Editing Megabat (section)

===Skeleton===
====Skull and dentition====
[[File:Pteropus melanotus 04 MWNH 237.jpg|thumb|alt=A bat skull with prominent canines on a white background.|Skull of the [[black-eared flying fox]] (''Pteropus melanotus'')]]
Megabats have large [[Orbit (anatomy)|orbits]], which are bordered by well-developed [[postorbital process]]es posteriorly. The postorbital processes sometimes join to form the [[postorbital bar]]. The [[snout]] is simple in appearance and not highly modified, as is seen in other bat families.<ref>{{cite book|last1=Vaughan| first1=T. A.| last2=Ryan| first2=J. M.| last3=Czaplewski| first3=N. J.|title=Mammalogy| date=11 December 2013| publisher=Jones & Bartlett Publishers| isbn=9781284032185| pages=255–256| edition=6|url=https://books.google.com/books?id=GVy2AgAAQBAJ&pg=PA256}}</ref> The length of the snout varies among genera. The [[premaxilla]] is well-developed and usually free,<ref name="Miller, 1907"/> meaning that it is not fused with the [[maxilla]]; instead, it articulates with the maxilla via [[ligament]]s, making it freely movable.<ref>{{cite journal|doi=10.1206/0003-0090(2001)258<0001:PROMBC>2.0.CO;2|issn=0003-0090|year=2001|volume=258|title=Phylogenetic Relationships of Mormoopid Bats (Chiroptera: Mormoopidae) Based on Morphological Data|journal=Bulletin of the American Museum of Natural History|last1=Simmons|first1=Nancy B.|last2=Conway|first2=Tenley M.|hdl=2246/1608|page=17|s2cid=83580917 |url=https://zenodo.org/record/5376511}}</ref><ref>{{cite journal|doi=10.23689/fidgeo-999|year=2011|last1=Lindenau|first1=Christa|title=Middle Pleistocene bats (Mammalia: Chiroptera) from the Yarimburgaz Cave in Turkish Thrace (Turkey)|journal=E&G – Quaternary Science Journal|volume=55|page=127}}</ref> The premaxilla always lack a palatal branch.<ref name="Miller, 1907"/> In species with a longer snout, the skull is usually arched. In genera with shorter faces (''Penthetor'', ''Nyctimene'', ''Dobsonia'', and ''Myonycteris''), the skull has little to no bending.<ref>{{cite journal|url=http://digitallibrary.amnh.org/bitstream/handle/2246/1781/B080a09.pdf;jsessionid=24A463ACFEB3921ED860E6934C4BCE11?sequence=1|title=Results of the Archbold Expeditions No. 48: Pteropodidae (Chiroptera) of the Archbold Collections| last=Tate| first=G. H. H.|year=1942| journal=Bulletin of the American Museum of Natural History| volume=80| pages=332–335}}</ref>

Megabat species have relatively small incisors and large canines. The premolars and molars are adapted to crush and pierce fruit, their primary food source.<ref>Berkovitz, B., & Shellis, P. (2018). The teeth of mammalian vertebrates. Academic Press.</ref> 

The most complete dental formula is: I2/2, C 1/1, P3/3, M2/3 x 2 = 34.<ref>Giannini, N. P., Wible, J. R., & Simmons, N. B. (2006). On the cranial osteology of chiroptera. I. Pteropus (Megachiroptera: Pteropodidae). Bulletin of the American Museum of Natural History, 2006(295), 1-134.</ref> The dental formula of 34 teeth is a homologous trait for megabats.<ref name="Giannini 2007" /> The total number of teeth varies among megabat species, and can range from 24 to 34. For example, some species of megabats have only 2 molars on either side of the lower jaw instead of 3. Others may lack one or more pairs of incisors on the upper or lower jaw.<ref name="Giannini 2007" /> 

All megabats have two to four each of upper and lower [[incisor]]s, with the exception [[Bulmer's fruit bat]] (''Aproteles bulmerae''), which completely lacks incisors,<ref name="Giannini 2007" /> and the [[São Tomé collared fruit bat]] (''Myonycteris brachycephala''), which has two upper and three lower incisors.<ref name="Juste 1993">{{cite journal|last1=Juste| first1= J.| last2= Ibáñez| first2= C.| year=1993| title= An asymmetric dental formula in a mammal, the Sao Tomé Island fruit bat Myonycteris brachycephala (Mammalia: Megachiroptera)| journal= [[Canadian Journal of Zoology]]| volume= 71| issue=1| pages= 221–224| doi= 10.1139/z93-030| bibcode= 1993CaJZ...71..221J| hdl= 10261/48798| hdl-access= free}}</ref> This makes it the only mammal species with an asymmetrical [[dentition#Dental formula|dental formula]].<ref name="Juste 1993" />

All species have two upper and lower [[canine tooth|canine teeth]]. The number of [[premolar]]s is variable, with four or six each of upper and lower premolars.
The first upper and lower [[molar (tooth)|molars]] are always present, meaning that all megabats have at least four molars. The remaining molars may be present, present but reduced, or absent.<ref name="Giannini 2007">{{cite journal|doi=10.1206/0003-0082(2007)3559[1:EHATEO]2.0.CO;2|last1=Giannini| first1= N. P.| last2= Simmons| first2= N. B.| year= 2007| title= Element homology and the evolution of dental formulae in megachiropteran bats (Mammalia: Chiroptera: Pteropodidae)| journal= [[American Museum Novitates]]|issue=3559| pages= 1–27| url=http://digitallibrary.amnh.org/bitstream/handle/2246/5849//v3/dspace/updateIngest/pdfs/N3559.pdf?sequence=1&isAllowed=y|hdl=2246/5849|s2cid=62823404 }}</ref> Megabat molars and premolars are simplified, with a reduction in the [[Cusp (anatomy)|cusps]] and ridges resulting in a more flattened [[crown (tooth)|crown]].<ref name="Wimsatt"/>

