1866

  • Laelaps aquilunguis.[13] This discovery proved that theropod dinosaurs walked on their hind limbs rather than on all fours like in earlier reconstructions.[14] He also erected the family Deinodontidae.[9]

1868

1870s

type specimen
(AMNH 3982) of Manospondylus gigas

1876

1877

  • Laelaps aquilunguis.[13]

1880s

1884

  • Joseph Burr Tyrrell discovered a partial Albertosaurus skull near Kneehills Creek in Alberta, Canada. This specimen is now catalogued as CMN 5600.[15]

1890s

Leaping Laelaps by Charles R. Knight, 1896.

1890

  • Marsh described the new species
    Ornithomimus grandis.[16]

1892

20th century

Skeletal reconstruction of T. rex from the original description.

1900s

1900

1902

1905

  • Dynamosaurus imperiosus.[16]

1910s

Gorgosaurus libratus
.

1914

1917

  • Lambe interpreted tyrannosaurids as
    scavengers.[11]

1920s

Gorgosaurus libratus
.

1922

  • Matthew and Brown named the
    coelurosaurs.[10]
Alectrosaurus olseni
.

1923

  • Matthew and Brown described the new species
    Gorgosaurus sternbergi.[13] They still regarded tyrannosaurs as members of the family Deinodontidae.[9]
  • Friedrich von Huene regarded tyrannosaurs as members of the family Deinodontidae[9] and advocated for the hypothesis that tyrannosaurs were more closely related to the small carnivores called coelurosaurs than to other large carnivorous dinosaurs like Allosaurus and Megalosaurus.[10]

1928

  • Albertosaurus arctunguis.[13]

1930s

1930

  • Albertosaurus periculosus.[16]

1932

  • Von Huene classified tyrannosaurs as carnosaurs.[10]

1933

  • Alectrosaurus olseni.[16]

1940s

Nanotyrannus
) lancensis.

1946

  • Gilmore described the new species
    Gorgosaurus lancensis.[16]

1950s

Tarbosaurus bataar PIN 551-1, Museum of Paleontology, Moscow
.

1955

1956

  • Alfred Sherwood Romer classified tyrannosaurs as carnosaurs.[10]

1958

1960s

1964

1970s

Daspletosaurus torosus
.

1970

1974

Alioramus remotus
.

1975

1976

  • Itemirus medullaris.[12]

1977

  • Shanshanosaurus huoyanshanensis.[16]

1978

1979

  • Dong described the new genus and species
    Tyrannosaurus luanchuanensis.[12]

1980s

A juvenile Tarbosaurus.

1980

  • Halszka Osmólska reported multiple Tarbosaurus of different life stages found preserved together in the same deposit.[18]

1981

Nanotyrannus lancensis
.

1983

1986

  • Jacques Gauthier classified tyrannosaurs as carnosaurs.[10]
  • Robert T. Bakker interpreted the "ornamentation" seen on the snouts and around the eyes of many tyrannosaurs were displays for other members of the same tyrannosaur species.[18]

1988

1990s

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

1990

  • José Bonaparte and others classified tyrannosaurs as carnosaurs.[10]
  • Molnar classified tyrannosaurs as carnosaurs.[10]
Paleontologists like Abler studied tyrannosaur tooth biomechanics (Tyrannosaurus teeth pictured) in the early 1990s.

1991

  • Farlow and others studied tyrannosaur tooth biomechanics, finding them to be more resistant to forces in both the front-to-back and side-to-side planes than the more blade-like teeth of other carnivorous dinosaurs.[19]
  • Scotty the T. rex is discovered near Eastend, Saskatchewan.

