{{Short description|Extinct order of flying reptiles}}{{Use British English|date=May 2026}} {{redirect|Pterodactyl|the genus commonly called "pterodactyl"|Pterodactylus|other uses|Pterodactyl (disambiguation)}} {{Good article}} {{Automatic taxobox | fossil_range = [[Late Triassic]]–[[Late Cretaceous]], {{Fossil range|228|earliest=236|66}} | image = {{multiple image |total_width=330 |perrow=2/2/2 |image1=Pteranodon_amnh_martyniuk.jpg |image2=Dimorphodon mount.jpg |image3=Rhamphorhynchus_munsteri.jpg |image4=Pterodactylus sp 374.jpg |image5=Anurognathus_ammoni_juvenile.jpg |image6=Tupandactylus_skeleton_-_Museu_Nacional,_Rio_de_Janeiro.jpg |border=infobox }} | image_caption = Six pterosaurs (clockwise from top left): ''[[Pteranodon]]'', ''[[Dimorphodon]]'', ''[[Pterodactylus]]'', ''[[Tupandactylus]]'', ''[[Anurognathus]]'', and ''[[Rhamphorhynchus]]'' | image_upright = 1.3 | taxon = Pterosauria | display_parents = 4 | authority = [[Johann Jakob Kaup|Kaup]], 1834/[[Richard Owen|Owen]], 1842 | subdivision_ranks = Subgroups | subdivision_ref = <ref name=kryptodrakon>{{Cite journal | doi = 10.1016/j.cub.2014.03.030| pmid = 24768054| title = The Earliest Pterodactyloid and the Origin of the Group| journal = Current Biology| volume = 24| issue = 9| pages = 1011–16| year = 2014| last1 = Andres | first1 = B. | last2 = Clark | first2 = J. | last3 = Xu | first3 = X.| doi-access = free| bibcode = 2014CBio...24.1011A}}</ref><ref>{{cite journal|first=Matthew G. |last=Baron |year=2020 |title=Testing pterosaur ingroup relationships through broader sampling of avemetatarsalian taxa and characters and a range of phylogenetic analysis techniques. |journal=PeerJ |volume=8 |article-number=e9604 |doi=10.7717/peerj.9604 |pmc=7512134|pmid=33005485 |doi-access=free }}</ref> | subdivision = *{{extinct}}''[[Eotephradactylus]]'' *{{extinct}}''[[Peteinosaurus]]'' *{{extinct}}[[Eopterosauria]] *{{extinct}}[[Dimorphodontidae]] *{{extinct}}'''Preondactylia''' **{{extinct}}''[[Austriadactylus]]'' **{{extinct}}''[[Preondactylus]]'' *{{extinct}}'''Novialoidea''' **{{extinct}}''[[Campylognathoides]]'' **{{extinct}}[[Anurognathidae]]? **{{extinct}}'''Breviquartossa''' ***{{extinct}}''[[Sordes]]'' ***{{extinct}}[[Rhamphorhynchidae]] ***{{extinct}}'''[[Monofenestrata]]''' | range_map = Pterosaur Fossil Distribution Map.png | range_map_caption = Distribution of pterosaur [[fossil]] locations. Colored species or genera names correspond to their taxonomic group.{{efn|Adapted from Witton (2013).<ref>{{Citation |title=Pterosaurs: Natural History, Evolution, Anatomy |author=Mark P. Witton |date=2013 |publisher=Princeton University Press |bibcode=2013pnhe.book.....W |isbn=978-0-691-15061-1}}</ref> Taxonomic groups based on Unwin et al. (2010).<ref>{{Citation |title=''Darwinopterus'' and its implications for pterosaur phylogeny |author=David M. Unwin |journal=Acta Geoscientica Sinica |year=2010 |volume=31 |issue=1 |pages=68–69}}</ref>}} | synonyms = Ornithosauria <small>[[Harry Govier Seeley|Seeley]], 1870</small> }} '''Pterosaurs'''{{efn|{{IPAc-en|ˈ|t|ɛr|ə|s|ɔr|,_|ˈ|t|ɛr|oʊ|-}} {{respell|TERR|ə|sor|,_|TERR|oh|-}}<ref>{{Citation |last=Jones |first=Daniel |author-link=Daniel Jones (phonetician) |title=English Pronouncing Dictionary |editor=Peter Roach |editor2=James Hartmann |editor3=Jane Setter |place=Cambridge |publisher=Cambridge University Press |orig-date=1917 |year=2003 |isbn=978-3-12-539683-8}}</ref><ref>{{MerriamWebsterDictionary|Pterosaur}}</ref>}}{{efn|from [[Greek language|Greek]] {{lang|el|pteron}} and {{lang|el|sauros}}, meaning {{gloss|wing lizard}}<ref>{{cite book |last1=Colbert |first1=Edwin H. (Edwin Harris) |last2=Knight |first2=Charles Robert |title=The dinosaur book: the ruling reptiles and their relatives |date=1951 |publisher=McGraw-Hill |location=New York |page=153 |url=https://archive.org/details/bookruli00colb/page/152/mode/2up}}</ref>}} are an extinct [[clade]] of warm-blooded flying reptiles in the [[Order (biology)|order]] '''Pterosauria'''. They existed during most of the [[Mesozoic]]: from the [[Late Triassic]] to the end of the [[Cretaceous]] (228 million to 66 million years ago).<ref name=pterosaur_distribution>{{cite journal |author1=Barrett, P. M. |author2=Butler, R. J. |author3=Edwards, N. P. |author4=Milner, A. R. |year=2008 |title=Pterosaur distribution in time and space: an atlas |url=https://epub.ub.uni-muenchen.de/12007/1/zitteliana_2008_b28_05.pdf |journal=Zitteliana |volume=28 |pages=61–107 |access-date=2015-08-31 |archive-url=https://web.archive.org/web/20170806150333/https://epub.ub.uni-muenchen.de/12007/1/zitteliana_2008_b28_05.pdf |archive-date=2017-08-06 |url-status=live}}</ref> Pterosaurs are the earliest [[vertebrate]]s known to have evolved [[flying and gliding animals|powered flight]]. Their wings were formed by a membrane of skin, muscle, and other [[tissue (biology)|tissues]] stretching from the ankles to a dramatically lengthened fourth finger.<ref name=Elgin2011>{{cite journal |vauthors=Elgin RA, Hone DW, Frey E |title=The Extent of the Pterosaur Flight Membrane |journal=Acta Palaeontologica Polonica |volume=56 |issue=1 |pages=99–111 |year=2011 | doi=10.4202/app.2009.0145|bibcode=2011AcPaP..56...99E |doi-access=free }}</ref>
Traditionally, pterosaurs were divided into two major types. Basal pterosaurs (also called non-pterodactyloid pterosaurs or '[[rhamphorhynchoid]]s') were smaller animals, with up to a {{Convert|2|m|adj=on|spell=in}} wingspan, fully toothed jaws and, typically, long tails. Their wide wing membranes probably included and connected the hindlimbs. On the ground, they would have had an awkward sprawling posture due to short [[metacarpals]], but the anatomy of their joints and strong claws would have made them effective climbers, and some may have lived in trees. Basal pterosaurs were [[insectivore]]s, [[piscivores]] or [[Predation|predators]] of small land vertebrates. Later pterosaurs ([[pterodactyloid]]s) evolved many sizes, shapes, and lifestyles. Pterodactyloids had narrower wings with free hindlimbs, highly reduced tails, and long necks with large heads. On the ground, they walked well on all four limbs due to long metacarpals with an upright posture, standing [[plantigrade]] on the hind feet and folding the wing finger upward to walk on the metacarpals with the three smaller fingers of the hand pointing to the rear. They could take off from the ground, and fossil trackways show that at least some species were able to run, wade, and/or swim.<ref>{{Cite web|url=https://pterosaur.net/terrestrial_locomotion.php|title=Pterosaur.net :: Terrestrial Locomotion|website=pterosaur.net|access-date=2020-02-01|archive-date=2009-09-03|archive-url=https://web.archive.org/web/20090903013833/https://pterosaur.net/terrestrial_locomotion.php|url-status=dead}}</ref> Their jaws had horny beaks, and some groups lacked teeth. Some groups developed elaborate head crests with [[sexual dimorphism]]. Since 2010 it is understood that many species, the basal [[Monofenestrata]], were intermediate in build, combining an advanced long skull with long tails.
Pterosaurs sported coats of hair-like filaments known as [[#Pycnofibers|pycnofibers]], which covered their bodies and parts of their wings. Pycnofibers grew in several forms, from simple filaments to branching down [[feather]]s. These may be [[Homology (biology)|homologous]] to the down feathers found on both [[Bird|avian]] and some non-avian [[dinosaurs]], suggesting that early feathers evolved in the common ancestor of pterosaurs and dinosaurs, possibly as insulation.<ref>{{Cite web|url=https://www.livescience.com/64324-pterosaurs-had-feathers.html|title=It's Official: Those Flying Reptiles Called Pterosaurs Were Covered in Fluffy Feathers|last=Geggel |first=Laura|website=livescience.com|date=17 December 2018 |access-date=2020-02-01}}</ref> They were warm-blooded (endothermic), active animals. The [[respiratory system]] had efficient unidirectional "flow-through" breathing using [[air sacs]], which hollowed out their bones to an extreme extent. Pterosaurs spanned a wide range of [[Pterosaur size|adult sizes]], from the very small [[anurognathid]]s to the largest known flying creatures, including ''[[Quetzalcoatlus]]'' and ''[[Hatzegopteryx]]'',<ref name=wangetal2008>{{cite journal | last1 = Wang | first1 = X. | last2 = Kellner | first2 = A.W.A. | last3 = Zhou | first3 = Z. | last4 = Campos | first4 = D.A. | year = 2008 | title = Discovery of a rare arboreal forest-dwelling flying reptile (Pterosauria, Pterodactyloidea) from China | journal = Proceedings of the National Academy of Sciences | volume = 105 | issue = 6| pages = 1983–87 | doi = 10.1073/pnas.0707728105 | pmid=18268340 | pmc=2538868 | bibcode = 2008PNAS..105.1983W| doi-access = free }}</ref><ref name="lawson1975">{{cite journal |author=Lawson DA |title=Pterosaur from the Latest Cretaceous of West Texas: Discovery of the Largest Flying Creature |journal=Science |volume=187 |issue=4180 |pages=947–948 |date=March 1975 |pmid=17745279 |doi=10.1126/science.187.4180.947 |author-link=Douglas A. Lawson |bibcode=1975Sci...187..947L|s2cid=46396417 }}</ref><ref name="buffetautetal2002">{{cite journal |vauthors=Buffetaut E, Grigorescu D, Csiki Z |title=A new giant pterosaur with a robust skull from the latest cretaceous of Romania |journal=Naturwissenschaften |volume=89 |issue=4 |pages=180–84 |date=April 2002 |pmid=12061403 |doi=10.1007/s00114-002-0307-1 |bibcode=2002NW.....89..180B|s2cid=15423666 |url=http://doc.rero.ch/record/16209/files/PAL_E3417.pdf }}</ref> which reached wingspans of at least nine metres. The combination of [[endothermy]], a good oxygen supply and strong muscles made pterosaurs powerful and capable flyers.
Pterosaurs are often referred to by popular media or the general public as "flying dinosaurs", but dinosaurs are defined as the descendants of the [[last common ancestor]] of the [[Saurischia]] and [[Ornithischia]], which excludes the pterosaurs.<ref name=MJB04dino>{{cite book |last=Benton |first=Michael J. |author-link=Michael J. Benton |editor=Weishampel, David B. |editor2=Dodson, Peter |editor3=Osmólska, Halszka |title=The Dinosauria |url=https://archive.org/details/dinosauriandedit00weis |url-access=limited |edition=2nd |year=2004|publisher=University of California Press |location=Berkeley |isbn=978-0-520-24209-8 |pages=[https://archive.org/details/dinosauriandedit00weis/page/n25 7]–19 |chapter=Origin and relationships of Dinosauria}}</ref> Pterosaurs are nonetheless more closely related to birds and other dinosaurs than to crocodiles or any other living reptile, though they are not bird ancestors. Pterosaurs are also colloquially referred to as '''pterodactyls''', particularly in fiction and journalism.<ref name="myths">{{cite web|url=http://www.pterosaur.net/myths.php|title=Pterosaurs: Myths and Misconceptions|author=Naish, Darren|publisher=Pterosaur.net|access-date=June 18, 2011|archive-date=September 1, 2009|archive-url=https://web.archive.org/web/20090901170509/http://www.pterosaur.net/myths.php|url-status=dead}}</ref> However, technically, ''pterodactyl'' may refer to members of the genus ''[[Pterodactylus]]'', and more broadly to members of the suborder [[Pterodactyloidea]] of the pterosaurs.<ref name="alexander">{{cite book|author1=Alexander, David E. |author2=Vogel, Steven |name-list-style=amp |title =Nature's Flyers: Birds, Insects, and the Biomechanics of Flight|publisher =JHU Press|year =2004|page=191|isbn =978-0-8018-8059-9|url =https://books.google.com/books?id=zj395mz_GYkC&pg=PA191}}</ref> Pterosaurs had a variety of lifestyles. Traditionally seen as fish-eaters, the group is now understood to have also included hunters of land animals, insectivores, fruit eaters and even predators of other pterosaurs. They reproduced by [[egg]]s, some fossils of which have been discovered.<ref>{{cite news |last1=St. Fleur |first1=Nicholas |title=Hundreds of Fossilized Pterosaur Eggs Uncovered in China |url=https://www.nytimes.com/2017/11/30/science/pterosaur-eggs.html |access-date=5 December 2024 |work=The New York Times |date=30 November 2017}}</ref>
==Anatomy== {{See also|Anatomy of pterosaurs}} [[File:Pterodactylus_BMMS7_life.png|thumb|left|Life reconstruction of ''[[Pterodactylus]]'']] The [[anatomy of pterosaurs]] was highly modified from their reptilian ancestors by the adaptation to flight. Pterosaur [[skeleton|bones]] were hollow and air-filled, like those of [[bird]]s. This provided a higher [[muscle]] attachment surface for a given skeletal weight. The bone walls were often paper-thin. They had a large and keeled [[breastbone]] for flight muscles and an enlarged [[brain]] able to coordinate complex flying behaviour.<ref name="Witmer_et_al_2003">{{cite journal |vauthors=Witmer LM, Chatterjee S, Franzosa J, Rowe T |title=Neuroanatomy of flying reptiles and implications for flight, posture and behaviour |journal=Nature |volume=425 |issue=6961 |pages=950–53 |year=2003 |pmid=14586467 |doi=10.1038/nature02048 |bibcode=2003Natur.425..950W |s2cid=4431861 |url=http://doc.rero.ch/record/15277/files/PAL_E2576.pdf }}</ref> Pterosaur skeletons often show considerable fusion. In the skull, the [[suture (anatomy)|suture]]s between elements disappeared. In some later pterosaurs, the backbone over the shoulders fused into a structure known as a [[notarium]], which served to stiffen the torso during flight, and provide a stable support for the [[scapula|shoulder blade]]. Likewise, the sacral vertebrae could form a single [[synsacrum]] while the pelvic bones fused also.
