Editing Gorgosaurus (section)

== Description ==
[[File:Gorgoscale.svg|left|thumb|''G. libratus'' adult and subadult with a human for scale]]

''Gorgosaurus'' was smaller than ''Tyrannosaurus'' or ''Tarbosaurus'', close in size to ''Albertosaurus''. Adults reached {{convert|8|to|9|m|ft|abbr=on}} in length from snout to tail,<ref name=russell1970>{{cite journal |last=Russell |first=Dale A. |author-link=Dale Russell |year=1970 |title=Tyrannosaurs from the Late Cretaceous of western Canada |journal=National Museum of Natural Sciences Publications in Paleontology |volume=1 |pages=1–34}}</ref><ref name=holtz2004>{{Cite book|last=Holtz |first=Thomas R. |author-link=Thomas R. Holtz Jr. |year=2004 |chapter=Tyrannosauroidea |editor= Weishampel, David B. |editor-link= David B. Weishampel |editor2=Dodson, Peter |editor2-link=Peter Dodson |editor3=Osmólska Halszka |title=The Dinosauria |edition=Second |publisher=University of California Press |location=Berkeley |pages=111–136 |isbn=978-0-520-24209-8}}</ref><ref>{{Cite book|last=Paul|first=Gregory S.|url=http://worldcat.org/oclc/985402380|title=The Princeton Field Guide to Dinosaurs|year=2016|publisher=Princeton University Press|isbn=978-1-78684-190-2|oclc=985402380|pages=110}}</ref> and weighed {{convert|2|-|3|MT|ST}} in body mass.<ref>{{cite book|editor1=Larson, P.|editor2=Carpenter, K.|year=2008|title=''Tyrannosaurus rex'', the Tyrant King (Life of the Past)|pages=310|isbn=9780253350879|publisher=Indiana University Press}}</ref><ref name=seebacher2001>{{cite journal |last=Seebacher |first=Frank |year=2001 |title=A new method to calculate allometric length-mass relationships of dinosaurs |journal=Journal of Vertebrate Paleontology |volume=21 |issue=1 |pages=51–60 |doi=10.1671/0272-4634(2001)021[0051:ANMTCA]2.0.CO;2 |issn=0272-4634|url=http://dinoweb.ucoz.ru/_fr/4/A_new_method_to.pdf |citeseerx=10.1.1.462.255 |s2cid=53446536 }}</ref><ref name=Campione_etal_2014>{{cite journal|last1=Campione|first1=Nicolas E.|last2=Evans|first2=David C.|last3=Brown|first3=Caleb M.|last4=Carrano|first4=Matthew T.|title=Body mass estimation in non-avian bipeds using a theoretical conversion to quadruped stylopodial proportions|journal=Methods in Ecology and Evolution|date=2014|volume=5|issue=9|doi=10.1111/2041-210X.12226|pages=913–923|bibcode=2014MEcEv...5..913C |s2cid=84317234 |doi-access=free}}</ref> The largest known skull measures {{convert|99|cm|in|abbr=on}} long, just slightly smaller than that of ''Daspletosaurus''.<ref name=russell1970/> As in other tyrannosaurids, the skull was large compared to its body size, although chambers within the skull bones and large openings ([[Fenestra (anatomy)|fenestra]]e) between bones reduced its weight. ''Albertosaurus'' and ''Gorgosaurus'' share proportionally longer and lower skulls than ''Daspletosaurus'' and other tyrannosaurids. The end of the snout was blunt, and the [[nasal bone|nasal]] and [[parietal bone]]s were fused along the midline of the skull, as in all other members of the family. The [[orbit (anatomy)|eye socket]] was circular rather than oval or keyhole-shaped as in other tyrannosaurid genera. A tall crest rose from the [[lacrimal bone]] in front of each eye, similar to ''Albertosaurus'' and ''Daspletosaurus''.<ref name=holtz2004/> Differences in the shape of bones surrounding the brain set ''Gorgosaurus'' apart from ''Albertosaurus''.<ref name=currie2003a>{{cite journal |last=Currie |first=Philip J. |author-link=Phil Currie |year=2003 |title=Cranial anatomy of tyrannosaurids from the Late Cretaceous of Alberta |journal=Acta Palaeontologica Polonica |volume=48 |issue=2 |pages=191–226 |url=http://www.app.pan.pl/article/item/app48-191.html?pdf=39 |format=PDF}}</ref>