1992

1993

1994

Lockley and Hunt reported a possible T. rex footprint in 1994.
  • Pérez-Moreno and others performed another phylogenetic analysis of the Tyrannosauridae and found additional support for reclassifying the family as coelurosaurs.[10] They found tyrannosaurids to lie outside of the Maniraptoriformes. In other words, they are less closely related to birds than the ostrich dinosaurs are.[10]
  • Thomas Holtz performed another phylogenetic analysis of the Tyrannosauridae and found additional support for reclassifying the family as coelurosaurs.[10] He found that within the coelurosaurs, tyrannosaurs were arctometatarsalians. In other words, they were more closely related to the ostrich dinosaurs than to birds.[10]
  • Horner interpreted tyrannosaurids as scavengers.[11]
  • Martin Lockley and Hunt described a possible Tyrannosaurus footprint.[19]

1995

  • Emily B. Giffin observed that the brachial plexus of the tyrannosaurid neural canal was smaller than those of other theropods, suggesting that tyrannosaurids really did have reduced forlimb function.[19]
  • Farlow and others calculated that an adult T. rex running at 20 m/s or faster would sustain fatal injuries if it tripped, suggesting that they didn't actually run that fast.[21]
Bagaraatan ostromi
.
  • Holtz observed that tyrannosaurids had the longest limbs relative to their body size of any theropod dinosaurs apart from the ostrich dinosaurs and a small, slender
    ceratosaur called Elaphrosaurus. Although the ostrich dinosaur on average had relatively longer limbs overall, the ratios of femur length to the length of the tibia and fibula were actually very close between the smaller tyrannosaurs and the largest ostrich dinosaurs. Holtz found ostrich dinosaurs and tyrannosaurs to have other traits of the hindlimb in common as well. Both groups had a pinched third metatarsal, called an arctometatarsus, that strengthened the foot. Holtz concluded that these traits indicated that tyrannosaurids were among the best adapted for running of all carnivorous dinosaurs.[19]

1996

1997

  • Richard Cifelli and others reported teeth from Utah that exhibited the distinctive thickening characterizing tyrannosaurid teeth that date back to the Albian-Cenomanian boundary. As such, they were the oldest known tyrannosaurid teeth.[18]
  • Kirkland and others reported teeth from Utah that exhibited the distinctive thickening characterizing tyrannosaurid teeth that date back to the Albian-Cenomanian boundary. As such, they were the oldest known tyrannosaurid teeth.[18]
  • Sereno concluded that the evolutionary history of tyrannosaurids suggested a relatively complex history of biogeographic dispersal between Asia and North America.[18]
  • Horner and Dobb interpreted tyrannosaurids as scavengers.[11]

1998

  • Sereno performed another phylogenetic analysis of the Tyrannosauridae and found additional support for reclassifying the family as coelurosaurs. He defined the tyrannosauridae as all tyrannosauroids closer to Tyrannosaurus than to Alectrosaurus, Aublysodon, or Nanotyrannus.[10]
  • Catherine Forster and others performed another phylogenetic analysis which provided further support for the idea that tyrannosaurs are coelurosaurs, but less closely related to birds than ornithomimosaurs.[10]
  • Peter Makovicky and Hans-Dieter Sues performed another phylogenetic analysis which provided further support for the idea that tyrannosaurs are coelurosaurs, but less closely related to birds than ornithomimosaurs.[10]
Santanaraptor placidus
.
  • Karen Chin and others reported a coprolite preserved in the Frenchman Formation of Saskatchewan that may have been left behind by Tyrannosaurus. The coprolite contained the partially digested bone fragments of the ornithischian dinosaurs it fed upon.[18] These bones composed 30–50% of its total volume.[19]
  • Holtz found that within the coelurosaurs, tyrannosaurs were arctometatarsalians. In other words, they were more closely related to the ornithomimosaurs than to birds.[10]

1999

  • Santanaraptor placidus.[12] Santanaraptor is a possible tyrannosauroid. If so, it is the only known member of the group that would have inhabited the super continent of Gondwana.[22]
  • Thomas Carr argued that Nanotyrannus was actually just a young Tyrannosaurus.[10] He noticed that adult T. rex had fewer and more widely spaced teeth in the front tip of their jaws than juvenile T. rex or tyrannosaurs of other species, suggesting differences in feeding within and between tyrannosaur species.[19]
  • Sereno performed another phylogenetic analysis of the Tyrannosauridae. He found that tyrannosaurs were closer to maniraptorans than Ornithomimosaurs were. He called the Tyrannosaur-Maniraptoran clade "
    Tyrannoraptora".[10]
  • Günter P. Wagner and Gauthier performed a phylogenetic analysis of the tyrannosaurs but found them equally related to the ornithomimosaurs and maniraptorans.[10]

