Editing Segnosaurus (section)

===Postcranial skeleton===
[[File:Segno.jpg|thumb|[[paleoart|Life restoration]]]]

The {{Dinogloss|scapula}} (shoulder blade) of ''Segnosaurus'' was straight and flat at the upper end, and was fused to the coracoid bone, forming the scapulocoracoid. The coracoid was very wide, rectangular in outline and thick at the middle. The massive humerus was {{convert|560|mm|in|abbr=on}} in length; it had an almost-cylindrical shaft and well-defined condyles for articulation with the radius and ulna of the lower arm. The deltopectoral crest, where the [[deltoid muscle]] was attached to the upper front of the humerus, was well-developed.<ref name=Perle1979/> The humerus was distinct from those of other therizinosaurs, being straight rather than [[sigmoid shaped]] and not expanded or deflected forwards at its upper end. The humerus was also not expanded at the middle, and the [[entepicondyle]] was not well-developed. The lack of these features was more similar to [[ornithomimosaurs]] and [[troodontids]] than to other therizinosaurs.<ref name=Zanno2010/> The radius was also massive—about 60 percent of the humerus—with a straight shaft. The ulna was thicker than the radius and slightly longer—about 70 percent of the humerus—and slightly twisted along its middle axis. The hand was [[tridactyl]] (three-fingered). The {{Dinogloss|phalanx bones}} of the fingers were flattened from top to bottom and the articular depressions on their sides were not very developed. The first phalanx of the first finger was long and thin while the first and second phalanxes of the second finger were short. The ungual of the third finger was somewhat longer than the second phalanx and quite flat from top to bottom, which may have been a unique feature of ''Segnosaurus''. This ungual was sharpy curved, very pointed, and compressed from side to side. The lower tubercle, where the flexor tendons attached to the ungual, was thick and robust.<ref name=Perle1979/><ref name=Zanno2010/><ref name="perle&barsbold80" /><ref name="Dinosauria2">{{cite book| last1 = Clark | first1 = J. M. |last2=Maryańska |first2=T.|last3=Barsbold |first3=R. |year= 2004 | pages =151–164 |title= The Dinosauria |publisher= University of California Press |isbn= 978-0-520-24209-8|location= Berkeley|chapter=Therizinosauroidea|edition= 2 | editor1 =Weishampel, D. B.| editor2 =Dodson, P.| editor3 =Osmolska, H.}}</ref>

[[File:Segnosaurus holotype.png|left|thumb|Reconstructed [[holotype]] pelvis in left side view and {{Dinogloss|metatarsus}} in top view]]
The pelvis of ''Segnosaurus'' was robust and had sharply sideways-directed lobes at the front. The pelvis was shortened at the front, a feature found among bird-like theropods but uncommon among theropods as a whole.<ref name=Perle1979/> The pubic bone was directed backwards and down in parallel with the ischium; this backwards orientation of the pubic bone is known as the {{Dinogloss|opisthopubic}} condition. This feature is only known from birds and their closest [[coelurosaurian]] relatives while other theropod dinosaurs had forwards-directed pubic bones.<ref name="Opisthopubic">{{cite journal |last1=Barsbold |first1=R. |title=Opisthopubic pelvis in the carnivorous dinosaurs |journal=Nature |date=1979 |volume=279 |issue=5716 |pages=792–793 |doi=10.1038/279792a0|bibcode=1979Natur.279..792B |s2cid=4348297 }}</ref><ref name="Dinosauria2"/> The pubic bone was elongated, flattened sideways, and had an ellipsoid projection or "boot" at the front of its lower end.<ref name="perle&barsbold80" /><ref name="Dinosauria2"/> The pelvis was distinct from those of other therizinosaurs in that the upper margin of the ilium had a pronounced overhang on the lower side and that the hindwards projecting process of the ischium was extensive, almost 50 percent of the front-to-back length of the {{Dinogloss|obturator process}}. Some features of the pelvis were similar to that of ''[[Nothronychus]]'', particularly the ischia, but it is uncertain whether these similarities were due to them having a common ancestor to the exclusion of other derived therizinosaurids, or because they retained basal features since lost in other relatives. The ischium of ''Segnosaurus'' was distinct from that of ''Nothronychus'' in that it had an almost-rectangular obturator process and an almost-circular obturator foramen. The pelvis was distinct from that of ''[[Enigmosaurus]]'' by its deep obturator process not fusing with its counterpart at the middle, by its unfused pubic boot, and because the lower part of the pubic shaft was wide from front to back. ''Segnosaurus'' was distinct from both ''Nothronychus'' and ''Enigmosaurus'' in having a deep {{Dinogloss|brevis fossa}} (a groove where the [[caudofemoralis brevis muscle]] of the tail originated) and because its pubic boot lacked a well developed hindwards projection.<ref name=Zanno2010/>

The femur was straight with an oval cross-section and was {{convert|840|mm|in|abbr=on}} in length. The head of the femur was placed on a long "neck" and the lower condyles were well-defined. The tibia was straight, slightly shorter than the femur, and twisted along its axis. The fibula was long and narrowed towards its lower end. The metatarsus of the foot was short, massive, and consisted of five bones—four of which functioned as support elements and terminated in four toes. Functionally tetradactyl (four-toed) feet were unique to derived therizinosaurs; basal therizinosaurs and all other theropods had tridactyl feet in which the first toe was short and did not reach the ground. Externally, the metatarsus was similar to, though proportionally larger than, those of [[prosauropods]], an early [[evolutionary grade]] of [[sauropodomorphs]]. The epiphyses on the upper metatarsals were hypertrophied (enlarged), a distinctive feature of the genus. The first toe was shorter than the others but was of equal functional importance; the second and third toes were equally long while the fourth was thinnest. The toe ungual was robust, sharply curved, flat at the side, and more pointed than those of prosauropods. The lower tubercle where the flexor ligaments attached was robust. While the lack of strong compression of the toe unguals distinguished ''Segnosaurus'' from ''Erlikosaurus'' from the same formation, the lack of compression was common among therizinosaurs and therefore not unique to ''Segnosaurus''.<ref name=Perle1979/><ref name=Zanno2010/><ref name="perle&barsbold80" /> The cervical vertebrae were platycoelous and had large, massive centra (bodies) and low neural arches. The sacrum consisted of six, firmly fused vertebrae; the centra of these vertebrae were broadened and relatively elongated, and each centrum was slightly longer than their width. The neural spines here were not very long but surpassed the level of the ilia. The caudal (tail) vertebrae closest to the body were massive, high, and somewhat compressed from side to side. The neural arch was low with a small neural canal. The caudal vertebrae closer to the tip of the tail were platycoelous and had short, massive centra. The transverse processes of the caudal vertebrae and the ribs were robust and elongated.<ref name=Perle1979/><ref name="perle&barsbold80" />