Editing Pterosaur (section)

===Terrestrial locomotion===
[[File:Hatzegopteryx.png|thumb|left|The [[fossil]] trackways show that pterosaurs like ''[[Hatzegopteryx]]'' were quadrupeds, and some rather efficient terrestrial predators.]]
Pterosaurs' hip sockets are oriented facing slightly upwards, and the head of the [[femur]] (thigh bone) is only moderately inward facing, suggesting that pterosaurs had an erect stance. It would have been possible to lift the thigh into a horizontal position during flight, as gliding lizards do.

There was considerable debate whether pterosaurs ambulated as [[quadruped]]s or as [[biped]]s. In the 1980s, paleontologist [[Kevin Padian]] suggested that smaller pterosaurs with longer hindlimbs, such as ''[[Dimorphodon]]'', might have walked or even run bipedally, in addition to flying, like [[Geococcyx|road runners]].<ref name="Padian1983">{{cite journal |author=Padian K |title=A Functional Analysis of Flying and Walking in Pterosaurs|jstor=2400656 |journal=Paleobiology |volume=9 |issue=3 |pages=218–39 |year=1983|doi=10.1017/S009483730000765X|bibcode=1983Pbio....9..218P |s2cid=88434056 }}</ref> However, a large number of pterosaur [[fossil trackway|trackways]] were later found with a distinctive four-toed hind foot and three-toed front foot; these are the unmistakable prints of pterosaurs walking on all fours.<ref>{{cite journal |author=Padian K |title=Pterosaur Stance and Gait and the Interpretation of Trackways |journal=Ichnos |volume=10 |issue=2–4 |pages=115–26 |year=2003 |doi=10.1080/10420940390255501|bibcode=2003Ichno..10..115P |s2cid=129113446 |url=http://doc.rero.ch/record/15320/files/PAL_E2625.pdf }}</ref><ref>{{cite journal |vauthors=Hwang K, Huh M, Lockley MG, Unwin DM, Wright JL |title=New pterosaur tracks (Pteraichnidae) from the Late Cretaceous Uhangri Formation, southwestern Korea |journal=Geological Magazine |volume=139 |issue=4 |pages=421–35 |year=2002 |doi=10.1017/S0016756802006647|bibcode=2002GeoM..139..421H |s2cid=54996027 |url=http://edoc.hu-berlin.de/18452/28485 }}</ref>
[[File:Haenamichnuswittonnaish2008.png|upright|thumb|The probable [[Azhdarchidae|azhdarchid]] trace [[fossil]] ''[[Haenamichnus|Haenamichnus uhangriensis]]''.]]
Fossil footprints show that pterosaurs stood with the entire foot in contact with the ground ([[plantigrade]]), in a manner similar to many mammals like [[human]]s and [[bear]]s. Footprints from [[Azhdarchidae|azhdarchids]] and several unidentified species show that pterosaurs walked with an erect posture with their four limbs held almost vertically beneath the body, an energy-efficient stance used by most modern birds and mammals, rather than the sprawled limbs of modern reptiles.<ref name="witton&naish2008">{{cite journal |vauthors=Witton MP, Naish D |title=A reappraisal of azhdarchid pterosaur functional morphology and paleoecology |journal=PLOS ONE |volume=3 |issue=5 |pages=e2271 |year=2008|pmc=2386974 |doi=10.1371/journal.pone.0002271 |pmid=18509539 |editor1-last=McClain |editor1-first=Craig R. |bibcode=2008PLoSO...3.2271W|doi-access=free }}</ref><ref name=wittongrauniad/> Indeed, erect-limbs may be omnipresent in pterosaurs.<ref name="ReferenceA">{{cite journal|doi=10.7717/peerj.1018|pmid=26157605|pmc=4476129|title=Were early pterosaurs inept terrestrial locomotors?|journal=PeerJ|volume=3|pages=e1018|year=2015|last1=Witton|first1=Mark P. |doi-access=free }}</ref>

Though traditionally depicted as ungainly and awkward when on the ground, the anatomy of some pterosaurs (particularly pterodactyloids) suggests that they were competent walkers and runners.<ref name=unwin1997>{{cite journal |author=Unwin DM |title=Pterosaur tracks and the terrestrial ability of pterosaurs |journal=Lethaia |volume=29 |pages=373–86 |year=1997 |doi=10.1111/j.1502-3931.1996.tb01673.x |issue=4|url=http://doc.rero.ch/record/16203/files/PAL_E3429.pdf }}</ref> Early pterosaurs have long been considered particularly cumbersome locomotors due to the presence of large [[Uropatagium|cruropatagia]], but they too appear to have been generally efficient on the ground.<ref name="ReferenceA"/>
[[File:Lot Plage aux ptérosaures 7 traces Dimitri.jpg|thumb|left|Fossil pterosaur footprints, [[Pterosaur Beach]] (France).]]
The forelimb bones of [[Azhdarchidae|azhdarchids]] and [[Ornithocheiridae|ornithocheirids]] were unusually long compared to other pterosaurs, and, in azhdarchids, the bones of the arm and hand (metacarpals) were particularly elongated. Furthermore, as a whole, azhdarchid front limbs were proportioned similarly to fast-running [[ungulate]] mammals. Their hind limbs, on the other hand, were not built for speed, but they were long compared with most pterosaurs, and allowed for a long stride length. While azhdarchid pterosaurs probably could not run, they would have been relatively fast and energy efficient.<ref name="witton&naish2008"/>

The relative size of the hands and feet in pterosaurs (by comparison with modern animals such as birds) may indicate the type of lifestyle pterosaurs led on the ground. Azhdarchid pterosaurs had relatively small feet compared to their body size and leg length, with foot length only about 25–30% the length of the lower leg. This suggests that azhdarchids were better adapted to walking on dry, relatively solid ground. ''[[Pteranodon]]'' had slightly larger feet (47% the length of the [[tibia]]), while filter-feeding pterosaurs like the [[Ctenochasmatoidea|ctenochasmatoids]] had very large feet (69% of tibial length in ''[[Pterodactylus]]'', 84% in ''[[Pterodaustro]]''), adapted to walking in soft muddy soil, similar to modern wading birds.<ref name="witton&naish2008"/> Though clearly forelimb-based launchers, basal pterosaurs have hindlimbs well adapted for hopping, suggesting a connection with archosaurs such as ''[[Scleromochlus]]''.<ref name="ReferenceA"/>