===Size=== [[File:Size disparity of late Maastrichtian pterosaurs and birds.svg|thumb|Wide variation in [[Late Cretaceous]] pterosaur size, compared to birds and a human]] Pterosaurs were highly diverse in size, and some were the largest flying organisms in earth's history.<ref name=hone2007>{{cite journal | url=https://academic.oup.com/jeb/article-abstract/20/3/1164/7324411?login=false | title=Cope's Rule in the Pterosauria, and differing perceptions of Cope's Rule at different taxonomic levels | last1=Hone | first1=D. W. E. | last2=Benton | first2=M. J. | journal=Journal of Evolutionary Biology | year=2007 | volume=20 | issue=3 | pages=1164–1170 | doi=10.1111/j.1420-9101.2006.01284.x | pmid=17465925 }}</ref><ref name=fabricio2017>{{Cite journal|first1=Fabricio|last1=Villalobos |first2=Miguel Á. |last2=Olalla-Tárraga |first3=Cleiber Marques |last3=Vieira |first4=Nicholas Diniz |last4=Mazzei |first5=Luis Mauricio |last5=Bini |year=2017 |title=Spatial dimension of body size evolution in Pterosauria: Bergmann's rule does not drive Cope's rule |journal=Evolutionary Ecology Research |volume=18 |pages=169–186 }}</ref> Early pterosaurs of the [[Triassic]] and [[Jurassic]] periods were typically small animals with wingspans only up to {{convert|2|m|ftin}}, while most [[Cretaceous]] pterosaurs were larger.<ref name=hone2007/><ref name=benson2014>{{cite journal | title=Competition and constraint drove Cope's rule in the evolution of giant flying reptiles | last1=Benson | first1=R. B. J. | last2=Frigot | first2=R. A. | last3=Goswami | first3=A. | last4=Andres | first4=B. | last5=Bulter | first5=R. J.| journal=Nature Communications | year=2014 | volume=5 | issue=1 | pages=3567 | doi=10.1038/ncomms4567| pmid=24694584 | pmc=3988819 | bibcode=2014NatCo...5.3567B }}</ref><ref name=smith2022>{{cite journal | last1=Smith | first1=RE |last2=Chinsamy |first2=A |last3=Unwin |first3=DM |last4=Ibrahim |first4=N |last5=Zouhri |first5=S |last6=Martill |first6=DM | title = Small, immature pterosaurs from the Cretaceous of Africa: implications for taphonomic bias and palaeocommunity structure in flying reptiles | journal = Cretaceous Research | volume = 130 | article-number = 105061 | year = 2022 | doi = 10.1016/j.cretres.2021.105061 | bibcode=2022CrRes.13005061S | s2cid = 239257717 | url = https://www.sciencedirect.com/science/article/abs/pii/S0195667121003098 |url-access=subscription }}</ref> Some isolated specimens indicate exceptions to this rule, and the divisions of size across time may be a partial result of an incomplete fossil record.<ref name=etienne2024>{{Cite journal|last1=Etienne |first1=J. L. |last2=Smith |first2=R. E. |last3=Unwin |first3=D. M. |last4=Smyth |first4=R. S. H. |last5=Martill |first5=D. M. |year=2024 |title=A 'giant' pterodactyloid pterosaur from the British Jurassic |journal=Proceedings of the Geologists' Association |volume=135 |issue=3 |pages=335–348 |doi=10.1016/j.pgeola.2024.05.002 |doi-access=free |bibcode=2024PrGA..135..335E }}</ref><ref name=jagielska2023>{{Cite journal|last1=Jagielska |first1=N. |last2=Challands |first2=T. J. |last3=O'Sullivan |first3=M. |last4=Ross |first4=D. A. |last5=Fraser |first5=N. C. |last6=Wilkinson |first6=M. |last7=Brusatte |first7=S. L. |year=2023 |title=New postcranial remains from the Lealt Shale Formation of the Isle of Skye, Scotland, showcase hidden pterosaur diversity in the Middle Jurassic |journal=Scottish Journal of Geology |volume=59 |issue=1–2 |page=001 |doi=10.1144/sjg2023-001 |bibcode=2023ScJG...59....1J |s2cid=258232744 |doi-access=free |hdl=20.500.11820/8bc004a4-ab80-4f9f-965d-f211f18e9876 |hdl-access=free }}</ref><ref name=martinsilverstone2016>{{cite journal | last1 = Martin-Silverstone | first1 = Elizabeth | last2 = Witton | first2 = Mark P. | last3 = Arbour | first3 = Victoria M. | last4 = Currie | first4 = Philip J. | year = 2016 | title = A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants | journal = Royal Society Open Science | volume = 3 | issue = 8| article-number = 160333 | doi = 10.1098/rsos.160333 | doi-access = free| pmid = 27853614 | pmc = 5108964 | bibcode = 2016RSOS....360333M}}</ref> [[Anurognathid]]s may have been the smallest pterosaurs, with wingspans of as small as {{convert|0.4|m|ftin}}, though the age of these individuals remains uncertain.<ref name=hone2020>{{cite journal |last1=Hone |first1=D.W.E. |year=2020 |title=A review of the taxonomy and palaeoecology of the Anurognathidae (Reptilia, Pterosauria) |journal=Acta Geologica Sinica - English Edition |volume=94 |issue=5 |pages=1676–1692 |doi=10.1111/1755-6724.14585|bibcode=2020AcGlS..94.1676H }}</ref>{{sfn|Witton|2013|p=107}} The largest pterosaurs were members of [[Azhdarchidae]] such as ''[[Hatzegopteryx]]'' and ''[[Quetzalcoatlus]]'', which could attain estimated wingspans of {{convert|10-11|m|ft}} and weights of {{convert|150-250|kg|lbs}}.<ref name=witton2010b>{{cite journal |last1=Witton |first1=M.P. |last2=Habib |first2=M.B. |date=2010 |title=On the Size and Flight Diversity of Giant Pterosaurs, the Use of Birds as Pterosaur Analogues and Comments on Pterosaur Flightlessness |journal=PLOS ONE |volume=5 |issue=11 |article-number=e13982 |doi=10.1371/journal.pone.0013982 |pmid=21085624 |pmc=2981443 |bibcode=2010PLoSO...513982W |doi-access=free}}</ref><ref name=andres2021>{{cite journal |last1=Andres |first1=B. |last2=Langston |first2=W. Jr. |year=2021 |title=Morphology and taxonomy of ''Quetzalcoatlus'' Lawson 1975 (Pterodactyloidea: Azhdarchoidea) |journal=Journal of Vertebrate Paleontology |volume=41 |issue=sup1 |pages=46–202 |bibcode=2021JVPal..41S..46A |doi=10.1080/02724634.2021.1907587 |issn=0272-4634 |s2cid=245125409 |doi-access=free}}</ref>
===Skull=== [[File:Seazzadactylus_skull.png|thumb|left|Skull of an early pterosaur, ''[[Seazzadactylus]]'']] Pterosaurs have large skulls compared to other flying vertebrates, the birds and bats. Later pterosaurs had very elongated skulls, sometimes longer than the whole torso. Many bones were fused in adults.{{sfn|Witton|2013|p=23}} The skulls were pierced by multiple large holes: the bony nostrils, eye sockets, the [[antorbital fenestra]]e in the snout side and two [[temporal fenestra]]e on each rear side. [[Monofenestrata]]n pterosaurs fused the nasal and antorbital fenestra into a single large nasantorbital fenestra.{{sfn|Wellnhofer|1991|p=47}}{{sfn|Witton|2013|p=23}} The back of the head was at first vertical in orientation, but rotated to nearly horizontal later in evolution of some groups.{{sfn|Witton|2013|p=26}} The paired lower jaws were fused at the front into an elongated [[mandibula]]r symphysis. The lower jaws of the earliest pterosaurs were pierced at the rear by a mandibular fenestra, but this was lost in later species.{{sfn|Witton|2013|p=27}} [[File:Cast_of_Thalassodromeus_sethi_-_Pterosaurs_Flight_in_the_Age_of_Dinosaurs.jpg|thumb|Skull of ''[[Thalassodromeus]]'' (front on left), showing extensive crest, nasantorbital fenestra, and toothless beak]] The snout or the back of the skull often sported an upward projecting crest, sometimes of enormous size. The lower jaws could likewise feature a downward projecting keel. These crests could be expanded in size and shape with soft tissues.{{sfn|Witton|2013|p=24}} Some crests entirely lacked a bone core, with their presence only known from exceptionally well preserved specimens.<ref name="naish&martill2003"/><ref name="frey&martill1998"/><ref name=CJ02>Czerkas, S.A., and Ji, Q. (2002). A new rhamphorhynchoid with a headcrest and complex integumentary structures. In: Czerkas, S.J. (Ed.). ''Feathered Dinosaurs and the Origin of Flight''. The Dinosaur Museum: Blanding, Utah, 15–41. {{ISBN|1-932075-01-1}}.</ref>
Early pterosaurs were [[heterodont]], with multiple tooth types. Later pterosaurs were [[homodont]], having a single tooth form, often elongated and conical, throughout the skull. The teeth were replaced continuously throughout life. Between species, the dentition varied considerably. Fish eaters often had longer teeth in an expansion of the jaw tips. Filter feeders could have a sieve of up to a thousand teeth. Some later pterosaur groups were entirely toothless, featuring a horny beak similar to that of birds.{{sfn|Witton|2013|p=27}}{{sfn|Wellnhofer|1991|p=47}} Most species had some [[keratin]]ized beak tissue, though never in the same snout section as the teeth.<ref name="frey&martill1998">{{cite journal |vauthors=Frey E, Martill DM |title=Soft tissue preservation in a specimen of ''Pterodactylus kochi'' (Wagner) from the Upper Jurassic of Germany |journal=Neues Jahrbuch für Geologie und Paläontologie, Abhandlungen |volume=210|issue=3 |pages=421–41 |year=1998|doi=10.1127/njgpa/210/1998/421 |bibcode=1998NJGPA.210..421F }}</ref>
===Neck and torso=== [[File:Anhanguera santanae - Pterosaurs Flight in the Age of Dinosaurs.jpg|left|thumb|Skull and torso of ''[[Anhanguera (pterosaur)|Anhanguera]]'', showing long neck and compact torso]] The [[vertebral column]] of pterosaurs had up to seventy [[vertebrae]]. Later pterosaurs have unique structures at the sides of the vertebrae, called [[exapophyses]],<ref name="Bennett94">{{cite journal|author=S. Christopher Bennett|year=1994|title=Taxonomy and systematics of the Late Cretaceous pterosaur ''Pteranodon'' (Pterosauria, Pterodactyloidea)|url=https://www.biodiversitylibrary.org/page/4467188#page/5/mode/1up|journal=Occasional Papers of the Natural History Museum of the University of Kansas|volume=169|pages=1–70}}</ref> and the concave fronts may possess a midline prong, the hypapophysis.{{sfn|Witton|2013|p=28}} Pterosaur necks were typically long, deep, and straight, and in pterodactyloids was longer than the torso.{{sfn|Wellnhofer|1991|p=50}}{{sfn|Witton|2013|p=45}}{{sfn|Witton|2013|p=46}} The number of neck vertebrae is always seven, or nine if one includes two trunk vertebrae.{{sfn|Wellnhofer|1991|p=50}} Pterodactyloids have lost all neck ribs.{{sfn|Witton|2013|p=28}} The neck was deep and well-muscled.{{sfn|Witton|2013|p=45}}{{sfn|Witton|2013|p=46}} [[File:UCMP Pteranodon dorsal body.JPG|thumb|Pterosaur torso showing the fused front of the torso ([[notarium]]), shoulder girdle connected to it and the large breastbone, and the fused pelvic region]] The torso was short and compact. Up to seven front [[dorsal vertebra|back vertebrae]] and ribs can be fused into a rigid structure known as a [[notarium]].{{sfn|Wellnhofer|1991|p=50}}{{sfn|Witton|2013|p=30}}
The [[shoulder girdle]] was strong and well-muscled, with the upper [[shoulder blade]] and connected lower [[coracoid]] fused in later species into a single scapulocoracoid. The top of this structure fitted to the notarium, while the lower end connected to the breastbone, forming a rigid closed loop, better to withstand the forces of flapping flight.{{sfn|Witton|2013|p=44}}{{sfn|Witton|2013|p=31}} The shoulder joint was saddle-shaped allowing considerable movement to the wing.{{sfn|Witton|2013|p=31}} It faced obliquely sideways and upwards.{{sfn|Wellnhofer|1991|p=52}}
The breastbone was wide with a shallow keel, via sternal ribs attached to the dorsal ribs.{{sfn|Wellnhofer|1991|p=51}} Behind it, belly ribs ([[gastralia]]) covered the entire belly.{{sfn|Wellnhofer|1991|p=52}} To the front, a long pointy structure termed the cristospina jutted obliquely upwards. The thorax was deepest at the rear of the breastbone.{{sfn|Witton|2013|p=32}} There were no (inter)clavicles.{{sfn|Wellnhofer|1991|p=52}}
The [[pelvis]] of pterosaurs was of moderate size compared to the body as a whole. Often the three pelvic bones were fused.{{sfn|Wellnhofer|1991|p=55}} The [[sacrum]] had up to ten sacral vertebrae, sometimes connected by a bar in a similar fashion to the notarium.{{sfn|Witton|2013|p=30}} The [[Ilium (bone)|ilium]] was long and low, its front and rear blades projecting horizontally beyond the edges of the lower pelvic bones. Despite this length, the rod-like form of these processes indicates that the hindlimb muscles attached to them were limited in strength.{{sfn|Witton|2013|p=46}} Then, in side view narrow, [[pubic bone]] fused with the broad [[ischium]] into an ischiopubic blade. Sometimes, the blades of both sides were also fused, closing the pelvis from below and forming the pelvic canal. The [[hip joint]] was not perforated and allowed considerable mobility to the leg.{{sfn|Witton|2013|p=35}} It was directed obliquely upwards, preventing a perfectly vertical position of the leg.{{sfn|Wellnhofer|1991|p=55}} The front of the pubic bones articulated with a unique structure, the paired prepubic bones. Together these formed a cusp covering the rear belly, between the pelvis and the belly ribs. The vertical mobility of this element suggests a function in breathing, compensating the relative rigidity of the chest cavity.{{sfn|Witton|2013|p=35}}
