Editing Tyrannosaurus (section)

===Additional species===
[[File:Tarbosaurus and Tyrannosaurus.jpg|thumb|Diagram showing the differences between a generalized ''Tarbosaurus'' (A) and ''Tyrannosaurus rex'' (B) skull]]
In 1955, Soviet [[paleontology|paleontologist]] [[Evgeny Maleev]] named a new species, ''Tyrannosaurus bataar'', from [[Mongolia]].<ref name="maleev1955">{{Cite journal |last=Maleev |first=E. A. |date=1955 |others=translated by F. J. Alcock |title=(title in Russian) |trans-title=Gigantic carnivorous dinosaurs of Mongolia |url=http://paleoglot.org/files/Maleev_55a.pdf |journal=[[Doklady Akademii Nauk SSSR]] |language=ru |volume=104 |issue=4 |pages=634–637 |archive-date=December 11, 2019 |access-date=April 30, 2013 |archive-url=https://web.archive.org/web/20191211124644/https://paleoglot.org/files/Maleev_55a.pdf |url-status=live }}</ref> By 1965, this species was renamed as a distinct genus, ''Tarbosaurus bataar''.<ref name="rozhdestvensky1965">{{Cite journal |last=Rozhdestvensky |first=A. K. |date=1965 |title=Growth changes in Asian dinosaurs and some problems of their taxonomy |journal=Paleontological Journal |volume=3 |pages=95–109}}</ref> While most palaeontologists continue to maintain the two as distinct genera, some authors such as [[Thomas Holtz]], [[Kenneth Carpenter]], and [[Thomas Carr (paleontologist)|Thomas Carr]] argue that the two species are similar enough to be considered members of the same genus, restoring the Mongolian [[taxon]]'s original [[binomial nomenclature|binomial name]].<ref name=holtz1994/><ref name=carpenter1992>{{Cite book |title=Aspects of nonmarine Cretaceous geology |last=Carpenter |first=K. |date=1992 |publisher=China Ocean Press |isbn=978-7-5027-1463-5 |editor-last=Mateer |editor-first=N. J. |location=Beijing |pages=250–268 |chapter=Tyrannosaurids (Dinosauria) of Asia and North America |oclc=28260578 |author-link=Kenneth Carpenter |editor-last2=Chen |editor-first2=P.-j.}}</ref><ref name=carr2017/>

Some specimens from the Late Cretaceous deposits of [[China]] have been described as new species of ''Tyrannosaurus'': ''T. lanpingensis'' based on isolated [[lateral (anatomy)|lateral]] tooth from the red beds of [[Yunnan]] in 1975; ''T. turpanensis'' from the [[Subashi Formation]], [[Turpan Basin]], [[Xinjiang]] in 1978; and ''T. luanchuanensis'' from the [[Quiba Formation]], [[Tantou Basin]], [[Henan Province]] in 1979–1980.<ref>{{cite journal|author=Hurum, J.H., Sabath, K.|year=2003|url=https://www.app.pan.pl/archive/published/app48/app48-161.pdf|title=Giant theropod dinosaurs from Asia and North America: Skulls of ''Tarbosaurus bataar'' and ''Tyrannosaurus rex'' compared|journal=Acta Palaeontologica Polonica|volume=48|issue=2|pages=161–190|archive-url=https://web.archive.org/web/20230517131646/https://www.app.pan.pl/archive/published/app48/app48-161.pdf|archive-date=May 17, 2023|url-status=dead}}</ref><ref name=Feng2016>{{cite journal|author=Li Feng, Bi Shundong, Michael Pittman, Stephen L. Brusatte, Xu Xing|year=2016|url=https://www.researchgate.net/publication/304145185|title=A new tyrannosaurine specimen (Theropoda: Tyrannosauroidea) with insect borings from the Upper Cretaceous Honglishan Formation of Northwestern China|journal=Cretaceous Research|volume=66|issue=|pages=155–162 |doi=10.1016/j.cretres.2016.06.002|bibcode=2016CrRes..66..155L |hdl=20.500.11820/a49b0878-3ba2-4c3e-b4b1-70fe282e43ea|hdl-access=free}}</ref><ref name=Lucas2018>{{cite journal|author=Sebastian G. Dalman, Spencer G. Lucas|date=January 2018|url=https://www.researchgate.net/publication/328676802|title=Tyrannosaurid dinosaurs (Theropoda: Tyrannosauridae) from the Upper Cretaceous (Early Campanian) Allison Member of the Menefee Formation, New Mexico: Implications for the origin of Tyrannosauridae in North America|series=New Mexico Museum of Natural History and Science Bulletin|journal=Fossil Record|volume=6|issue=79|pages=99–112|doi=}}</ref> All these taxa were published without detailed descriptions and were later accepted as [[synonym (taxonomy)|junior synonyms]] of ''Tarbosaurus bataar'' by Holtz in 2004.<ref name="holtz2004"/><ref name=Feng2016/><ref name=Lucas2018/>