21st century

2000s

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

2000

  • Oliver Walter Mischa Rauhut reported the presence of Stokesosaurus or an extremely close relative in Portugal.[23]
  • Carpenter reported a partially healed bite wound on a tail vertebra of an Edmontosaurus annectens, the size and shape of which suggested that it had been inflicted by Tyrannosaurus rex.[19]
  • Carr and Williamson observed that tyrannosaurines were the most common type of tyrannosaurid in the southwestern US during the Campanian and Maastrichtian.[18]
  • Phil Currie reported the discovery of at least nine Albertosaurus of different age groups preserved together in the same deposit. He speculated that if these animals were part of a social group, that members of different ages might perform different tasks in the course of a hunt. This interpretation derives by analogy from the behavior of modern pack hunting carnivorous mammals.[18]
Eotyrannus lengi
.
  • Mark Norell and others found tyrannosaurids to lie outside of the Maniraptoriformes. In other words, they are less closely related to birds than the ostrich dinosaurs are.[10]

2001

Diagram of T. rex forelimb anatomy.
  • David Varrichio and others reported a Daspletosaurus specimen from the Two Medicine Formation of Montana. This specimen notably preserved the contents of the animal's gut when it died, including fragments of bone from young ornithischian dinosaurs.[18]
  • Foster and others observed that no other theropod inhabiting Asia or North America during the Campanian or Maastrichtian achieved a body size within "two orders of magnitude" of contemporary tyrannosaurs.~paleobio133-134~ They further speculated that this gap in body size may be attributable to juvenile tyrannosaurs occupying the ecological niches once exploited by other medium-to-large sized theropods.[18]
  • Holtz found that within the coelurosaurs, tyrannosaurs were arctometatarsalians; meaning they were closer to ornithomimosaurs than to birds.[10]

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.

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:

  • William L. Abler studied tyrannosaur tooth serration biomechanics.
    tooth serrations are so thin that they are practically a shallow crack in the tooth.[30] However, at the base of each serration is round void called an ampulla which would have functioned to distribute force over a larger surface area, hindering the ability of the "crack" formed by the serration to propagate through the tooth.[30]
    Teeth of Aublysodon.
    This form resembles techniques used by guitar makers to "impart alternating regions of flexibility and rigidity" to wood.[31] As a proof of concept demonstrated that a plexiglass bar bearing regular incisions ending in drilled holes was more than 25% stronger than one with only regularly placed incisions.[32] Abler interpreted tyrannosaurid teeth as holdfasts for pulling meat off a body, rather than knife-like cutting implements.[33]
  • formation's tyrannosaurids, like Gorgosaurus, Daspletosaurus, or Aublysodon.[36] All of the marks on the jawbone seem to have been left by the same animal because the serration marks all share the same morphology.[37]

2002

  • Brochu observed that the only distinguishing character of Aublysodon was the lack of serrations on its teeth, and that this condition might actually be due to damage sustained after the death of the animal. As such, he deemed that Aublysodon made a poor choice of anchor taxon for the Tyrannosauridae.[10]
  • Farlow and Holtz published a study concluding that the ancient ecology of tyrannosaur habitats and morphology of tyrannosaur bodies were inconsistent with the idea that they were scavengers.[19]
  • Holtz published a study concluding that the ancient ecology of tyrannosaur habitats and morphology of tyrannosaur bodies were inconsistent with the idea that they were scavengers.[19] He also suggested that the tyrannosaur skull was subjected to greater torsional forces hunting and/or feeding than the skulls of other large carnivorous dinosaurs like allosaurs and ceratosaurs. He interpretd the breadth of the tyrannosaur skull and high development of its secondary palate as adaptations for enduring these forces.[19] He theorized that tyrannosaurids exploited a similar hunting tactic to modern wolves and hyenas by running after prey and attacking it with their jaws. This tactic would distinguish tyrannosaurid hunting behavior from that of modern big cats, who depend more heavily on their forelimbs to take down prey.[19]
  • Carrano and Hutchinson tried to reconstruct the life musculature of T. rex.[19]
  • Hutchinson and Garcia used the reconstruction of T. rex musculature produced by Carrano and Hutchinson to ascertain its running abilities. They found that T. rex was not muscular enough for its body size to run quickly.[19]
  • Hunt coined the name "
    Fusinasus
    ".
Skeletal mount of Appalachiosaurus.

