Timeline of tyrannosaur research

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. Other legends possibly inspired by tyrannosaur remains include Cheyenne stories about a mythical creature called the Ahke, and Delaware stories about smoking the bones of ancient monsters to have wishes granted.

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. 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. ''Laelaps'' was also among the first dinosaurs to be portrayed artistically as a vigorous, active animal, presaging the Dinosaur Renaissance by decades. 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''.

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. 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. 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.

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.

Prescientific

* The Delaware people of what is now New Jersey or Pennsylvania had a tradition regarding a hunting party that returned with a piece of an ancient bone supposedly belonging to a monster that killed humans. One of the village's wise men instructed people to burn bits of the bone in clay spoons with tobacco and make a wish while the concoction was still smoking. This ritual could bestow such favors as success in hunting, long life, and health for one's children. This tale might be inspired by local fossils, which include ''Dryptosaurus'', ankylosaurs, '' Coelosaurus'', and ''Hadrosaurus''.
* The Cheyenne believed that a mythical creature called an Ahke once lived in the prairies of the western United States. These creatures were thought to resemble giant buffalo, whose bones turned to stone. Ahke bones were found both on land as well as buried in the banks of streams. ''Tyrannosaurus'' fossils preserved in Hell Creek Formation strata may have been influences on this old legend. Its contemporary ''Triceratops'' is another possible influence, as well as the more recent Cenozoic fossils of ''Titanotherium'' and mastodons.

19th century

1850s

1856
* Joseph Leidy described the new genus and species ''Deinodon horridus''.

1860s

1865
* Leidy described the new genus and species '' Tomodon horrificus''.

1866
* Edward Drinker Cope described the new genus and species ''Laelaps aquilunguis''. This discovery proved that theropod dinosaurs walked on their hind limbs rather than on all fours like in earlier reconstructions. He also erected the family Deinodontidae.

1868
* Leidy described the new genus and species '' Aublysodon mirandus''.
* Leidy described the new genus ''Diplotomodon'' for the species '' Tomodon horrificus''.
* Cope described the new species ''Laelaps macropus''.

1870s

1876
* Cope described the new species '' Laelaps incrassatus'' and '' Laelaps falculus''. He also described '' Aublysodon lateralis''.
* Cope described the new species '' Laelaps hazenianus''.

1877
* Othniel Charles Marsh described the new genus ''Dryptosaurus'' to house the species ''Laelaps aquilunguis''.

1880s

1884
* Joseph Burr Tyrrell discovered a partial ''Albertosaurus'' skull near Kneehills Creek in Alberta, Canada. This specimen is now catalogued as CMN 5600.

1890s

1890
* Marsh described the new species '' Ornithomimus grandis''.

1892
* Cope described the new genus and species '' Manospondylus gigas''.
* Marsh described the new species ''Aublysodon amplus'' and '' A. cristatus''.
* Oliver Perry Hay described the new species '' Dryptosaurus kenabakides''.

20th century

1900s

1900
* Barnum Brown found a partial skeleton of ''Tyrannosaurus'' in eastern Wyoming.
1902
* Barnum Brown found a substantially complete skeleton of ''Tyrannosaurus'' in the Hell Creek Formation of Montana.
1905
* Henry Fairfield Osborn named the Tyrannosauridae. Osborn described the new genus and species ''Albertosaurus sarcophagus''. Osborn described the new genus and species ''Tyrannosaurus rex''. Osborn described the new genus and species '' Dynamosaurus imperiosus''.

1910s

1914
* Lawrence Lambe described the new genus and species ''Gorgosaurus libratus''.
* Barnum Brown emended Cope's "Dinodontidae" to "Deinodontidae".

1917
* Lambe interpreted tyrannosaurids as scavengers.

1920s

1922
* Matthew and Brown named the Tyrannosaurinae. Despite still classifying tyrannosaurs as members of the family Deinodontidae, they proposed that, contrary to researchers who regarded tyrannosaurs as carnosaurs related to other large carnivorous dinosaurs like ''Allosaurus'' and ''Megalosaurus'', the tyrannosaurs were actually more closely related to the small carnivores known as coelurosaurs.

1923
* Matthew and Brown described the new species '' Gorgosaurus sternbergi''. They still regarded tyrannosaurs as members of the family Deinodontidae.
* Friedrich von Huene regarded tyrannosaurs as members of the family Deinodontidae 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''.

1928
* William Parks described the new species ''Albertosaurus arctunguis''.

1930s

1930
* Anatoly Nikolaevich Riabinin described the new species '' Albertosaurus periculosus''.

1932
* Von Huene classified tyrannosaurs as carnosaurs.

1933
* Charles Whitney Gilmore described the new genus and species '' Alectrosaurus olseni''.

1940s

1946
* Gilmore described the new species '' Gorgosaurus lancensis''.

1950s

1955
* Colbert classified tyrannosaurs as carnosaurs.
* Evgeny Maleev described the new genus and species ''Tarbosaurus bataar''. He also described the species '' T. efremovi''. He also described the species '' Gorgosaurus lancinator''.
* Maleev described the new species of ''Maleevosaurus'', ''Albertosaurus'', ''Aublysodon'', ''Deinodon novojilovi''.

1956
* Alfred Sherwood Romer classified tyrannosaurs as carnosaurs.

1958
* Young described the new genus and species '' Chingkankosaurus fragilis''.

1960s

1964
* Walker named the Tyrannosauroidea. He regarded tyrannosaurs as carnosaurs.

