Editing Allosaurus (section)

===Postcranial skeleton===
[[File:Allosaurus Revised.jpg|thumb|left|Life restoration of ''A. fragilis'']]
''Allosaurus'' had nine [[vertebra]]e in the neck, 14 in the back, and five in the [[sacrum]] supporting the hips.<ref>Madsen, 1976; note that not everyone agrees on where the neck ends and the back begins, and some authors such as Gregory S. Paul interpret the count as 10 neck and 13 back vertebrae.</ref> The number of tail vertebrae is unknown and varied with individual size; [[James Henry Madsen Jr.|James Madsen]] estimated about 50,<ref name=JM76/> while [[Gregory S. Paul]] considered that to be too many and suggested 45 or less.<ref name=GSP88/> There were hollow spaces in the neck and [[Anatomical terms of location|anterior]] back vertebrae.<ref name=JM76/> Such spaces, which are also found in modern theropods (that is, the birds), are interpreted as having held [[Parabronchi|air sacs]] used in [[Respiratory system|respiration]].<ref name="HMC04">{{cite book |last1=Holtz |first1=Thomas R. Jr. |author-link1=Thomas R. Holtz Jr. |title=The Dinosauria |last2=Molnar |first2=Ralph E. |author-link2=Ralph Molnar |last3=Currie |first3=Philip J. |author-link3=Philip J. Currie |publisher=University of California Press |year=2004 |isbn=978-0-520-24209-8 |editor=Weishampel |editor-first=David B. |editor-link=David B. Weishampel |edition=2nd |location=Berkeley |pages=71–110 |chapter=Basal Tetanurae |editor2=Dodson |editor-first2=Peter |editor-link2=Peter Dodson |editor3=Osmólska |editor-first3=Halszka |editor-link3=Halszka Osmólska}}</ref> The rib cage was broad, giving it a barrel chest, especially in comparison to less [[Synapomorphy|derived]] theropods like ''Ceratosaurus''.<ref name="GSP88b">[[Gregory S. Paul|Paul, Gregory S.]] (1988). ''Predatory Dinosaurs of the World''. 277.</ref> ''Allosaurus'' had [[Gastralium|gastralia]] (belly ribs), but these are not common findings,<ref name=JM76/> and they may have [[Ossification|ossified]] poorly.<ref name=GSP88/> In one published case, the gastralia show evidence of injury during life.<ref name=DJC00b>{{cite journal |last=Chure |first=Daniel J. |year=2000 |title=Observations on the morphology and pathology of the gastral basket of ''Allosaurus'', based on a new specimen from Dinosaur National Monument |journal=Oryctos |volume=3 |pages=29–37|issn=1290-4805}}</ref> A [[furcula]] (wishbone) was also present, but has only been recognized since 1996; in some cases furculae were confused with gastralia.<ref name=DJC00b/><ref name=CM96>{{cite journal |doi=10.1080/02724634.1996.10011341 |last1=Chure |first1=Daniel J. |year=1996 |last2=Madsen |first2=James |title=On the presence of furculae in some non-maniraptoran theropods |journal=Journal of Vertebrate Paleontology |volume=16| issue=3 |pages=573–577|bibcode=1996JVPal..16..573C }}</ref> The [[Ilium (bone)|ilium]], the main hip bone, was massive, and the [[Pubis (bone)|pubic bone]] had a prominent foot that may have been used for both muscle attachment and as a prop for resting the body on the ground. Madsen noted that in about half of the individuals from the [[Cleveland-Lloyd Dinosaur Quarry]], independent of size, the pubes had not fused to each other at their foot ends. He suggested that this was a [[Sexual dimorphism|sexual characteristic]], with females lacking fused bones to make egg-laying easier.<ref name=JM76/> This proposal has not attracted further attention, however.
[[File:Allosaurus-fragilis-Klauen.JPG|thumb|Hand and claws of ''A. fragilis'']]
The forelimbs of ''Allosaurus'' were short in comparison to the hindlimbs (only about 35% the length of the hindlimbs in adults)<ref name=MG98>{{cite journal|last=Middleton |first=Kevin M. |year=2000 |title=Theropod forelimb design and evolution |journal=Zoological Journal of the Linnean Society |volume=128 |pages=149–187 |doi=10.1006/zjls.1998.0193 |url=http://www.brown.edu/Departments/EEB/EML/files/kevin_zjls00.pdf |access-date=October 25, 2007 |issue=2 |archive-url=https://web.archive.org/web/20071025123319/http://www.brown.edu/Departments/EEB/EML/files/kevin_zjls00.pdf |archive-date=October 25, 2007 |url-status=dead }}</ref> and had three fingers per hand, tipped with large, strongly curved and pointed [[claw]]s.<ref name=JM76/> The arms were powerful,<ref name=GSP88/> and the forearm was somewhat shorter than the upper arm (1:1.2 [[ulna]]/[[humerus]] ratio).<ref name=CWG20>{{cite journal |last=Gilmore |first=Charles W. |author-link=Charles W. Gilmore |year=1920 |title=Osteology of the carnivorous dinosauria in the United States National Museum, with special reference to the genera ''Antrodemus'' (''Allosaurus'') and ''Ceratosaurus'' |journal=Bulletin of the United States National Museum |issue=110 |pages=1–159 |doi=10.5479/si.03629236.110.i|url=http://repository.si.edu/bitstream/handle/10088/10107/1/USNMB_1101920_unitfo.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://repository.si.edu/bitstream/handle/10088/10107/1/USNMB_1101920_unitfo.pdf |archive-date=October 9, 2022 |url-status=live |hdl=2027/uiug.30112032536010 }}</ref> The wrist had a version of the semilunate [[Carpal bones|carpal]]<ref name=KC02>{{cite journal |last=Carpenter |first=Kenneth |year=2002 |title=Forelimb biomechanics of nonavian theropod dinosaurs in predation |journal=[[Senckenbergiana Lethaea]] |volume=82 |issue=1 |pages=59–76 |doi=10.1007/BF03043773|s2cid=84702973 }}</ref> also found in more derived theropods like [[maniraptora]]ns. Of the three fingers, the innermost (or thumb) was the largest,<ref name=GSP88/> and diverged from the others.<ref name=CWG20/> The phalangeal formula is 2-3-4-0-0, meaning that the innermost finger (phalange) has two bones, the next has three, and the third finger has four.<ref>Martin, A.J.  (2006). Introduction to the Study of Dinosaurs. Second Edition. Oxford, Blackwell Publishing. 560 pp. {{ISBN|1-4051-3413-5}}.</ref> The legs were not as long or suited for speed as those of [[tyrannosaurid]]s, and the claws of the toes were less developed and more [[hoof]]-like than those of earlier theropods.<ref name=GSP88/> Each foot had three weight-bearing toes and an inner [[dewclaw]], which Madsen suggested could have been used for grasping in juveniles.<ref name=JM76/> There was also what is interpreted as the splint-like remnant of a fifth (outermost) [[Metatarsus|metatarsal]], perhaps used as a lever between the [[Achilles tendon]] and foot.<ref name=GSP88d>Paul, Gregory S. (1988). ''Predatory Dinosaurs of the World''. 113; note illustrations of ''Allosaurus'' on 310 and 311 as well; Madsen (1976) interpreted these bones as possible upper portions of the inner metatarsal.</ref>