VGI, no. 231/3, a large [[phalanx bone]], assigned to ''Tyrannosaurus'' sp. by Yarkov in 2000, was found in the Lower Maastrichtian of [[Bereslavka, Russia]]. In 2004, Averianov and Yarkov reinterpreted it as a [[metacarpal]] I or [[metatarsal]] I that possibly belongs to [[ceratosaur]].<ref>{{cite journal|author=A. O. Averianov, A. A. Yarkov|year=2004|url=https://repository.geologyscience.ru/bitstream/handle/123456789/39408/Aver_04.pdf?sequence=1|title=Carnivorous dinosaurs (Saurischia, Theropoda) from the Maastrichtian of the Volga-Don Interfluve, Russia|journal=Paleontological Journal|volume=38|issue=1|pages=78–82|archive-url=https://web.archive.org/web/20240305115625/https://repository.geologyscience.ru/bitstream/handle/123456789/39408/Aver_04.pdf?sequence=1|archive-date=March 5, 2024|url-status=live}}</ref> In their 2023 overview, Averianov and Lopatin mention this specimen as well as a single tooth from the same site only as Theropoda indet.<ref>{{cite journal|author=A. O. Averianov, A. V. Lopatin|year=2023|url=https://new.ras.ru/upload/iblock/a8f/vfw1g7hafto3gx7qbnwgpmuljd0j8ykk.pdf#page=45|title=Динозавры России: обзор местонахождений [Dinosaurs of Russia: Overview of locations]|journal=[[Herald of the Russian Academy of Sciences|Vestnik Rossiiskoi Akademii Nauk]]|volume=93|issue=4|pages=342–354|language=ru|doi=10.31857/S0869587323040023|archive-url=https://web.archive.org/web/20240216183756/https://new.ras.ru/upload/iblock/a8f/vfw1g7hafto3gx7qbnwgpmuljd0j8ykk.pdf#page=45|archive-date=February 16, 2024|url-status=live}}</ref>

In 2001, various tyrannosaurid teeth and a metatarsal unearthed in a quarry near [[Zhucheng]], China were assigned by Chinese paleontologist [[Hu Chengzhi]] to the newly erected species ''Tyrannosaurus zhuchengensis''. However, in a nearby site, a right maxilla and left jawbone were assigned to the newly erected tyrannosaurid genus ''Zhuchengtyrannus'' in 2011. It is possible that ''T. zhuchengensis'' is [[synonym (taxonomy)|synonymous]] with ''Zhuchengtyrannus''. In any case, ''T. zhuchengensis'' is considered to be a ''[[nomen dubium]]'' as the holotype lacks [[diagnosis (taxonomy)|diagnostic]] features below the level Tyrannosaurinae.<ref>{{cite journal|first1=D. W. E.|last1=Hone|first2=K.|last2=Wang|first3=C.|last3=Sullivan|first4=X.|last4=Zhao|first5=S.|last5=Chen|first6=D.|last6=Li|first7=S.|last7=Ji|first8=Q.|last8=Ji|first9=X.|last9=Xu|year=2011|title=A new, large tyrannosaurine theropod from the Upper Cretaceous of China|journal=Cretaceous Research|volume=32|issue=4|pages=495–503|doi=10.1016/j.cretres.2011.03.005|bibcode=2011CrRes..32..495H }}</ref>

In 2006, a fragmentary tyrannosaurid lacrimal (CM 9401) from the [[Judith River Formation]] of Fergus County, Montana was described as ?''Tyrannosaurus'' sp. This isolated right lacrimal was originally collected alongside the holotype specimen of ''Deinosuchus rugosus'', a giant crocodylian, and remained undescribed until its re-identification as belonging to a tyrannosaurid theropod in the 1980s by paleontologist [[Dale Russell]]. The lacrimal closely resembles those of ''Tyrannosaurus rex'' in both size and morphology. Notably, it lacks the "lacrimal horn" typically present in earlier tyrannosaurids like ''[[Albertosaurus]]'' and ''[[Gorgosaurus]]'', instead exhibiting a distinct rugosity along the dorsal surface—consistent with ''T. rex'' and its Asian relative ''Tarbosaurus''. The specimen's considerable size places it within the range of known ''T. rex'' individuals, suggesting the presence of large tyrannosaurids during the Campanian stage (~75 million years ago), a temporal range earlier than the established Maastrichtian age (~68–66 Ma) for ''Tyrannosaurus rex''. However, the exact age and provenance of CM 9401 remain uncertain due to a lack of detailed field documentation.<ref>{{Cite journal |last1=Urban |first1=Michael A. |last2=Lamanna |first2=Matthew C. |date=December 2006 |title=Evidence of a Giant Tyrannosaurid (Dinosauria: Theropoda) from the Upper Cretaceous (?Campanian) of Montana |url=http://www.bioone.org/doi/abs/10.2992/0097-4463%282006%2975%5B231%3AEOAGTD%5D2.0.CO%3B2 |journal=Annals of Carnegie Museum |language=en |volume=75 |issue=4 |pages=231–235 |doi=10.2992/0097-4463(2006)75[231:EOAGTD]2.0.CO;2 |issn=0097-4463}}</ref>