===Wings=== ====Wing membranes==== [[File:Pterosaur wing configurations.jpg|thumb|left|Various configurations proposed for the wings of pterosaurs]] The primary wing membranes attached to the extremely long fourth [[finger]]s, probably extending to the ankles. The profile of the trailing edge is uncertain.{{sfn|Witton|2013|p=54}} The membranes were not leathery flaps composed of skin but highly complex dynamic structures suited to serve an active flight style.{{sfn|Witton|2013|p=53}} They were strengthened by closely spaced fibers called ''[[actinofibrils]]'',<ref>{{cite journal |author=Bennett SC |title=Pterosaur flight: the role of actinofibrils in wing function |journal=Historical Biology |volume=14 |issue=4 |pages=255–84 |year=2000 |doi=10.1080/10292380009380572|bibcode=2000HBio...14..255B |s2cid=85185457 }}</ref> in three distinct layers in the wing, in a crisscross pattern superimposed on one another. They had a stiffening or strengthening function.<ref name=kellneretal2009>{{cite journal | last1 = Kellner | first1 = A.W.A. | last2 = Wang | first2 = X. | last3 = Tischlinger | first3 = H. | last4 = Campos | first4 = D. | last5 = Hone | first5 = D.W.E. | last6 = Meng | first6 = X. | year = 2009 | title = The soft tissue of ''Jeholopterus'' (Pterosauria, Anurognathidae, Batrachognathinae) and the structure of the pterosaur wing membrane | journal = Proceedings of the Royal Society B | volume = 277| issue = 1679| pages = 321–29| doi = 10.1098/rspb.2009.0846 | pmid = 19656798 | pmc=2842671}}</ref> Also a thin layer of muscle, fibrous tissue, and a unique, complex circulatory system of looping blood vessels was present.<ref name="naish&martill2003">{{cite journal |vauthors=Naish D, Martill DM |title=Pterosaurs – a successful invasion of prehistoric skies |journal=Biologist |volume=50 |issue=5 |pages=213–16 |year=2003}}</ref> This combination may have allowed the animal to adjust the wing slackness and [[Camber (aerodynamics)|camber]] to control lift.{{sfn|Witton|2013|p=53}} [[File:Pterosaur wing surfaces (labeled).png|thumb|Two pterosaurs (''[[Scaphognathus]]'' and ''[[Balaenognathus]]'') in dorsal view, with wing parts labeled<br /><br />('''bp''': brachiopatagium, '''cp''': cruropatagium, '''pp''': propatagium)]] The wing membrane is divided into three parts.{{sfn|Witton|2013|p=52}} The ''propatagium'' ("fore membrane"), was the forward-most part of the wing and attached between the wrist and shoulder, creating the "leading edge" during flight. The ''[[patagium|brachiopatagium]]'' ("arm membrane") stretched from the fourth finger to the hindlimb. Finally, a membrane that stretched between the legs, possibly incorporated the tail, called the '''uropatagium'''.{{sfn|Witton|2013|p=52}} It might only have connected the legs, rendering it a '''cruropatagium'''. Early pterosaurs perhaps had a broader uro/cruropatagium stretching between their long fifth toes; pterodactyloids, lacking such toes, only had membranes running along the legs.{{sfn|Witton|2013|p=55}} Fossils of the rhamphorhynchoid ''[[Sordes]]'',<ref name=Unwin_Bakhurina_1994>{{cite journal |vauthors=Unwin DM, Bakhurina NN |title=''Sordes pilosus'' and the nature of the pterosaur flight apparatus |journal=Nature |volume=371 |issue= 6492|pages=62–64 |year=1994 |doi=10.1038/371062a0|bibcode=1994Natur.371...62U |s2cid=4314989 }}</ref> the [[anurognathid]] ''[[Jeholopterus]]'',<ref>{{cite journal |vauthors=Wang X, Zhou Z, Zhang F, Xu X |title=A nearly completely articulated rhamphorhynchoid pterosaur with exceptionally well-preserved wing membranes and "hairs" from Inner Mongolia, northeast China |journal=Chinese Science Bulletin |volume=47 |page=3 |year=2002 |doi=10.1360/02tb9054 |issue=3 |doi-broken-date=12 July 2025 |bibcode=2002ChSBu..47..226W|s2cid=86641794 }}</ref> suggest that the wing membrane did attach to the hindlimbs.<ref>{{cite journal|year=2003|title= New specimens of Pterosauria (Reptilia) with soft parts with implications for pterosaurian anatomy and locomotion |journal=Geological Society, London, Special Publications|doi=10.1144/GSL.SP.2003.217.01.14|last1=Frey|first1=E.|last2=Tischlinger|first2=H.|last3=Buchy|first3=M.-C.|last4=Martill|first4=D. M.|volume=217|issue= 1 |pages=233–66|bibcode= 2003GSLSP.217..233F |s2cid= 130462931 }}</ref> However, pterosaur limb proportions show that there was considerable variation in wing-plans.<ref>{{cite journal |vauthors=Dyke GJ, Nudds RL, Rayner JM |title=Limb disparity and wing shape in pterosaurs |journal=J. Evol. Biol. |volume=19 |issue=4 |pages=1339–42 |date=July 2006 |pmid=16780534 |doi=10.1111/j.1420-9101.2006.01096.x|s2cid=30516133 |doi-access=free }}</ref> ====Wing bones==== [[File:Coloborhynchus_spielbergi2.jpg|thumb|left|Skeletal reconstruction of ''[[Maaradactylus]]'', showing outstretched wings]] The arm bones supported and extended the wing. The [[humerus]] or upper arm bone is short but powerful.{{sfn|Wellnhofer|1991|p=53}} It has a large deltopectoral crest, to which the major flight muscles are attached.{{sfn|Wellnhofer|1991|p=53}} The humerus is hollow or pneumatised inside, reinforced by bone struts.{{sfn|Witton|2013|p=32}} The long bones of the lower arm, the [[ulna]] and [[Radius (bone)|radius]], are much longer than the humerus.{{sfn|Witton|2013|p=33}} A bone unique to pterosaurs, the pteroid, supported the propatagium between the wrist and shoulder.{{sfn|Witton|2013|p=34}} The pterosaur wrist consists of two inner and four outer carpals. Two inner and three outer carpals are fused together into "syncarpals". The remaining outer carpal bears a deep concave fovea within which the pteroid articulates, according to Wilkinson.<ref name=wilkinsonetal2006>{{cite journal |author1=Wilkinson M.T. |author2=Unwin D.M. |author3=Ellington C.P. | year = 2006 | title = High lift function of the pteroid bone and forewing of pterosaurs | journal = [[Proceedings of the Royal Society B]] | volume = 273 | issue = 1582| pages = 119–26 | doi = 10.1098/rspb.2005.3278 | pmid=16519243 | pmc = 1560000}}</ref>
In derived pterodactyloids metacarpals I-III are small and do not connect to the carpus, instead hanging in contact with the fourth metacarpal.{{sfn|Witton|2013|p=35}} In that case the fourth metacarpal has been enormously elongated, typically equalling or exceeding the length of the long bones of the lower arm.{{sfn|Wellnhofer|1991|p=55}} The fifth metacarpal had been lost.{{sfn|Wellnhofer|1991|p=53}} The first to third fingers are much smaller than the fourth, the "wingfinger", and contain two, three and four phalanges respectively.{{sfn|Witton|2013|p=35}} The smaller fingers are clawed. The wingfinger accounts for about half or more of the total wing length.{{sfn|Witton|2013|p=35}} It normally consists of four phalanges. Their relative lengths vary among species, allowing to distinguish related forms.{{sfn|Witton|2013|p=35}} The fourth phalanx is usually the shortest. It lacks a claw and has been lost completely by nyctosaurids. It is curved to behind, resulting in a rounded wing tip, which reduces [[induced drag]]. The wingfinger is also bent somewhat downwards.{{sfn|Wellnhofer|1991|p=55}} Standing, pterosaurs rested on their metacarpals, with the outer wing folded to behind. The "anterior" sides of the metacarpals were then rotated to the rear. This would point the smaller fingers obliquely to behind. According to Bennett, this would imply that the wingfinger, able to describe the largest arc of any wing element, up to 175°, was not folded by flexion but by an extreme extension. The wing was automatically folded when the elbow was bowed.{{sfn|Witton|2013|p=46}}{{sfn|Wellnhofer|1991|pp=53–54}}
===Hindlimbs=== [[File:Rhamphorhynchoid Patagia.jpg|thumb|Diagram of hindlimb and uropatagium anatomy of early pterosaur ''[[Sordes]]'' (A), and in context of entire skeleton in related genus ''[[Rhamphorhynchus]]'' (B)]] The hindlimbs of pterosaurs were strongly built, yet relative to their wingspans smaller than those of birds. They were long in comparison to the torso length.{{sfn|Wellnhofer|1991|p=56}} The thighbone was rather straight, with the head making only a small angle with the shaft.{{sfn|Witton|2013|p=35}} This implies that the legs were not held vertically below the body but were somewhat sprawling.{{sfn|Wellnhofer|1991|p=56}} The shinbone was often fused with the upper ankle bones into a tibiotarsus that was longer than the thighbone.{{sfn|Wellnhofer|1991|p=56}} It could attain a vertical position when walking.{{sfn|Wellnhofer|1991|p=56}} The calf bone tended to be slender, especially at its lower end that in advanced forms did not reach the ankle, sometimes reducing total length to a third. Typically, it was fused to the shinbone.{{sfn|Witton|2013|p=35}} The ankle was a simple, "mesotarsal", hinge.{{sfn|Wellnhofer|1991|p=56}} The, rather long and slender,{{sfn|Wellnhofer|1991|p=57}} [[metatarsus]] was always splayed to some degree.{{sfn|Witton|2013|p=36}} The foot was plantigrade, meaning that during the walking cycle the sole of the metatarsus was pressed onto the soil.{{sfn|Wellnhofer|1991|p=57}}
The first to fourth toes were long. They had two, three, four and five phalanges respectively.{{sfn|Wellnhofer|1991|p=56}} Often the third toe was longest; sometimes the fourth. Flat joints indicate a limited mobility. These toes were clawed but the claws were smaller than the hand claws.{{sfn|Witton|2013|p=36}} There was a clear difference between early pterosaurs and advanced species regarding the form of the fifth digit. Originally, the fifth [[metatarsal]] was robust and not very shortened. It was connected to the ankle in a higher position than the other metatarsals.{{sfn|Wellnhofer|1991|p=57}} It bore a long, and often curved, mobile clawless fifth toe consisting of two phalanges.{{sfn|Witton|2013|p=36}} It's thought that these toes support the uropatagium (or cruropatagium). As the fifth toes were on the outside of the feet, such a configuration would only have been possible if these rotated their fronts outwards in flight. Such a rotation could be caused by an [[Abduction (anatomy)|abduction]] of the thighbone, meaning that the legs would be spread. This would also turn the feet into a vertical position.{{sfn|Wellnhofer|1991|p=57}} In more advanced pterosaurs, the fifth metatarsal was much reduced and the fifth toe, if present, little more than a stub.{{sfn|Witton|2013|p=37}}
===Tail=== The tail, a continuation of the vertebral column, was slender, incapable of powering the hindlimb.{{sfn|Witton|2013|p=46}} Early species had long tails of up to fifty vertebrae, stiffened by elongated [[zygapophyses]] and [[Chevron (anatomy)|chevron]]s.{{sfn|Wellnhofer|1991|p=51}} They acted as rudders, ending at the rear in a vertical vane.{{sfn|Wellnhofer|1991|p=52}} In pterodactyloids, the tails were short and flexible,{{sfn|Wellnhofer|1991|p=52}} with as few as ten vertebrae.{{sfn|Witton|2013|p=30}}
===Pycnofibers=== [[File:Filaments_of_Tupandactylus.jpg|thumb|Diagram showing complex branched filaments in ''[[Tupandactylus]]'', with a reconstruction at right showing thick pelt of pycnofibres]] All pterosaurs had [[hair]]-like filaments known as pycnofibers on the head and torso.{{sfn|Witton|2013|p=51}} Pycnofibres were unique structures similar to [[mammal]]ian hair, an example of [[convergent evolution]],<ref name=Unwin_Bakhurina_1994/> and pterosaur pelts might have been comparable in density to those of mammals{{sfn|Witton|2013|p=51}} Skin patches show small round non-overlapping scales on the soles of the hands and feet, but these were absent from the rest of the body.{{sfn|Witton|2013|p=47}}{{sfn|Witton|2013|p=48}}<ref>{{Cite journal |last1=Hone |first1=D. |last2=Lauer |first2=R. |last3=Lauer |first3=B. |title=Soft tissue anatomy of pterosaur hands and feet – new information from Solnhofen region pterodactyloid specimens |year=2025 |journal=Lethaia |volume=58 |issue=3 |pages=1–12 |doi=10.18261/let.58.3.1 |bibcode=2025Letha..58..3.1H |doi-access=free }}</ref> The pycnofibers show that pterosaurs were warm-blooded, providing insulation to prevent heat-loss.{{sfn|Witton|2013|p=51}}
Remains of two small [[Jurassic]]-age pterosaurs from [[Inner Mongolia]], China, demonstrated that some pterosaurs had a wide array of pycnofiber shapes and structures, as opposed to the homogeneous structures that had previously documented. Some of these had frayed ends, very similar in structure to certain feather types known from birds or other dinosaurs.<ref name="Benton2019">{{cite journal |last1=Yang |first1=Zixiao |last2=Jiang |first2=Baoyu |last3=McNamara |first3=Maria E. |last4=Kearns |first4=Stuart L. |last5=Pittman |first5=Michael |last6=Kaye |first6=Thomas G. |last7=Orr |first7=Patrick J. |last8=Xu |first8=Xing |last9=Benton |first9=Michael J. |title=Pterosaur integumentary structures with complex feather-like branching |journal=Nature Ecology & Evolution |date=January 2019 |volume=3 |issue=1 |pages=24–30 |doi=10.1038/s41559-018-0728-7 |pmid=30568282 |hdl=1983/1f7893a1-924d-4cb3-a4bf-c4b1592356e9 |s2cid=56480710 |url=https://research-information.bris.ac.uk/en/publications/1f7893a1-924d-4cb3-a4bf-c4b1592356e9 |hdl-access=free }}</ref> A well preserved fossil of ''[[Tupandactylus]]'' was found to have pigment cells with similar forms to those seen in modern birds, more complex in organisation than those previously known from other pterosaurs. This specimen also suggests the presence of Stage IIIa feathers, further indication of more complex filament structures in pterosaurs. Supporting a model of common ancestry with the filaments of birds, the authors termed these structures as pterosaur feathers rather than pycnofibres.<ref>{{Cite journal|last=Cincotta |display-authors=et al |date=2022|title=Pterosaur melanosomes support signalling functions for early feathers|url=|journal=Nature|volume=604 |issue= 7907|pages=684–688|doi=10.1038/s41586-022-04622-3 |pmid= 35444275|pmc= 9046085|bibcode=2022Natur.604..684C }}</ref> This common origin had been suggested before, but remains controversial.<ref name=CJ02/><ref name="kellneretal2009" />{{sfn|Witton|2013|p=51}}
==History of discovery== {{see also|Timeline of pterosaur research}}
===First finds=== [[File:Pterodactylus holotype Collini 1784.jpg|thumb|left|Engraving of the original ''[[Pterodactylus antiquus]]'' specimen by [[Egid Verhelst the Younger|Egid Verhelst II]], 1784]] Pterosaur [[fossil]]s are very rare, due to their light bone construction. Complete skeletons can generally only be found in geological layers with exceptional preservation conditions, the so-called ''[[Lagerstätten]]''. The pieces from one such ''Lagerstätte'', the [[Late Jurassic]] [[Solnhofen Limestone]] in [[Bavaria]],{{sfn|Witton|2013|p=5}} became much sought after by rich collectors.{{sfn|Wellnhofer|1991|p=22}} In 1784, Italian naturalist [[Cosimo Alessandro Collini]] was the first scientist to describe a pterosaur fossil.{{sfn|Witton|2013|p=6}} At that time the concepts of evolution and extinction were imperfectly developed. The bizarre build of the pterosaur was shocking, as it could not clearly be assigned to any existing animal group.{{sfn|Witton|2013|pp=6–7}} The discovery of pterosaurs would thus play an important role in the progress of modern paleontology and geology.{{sfn|Witton|2013|p=7}} Scientific opinion at the time was that if such creatures were still alive, only the sea was a credible habitat; Collini suggested it might be a swimming animal that used its long front limbs as paddles.<ref name="collini1784">Collini, C.A. (1784). "Sur quelques Zoolithes du Cabinet d'Histoire naturelle de S. A. S. E. Palatine & de Bavière, à Mannheim." ''Acta Theodoro-Palatinae Mannheim 5 Pars Physica'', pp. 58–103 (1 plate).</ref> A few scientists continued to support the aquatic interpretation even until 1830, when German zoologist [[Johann Georg Wagler]] suggested that ''Pterodactylus'' used its wings as flippers and was affiliated with [[Ichthyosauria]] and [[Plesiosauria]].<ref name="wagler1830">Wagler, J. (1830). ''Natürliches System der Amphibien'' Munich, 1830: 1–354.</ref> [[File:Pterodactyl reconstruction Newman 1843.jpg|thumb|Newman's marsupial pterosaurs]] In 1800, [[Johann Hermann]] first suggested that it represented a flying creature in a letter to [[Georges Cuvier]]. Cuvier agreed in 1801, understanding it was an extinct flying reptile.<ref name="cuvier1801">{{cite journal | author = Cuvier G | year = 1801 | title = [Reptile volant]. In: Extrait d'un ouvrage sur les espèces de quadrupèdes dont on a trouvé les ossemens dans l'intérieur de la terre | journal = Journal de Physique, de Chimie et d'Histoire Naturelle | volume = 52 | pages = 253–67}}</ref> In 1809, he coined the name ''Ptéro-Dactyle'', "wing-finger".<ref>Cuvier, G., 1809, "Mémoire sur le squelette fossile d'un Reptil volant des environs d'Aichstedt, que quelques naturalistes ont pris pour un oiseau, et donc nous formons un genre de Sauriens, sous le nom de Ptero-Dactyle", ''Annales du Musée d'Histoire Naturelle'', Paris, '''13''' pp. 424–37</ref> This was in 1815 Latinised to ''[[Pterodactylus]]''.<ref>Rafinesque, C.S., 1815, ''Analyse de la Nature ou tableau de l'univers et des corps organisés'', Palermo</ref> At first most species were assigned to this genus and ultimately "pterodactyl" was popularly and incorrectly applied to all members of Pterosauria.<ref name="myths"/> Today, paleontologists limit the term to the genus ''Pterodactylus'' or members of the [[Pterodactyloidea]].<ref name="alexander"/>
