Editing Apodiformes (section)

==Description, etymology and taxonomy==
As the name ''apodiforme''—meaning "footless" in [[Greek language|Greek]]—suggests, the legs of hummingbirds, swifts and treeswifts (or 'crested' swifts) are rather small and offer limited functional uses, aside from perching; their feet are covered with bare skin, rather than the [[Scute|scutes]] seen on many birds. Another commonality amongst Apodiformes is their [[Evolution|evolving]] longer [[Wing|wings]] with short and stout [[humerus]] bones,<ref>Hyman, Libbie Henrietta (1992). ''[https://books.google.com/books?id=VKlWjdOkiMwC Hyman's Comparative Vertebrate Anatomy].''  Chicago: University of Chicago Press, page 39.  {{ISBN|0-226-87013-8}}</ref> a development which has provided the hummingbirds, in particular, with the ideal wings for [[Flying and gliding animals|hovering]].<ref name="mayr">Mayr, Gerald (2003): Phylogeny of early tertiary swifts and hummingbirds (Aves: Apodiformes). ''[[Auk (journal)|Auk]]'' 120(1): 145–151. {{doi|10.1642/0004-8038(2003)120[0145:POETSA]2.0.CO;2}} [https://web.archive.org/web/20060721204557/http://biology.georgefox.edu/~dpowers/Powers/HumPubs/GM_AUK120.pdf PDF fulltext]
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Together, the hummingbirds, swifts and treeswifts share several anatomical commonalities with their likely-closest extant relatives in the genus ''[[Owlet-nightjar|Aegotheles]]''—the owlet-nightjars; in particular, similarities are noted between the birds' [[skull]] structures.<ref>Mayr, Gerald (2002): Osteological evidence for paraphyly of the avian order Caprimulgiformes (nightjars and allies). ''Journal für Ornithologie'' '''143''': 82–97. [http://www.senckenberg.de/files/content/forschung/abteilung/terrzool/ornithologie/caprimulgiformes.pdf PDF fulltext]</ref> 

The owlet-nightjars are, apparently, [[convergent evolution|convergent]] with the closely-related [[Caprimulgiformes]] (nightjars), which form a [[clade]] known as [[Cypselomorphae]]<!-- Condor107:342 --> together with the Apodiformes and the [[Frogmouth|frogmouths]], [[Oilbird|oilbirds]] and [[Potoo|potoos]].<ref name="mayr" />