Like most mammals, megabats are [[diphyodont]], meaning that the young have a set of [[deciduous teeth]] (milk teeth) that falls out and is replaced by permanent teeth. For most species, there are 20 deciduous teeth. As is typical for mammals,<ref>{{cite journal|last1=Luo| first1= Z. X.| last2= Kielan-Jaworowska| first2=Z.| last3= Cifelli| first3= R. L.| year= 2004| title= Evolution of dental replacement in mammals| journal= Bulletin of Carnegie Museum of Natural History| volume=2004| issue=36| pages=159–176|url=https://pdfs.semanticscholar.org/f49e/b498515c8cf669c24884e66dc55246d0219a.pdf|archive-url=https://web.archive.org/web/20190523184301/https://pdfs.semanticscholar.org/f49e/b498515c8cf669c24884e66dc55246d0219a.pdf|url-status=dead|archive-date=2019-05-23| doi= 10.2992/0145-9058(2004)36[159:EODRIM]2.0.CO;2| s2cid= 5630875}}</ref> the deciduous set does not include molars.<ref name="Wimsatt"/>

====Postcrania====
[[File:Pteropus samoensis-3.jpg|thumb|alt=An articulated bat skeleton on a black background.|Skeleton of the [[Samoa flying fox]] (''Pteropus samoensis'')]]
The [[scapula]]e (shoulder blades) of megabats have been described as the most primitive of any chiropteran family.<ref name="Wimsatt"/> The shoulder is overall of simple construction, but has some specialized features. The primitive insertion of the [[omohyoid muscle]] from the [[clavicle]] (collarbone) to the scapula is [[Anatomical terms of location#Medial and lateral|laterally]] displaced (more towards the side of the body)—a feature [[Convergent evolution|also seen]] in the [[Phyllostomidae]]. The shoulder also has a well-developed system of muscular slips (narrow bands of muscle that augment larger muscles) that anchor the tendon of the occipitopollicalis muscle (muscle in bats that runs from base of neck to the base of the thumb)<ref name="Hall">{{cite book| title=Flying Foxes: Fruit and Blossom Bats of Australia| first1=L. S.| last1= Hall| first2= G.| last2= Richards| year=2000| publisher=[[University of New South Wales|UNSW Press]]|isbn=9780868405612}}</ref> to the skin.<ref name="Nelson"/>

While microbats only have claws on the [[thumb]]s of their forelimbs, most megabats have a clawed second digit as well;<ref name="Wimsatt">{{cite book|editor-last1=Wimsatt| editor-first1= W.| year=1970| title= Biology of Bats| publisher= [[Academic Press]]| isbn=9780323151191|pages=103–136|chapter=Chapter 3: The Skeletal System| last=Vaughan| first=T.}}</ref> only ''Eonycteris'', ''Dobsonia'', ''Notopteris'', and ''Neopteryx'' lack the second claw.<ref name="Nowak">{{cite book|first1=R. M.| last1= Nowak| first2= E.| last2= Pillsbury Walker| year=1999|title=Walker's Mammals of the World| volume=1| publisher=JHU Press| isbn=9780801857898|page=258}}</ref> The first digit is the shortest, while the third digit is the longest. The second digit is incapable of [[flexion]].<ref name="Wimsatt"/> Megabats' thumbs are longer relative to their forelimbs than those of microbats.<ref name="Hall"/>

Megabats' hindlimbs have the same skeletal components as humans. Most megabat species have an additional structure called the [[calcar]], a cartilage spur arising from the [[calcaneus]].<ref name="Bennett"/> Some authors alternately refer to this structure as the uropatagial spur to differentiate it from microbats' calcars, which are structured differently. The structure exists to stabilize the uropatagium, allowing bats to adjust the [[Camber (aerodynamics)|camber]] of the membrane during flight. Megabats lacking the calcar or spur include ''Notopteris'', ''Syconycteris'', and ''[[Harpyionycteris]]''.<ref>{{cite journal|doi=10.1023/A:1020566902992|year=1998|last1=Schutt|first1=W. A.|journal=[[Journal of Mammalian Evolution]]|volume=5|page=2|last2=Simmons|first2=N. B.| title=Morphology and Homology of the Chiropteran Calca, with Comments on the Phylogenetic Relationships of ''Archaeopteropus''|s2cid=20426664}}</ref> The entire leg is rotated at the hip compared to normal mammal orientation, meaning that the knees face [[Anatomical terms of location#Anterior and posterior|posteriorly]]. All five digits of the foot flex in the direction of the [[sagittal plane]], with no digit capable of flexing in the opposite direction, as in the feet of perching birds.<ref name="Bennett">{{cite journal|doi=10.1111/j.1469-7998.1993.tb02633.x|title=Structural modifications involved in the fore- and hind limb grip of some flying foxes (Chiroptera: Pteropodidae)|journal=[[Journal of Zoology]]|volume=229|issue=2|pages=237–248|year=1993|last1=Bennett|first1=M. B.}}</ref>