In 2018, a paper describing tyrannosaurid teeth from the Two Medicine Formation noted a premaxillary tooth (YPM VPPU 023469) had a strong resemblance to the teeth of [[Sue (Tyrannosaurus)|Sue]] to the exclusion of any Campanian tyrannosaurid. Additionally, the authors of this paper suggested that CM 9401 also comes from the Two Medicine Formation, as there were preservational similarities between its locality and the Willow Creek anticline, which is where the tooth was found.<ref>{{Cite journal |last1=Dalman |first1=Sebastian G. |last2=Lucas |first2=Spencer G. |last3=Malinzak |first3=D. Edward |date=2018 |title=Tyrannosaurid teeth from the upper Cretaceous (Campanian) Two Medicine Formation of Montana |url=https://www.researchgate.net/publication/328676947 |journal=New Mexico Museum of Natural History and Science Bulletin |volume=79 |issue= |pages=125–139}}</ref> Notably, this would place both specimens in the Flag Butte Member of the Two Medicine Formation, which dates from 77 to 76.3 Ma, far younger than any other ''Tyrannosaurus'' specimen, and directly contemporaneous with ''Daspletosaurus.'' In 2025, these specimens, with their old geologic age, were used as evidence by Charlie Scherer to suggest that the Tyrannosaurini did not evolve directly from ''Daspletosaurus''.<ref name=Scherer2025>{{Cite journal |last=Scherer |first=Charlie Roger |date=January 11, 2025 |title=Multiple lines of evidence support anagenesis in Daspletosaurus and cladogenesis in derived tyrannosaurines |url=https://linkinghub.elsevier.com/retrieve/pii/S0195667125000035 |journal=Cretaceous Research |volume=169 |pages=106080 |doi=10.1016/j.cretres.2025.106080 |bibcode=2025CrRes.16906080S |issn=0195-6671 |archive-date=January 18, 2025 |access-date=January 17, 2025 |archive-url=https://web.archive.org/web/20250118220857/https://linkinghub.elsevier.com/retrieve/pii/S0195667125000035 |url-status=live }}</ref>

In a 2022 study, Gregory S. Paul and colleagues argued that ''Tyrannosaurus rex'', as traditionally understood, actually represents three species: the type species ''Tyrannosaurus rex'', and two new species: ''T. imperator'' (meaning "tyrant lizard emperor") and ''T. regina'' (meaning "tyrant lizard queen"). The holotype of the former (''T. imperator'') is the [[Sue (dinosaur)|Sue]] specimen, and the holotype of the latter (''T. regina'') is [[Wankel rex]]. The division into multiple species was primarily based on the observation of a very high degree of variation in the proportions and robusticity of the [[femur]] (and other skeletal elements) across catalogued ''T. rex'' specimens, more so than that observed in other theropods recognized as one species. Differences of general body proportions representing robust and gracile morphotypes were also used as a line of evidence, in addition to the number of small, slender incisiform teeth in the dentary, as based on tooth sockets. Specifically, the paper's ''T. rex'' was distinguished by robust anatomy, a moderate ratio of femur length vs circumference, and the possession of a singular slender incisiform dentary tooth; ''T. imperator'' was considered to be robust with a small femur length to circumference ratio and two of the slender teeth; and ''T. regina'' was a gracile form with a high femur ratio and one of the slender teeth. It was observed that variation in proportions and robustness became more extreme higher up in the sample, [[Stratigraphy|stratigraphically]]. This was interpreted as a single earlier population, ''T. imperator'', speciating into more than one taxon, ''T. rex'' and ''T. regina''.<ref name="paul2022">{{cite journal | url=https://link.springer.com/article/10.1007/s11692-022-09561-5#Sec12 | title=The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus Tyrannosaurus | last1=Paul | first1=Gregory S. | last2=Persons IV | first2=W. Scott | last3=van Raalte | first3=Jay | journal=Evolutionary Biology | year=2022 | volume=49 | issue=2 | pages=156–179 | doi=10.1007/s11692-022-09561-5 | bibcode=2022EvBio..49..156P | s2cid=247200214 | archive-date=June 12, 2022 | access-date=March 1, 2022 | archive-url=https://web.archive.org/web/20220612011450/https://link.springer.com/article/10.1007/s11692-022-09561-5#Sec12 | url-status=live }}</ref>