1970s

1970
* Dale Russell described the new genus and species ''Daspletosaurus torosus''. He classified it in the family Tyrannosauridae rather than the historical home of tyrannosaurs, the Deinodontidae, setting a trend among paleontologists that would see the latter familial name fall into disuse in favor of the former. He observed that ''Daspletosaurus'' and ''Gorgosaurus'' lived at the same time and place, while ''Daspletosaurus'' was less common. He also noticed that hadrosaurs and ceratopsians were both present in the same deposits, with ceratopsians being less common. He speculated that this parallel may have been due to niche partitioning between the tyrannosaurs as each specialized in prey, with the lighter built and more common ''Gorgosaurus'' feeding on hadrosaurs and the more rugged and less common ''Daspletosaurus'' specializing in the rarer and more dangerous ceratopsians. He noted that while adult tyrannosaurs may have fed on such large prey, very young individuals would be limited to quarry like birds, frogs, mammals, and small reptiles.
* Rodney Steel classified tyrannosaurs as carnosaurs.

1974
* Madsen described the new genus and species '' Stokesosaurus clevelandi''. This is the oldest known tyrannosauroid.
* Maleev still classified tyrannosaurs in the family Deinodontidae.

* Ralph Molnar described the new genus and species ''Labocania anomala''.

1975

1976
* Sergei Mikhailovich Kurzanov described the new genus and species ''Alioramus remotus'' as well as the new genus and species ''Itemirus medullaris''.

1977
* Dong described the new genus and species '' Shanshanosaurus huoyanshanensis''.

1978
* Paul Colinvaux interpreted tyrannosaurids as scavengers.

1979
* Dong described the new genus and species '' Tyrannosaurus luanchuanensis''.

1980s

1980
* Halszka Osmólska reported multiple ''Tarbosaurus'' of different life stages found preserved together in the same deposit.

1981
* Lambert Beverly Halstead and his wife Jennifer Middleton interpreted tyrannosaurids as scavengers.

1983
* Rinchen Barsbold interpreted tyrannosaurids as scavengers.

1986
* Jacques Gauthier classified tyrannosaurs as carnosaurs.
* 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.

1988
* Bakker described the new genus '' Nanotyrannus lancensis'' to house the species ''Gorgosaurus lancensis''.
* Gregory S. Paul described the new species '' Albertosaurus megagracilis'' and '' Aublysodon molnari''.

1990s

1990
* José Bonaparte and others classified tyrannosaurs as carnosaurs.
* Molnar classified tyrannosaurs as carnosaurs.

* Sue, catalog name FMNH PR 2081, the largest and most complete ''T. rex'' skeleton found at the time, discovered on August 12, 1990 on the Cheyenne River Indian Reservation in South Dakota.

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.
* Scotty the ''T. rex'' is discovered near Eastend, Saskatchewan.

1992
* Kenneth Carpenter described the new genus ''Maleevosaurus''.
* William Abler studied tyrannosaur tooth biomechanics. He concluded that the serrations on tyrannosaur teeth did not function like the serrations on a saw blade. Instead he thought the serrations may have caught pieces of rotting meat inside them, sustaining bacterial colonies that make its bite likely to transmit deadly infections to potential prey items. Similar use of decaying meat trapped in tooth serrations as a vector for infected prey had been reported in monitor lizards.
* Fernando Emilio Novas performed a phylogenetic analysis of the tyrannosauridae, finding tyrannosaurs to actually be coelurosaurs, as advocated by a few contrarian workers during the 1920s, rather than carnosaurs as had been generally supposed for decades. Novas found them equally related to the ornithomimosaurs and maniraptorans.

1993
* Bernardino Pérez Pérez-Moreno and others performed another phylogenetic analysis of the Tyrannosauridae and found additional support for reclassifying the family as coelurosaurs. They found that within the coelurosaurs, tyrannosaurs were arctometatarsalians. In other words, they were more closely related to the ostrich dinosaurs than to birds.
* Farlow found that the ancient ecology of tyrannosaur habitats were inconsistent with the idea that they were scavengers.
* Horner and Donald Lessem interpreted tyrannosaurids as scavengers.

1994

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

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.
* 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.

* 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.

1996
* Osmólska described the new genus and species '' Bagaraatan ostromi''.
* Gregory Erickson and Kenneth Olson reported the existence of ornithischian bones with ''T. rex'' bite marks.

* Erickson and Olson others calculated the bite force of ''T. rex'', finding it to have some of the strongest jaws of any carnivorous vertebrate. By contrast, other carnivorous dinosaurs like ''Allosaurus'' had relatively weak jaws.

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.
* 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.
* Sereno concluded that the evolutionary history of tyrannosaurids suggested a relatively complex history of biogeographic dispersal between Asia and North America.
* Horner and Dobb interpreted tyrannosaurids as scavengers.

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''.
* 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.
* 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.

* 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. These bones composed 30–50% of its total volume.
* Holtz found that within the coelurosaurs, tyrannosaurs were arctometatarsalians. In other words, they were more closely related to the ornithomimosaurs than to birds.

1999
* Alexander Kellner described the new genus and species '' Santanaraptor placidus''. ''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.
* Thomas Carr argued that ''Nanotyrannus'' was actually just a young ''Tyrannosaurus''. 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.
* 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".
* Günter P. Wagner and Gauthier performed a phylogenetic analysis of the tyrannosaurs but found them equally related to the ornithomimosaurs and maniraptorans.

21st century

2000s

2000
* Oliver Walter Mischa Rauhut

HOME


Content is Copyleft
Website design, code, and AI is Copyrighted (c) 2014-2017 by Stephen Payne


Consider donating to Wikimedia



As an Amazon Associate I earn from qualifying purchases