In 1812 and 1817, [[Samuel Thomas von Soemmerring]] redescribed the original specimen and an additional one.<ref>Von Soemmerring, S. T., 1812, "Über einen Ornithocephalus oder über das unbekannten Thier der Vorwelt, dessen Fossiles Gerippe Collini im 5. Bande der Actorum Academiae Theodoro-Palatinae nebst einer Abbildung in natürlicher Grösse im Jahre 1784 beschrieb, und welches Gerippe sich gegenwärtig in der Naturalien-Sammlung der königlichen Akademie der Wissenschaften zu München befindet", ''Denkschriften der königlichen bayerischen Akademie der Wissenschaften'', München: mathematisch-physikalische Classe '''3''': 89–158</ref> He saw them as affiliated to birds and bats. Although he was mistaken in this, his "bat model" would be influential during the 19th century.{{sfn|Wellnhofer|1991|p=27}} In 1843, [[Edward Newman (entomologist)|Edward Newman]] thought pterosaurs were flying [[marsupials]].<ref>{{cite journal | last1 = Newman | first1 = E | year = 1843 | title = Note on the Pterodactyle Tribe considered as Marsupial Bats | journal = Zoologist | volume = 1 | pages = 129–31 }}</ref> Ironically, as the "bat model" depicted pterosaurs as warm-blooded and furred, it would turn out to be more correct in certain aspects than Cuvier's "reptile model" in the long run. In 1834, [[Johann Jakob Kaup]] named an order "Pterosaurii" to contain the "Pterodactylii" (''Pterodactylus)'' and suggested it probably consisted of several genera.<ref>{{cite journal | last1 = Kaup | first1 = J. | year = 1834 | title = Versuch einer Eintheilung der Säugethiere in 6 Stämme und der Amphibien in 6 Ordnungen | journal = Isis von Oken | volume = 1834 | pages = 311–315 |url=https://www.biodiversitylibrary.org/page/27509907}}</ref> Kaup has often been mentioned as the author of the name Pterosauria. The first to actually use the spelling Pterosauria was in 1841/1842 [[Richard Owen]], referring ''Pterodactylus cuvieri'' (''[[Cimoliopterus]]''), ''Pterodactylus giganteus'' (''[[Lonchodraco]]''), ''Pterodactylus compressirostris'' (''[[Lonchodectes]]'') and ''Pterodactylus micronyx'' (''[[Dimorphodon]])'' to the order. Brian Andres and Timothy Myers have pointed out that Owen's description of Pterosauria as "reptiles that achieved flight by modification of their pectoral extremity" would be useful as a modern [[apomorphy]]-based [[clade]] definition.<ref>{{Cite journal |last=Owen |first=Richard |date=1842 |title=Report on British Fossil Reptiles, Part II |journal=Report of the British Association for the Advancement of Science |pages=60-204}}</ref><ref>{{Cite journal |last=Andres |first=Brian |last2=Myers |first2=Timothy S. |date=September 2012 |title=Lone Star Pterosaurs |url=https://www.cambridge.org/core/product/identifier/S1755691013000303/type/journal_article |journal=Earth and Environmental Science Transactions of the Royal Society of Edinburgh |language=en |volume=103 |issue=3-4 |pages=383–398 |doi=10.1017/S1755691013000303 |issn=1755-6910|url-access=subscription }}</ref>
===Expanding research=== [[File:Dimorphodon_reconstruction_Seeley_1901.jpg|thumb|left|Historical reconstruction of ''[[Dimorphodon]]'' as a biped by Seeley]] In 1828, [[Mary Anning]] found in England the first pterosaur genus outside Germany,{{sfn|Wellnhofer|1991|p=28}} named as ''[[Dimorphodon]]'' by [[Richard Owen]], also the first non-pterodactyloid pterosaur known.{{sfn|Wellnhofer|1991|p=29}} Later in the century, the [[Early Cretaceous]] [[Cambridge Greensand]] produced thousands of pterosaur fossils, that however, were of poor quality, consisting mostly of strongly eroded fragments.{{sfn|Wellnhofer|1991|p=33}} Nevertheless, based on these, numerous genera and species would be named.{{sfn|Witton|2013|p=7}} Many were described by [[Harry Govier Seeley]], at the time the main English expert on the subject, who also wrote the first pterosaur book, ''Ornithosauria'',<ref>Seeley, H.G., 1870, ''Ornithosauria – an elementary study of the bones of Pterodactyles'', Cambridge University Press</ref> and in 1901 the first popular book,{{sfn|Witton|2013|p=7}} ''Dragons of the Air''. Seeley thought that pterosaurs were warm-blooded and dynamic creatures, closely related to birds.<ref>Seeley, H.G., 1901, ''Dragons of the Air: An account of extinct flying reptiles'', Londen: Methuen</ref> Earlier, the evolutionist [[St. George Jackson Mivart]] had suggested pterosaurs were the direct ancestors of birds.<ref>{{cite journal | last1 = Mivart | first1 = G | year = 1881 | title = A popular account of chamaeleons | journal = Nature | volume = 24 | issue = 615 | pages = 309–38 | doi = 10.1038/024335f0 | bibcode = 1881Natur..24..335. | s2cid = 30819954 }}</ref> Owen opposed the views of both men, seeing pterosaurs as cold-blooded "true" reptiles.{{sfn|Wellnhofer|1991|p=35}}
In the US, [[Othniel Charles Marsh]] in 1870 discovered ''Pteranodon'' in the [[Niobrara Chalk]], then the largest known pterosaur,{{sfn|Wellnhofer|1991|p=35}} the first toothless one and the first from America.{{sfn|Wellnhofer|1991|p=36}} These layers too rendered thousands of fossils,{{sfn|Wellnhofer|1991|p=36}} also including relatively complete skeletons that were three-dimensionally preserved instead of being strongly compressed as with the Solnhofen specimens. This led to a much better understanding of many anatomical details,{{sfn|Wellnhofer|1991|p=36}} such as the hollow nature of the bones. [[File:Rhamphorhynchus_reconstruction_Riou_1863.jpg|thumb|Early reconstruction of ''[[Rhamphorhynchus]]'']] Meanwhile, finds from the Solnhofen had continued, accounting for the majority of complete high-quality specimens discovered.{{sfn|Wellnhofer|1991|p=31}} They allowed to identify most new basal taxa, such as ''[[Rhamphorhynchus]]'', ''[[Scaphognathus]]'' and ''[[Dorygnathus]]''.{{sfn|Wellnhofer|1991|p=31}} This material gave birth to a German school of pterosaur research, which saw flying reptiles as the warm-blooded, furry and active Mesozoic counterparts of modern bats and birds.{{sfn|Wellnhofer|1991|pp=37–38}} In 1882, Marsh and [[Karl Alfred Zittel]] published studies about the wing membranes of specimens of ''Rhamphorhynchus''.<ref>{{cite journal | last1 = Marsh | first1 = O.C. | year = 1882 | title = The wings of Pterodactyles | journal = American Journal of Science | volume = 3 | issue = 16| page = 223 }}</ref><ref>{{cite journal | last1 = Zittel | first1 = K.A. | year = 1882 | title = Über Flugsaurier aus dem lithografischen Schiefer Bayerns | journal = Palaeontographica | volume = 29 | pages = 47–80 }}</ref> German studies continued well into the 1930s, describing new species such as ''[[Anurognathus]]''. In 1927, [[Ferdinand Broili]] discovered hair follicles in pterosaur skin,<ref>Broili, F., 1927, "Ein Ramphorhynchus mit Spuren von Haarbedeckung", ''Sitzungsberichte der Bayerischen Akademie der Wissenschaften'' p. 49-67</ref> and [[paleoneurology|paleoneurologist]] [[Tilly Edinger]] determined that the brains of pterosaurs more resembled those of birds than modern cold-blooded reptiles.<ref>{{cite journal | last1 = Edinger | first1 = T | year = 1927 | title = Das Gehirn der Pterosaurier | url = http://bigcat.fhsu.edu/biology/cbennett/bib-arch-pter/Edinger-1927.pdf | journal = [[Zeitschrift für Anatomie und Entwicklungsgeschichte]] | volume = 83 | issue = 1/3 | pages = 105–12 | doi = 10.1007/bf02117933 | s2cid = 19084773 | access-date = 2019-10-27 | archive-date = 2020-07-28 | archive-url = https://web.archive.org/web/20200728093840/http://bigcat.fhsu.edu/biology/cbennett/bib-arch-pter/Edinger-1927.pdf }}</ref>
In contrast, English and American paleontologists by the middle of the twentieth century largely lost interest in pterosaurs. They saw them as failed evolutionary experiments, cold-blooded and scaly, that hardly could fly, the larger species only able to glide, being forced to climb trees or throw themselves from cliffs to achieve a take-off. In 1914, for the first-time pterosaur aerodynamics were quantitatively analysed, by [[Ernest Hanbury Hankin]] and [[David Meredith Seares Watson]], but they interpreted ''Pteranodon'' as a pure glider.<ref>Hankin E.H. & Watson D.S.M.; "On the Flight of Pterodactyls", ''The Aeronautical Journal'', October 1914, pp. 324–35</ref> Little research was done on the group during the 1940s and 1950s.{{sfn|Witton|2013|p=7}}
===Pterosaur renaissance=== [[File:Zhenjiangopterus jconway.jpg|thumb|left|This drawing of ''[[Zhejiangopterus]]'' by John Conway exemplifies the "new look" of pterosaurs]] The situation for dinosaurs was comparable. From the 1960s onwards, a [[dinosaur renaissance]] took place, a quick increase in the number of studies and critical ideas, influenced by the discovery of additional fossils of ''[[Deinonychus]]'', whose spectacular traits refuted what had become entrenched orthodoxy. In 1970, likewise the description of the furry pterosaur ''[[Sordes]]'' began what [[Robert Bakker]] named a renaissance of pterosaurs.<ref>Bakker, Robert, 1986, ''The Dinosaur Heresies'', Londen: Penguin Books, 1988, p. 283</ref> [[Kevin Padian]] especially propagated the new views, publishing a series of studies depicting pterosaurs as warm-blooded, active and running animals.<ref>{{cite journal | last1 = Padian | first1 = K | year = 1979 | title = The wings of pterosaurs: A new look | journal = Discovery | volume = 14 | pages = 20–29 }}</ref><ref>Padian, K., 1980, ''Studies of the structure, evolution, and flight of pterosaurs (reptilia: Pterosauria)'', Ph.D. diss., Department of Biology, Yale University</ref><ref name="Padian1983"/> This coincided with a revival of the German school through the work of [[Peter Wellnhofer]], who in 1970s laid the foundations of modern pterosaur science.{{sfn|Witton|2013|p=5}} In 1978, he published the first pterosaur textbook,{{sfn|Witton|2013|p=9}} the ''Handbuch der Paläoherptologie, Teil 19: Pterosauria'',<ref>Wellnhofer, P., 1978, ''Handbuch der Paläoherpetologie XIX. Pterosauria'', Urban & Fischer, München</ref> and in 1991 the second ever popular science pterosaur book,{{sfn|Witton|2013|p=9}} the ''Encyclopedia of Pterosaurs''.{{sfn|Wellnhofer|1991|pp=1–192}}
This development accelerated through the exploitation of two new ''Lagerstätten''.{{sfn|Witton|2013|p=9}} During the 1970s, the Early Cretaceous [[Santana Formation]] in Brazil began to produce chalk nodules that, though often limited in size and the completeness of the fossils they contained, perfectly preserved three-dimensional pterosaur skeletal parts.{{sfn|Witton|2013|p=9}} German and Dutch institutes bought such nodules from fossil poachers and prepared them in Europe, allowing their scientists to describe many new species and revealing a whole new fauna. Soon, Brazilian researchers, among them [[Alexander Kellner]], intercepted the trade and named even more species. [[File:Sinopterus_dongi_NMNS.jpg|thumb|Specimen of ''[[Sinopterus]]'', one of many excellent pterosaur fossils from [[Liaoning]], China]] Even more productive was the Early Cretaceous Chinese [[Jehol Biota]] of [[Liaoning]] that since the 1990s has brought forth hundreds of exquisitely preserved two-dimensional fossils, often showing soft tissue remains. Chinese researchers such as [[Lü Junchang]] have again named many new taxa. As discoveries also increased in other parts of the world, a sudden surge in the total of named genera took place. By 2009, when they had increased to about ninety, this growth showed no sign of levelling-off.<ref>{{cite journal | last1 = Dyke | first1 = G.J. McGowan | last2 = Nudds | first2 = R.L. | last3 = Smith | first3 = D. | year = 2009 | title = The shape of pterosaur evolution: evidence from the fossil record | journal = Journal of Evolutionary Biology | volume = 22 | issue = 4| pages = 890–98 | doi = 10.1111/j.1420-9101.2008.01682.x | pmid = 19210587 | s2cid = 32518380 | doi-access = free }}</ref> In 2013, M.P. Witton indicated that the number of discovered pterosaur species had risen to 130.<ref name=WittonPycnofibres>{{harvnb|Witton|2013}}</ref> Over ninety percent of known taxa has been named during the "renaissance". Many of these were from groups the existence of which had been unknown.{{sfn|Witton|2013|p=9}} Advances in computing power enabled researchers to determine their complex relationships through the [[quantitative method]] of [[cladistics]]. New and old fossils yielded much more information when subjected to modern ultraviolet light or roentgen photography, or [[CAT-scan]]s.{{sfn|Witton|2013|p=10}} Insights from other fields of biology were applied to the data obtained.{{sfn|Witton|2013|p=10}} All this resulted in a substantial progress in pterosaur research, rendering older accounts in popular science books completely outdated.