[[File:Gorgosaurus 2022 Life Reconstruction.png|thumb|[[Life restoration]]]]''Gorgosaurus'' teeth were typical of all known tyrannosaurids. The eight [[premaxilla]]ry teeth at the front of the snout were smaller than the rest, closely packed and ''D''-shaped in [[Cross section (geometry)|cross section]]. In ''Gorgosaurus'', the first tooth in the [[maxilla]] was also shaped like the premaxillary teeth. The rest of the teeth were oval in cross section, rather than blade-like as in most other theropods.<ref name=holtz2004/> Along with the eight premaxillary teeth, ''Gorgosaurus'' had 26 to 30&nbsp;maxillary teeth and 30 to 34&nbsp;teeth in the [[dentary bone]]s of the lower jaw. This number of teeth is similar to ''Albertosaurus'' and ''Daspletosaurus'' but is fewer than those of ''Tarbosaurus'' or ''Tyrannosaurus''.<ref name=currieetal2003>{{cite journal |last=Currie |first=Philip J. |author2=Hurum, Jørn H |author3=Sabath, Karol |author-link=Phil Currie |year=2003 |title=Skull structure and evolution in tyrannosaurid phylogeny |journal=Acta Palaeontologica Polonica |volume=48 |issue=2 |pages=227–234 |url=http://www.app.pan.pl/archive/published/app48/app48-227.pdf }}</ref>[[File:Dr. Bob Bakker with Dino.jpg|thumb|[[Robert T. Bakker|Bob Bakker]] and a skeleton with several bone injuries, from the "Dinosaur Mummy: CSI" exhibit at the HMNS]]
''Gorgosaurus'' shared its general body plan with all other tyrannosaurids. Its massive head was perched on the end of an ''S''-shaped neck. In contrast to its large head, its forelimbs were very small. The forelimbs had only two digits, although a third [[metacarpal]] is known in some specimens, the [[vestigial]] remains of the third digit seen in other theropods. ''Gorgosaurus'' had four digits on each hindlimb, including a small first toe ([[hallux]]) which did not contact the ground. Tyrannosaurid hindlimbs were long relative to overall body size compared with other theropods.<ref name="holtz2004" /> The largest known ''Gorgosaurus'' [[femur]] measured {{convert|105|cm|in|abbr=on}} long. In several smaller specimens of ''Gorgosaurus'', the [[tibia]] was longer than the femur, a proportion typical of [[cursorial|fast-running]] animals.<ref name="russell1970" /> The two bones were of equal length in the largest specimens.<ref name="matthewbrown1923">{{cite journal |last=Matthew |first=William D. |author-link=William Diller Matthew |author2=Brown, Barnum |author2-link=Barnum Brown |year=1923 |title=Preliminary notices of skeletons and skulls of Deinodontidae from the Cretaceous of Alberta |journal=American Museum Novitates |issue=89 |pages=1–9 |hdl=2246/3207 |hdl-access=free }}</ref> The long, heavy tail served as a [[counterweight]] to the head and torso and placed the [[center of gravity]] over the hips.<ref name="holtz2004" />

In 2001, paleontologist [[Phil Currie]] reported skin impressions from the holotype specimen of ''G. libratus''. He originally reported the skin as being essentially smooth and lacking the scales found in other dinosaurs, similar to the secondarily featherless skin found in large modern birds.<ref name="currie2001lecture">Currie, P. (2001). 2001 A. Watson Armour Symposium: The Paleobiology and Phylogenetics of Large Theropods. Field Museum of Natural History, Chicago.</ref> Scales of some sort were present in this specimen, but they are reportedly widely dispersed from each other and very small. Other patches of isolated ''Gorgosaurus'' skin shows denser, and larger though still relatively fine scales (smaller than [[hadrosaurid]] scales and approximately as fine as a Gila monster's).<ref name="DML">Holtz, T. 2001. Phil Currie celebration, tyrant skin, and other things. Dinosaur Mailing List post. http://dml.cmnh.org/2001Jul/msg00243.html {{Webarchive|url=https://web.archive.org/web/20200801090823/http://dml.cmnh.org/2001Jul/msg00243.html |date=August 1, 2020 }}. Accessed: March 15, 2014</ref> Neither of these specimens was associated with any particular bone or specific body area.<ref name="DML" /> In the ''Encyclopedia of Dinosaurs'' [[Kenneth Carpenter]] pointed out that traces of skin impressions from the tail of ''Gorgosaurus'' showed similar small rounded or hexagonal scales.<ref>{{Cite book|last=Carpenter |first=Kenneth |year=1997 |chapter=Tyrannosauridae |editor=Currie, Philip J. |editor-link=Phil Currie |editor2=Padian Kevin |title=Encyclopedia of Dinosaurs |publisher= Academic Press |location=San Diego |pages=768 |isbn=978-0-12-226810-6}}</ref>