2003

  • Currie interpreted Nanotyrannus lancensis as a juvenile T. rex.[10] Currie argued that the type specimen of Alectrosaurus olseni was too incomplete to ascertain its position in the tyrannosaur family tree.[10]
  • Rauhut described the new genus and species Aviatyrannis.[38]

2004

2005

  • T. D. Carr, T. E. Williamson, D. R. Schwimmer described the new genus and species Appalachiosaurus.[40]
Artist's restoration of Guanlong.
  • K. Carpenter, C. Miles, and K. Cloward described the new genus and species Tanycolagreus.[41]

2006

  • Xu and others described the new genus and species Guanlong.[42]

2009

  • Sereno et al. described the new genus and species Raptorex.[43]
  • Q. Ji, S.-A. Ji, and L.-J. Zhang described the new genus and species Sinotyrannus.[44]

2010s

Artist's restoration of Xiongguanlong.

2010

2011

  • Carr and others described the new genus and species
    Teratophoneus curriei.[48]
Artist's restoration of Yutyrannus.
  • Hone and others described the new genus and species
    Zhuchengtyrannus magnus.[49]

2012

  • Xu and others described the new genus and species
    Yutyrannus huali.[50]

2013

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

2014

2015

  • The
    Steven Brusatte autopsying a life-size model of Tyrannosaurus rex.[55]

2016

  • Brusatte and others described the new genus and species
    Timurlengia euotica.[56]

2017

2018

  • McDonald and others described the new genus and species
    Dynamoterror dynastes.[58]

2019

2020s

2020

See also

Footnotes

  1. ^ Mayor (2005); "Crow Fossil Collectors," page 276.
  2. ^ a b Mayor (2005); "Cheyenne Fossil Knowledge," pages 211–212.
  3. ^ a b 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. ^ a b c d e f g h Holtz (2004); "Introduction", page 114.
  10. ^ a b c d e f g h i j k l m n o p q r s t u v w x y z aa ab ac ad ae af Holtz (2004); "Systematics and Evolution", page 127.
  11. ^ a b c d e f g h Holtz (2004); "Paleobiology", pages 134–135.
  12. ^ a b c d e f g h i j k Holtz (2004); "Table 5.1: Tyrannosauroidea", page 114.
  13. ^ a b c d e f g h i j k l m n Holtz (2004); "Table 5.1: Tyrannosauroidea", page 112.
  14. ^ a b Holtz (2004); "Introduction", page 111.
  15. ^ Tanke (2010); "Background and Collection History," page 542.
  16. ^ a b c d e f g h i j k l m Holtz (2004); "Table 5.1: Tyrannosauroidea", page 113.
  17. ^ "Barnum Brown". Strange Science. 2015-06-14. Retrieved 2017-12-12.
  18. ^ a b c d e f g h i j k l m Holtz (2004); "Paleobiology", page 134.
  19. ^ a b c d e f g h i j k l m n o p q r s t 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. ^ a b Carpenter and Smith (2001); "Abstract," page 90.
  25. ^ Carpenter and Smith (2001); "Introduction," page 91.
  26. ^ a b c Holtz (2001); "Abstract," page 64.
  27. ^ a b Holtz (2001); "Results," page 66.
  28. ^ Holtz (2001); "Results," page 66-67.
  29. ^ a b Holtz (2001); "Results," page. 67.
  30. ^ a b 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. PMID 28358353
    .
  58. .
  59. .
  60. .
  61. .
  62. .
  63. .
  64. .
  65. .
  66. ^ "Tiny "Coyote of the Cretaceous" Fills a Gap in the Tyrannosaur Tree". PBS. 6 May 2019.
  67. PMID 31780682
    .
  68. .
  69. .

References

External links