In 2017 a fossil from a 170-million-year-old pterosaur, later named as the species ''[[Dearc sgiathanach]]'' in 2022, was discovered on the [[Isle of Skye]] in [[Scotland]]. The [[National Museum of Scotland]] claims that it is the largest of its kind ever discovered from the [[Jurassic period]], and it has been described as the world's best-preserved skeleton of a pterosaur.<ref>{{cite web |title='Superbly preserved' pterosaur fossil unearthed in Scotland |date=22 Feb 2022 |website=Associated Press (AP) |url=https://phys.org/news/2022-02-superbly-pterosaur-fossil-unearthed-scotland.html}}</ref>
==Evolution and extinction==
===Origins=== [[File:Scleromochlus restoration.jpg|left|thumb|[[Paleoart|Life restoration]] of ''[[Scleromochlus]],'' an [[archosauromorph]] theorized to be related to pterosaurs.]] Because pterosaur [[anatomy]] has been so heavily modified for flight, and immediate [[transitional fossil]] predecessors have not so far been described, the ancestry of pterosaurs is not fully understood.{{sfn|Witton|2013|p=13}} The oldest known pterosaurs were already fully adapted to a flying lifestyle. Since Seeley, it was recognised that pterosaurs were likely to have had their origin in the "archosaurs", what today would be called the [[Archosauromorpha]]. In the 1980s, early cladistic analyses found that they were [[Avemetatarsalia]]ns (archosaurs closer to [[dinosaur]]s than to [[crocodilia]]ns). As this would make them also rather close relatives of the dinosaurs, these results were seen by Kevin Padian as confirming his interpretation of pterosaurs as bipedal warm-blooded animals. Because these early analyses were based on a limited number of taxa and characters, their results were inherently uncertain.{{sfn|Witton|2013|pp=14, 17}}
Several influential researchers who rejected Padian's conclusions offered alternative hypotheses. [[David Unwin]] proposed an ancestry among the basal Archosauromorpha, specifically long-necked forms ("[[Protorosauria|protorosaurs]]") such as [[tanystropheid]]s. A placement among [[archosauriformes|basal archosauriforms]] like ''[[Euparkeria]]'' was also suggested.<ref name=DU06b/> Basal archosauromorphs such as these seemed to be good candidates for close pterosaur relatives due to their long-limbed anatomy; especially notable is ''[[Sharovipteryx]]'', which possessed skin membranes on its hindlimbs likely used for gliding.{{sfn|Witton|2013|pp=14, 17}} A 1999 study by [[Michael Benton]] reinforced that pterosaurs were avemetatarsalians closely related to ''[[Scleromochlus]],'' and named the group Ornithodira to encompass pterosaurs and dinosaurs''.<ref name="Benton, 1999">{{cite journal|last1=Benton|first1=M.J.|year=1999|title=''Scleromochlus taylori'' and the origin of dinosaurs and pterosaurs|journal=Philosophical Transactions of the Royal Society B: Biological Sciences|volume=354|issue=1388|pages=1423–46|doi=10.1098/rstb.1999.0489|pmc=1692658}}</ref>'' In 1996, research S. Christopher Bennett published an analysis finding pterosaurs to be protorosaurs or closely related to them after removing characteristics of the hindlimb from his analysis, to test the possibility of locomotion-based [[convergent evolution]] between pterosaurs and [[dinosaur]]s.<ref>{{cite journal | last1 = Bennett | first1 = S. Christopher | year = 1996 | title = The phylogenetic position of the Pterosauria within the Archosauromorpha | journal = Zoological Journal of the Linnean Society | volume = 118 | issue = 3| pages = 261–308 | doi = 10.1111/j.1096-3642.1996.tb01267.x | doi-access = free }}</ref> A 2007 reply by Dave Hone and Michael Benton could not reproduce this result, finding pterosaurs to be closely related to dinosaurs even without hindlimb characters. They concluded that, although more basal pterosauromorphs are needed to clarify their relationships, current evidence indicates that pterosaurs are avemetatarsalians, as either the sister group of ''Scleromochlus'' or a branch between the latter and ''[[Lagosuchus]]''.<ref name="hone&benton2007">{{cite journal |author1=Hone D.W.E. |author2=Benton M.J. | year = 2007 | title = An evaluation of the phylogenetic relationships of the pterosaurs to the archosauromorph reptiles | journal = Journal of Systematic Palaeontology | volume = 5 | issue = 4| pages = 465–69 | doi = 10.1017/S1477201907002064|s2cid=86145645 }}</ref> [[File:Lagerpeton NT small.jpg|thumb|Life restoration of ''[[Lagerpeton]]''. [[Lagerpetidae|Lagerpetid]]s share many [[anatomical]] and [[Neuroanatomy|neuroanatomical]] similarities with pterosaurs and may be close relatives]] A 2011 archosaur-focused phylogenetic analysis by [[Sterling Nesbitt]] benefited from far more data and found strong support for pterosaurs being avemetatarsalians, though ''Scleromochlus'' was not included due to its poor preservation.<ref name="NSJ11">{{cite journal|last=Nesbitt|first=S.J.|year=2011|title=The early evolution of archosaurs: relationships and the origin of major clades|journal=Bulletin of the American Museum of Natural History|volume=352|pages=1–292|doi=10.1206/352.1|hdl=2246/6112|s2cid=83493714|doi-access=free}}</ref> A 2016 archosauromorph-focused study by [[Martin Ezcurra]] included various proposed pterosaur relatives, yet also found pterosaurs to be closer to dinosaurs and unrelated to more basal taxa.<ref>{{cite journal |last1=Ezcurra |first1=Martín D. |title=The phylogenetic relationships of basal archosauromorphs, with an emphasis on the systematics of proterosuchian archosauriforms |journal=PeerJ |date=28 April 2016 |volume=4 |article-number=e1778 |doi=10.7717/peerj.1778 |pmid=27162705 |pmc=4860341 |doi-access=free }}</ref> Working from his 1996 analysis, Bennett published a 2020 study on ''[[Scleromochlus]]'' which argued that both ''Scleromochlus'' and pterosaurs were non-archosaur archosauromorphs, albeit not particularly closely related to each other.<ref>{{cite journal | last1 = Bennett | first1 = S.C. | year = 2020 | title = Reassessment of the Triassic archosauriform ''Scleromochlus taylori'': neither runner nor biped, but hopper | journal = PeerJ | volume = 8 | article-number = e8418 | doi = 10.7717/peerj.8418 | pmid = 32117608 | pmc = 7035874 | doi-access = free }}</ref> By contrast, a later 2020 study proposed that [[lagerpetid]] [[archosaur]]s were the sister clade to pterosauria.<ref name="Ezcurra Nesbitt Bronzati 2020">{{cite journal |last1=Ezcurra |first1=Martín D. |last2=Nesbitt |first2=Sterling J. |last3=Bronzati |first3=Mario |last4=Dalla Vecchia |first4=Fabio Marco |last5=Agnolin |first5=Federico L. |last6=Benson |first6=Roger B. J. |last7=Brissón Egli |first7=Federico |last8=Cabreira |first8=Sergio F. |last9=Evers |first9=Serjoscha W. |last10=Gentil |first10=Adriel R. |last11=Irmis |first11=Randall B. |last12=Martinelli |first12=Agustín G. |last13=Novas |first13=Fernando E. |last14=Roberto da Silva |first14=Lúcio |last15=Smith |first15=Nathan D. |last16=Stocker |first16=Michelle R. |last17=Turner |first17=Alan H. |last18=Langer |first18=Max C. |title=Enigmatic dinosaur precursors bridge the gap to the origin of Pterosauria |journal=Nature |date=17 December 2020 |volume=588 |issue=7838 |pages=445–449 |doi=10.1038/s41586-020-3011-4 |pmid=33299179 |bibcode=2020Natur.588..445E |s2cid=228077525 |url=http://doc.rero.ch/record/329918/files/ser_edp.pdf }}</ref> This was based on newly described fossil [[skull]]s and [[forelimb]]s showing various [[anatomical]] similarities with pterosaurs and reconstructions of lagerpetid [[brain]]s and [[sensory system]]s based on [[CT scan]]s also showing [[Neuroanatomy|neuroanatomical]] similarities with pterosaurs.<ref>{{Cite web|title=Paleontologists find pterosaur precursors that fill a gap in early evolutionary history|url=https://phys.org/news/2020-12-paleontologists-pterosaur-precursors-gap-early.html|access-date=2020-12-14|website=phys.org|language=en}}</ref><ref>{{Cite web|last=Black|first=Riley|title=Pterosaur Origins Flap into Focus|url=https://www.scientificamerican.com/article/pterosaur-origins-flap-into-focus/|access-date=2020-12-14|website=Scientific American|language=en}}</ref> The results of the latter study were subsequently supported by an independent analysis of early pterosauromorph interrelationships.<ref>{{cite journal |last1=Baron |first1=Matthew G. |title=The origin of Pterosaurs |journal=Earth-Science Reviews |date=October 2021 |volume=221 |article-number=103777 |doi=10.1016/j.earscirev.2021.103777 |bibcode=2021ESRv..22103777B }}</ref>
A related problem is the origin of pterosaur flight.{{sfn|Witton|2013|p=18}} Like with birds, hypotheses can be ordered into two main varieties: "ground up" or "tree down". Climbing a tree would cause height and gravity to provide both the energy and a strong [[selection pressure]] for incipient flight, as a fall could kill a climbing animal. [[Rupert Wild]] in 1983 proposed a hypothetical "propterosaurus": a lizard-like arboreal animal developing a membrane between its limbs, first to safely parachute and then, gradually elongating the fourth finger, to glide.<ref>Rupert Wild, 1983, "Über die Ursprung der Flugsaurier", ''Weltenberger Akademie, Erwin Rutte-Festschrift'', pp. 231–38</ref> However, subsequent cladistic results did not fit this model well. Neither protorosaurs nor ornithodirans are biologically equivalent to lizards. Furthermore, the transition between gliding and flapping flight is not well-understood. More recent studies on basal pterosaur hindlimb morphology seem to vindicate a connection to ''Scleromochlus''. Like this archosaur, basal pterosaur lineages have plantigrade hindlimbs that show adaptations for saltation.<ref name="ReferenceA" />
At least one study found that the early Triassic [[ichnofossil]] ''[[Prorotodactylus]]'' is anatomically similar to that of early pterosaurs.<ref name="Ezcurra Nesbitt Bronzati 2020"/>
===Extinction=== [[File:Arambourgiania_philadelphiae.png|thumb|left|[[Azhdarchid]] pterosaurs such as ''[[Arambourgiana]]'' thrived at the end of the Cretaceous]] It was once assumed that competition with early [[bird]] species resulted in the [[extinct]]ion of many of the pterosaurs.<ref>BBC Documentary: ''Walking with dinosaurs (episode 4 ) – Giant Of The Skies'' at 22', Tim Haines, 1999</ref> It was thought that by the end of the Cretaceous, only very large species of pterosaurs were present. The smaller species were presumed to have become extinct, their niche filled by birds.<ref>{{cite journal |vauthors=Slack KE, Jones CM, Ando T, etal |title=Early penguin fossils, plus mitochondrial genomes, calibrate avian evolution |journal=Molecular Biology and Evolution |volume=23 |issue=6 |pages=1144–55 |date=June 2006 |pmid=16533822 |doi=10.1093/molbev/msj124 |doi-access=free }}</ref> However, pterosaur decline (if actually occurring) seems unrelated to bird diversity, as ecological overlap between the two groups appears to be minimal.<ref>{{cite journal |title=Estimating the effects of sampling biases on pterosaur diversity patterns: implications for hypotheses of bird/pterosaur competitive replacement|journal=Paleobiology|issue=3|pages=432–46|year= 2009|author1=Butler, Richard J. |author2=Barrett, Paul M. |author3=Nowbath, Stephen |author4=Upchurch, Paul |name-list-style=amp |volume=35 |doi=10.1666/0094-8373-35.3.432|bibcode=2009Pbio...35..432B |s2cid=84324007}}</ref> In fact, at least some avian niches were reclaimed by pterosaurs prior to the [[Cretaceous–Paleogene extinction event]].<ref name="longrichetal2018"/> It seems that this K-Pg extinction event at the end of the Cretaceous, which wiped out all non-avian dinosaurs and many other animals, was the direct cause of the extinction of the pterosaurs.