However, several other leading paleontologists, including [[Stephen Brusatte]], [[Thomas Carr (paleontologist)|Thomas Carr]], [[Thomas Holtz]], David Hone, [[Jingmai O'Connor]], and [[Lindsay Zanno]], criticized the study or expressed skepticism of its conclusions when approached by various media outlets for comment.<ref name="newyorktimes">{{cite journal| url=https://www.nytimes.com/2022/02/28/science/tyrannosaurus-rex-species.html? |archive-url=https://web.archive.org/web/20220301014637/https://www.nytimes.com/2022/02/28/science/tyrannosaurus-rex-species.html |archive-date=March 1, 2022 |url-access=subscription |url-status=live | title=They Want to Break T. Rex Into 3 Species. Other Paleontologists Aren't Pleased. | date=February 28, 2022 | journal=The New York Times | access-date=March 1, 2022 | last1=Elbein|first1=Asher}}</ref><ref>{{cite web | url = https://edition.cnn.com/2022/02/28/world/t-rex-three-different-dinosaurs-scn/index.html | title = Tyrannosaurus rex may have been misunderstood | first1 = Katie | last1 = Hunt | date = March 1, 2022 | work = CNN | access-date = March 4, 2022 | archive-date = March 4, 2022 | archive-url = https://web.archive.org/web/20220304034107/https://edition.cnn.com/2022/02/28/world/t-rex-three-different-dinosaurs-scn/index.html | url-status = live }}</ref><ref>{{cite web | url = https://www.nationalgeographic.com/science/article/call-to-split-tyrannosaurus-rex-into-3-species-sparks-fierce-debate | archive-url = https://web.archive.org/web/20220301010250/https://www.nationalgeographic.com/science/article/call-to-split-tyrannosaurus-rex-into-3-species-sparks-fierce-debate | url-status = dead | archive-date = March 1, 2022 | title = Call to split T. rex into 3 species sparks fierce debate | work = National Geographic | first1 = Michael | last1 = Greshko | date = March 1, 2022 }}</ref> Their criticism was subsequently published in a technical paper.<ref name="Carr_et.al.(2022)">{{cite journal|last1=Carr|first1=T.D.|last2=Napoli|first2=J.G.|last3=Brusatte|first3=S.L.|last4=Holtz|first4=T.R.|last5=Hone|first5=D.W.E.|last6=Williamson|first6=T.E.|last7=Zanno|first7=L.E.|year=2022|title=Insufficient Evidence for Multiple Species of ''Tyrannosaurus'' in the Latest Cretaceous of North America: A Comment on "The Tyrant Lizard King, Queen and Emperor: Multiple Lines of Morphological and Stratigraphic Evidence Support Subtle Evolution and Probable Speciation Within the North American Genus ''Tyrannosaurus''"|journal=Evolutionary Biology|volume=49|issue=3|pages=314–341|doi=10.1007/s11692-022-09573-1|doi-access=free|bibcode=2022EvBio..49..327C }}</ref> Holtz and Zanno both remarked that it was plausible that more than one species of ''Tyrannosaurus'' existed, but felt the new study was insufficient to support the species it proposed. Holtz remarked that, even if ''Tyrannosaurus imperator'' represented a distinct species from ''Tyrannosaurus rex'', it may represent the same species as ''Nanotyrannus lancensis'' and would need to be called ''Tyrannosaurus lancensis''. O'Connor, a curator at the Field Museum, where the ''T. imperator'' holotype Sue is displayed, regarded the new species as too poorly-supported to justify modifying the exhibit signs. Brusatte, Carr, and O'Connor viewed the distinguishing features proposed between the species as reflecting natural variation within a species. Both Carr and O'Connor expressed concerns about the study's inability to determine which of the proposed species several well-preserved specimens belonged to. Another paleontologist, [[Philip J. Currie]], originally co-authored the study but withdrew from it as he did not want to be involved in naming the new species.<ref name="newyorktimes"/> Paul still rejected the objections raised by critics, insisting that they are unwilling to consider that ''Tyrannosaurus'' might represent more than one species.<ref name="Smithsonian Magazine 27-7-2022">Osborne M. [https://www.smithsonianmag.com/smart-news/study-refutes-controversial-research-that-divided-the-t-rex-into-three-species-180980477/ "Study Refutes Controversial Research That Divided the T. Rex Into Three Species"] {{Webarchive|url=https://web.archive.org/web/20230208044931/https://www.smithsonianmag.com/smart-news/study-refutes-controversial-research-that-divided-the-t-rex-into-three-species-180980477/ |date=February 8, 2023 }}. Smithsonian Magazine July 27, 2022</ref>