Small-sized pterosaur species apparently were present in the [[Csehbánya Formation]], indicating a higher diversity of Late Cretaceous pterosaurs than previously accounted for.<ref>{{cite journal|author1=Prondvai, E. |author2=Bodor, E. R. |author3=Ösi, A. |year=2014 |title=Does morphology reflect osteohistology-based ontogeny? A case study of Late Cretaceous pterosaur jaw symphyses from Hungary reveals hidden taxonomic diversity |journal=Paleobiology |volume=40 |issue=2 |pages=288–321 |doi=10.1666/13030|bibcode=2014Pbio...40..288P |hdl=10831/75031 |s2cid=85673254 |url=http://real.mtak.hu/21860/1/Prondvai_et_al.2014_reposit1_u_110445.946242.pdf }}</ref> The recent findings of a small [[cat]]-sized adult azhdarchid further indicate that small pterosaurs from the Late Cretaceous might actually have simply been rarely preserved in the fossil record, helped by the fact that there is a strong bias against terrestrial small sized vertebrates such as juvenile [[dinosaurs]], and that their diversity might actually have been much larger than previously thought.<ref>{{cite journal | last1 = Martin-Silverstone | first1 = Elizabeth | last2 = Witton | first2 = Mark P. | last3 = Arbour | first3 = Victoria M. | last4 = Currie | first4 = Philip J. | year = 2016 | title = A small azhdarchoid pterosaur from the latest Cretaceous, the age of flying giants | journal = Royal Society Open Science | volume = 3 | issue = 8| article-number = 160333 | doi = 10.1098/rsos.160333 | doi-access = free| pmid = 27853614 | pmc = 5108964 | bibcode = 2016RSOS....360333M}}</ref>
A 2021 study showcases that niches previously occupied by small pterosaurs were increasingly occupied by the juvenile stages of larger species in the Late Cretaceous, indicating that pterosaurs continued to be successful as small flying animals even in the presence of avians. Rather than being outcompeted by birds, pterosaurs essentially specialised, a trend already occurring in previous eras of the Mesozoic.<ref name="Smith et al 2021">{{cite journal |last1=Smith |first1=Roy E. |last2=Chinsamy |first2=Anusuya |last3=Unwin |first3=David M. |last4=Ibrahim |first4=Nizar |last5=Zouhri |first5=Samir |last6=Martill |first6=David M. |title=Small, immature pterosaurs from the Cretaceous of Africa: implications for taphonomic bias and palaeocommunity structure in flying reptiles |journal=Cretaceous Research |date=16 October 2021 |volume=130 |article-number=105061 |doi=10.1016/j.cretres.2021.105061 |bibcode=2022CrRes.13005061S |s2cid=239257717 |url=https://figshare.com/articles/journal_contribution/20261157 }}</ref>
==Classification and phylogeny== {{further|Phylogeny of pterosaurs}} [[File:Eudimorphodon_ranzii.jpg|thumb|Fossil of ''[[Eudimorphodon]]'', one of the most primitive pterosaurs]] In [[phylogenetic taxonomy]], the [[clade]] Pterosauria has usually been defined as node-based and anchored to several extensively studied taxa as well as those thought to be primitive. One 2003 study defined Pterosauria as "The most recent common ancestor of the Anurognathidae, ''[[Preondactylus]]'' and ''Quetzalcoatlus'' and all their descendants."<ref name="kellner2003">{{cite journal | last1 = Kellner | first1 = A. W. | year = 2003 | title = Pterosaur phylogeny and comments on the evolutionary history of the group | journal = Geological Society, London, Special Publications | volume = 217 | issue = 1| pages = 105–37 | doi=10.1144/gsl.sp.2003.217.01.10 | bibcode = 2003GSLSP.217..105K| s2cid = 128892642 }}</ref> However, these types of definition would inevitably leave any related species that are slightly more primitive out of the Pterosauria. To remedy this, a new definition was proposed that would anchor the name not to any particular species but to an anatomical feature, the presence of an enlarged fourth finger that supports a wing membrane.<ref name=earlyarchosaurs>Nesbitt, S.J., Desojo, J.B., & Irmis, R.B. (2013). ''Anatomy, Phylogeny and Palaeobiology of Early Archosaurs and Their Kin''. Geological Society of London. {{ISBN|1862393613}}</ref> This apomorphy-based definition was adopted by the [[PhyloCode]] in 2020 as "[T]he clade characterized by the apomorphy fourth manual digit hypertrophied to support a wing membrane, as inherited by ''Pterodactylus'' (originally ''Ornithocephalus'') ''antiquus'' (Sömmerring 1812)".<ref>{{cite book |editor1-last=de Queiroz |editor1-first=K. |editor2-last=Cantino |editor2-first=P. D. |editor3-last=Gauthier |editor3-first=J. A. |year=2020 |title=Phylonyms: A Companion to the PhyloCode |publisher=CRC Press Boca Raton, FL |page=2072 |isbn=978-0-429-82120-2 |url=https://books.google.com/books?id=McHgDwAAQBAJ&pg=PA2072 }}</ref> A broader clade, '''Pterosauromorpha''', has been defined as all [[ornithodira]]ns more closely related to pterosaurs than to [[dinosaur]]s.<ref name=padian1997>Padian, K. (1997). "Pterosauromorpha", pp. 617–18 in Currie, P.J. and Padian, K. ''The Encyclopedia of Dinosaurs''. Academic Press. {{ISBN|0122268105}}.</ref>
The internal [[biological classification|classification]] of pterosaurs has historically been difficult, because there were many gaps in the [[fossil record]]. Starting from the 21st century, new discoveries are now filling in these gaps and giving a better picture of the evolution of pterosaurs. Traditionally, they were organized into two [[suborders]]: the [[Rhamphorhynchoidea]], a "primitive" group of long-tailed pterosaurs, and the [[Pterodactyloidea]], "advanced" pterosaurs with short tails.<ref name=DU06b>{{cite book |last=Unwin |first=David M. |title=The Pterosaurs: From Deep Time |year=2006 |publisher=Pi Press |location=New York |isbn=978-0-13-146308-0 |page=246}}</ref> However, this traditional division has been largely abandoned. Rhamphorhynchoidea is a [[paraphyletic]] (unnatural) group, since the pterodactyloids evolved directly from them and not from a common ancestor, so, with the increasing use of [[cladistics]], it has fallen out of favor among most scientists.<ref name=WittonPycnofibres/><ref name=luetal2008>{{cite journal |author1=Lü J. |author2=Unwin D.M. |author3=Xu L. |author4=Zhang X. | year = 2008 | title = A new azhdarchoid pterosaur from the Lower Cretaceous of China and its implications for pterosaur phylogeny and evolution | journal = Naturwissenschaften | volume = 95 | issue = 9| pages = 891–97 | doi = 10.1007/s00114-008-0397-5 | pmid = 18509616 | bibcode = 2008NW.....95..891L|s2cid=13458087 }}</ref>
Within pterosaurs, several smaller clades have been named. The clade '''Novialoidea''' was named by paleontologist [[Alexander Kellner|Alexander Wilhelm Armin Kellner]] in [[2003 in paleontology|2003]] as a [[node-based taxon]] consisting of the last common ancestor of ''[[Campylognathoides]]'', ''[[Quetzalcoatlus]]'' and all its descendants. This name was derived from [[Latin]] ''novus'' "new", and ''ala'', "wing", in reference to the wing [[synapomorphy|synapomorphies]] that the members of the clade possess.<ref name=Kellner03>Kellner, A. W. A., (2003): Pterosaur phylogeny and comments on the evolutionary history of the group. pp. 105–137. — ''in'' Buffetaut, E. & Mazin, J.-M., (eds.): ''Evolution and Palaeobiology of Pterosaurs''. Geological Society of London, Special Publications 217, London, 1-347</ref>
Paleontologist David Unwin in 2003 had named the group '''Lonchognatha''' in the same issue of the journal that published Novialoidea ([[Geological Society of London]], Special Publications 217) and defined it as ''[[Eudimorphodon ranzii]]'', ''[[Rhamphorhynchus muensteri]]'', their most recent common ancestor and all its descendants (as a node-based taxon).<ref name=Unwin03>Unwin, D. M., (2003): On the phylogeny and evolutionary history of pterosaurs. pp. 139–190. — ''in'' Buffetaut, E. & Mazin, J.-M., (eds.): ''Evolution and Palaeobiology of Pterosaurs''. Geological Society of London, Special Publications 217, London, 1-347</ref> Under Unwin's and Kellner's [[phylogenetic]] analyses (where ''[[Eudimorphodon]]'' and ''Campylognathoides'' form a group that is basal to both ''[[Rhamphorhynchus]]'' and ''Quetzalcoatlus''), Novialoidea is materially identical to Lonchognatha. However, other analyses find Lonchognatha to be a separate concept (Andres et al., 2010),<ref>Brian Andres, James M. Clark & Xu Xing (2010) A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs, Journal of Vertebrate Paleontology, 30:1, 163-187, DOI: 10.1080/02724630903409220</ref> or synonymous with the [[Pterosauria]] (Andres, 2010).<ref name=BBA10>{{cite book |last=Andres |first=Brian Blake |year=2010 |title=Systematics of the Pterosauria |url=http://gradworks.umi.com/34/40/3440534.html |publisher=Yale University |page=366}} [https://www.proquest.com/docview/846734901 A preview that shows the cladogram without clade names]</ref>
The precise relationships between pterosaurs is still unsettled. Many studies of pterosaur relationships in the past have included limited data and were highly contradictory. However, newer studies using larger data sets are beginning to make things clearer. The [[cladogram]] (family tree) below follows a [[phylogenetic]] analysis presented by Longrich, Martill and Andres in 2018, with clade names after Andres et al. (2014).<ref name=kryptodrakon/><ref name=longrichetal2018>{{cite journal | last1 = Longrich | first1 = N.R. | last2 = Martill | first2 = D.M. | last3 = Andres | first3 = B. | year = 2018 | title = Late Maastrichtian pterosaurs from North Africa and mass extinction of Pterosauria at the Cretaceous-Paleogene boundary | journal = PLOS Biology | volume = 16 | issue = 3| article-number = e2001663 | doi = 10.1371/journal.pbio.2001663 | pmid = 29534059 | pmc = 5849296 | doi-access = free }}</ref> <div style="overflow:auto"> {{clade| style=font-size:90%; line-height:100%; |label1='''Pterosauria''' |1={{clade |1=[[Eopterosauria]][[File:Eudimorphodon BW.jpg|30px]] |label2=[[Macronychoptera]] |2={{clade |1=[[Dimorphodontia]][[File:Dimorphodon2DB white background.jpg|30px]] |sublabel2={{clade label|[[Novialoidea]] |right=0.7em |top=-1.8em}} |2={{clade |1=[[Campylognathoididae]][[File:Campylogn DB.jpg|30px]] |sublabel2={{clade label|[[Breviquartossa]] |right=0.7em |top=-1.8em}} |2={{clade |1=[[Rhamphorhynchidae]][[File:Rhamphorhynchus DB.jpg|30px]] |sublabel2={{clade label|[[Pterodactylomorpha]] |right=0.7em |top=-1.8em}} |2={{clade |1=''[[Sordes]]''[[File:SordesDB flipped.jpg|30px]] |sublabel2={{clade label|[[Monofenestrata]] |right=0.7em |top=-1.8em}} |2={{clade |1=[[Darwinoptera]] |sublabel2={{clade label|[[Pterodactyliformes]] |right=0.7em |top=-1.8em}} |2={{clade |1=''[[Changchengopterus]]'' |sublabel2={{clade label|[[Caelidracones]] |right=0.7em |top=-1.8em}} |2={{clade |1=[[Anurognathidae]][[File:AnurognathusDB white background.jpg|25px]] |label2=[[Pterodactyloidea]] |2={{clade |1=''[[Kryptodrakon]]''[[File:Kryptodrakon.jpeg|30px]] |label2=[[Lophocratia]] |2={{clade |label1=[[Archaeopterodactyloidea]] |1={{clade |1=[[Germanodactylidae]][[File:Altmuehlopterus DB.jpg|30px]] |label2=[[Euctenochasmatia]] |2={{clade |1=''[[Pterodactylus]]''[[File:Pterodactylus BMMS7 life.png|30px]] |2=[[Ctenochasmatoidea]][[File:Plataleorhynchus.jpg|35px]] }} }} |label2=[[Eupterodactyloidea]] |2={{clade |1=''[[Haopterus]]'' |label2=[[Ornithocheiroidea]] |2={{clade |label1=[[Azhdarchoidea]] |1={{clade |1=[[Tapejaromorpha]][[File:Bakonydraco as tapejarid DB.jpg|30px]] |2=[[Neoazhdarchia]][[File:Quetzalcoatlus07.jpg|30px]] }} |2={{clade |1=''[[Piksi]]'' |label2=[[Pteranodontoidea]] |2={{clade |1=[[Pteranodontia]][[File:Pteranodon longiceps mmartyniuk wiki.png|30px]] |2=[[Ornithocheiromorpha]][[File:LiaoningopterusDB flipped.jpg|25px]] }} }} }} }} }} }} }} }} }} }} }} }} }} }} }} </div>
The position of the clade Anurognathidae (''[[Anurognathus]], [[Jeholopterus]], [[Vesperopterylus]]'') is debated.<ref>{{cite journal |last1=Andres |first1=Brian |last2=Clark |first2=James M. |last3=Xing |first3=Xu |title=A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs |journal=Journal of Vertebrate Paleontology |date=29 January 2010 |volume=30 |issue=1 |pages=163–187 |doi=10.1080/02724630903409220 |bibcode=2010JVPal..30..163A |s2cid=53688256 |url=http://doc.rero.ch/record/31614/files/PAL_E956.pdf }}</ref> Anurognathids were highly specialized, small flyers with shortened jaws and a wide gape. Some had large eyes suggesting [[nocturnal]] or [[Crepuscular animal|crepuscular]] habits, mouth bristles, and feet adapted for clinging. Parallel adaptations are seen in birds and bats that prey on insects in flight.
==Paleobiology== ===Flight=== [[File:Pterosaur respiratory system.jpg|thumb|left|upright|Diagrams showing breathing motion (top two) and internal air sac system (bottom two)]] The mechanics of pterosaur flight are not completely understood or modelled {{As of|2008|lc=y}}.<ref name=Sato>{{cite news|last=Alleyne|first=Richard|title=Pterodactyls were too heavy to fly, scientist claims|url=https://www.telegraph.co.uk/science/science-news/3352699/Pterodactyls-were-too-heavy-to-fly-scientist-claims.html|archive-url=https://web.archive.org/web/20091031071320/http://www.telegraph.co.uk/science/science-news/3352699/Pterodactyls-were-too-heavy-to-fly-scientist-claims.html|archive-date=31 October 2009|access-date=2 March 2012|newspaper=The Telegraph|date=1 October 2008}}</ref><ref>{{cite news|last=Powell|first=Devin|title=Were pterosaurs too big to fly?|url=https://www.newscientist.com/article/mg20026763.800-albatross-study-suggests-pterosaurs-were-too-big-to-fly.html|access-date=2 March 2012|newspaper=NewScientist|date=2 October 2008}}</ref>{{update inline|date=July 2022}}
Katsufumi Sato, a Japanese scientist, did calculations using modern birds and concluded that it was impossible for a pterosaur to stay aloft.<ref name=Sato /> In the book ''Posture, Locomotion, and Paleoecology of Pterosaurs'' it is theorised that they were able to fly due to the oxygen-rich, dense atmosphere of the [[Late Cretaceous]] period.<ref>{{cite book |author1=Templin, R. J. |author2=Chatterjee, Sankar |title=Posture, locomotion, and paleoecology of pterosaurs |publisher=Geological Society of America |location=Boulder, Colo |year=2004 |page=60 |isbn=978-0-8137-2376-1 |url=https://books.google.com/books?id=idta6AVV-tIC&pg=PA60}}</ref> However, both Sato and the authors of ''Posture, Locomotion, and Paleoecology of Pterosaurs'' based their research on the now-outdated theories of pterosaurs being seabird-like, and the size limit does not apply to terrestrial pterosaurs, such as [[Azhdarchidae|azhdarchid]]s and [[Tapejaridae|tapejarid]]s. Furthermore, [[Darren Naish]] concluded that atmospheric differences between the present and the Mesozoic were not needed for the giant size of pterosaurs.<ref name=Nash>{{cite web|date=February 18, 2009 |author=Naish, Darren |author-link=Darren Naish |title=Pterosaurs breathed in bird-like fashion and had inflatable air sacs in their wings |work=[[ScienceBlogs]] |url=https://scienceblogs.com/tetrapodzoology/2009/02/18/pterosaur-breathing-air-sacs/ |access-date=3 April 2016 |url-status=live |archive-url=https://web.archive.org/web/20090221143325/http://scienceblogs.com/tetrapodzoology/2009/02/pterosaur_breathing_air_sacs.php |archive-date=February 21, 2009}}</ref> [[File:Quad launch.jpg|thumb|Skeletal reconstruction of a quadrupedally launching ''[[Pteranodon|Pteranodon longiceps]]'']] Another issue that has been difficult to understand is how they [[Takeoff|took off]]. Earlier suggestions were that pterosaurs were largely cold-blooded gliding animals, deriving warmth from the environment like modern lizards, rather than burning calories. In this case, it was unclear how the larger ones of enormous size, with an inefficient cold-blooded metabolism, could manage a bird-like takeoff strategy, using only the hind limbs to generate thrust for getting airborne. Later research shows them instead as being warm-blooded and having powerful flight muscles, and using the flight muscles for walking as quadrupeds.<ref name=wittongrauniad>{{cite news | url=https://www.theguardian.com/science/2013/aug/11/pterosaurs-fossils-research-mark-witton | title=Why pterosaurs weren't so scary after all | work=The Observer newspaper | date=11 August 2013 | access-date=12 August 2013}}</ref> [[Mark Witton]] of the [[University of Portsmouth]] and Mike Habib of [[Johns Hopkins University]] suggested that pterosaurs used a vaulting mechanism to obtain flight.<ref name=wittonhabibnews>{{cite news|last=Hecht|first=Jeff|title=Did giant pterosaurs vault aloft like vampire bats?|url=https://www.newscientist.com/article/dn19724-did-giant-pterosaurs-vault-aloft-like-vampire-bats.html|access-date=2 March 2012|newspaper=NewScientist|date=16 November 2010}}</ref> The tremendous power of their winged forelimbs would enable them to take off with ease.<ref name=wittongrauniad/> Once aloft, pterosaurs could reach speeds of up to {{convert|120|km/h|mph|round=5|abbr=on}} and travel thousands of kilometres.<ref name=wittonhabibnews/>
In 1985, the Smithsonian Institution commissioned aeronautical engineer [[Paul MacCready]] to build a half-scale working model of ''[[Quetzalcoatlus northropi]]''. The replica was launched with a ground-based winch. It flew several times in 1986 and was filmed as part of the Smithsonian's IMAX film ''[[On the Wing (1986 film)|On the Wing]]''.<ref name=maccready1985>{{cite journal| last= MacCready| first= P.| year= 1985| url= http://calteches.library.caltech.edu/596/02/MacCready.pdf| title= The Great Pterodactyl Project| journal= Engineering & Science| volume= 49| number= 2| pages= 18–24| archive-date= 2020-07-28| access-date= 2018-11-23| archive-url= https://web.archive.org/web/20200728093832/https://596/2/MacCready.pdf| url-status= dead}}</ref><ref>{{Cite news|url=https://www.nytimes.com/1986/01/28/science/with-wings-flapping-model-pterodactyl-takes-to-air.html|title=With Wings Flapping, Model Pterodactyl Takes to Air|date=28 January 1986|newspaper=New York Times|first=Irvin|last=Molotsky}}</ref>
Large-headed species are thought to have [[Forward-swept wing|forwardly swept their wings]] in order to better balance.<ref>{{cite web|url=https://qmro.qmul.ac.uk/xmlui/bitstream/handle/123456789/10947/Hone%20The%20wingtips%20of%20the%20pterosaurs%202015%20Accepted.pdf?sequence=1&isAllowed=y|title=The wingtips of the pterosaurs: Anatomy, aeronautical function and 3 ecological implications|website=Qmro.qmul.ac.uk|access-date=25 June 2022}}</ref>
===Air sacs and respiration=== A 2009 study showed that pterosaurs had a lung-and-air-sac system and a precisely controlled skeletal breathing pump, which supports a flow-through pulmonary ventilation model in pterosaurs, analogous to that of birds. The presence of a [[wikt:subcutaneous|subcutaneous]] air sac system in at least some pterodactyloids would have further reduced the density of the living animal.<ref name=claessensetal2009>{{cite journal |vauthors=Claessens LP, O'Connor PM, Unwin DM |title=Respiratory evolution facilitated the origin of pterosaur flight and aerial gigantism |journal=PLOS ONE |volume=4 |issue=2 |article-number=e4497 |year=2009 |pmid=19223979 |pmc=2637988 |doi=10.1371/journal.pone.0004497 |editor1-last=Sereno |editor1-first=Paul |bibcode=2009PLoSO...4.4497C|doi-access=free }}</ref> Like modern crocodilians, pterosaurs are sometimes hypothesized to have had a [[Reptile#Respiratory system|hepatic piston]], seeing as their shoulder-pectoral girdles were too inflexible to move the sternum as in birds, and they possessed a smooth thoracic ceiling posteriorly along their ribcage and strong [[gastralia]], features consistent with the ability to inflate and deflate the lungs with craniocaudal movements as seen in a hepatic piston.<ref>{{cite journal | last1 = Geist | first1 = N. | last2 = Hillenius | first2 = W. | last3 = Frey | first3 = E. | last4 = Jones | first4 = T. | last5 = Elgin | first5 = R. | year = 2014 | title = Breathing in a box: Constraints on lung ventilation in giant pterosaurs | journal = The Anatomical Record | volume = 297 | issue = 12| pages = 2233–53 | doi = 10.1002/ar.22839 | pmid = 24357452| s2cid = 27659270 | doi-access = free }}</ref> This mechanism, however, has the obvious problem of constantly shifting the animal's centre of mass back and forth while it breathes, which would make flying highly unstable, rendering the mechanism highly unlikely. Nevertheless, it does not rule out alternative forms of extra-costal modes of ventilation, especially ones that would shift the centre of mass up and down instead of back and forth, similar to birds, as it makes flying much more stable.<ref>{{Cite journal |last=J. |first=Brocklehurst, Robert |last2=R. |first2=Schachner, Emma |last3=R. |first3=Codd, Jonathan |last4=I. |first4=Sellers, William |date=2020-03-02 |title=Respiratory evolution in archosaurs |url=https://royalsocietypublishing.org/rstb/article/375/1793/20190140/42505/Respiratory-evolution-in-archosaursArchosaur |journal=Philosophical Transactions of the Royal Society B: Biological Sciences |language=en |volume=375 |issue=1793 |doi=10.1098/r |issn=0962-8436 |archive-url=https://web.archive.org/web/20260215011001/https://royalsocietypublishing.org/rstb/article/375/1793/20190140/42505/Respiratory-evolution-in-archosaursArchosaur |archive-date=2026-02-15 |access-date=2026-03-07 |url-status=live }}</ref> Thus, their respiratory system had characteristics comparable to both modern archosaur clades.
===Nervous system=== [[File:Allkaruen_endocast.png|thumb|Brain [[endocast]] of ''[[Allkaruen]]'']] An X-ray study of pterosaur [[brain]] cavities revealed that the animals (''Rhamphorhynchus muensteri'' and ''[[Anhanguera (pterosaur)|Anhanguera]] santanae'') had massive flocculi. The [[flocculus (cerebellar)|flocculus]] is a brain region that integrates signals from joints, muscles, skin and balance organs.<ref name=Witmer_et_al_2003/> The pterosaurs' flocculi occupied 7.5% of the animals' total brain mass, more than in any other vertebrate. Birds have unusually large flocculi compared with other animals, but these only occupy between 1 and 2% of total brain mass.<ref name=Witmer_et_al_2003/>
The flocculus sends out neural signals that produce small, automatic movements in the eye muscles. These keep the image on an animal's retina steady. Pterosaurs may have had such a large flocculus because of their large wing size, which would mean that there was a great deal more sensory information to process.<ref name=Witmer_et_al_2003/> The low relative mass of the flocculi in birds is also a result of birds having a much larger brain overall; though this has been considered an indication that pterosaurs lived in a structurally simpler environment or had less complex behaviour compared to birds,<ref>{{cite journal | author = Hopson J.A. | year = 1977 | title = Relative Brain Size and Behavior in Archosaurian Reptiles | journal = Annual Review of Ecology and Systematics | volume = 8 | issue = 1 | pages = 429–48 | doi = 10.1146/annurev.es.08.110177.002241| bibcode = 1977AnRES...8..429H }}</ref> recent studies of crocodilians and other reptiles show that it is common for [[sauropsids]] to achieve high intelligence levels with small brains.<ref>{{Cite news|url=https://www.nytimes.com/2013/11/19/science/coldblooded-does-not-mean-stupid.html|title=Coldblooded Does Not Mean Stupid|first=Emily|last=Anthes|newspaper=The New York Times|date=November 18, 2013}}</ref> Studies on the endocast of ''[[Allkaruen]]'' show that brain evolution in [[pterodactyloids]] was a modular process.<ref>{{cite journal | last1 = Codorniú | first1 = Laura | last2 = Paulina Carabajal | first2 = Ariana | last3 = Pol | first3 = Diego | last4 = Unwin | first4 = David | last5 = Rauhut | first5 = Oliver W.M. | year = 2016 | title = A Jurassic pterosaur from Patagonia and the origin of the pterodactyloid neurocranium | journal = PeerJ | volume = 4 | article-number = e2311 | doi = 10.7717/peerj.2311 | pmid=27635315 | pmc=5012331 | doi-access = free }}</ref>
===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 |article-number=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|article-number=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"/>
===Swimming=== Tracks made by ctenochasmatoids indicate that these pterosaurs swam using their hindlimbs. In general, these have large hindfeet and long torsos, indicating that they were probably more adapted for swimming than other pterosaurs.<ref name= "witton2013">{{harvnb|Witton|2013|p=51}}</ref> Pteranodontians conversely have several speciations in their humeri interpreted to have been suggestive of a water-based version of the typical quadrupedal launch, and several like [[boreopterid]]s must have foraged while swimming, as they seem incapable of [[frigatebird]]-like aerial hawking.<ref name="witton2013"/> These adaptations are also seen in terrestrial pterosaurs like [[azhdarchid]]s, which presumably still needed to launch from water in case they found themselves in it. The [[nyctosaurid]] ''[[Alcione (pterosaur)|Alcione]]'' may display adaptations for wing-propelled diving like modern [[gannet]]s and [[tropicbird]]s.<ref name="longrichetal2018" />
===Diet and feeding habits=== [[File:Dimorphodon.png|thumb|Modern interpretations of the diet of ''[[Dimorphodon]]'' have challenged traditional ideas of all pterosaurs being piscivorous]] Traditionally, almost all pterosaurs were seen as surface-feeding piscivores or fish-eaters, a view that still dominates popular science. Today, many pterosaurs groups are thought to have been terrestrial carnivores, omnivores or insectivores.
Early-on it was recognised that the small [[Anurognathidae]] were nocturnal, aerial insectivores. With highly flexible joints on the wing finger, a broad, triangular wing shape, large eyes and short tail, these pterosaurs were likely analogous to [[nightjars]] or extant insectivorous bats, being capable of high manoeuvrability at relatively low speeds.<ref>{{cite journal | last1 = Bennett | first1 = S. C. | year = 2007 | title = A second specimen of the pterosaur ''Anurognathus ammoni'' | doi = 10.1007/bf02990250 | journal = Paläontologische Zeitschrift | volume = 81 | issue = 4| pages = 376–98| bibcode = 2007PalZ...81..376B | s2cid = 130685990 }}</ref> [[File:Lusognathus.png|thumb|left|[[Ctenochasmatoid]] pterosaurs such as ''[[Lusognathus]]'' may have had specialised niches in freshwater ecosystems]] Interpretations of the habits of basal groups have changed profoundly. ''[[Dimorphodon]]'', envisioned as a [[puffin]] analogue in the past, is indicated by its jaw structure, gait, and poor flight capabilities, as a terrestrial/semiarboreal predator of small mammals, [[squamates]], and large insects.{{sfn|Witton|2013|p=103}} Its robust dentition caused ''[[Campylognathoides]]'' to be seen as a generalist or a terrestrial predator of small vertebrates, but the highly robust humerus and high-aspect wing morphology, suggest it may have been capable of grabbing prey on the wing;{{sfn|Witton|2013|p=121}} a later study indicates it was [[teuthophagous]] based on squid findings within its gut.<ref>Cooper, S. L. A.; Smith, R. E.; Martill, D. M. (2024). "Dietary tendencies of the Early Jurassic pterosaurs Campylognathoides Strand, 1928, and Dorygnathus Wagner, 1860, with additional evidence for teuthophagy in Pterosauria". Journal of Vertebrate Paleontology. e2403577. doi:10.1080/02724634.2024.2403577.</ref> The small insectivorous ''[[Carniadactylus]]'' and the larger ''[[Eudimorphodon]]'' were highly aerial animals and fast, agile flyers with long robust wings. ''Eudimorphodon'' has been found with fish remains in its stomach, but its dentition suggests an opportunistic diet. Slender-winged ''[[Austriadactylus]]'' and ''[[Caviramus]]'' were likely terrestrial/semiarboreal generalists. ''Caviramus'' likely had a strong bite force, indicating an adaptation towards hard food items that might have been chewed in view of the tooth wear.{{sfn|Witton|2013|p=122}} [[File:Haliskia_Life_Restoration.png|thumb|Many [[pteranodontoid]] pterosaurs such as ''[[Haliskia]]'' likely fed on fish at sea]] Some [[Rhamphorhynchidae]], such as ''[[Rhamphorhynchus]]'' itself or ''[[Dorygnathus]]'', were fish-eaters with long, slender wings, needle-like dentition and long, thin jaws. ''[[Sericipterus]]'', ''[[Scaphognathus]]'' and ''[[Harpactognathus]]'' had more robust jaws and teeth (which were ziphodont, dagger-shaped, in '' Sericipterus''), and shorter, broader wings. These were either terrestrial/aerial predators of vertebrates<ref name=ACX10>{{cite journal |last1=Andres |first1=B. | last2=Clark |first2=J. M. | last3=Xing | first3=X. |year=2010 |title=A new rhamphorhynchid pterosaur from the Upper Jurassic of Xinjiang, China, and the phylogenetic relationships of basal pterosaurs |journal=Journal of Vertebrate Paleontology |volume=30 |issue=1 |pages=163–87 |doi=10.1080/02724630903409220|bibcode=2010JVPal..30..163A |s2cid=53688256 |url=http://doc.rero.ch/record/31614/files/PAL_E956.pdf }}</ref> or [[corvid]]-like generalists.{{sfn|Witton|2013|p=134}} [[Wukongopteridae]] like ''[[Darwinopterus]]'' were first considered aerial predators. Lacking a robust jaw structure or powerful flying muscles, they are now seen as arboreal or semiterrestrial insectivores. ''Darwinopterus robustidens'', in particular, seems to have been a beetle specialist.<ref name=robustidens>{{cite journal |author1=Lü J. |author2=Xu L. |author3=Chang H. |author4=Zhang X. | year = 2011 | title = A new darwinopterid pterosaur from the Middle Jurassic of western Liaoning, northeastern China and its ecological implications | journal = Acta Geologica Sinica - English Edition | volume = 85 | issue = 3| pages = 507–14 | doi = 10.1111/j.1755-6724.2011.00444.x|bibcode=2011AcGlS..85..507L |s2cid=128545851 }}</ref>
Among pterodactyloids, a greater variation in diet is present. [[Pteranodontia]] contained many piscivorous taxa, such as the [[Ornithocheirae]], [[Boreopteridae]], [[Pteranodontidae]] and Nyctosauridae. [[Niche partitioning]] caused ornithocheirans and the later nyctosaurids to be aerial dip-feeders like today's [[frigatebird]]s (with the exception of the plunge-diving adapted ''[[Alcione elainus]]''), while boreopterids were freshwater diving animals similar to [[cormorants]], and pteranodonts pelagic plunge-divers akin to [[boobies]] and [[gannets]]. An analysis of ''[[Lonchodraco]]'' found clusters of [[Foramen|foramina]] at the tip of its beak; birds with similarly numerous foramina have sensitive beaks used to feel for food, so ''Lonchodraco'' may have used its beak to feel for fish or invertebrates in shallow water.<ref>{{Cite journal |last1=Martill |first1=David M. |last2=Smith |first2=Roy E. |last3=Longrich |first3=Nicholas |last4=Brown |first4=James |date=2021-01-01 |title=Evidence for tactile foraging in pterosaurs: a sensitive tip to the beak of Lonchodraco giganteus (Pterosauria, Lonchodectidae) from the Upper Cretaceous of southern England |url=https://www.sciencedirect.com/science/article/pii/S0195667120303232 |journal=Cretaceous Research |language=en |volume=117 |article-number=104637 |doi=10.1016/j.cretres.2020.104637 |bibcode=2021CrRes.11704637M |s2cid=225130037 |issn=0195-6671|url-access=subscription }}</ref> The [[Istiodactylidae|istiodactylids]] were likely primarily scavengers.{{sfn|Witton|2013|pp=150–51}} [[Archaeopterodactyloidea]] obtained food in coastal or freshwater habitats. ''[[Germanodactylus]]'' and ''[[Pterodactylus]]'' were piscivores, while the [[Ctenochasmatidae]] were suspension feeders, using their numerous fine teeth to filter small organisms from shallow water. ''[[Pterodaustro]]'' was adapted for [[flamingo]]-like filter-feeding.{{sfn|Witton|2013|p=199}} [[File:Kariridraco_by_Júlia_d’Oliveira.jpg|thumb|left|[[Azhdarchoid]] pterosaurs such as ''[[Kariridraco]]'' fed on terrestrial prey]] In contrast, [[Azhdarchoidea]] mostly were terrestrial pterosaurs. [[Tapejaridae]] were arboreal omnivores, likely supplementing seeds and fruits with small insects and vertebrates.<ref name="witton2013"/><ref>{{cite journal | last1 = Wu | first1 = Wen-Hao | last2 = Zhou | first2 = Chang-Fu | last3 = Andres | first3 = Brian | year = 2017 | title = The toothless pterosaur ''Jidapterus edentus'' (Pterodactyloidea: Azhdarchoidea) from the Early Cretaceous Jehol Biota and its paleoecological implications | journal = PLOS ONE | volume = 12 | issue = 9| article-number = e0185486 | doi = 10.1371/journal.pone.0185486 | pmid = 28950013 | pmc = 5614613 | bibcode = 2017PLoSO..1285486W | doi-access = free }}</ref> Gut contents consisting of [[phytoliths]] from various plants in a specimen of the tapejarid ''[[Sinopterus]]'' constitute the first evidence of herbivory in a pterosaur.<ref>{{cite journal|author1=Jiang, S.|author2=Zhang, X.|author3=Wu, Y.|author4=Zheng, M.|author5=Kellner, A.W.A.|author6=Wang, X.|year=2025|title=First occurrence of phytoliths in pterosaurs—evidence for herbivory|journal=Science Bulletin|volume=70 |issue=19 |pages=3134–3138 |doi=10.1016/j.scib.2025.06.040 |pmid=40683846 |bibcode=2025SciBu..70.3134J }}</ref> [[Dsungaripteridae]] were specialist molluscivores, using their powerful jaws to crush the shells of molluscs and crustaceans. [[Thalassodromidae]] were likely terrestrial carnivores. ''[[Thalassodromeus]]'' itself was named after a fishing method known as "skim-feeding", later understood to be biomechanically impossible. Perhaps it pursued relatively large prey, in view of its reinforced jaw joints and relatively high bite force.<ref>Pêgas, R. V., & Kellner, A. W. (2015). Preliminary mandibular myological reconstruction of ''Thalassodromeus sethi'' (Pterodactyloidea: Tapejaridae). Flugsaurier 2015 Portsmouth, abstracts, 47–48</ref> [[Azhdarchidae]] are now understood to be terrestrial predators akin to ground [[hornbills]] or some [[storks]], eating any prey item they could swallow whole.<ref name="wittonnaish2015">{{cite journal | first1 = M.P. | last1 = Witton | first2 = D. | last2 = Naish | title = Azhdarchid pterosaurs: water-trawling pelican mimics or "terrestrial stalkers"? | journal = Acta Palaeontologica Polonica | date = 2015 | volume = 60 | issue = 3 | page = 651 | doi = 10.4202/app.00005.2013| bibcode = 2015AcPaP..60..651W | doi-access = free }}</ref> ''[[Hatzegopteryx]]'' was a robustly built predator of relatively large prey, including medium-sized dinosaurs.<ref name="witton2017">{{cite journal | first2 = M.P. | last2 = Witton | first1 = D. | last1 = Naish | title = Neck biomechanics indicate that giant Transylvanian azhdarchid pterosaurs were short-necked arch predators | volume = 5 | doi = 10.7717/peerj.2908 | pmid = 28133577 | pmc = 5248582 | journal = PeerJ | date = 2017 | article-number=e2908 | doi-access = free }}</ref><ref>{{cite conference | last1 = Witton | first1 = M. | last2 = Brusatte | first2 = S. | last3 = Dyke | first3 = G. | last4 = Naish | first4 = D. | last5 = Norell | first5 = M. | last6 = Vremir | first6 = M. | title = Pterosaur overlords of Transylvania: short-necked giant azhdarchids in Late Cretaceous Romania | conference = The Annual Symposium of Vertebrate Paleontology and Comparative Anatomy | date = 2013 | location = Edinburgh | url = http://svpca.org/abstracts/abstract.php?abstID=00000001864&prog=on | archive-url = https://web.archive.org/web/20160406020702/http://svpca.org/abstracts/abstract.php?abstID=00000001864&prog=on | archive-date = 2016-04-06}}</ref> ''[[Alanqa]]'' may have been a specialist molluscivore.<ref name="martillandibrahim2015">{{cite journal |last1=Martill |first1=David M. |last2=Ibrahim |first2=Nizar |title=An unusual modification of the jaws in cf. Alanqa, a mid-Cretaceous azhdarchid pterosaur from the Kem Kem beds of Morocco |journal=Cretaceous Research |date=March 2015 |volume=53 |pages=59–67 |doi=10.1016/j.cretres.2014.11.001 |bibcode=2015CrRes..53...59M |url=https://researchportal.port.ac.uk/portal/en/publications/an-unusual-modification-of-the-jaws-in-cf-alanqa-a-midcretaceous-azhdarchid-pterosaur-from-the-kem-kem-beds-of-morocco(ce004df9-c86a-4cf9-9fb8-1172211774cc).html }}</ref>
A 2021 study reconstructed the adductor musculature of skulls from [[Pterodactyloidea|pterodactyloids]], estimating the bite force and potential dietary habits of nine selected species.<ref name="pegas">{{cite journal |last1=Pêgas |first1=Rubi V. |last2=Costa |first2=Fabiana R |last3=Kellner |first3=Alexander W A |title=Reconstruction of the adductor chamber and predicted bite force in pterodactyloids (Pterosauria) |journal=Zoological Journal of the Linnean Society |date=24 September 2021 |volume=193 |issue=2 |pages=602–635 |doi=10.1093/zoolinnean/zlaa163 }}</ref> The study corroborated the view of [[pteranodontids]], [[nyctosaurids]] and [[Anhanguera (pterosaur)|anhanuerids]] as [[piscivores]] based on them being relatively weak but fast biters, and suggest that ''[[Tropeognathus mesembrinus]]'' was specialised in consuming relatively large prey compared to ''[[Anhanguera (pterosaur)|Anhanguera]]''. ''[[Dsungaripterus]]'' was corroborated as a [[durophagy|durophage]], with ''[[Thalassodromeus]]'' proposed to share this feeding habit based on high estimated [[bite force quotient]]s (BFQ) and absolute bite force values.<ref name="pegas"/> ''[[Tapejara wellnhoferi]]'' was corroborated as a specialised consumer of hard plant material with a relatively high BFQ and high mechanical advantage, and ''[[Caupedactylus ybaka]]'' and ''[[Tupuxuara leonardii]]'' were proposed to be ground-feeding generalists with intermediate bite force values and less specialised jaws.<ref name="pegas"/>
===Natural predators=== [[File:20130825_Brazil_Rio_de_Janeiro_0144.jpg|thumb|left|[[Theropod]] dinosaur ''[[Irritator]]'' shown feeding on a pterosaur]] Pterosaurs are known to have been eaten by [[theropoda|theropods]]. In the 1 July 2004 edition of ''[[Nature (journal)|Nature]]'', paleontologist [[Éric Buffetaut]] discusses an Early Cretaceous fossil of three cervical [[vertebra]]e of a pterosaur with the broken tooth of a [[spinosaur]], most likely ''[[Irritator]]'', embedded in it. The vertebrae are known not to have been eaten and exposed to digestion, as the joints are still articulated.<ref>{{cite journal |vauthors=Buffetaut E, Martill D, Escuillié F |title=Pterosaurs as part of a spinosaur diet |journal=Nature |volume=430 |issue=6995 |page=33 |date=July 2004 |pmid=15229562 |doi=10.1038/430033a |bibcode=2004Natur.429...33B|s2cid=4398855 |doi-access=free }}</ref> Fossils of ''Pteranodon'' have been found with tooth marks from sharks such as ''[[Squalicorax]]'',<ref>{{Cite web|url=https://www.nationalgeographic.com/science/2018/10/news-sharks-eating-pterosaurs-fossils-cretaceous-paleontology/|archive-url=https://web.archive.org/web/20181003163916/https://www.nationalgeographic.com/science/2018/10/news-sharks-eating-pterosaurs-fossils-cretaceous-paleontology/|archive-date=October 3, 2018|title=Prehistoric sharks feasted on flying reptiles, fossil reveals|date=October 3, 2018|website=Science & Innovation}}</ref> and a fossil with tooth marks from the [[Toolebuc Formation]] has been interpreted as being attacked or scavenged by an [[Ichthyosauria|ichthyosaur]] (most likely ''[[Platypterygius]]'').
===Reproduction and life history=== [[File:Pterodactylus micronyx - IMG 0677.jpg|thumb|Fossil [[Pterodactyloidea|pterodactyloid]] juvenile from the Solnhofen Limestone]] While very little is known about pterosaur reproduction, it is believed that, similar to all dinosaurs, all pterosaurs reproduced by laying eggs, though such findings are very rare. The first known pterosaur eggs were found in the quarries of Liaoning, the same place that yielded feathered dinosaurs, and in Loma del Pterodaustro ([[Lagarcito Formation]], Argentina). The eggs from [[Liaoning]] were squashed flat with no signs of cracking, so evidently the eggs had leathery shells, as in modern lizards.<ref name="Ji_et_al_2004">{{cite journal |vauthors=Ji Q, Ji SA, Cheng YN, etal |title=Palaeontology: pterosaur egg with a leathery shell |journal=Nature |volume=432 |issue=7017 |page=572 |date=December 2004|doi=10.1038/432572a |pmid=15577900|bibcode=2004Natur.432..572J |s2cid=4416203 |url=http://doc.rero.ch/record/14929/files/PAL_E2072.pdf }}</ref> The egg from the [[Lagarcito Formation]] was laid by a ''[[Pterodaustro]]'',<ref name="Codorniú et al. 2004">{{cite journal |last1=Codorniú |first1=L. |last2=Chiappe |first2=L. |last3=Rivarola |first3=D. |title=Primer reporte de un embrión de pterosaurio (Cretácico inferior, San Luis, Argentina) |journal=Ameghiniana |date=2004 |volume=41 |issue=4 (supplement; abstracts from XX Jornadas Argentinas de Paleontología de Vertebrados, La Plata, 26–28 May 2004) |page=40R |url=https://www.ameghiniana.org.ar/index.php/ameghiniana/article/view/2705 }}</ref><ref name="Chiappe et al. 2004">{{cite journal |last1=Chiappe |first1=Luis M. |last2=Codorniú |first2=Laura |last3=Grellet-Tinner |first3=Gerald |last4=Rivarola |first4=David |title=Argentinian unhatched pterosaur fossil |journal=Nature |date=December 2004 |volume=432 |issue=7017 |pages=571–572 |doi=10.1038/432571a |pmid=15577899 |language=en |issn=1476-4687|hdl=11336/156308 |hdl-access=free }}</ref> a pterosaur known by abundant material.<ref name="Codorniú et al. 2013">{{cite journal |last1=Codorniú |first1=Laura |last2=Chiappe |first2=Luis M. |last3=Cid |first3=Fabricio D. |title=First occurrence of stomach stones in pterosaurs |journal=Journal of Vertebrate Paleontology |date=May 2013 |volume=33 |issue=3 |pages=647–654 |doi=10.1080/02724634.2013.731335 |bibcode=2013JVPal..33..647C |language=en |issn=0272-4634|hdl=11336/4391 |hdl-access=free }}</ref> This was supported by the description of an additional pterosaur egg belonging to the genus ''[[Darwinopterus]]'', described in 2011, which also had a leathery shell and, also like modern reptiles but unlike birds, was fairly small compared to the size of the mother.<ref name=luetal2011>{{cite journal |author1=Lü J. |author2=Unwin D.M. |author3=Deeming D.C. |author4=Jin X. |author5=Liu Y. |author6=Ji Q. | year = 2011 | title = An egg-adult association, gender, and reproduction in pterosaurs | journal = Science | volume = 331 | issue = 6015| pages = 321–24 | doi = 10.1126/science.1197323 | pmid = 21252343|bibcode=2011Sci...331..321L |s2cid=206529739 }}</ref> In 2014 five unflattened eggs from the species ''[[Hamipterus|Hamipterus tianshanensis]]'' were found in an Early Cretaceous deposit in northwest China. Examination of the shells by scanning electron microscopy showed the presence of a thin calcareous eggshell layer with a membrane underneath.<ref name=":0">{{cite journal|last1=Wang|first1=Xiaolin|title=Sexually Dimorphic Tridimensionally Preserved Pterosaurs and Their Eggs from China|journal=Current Biology|doi=10.1016/j.cub.2014.04.054|pmid=24909325|volume=24|issue=12|pages=1323–30|year=2014|doi-access=free|bibcode=2014CBio...24.1323W }}{{Dead link|date=May 2020 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> A study of pterosaur eggshell structure and chemistry published in 2007 indicated that it is likely pterosaurs buried their eggs, like modern [[crocodile]]s and [[turtle]]s. Egg-burying would have been beneficial to the early evolution of pterosaurs, as it allows for more weight-reducing adaptations, but this method of reproduction would also have put limits on the variety of environments pterosaurs could live in and may have disadvantaged them when they began to face ecological competition from [[bird]]s.<ref name="grellet-tinneretal2007">{{cite journal |vauthors=Grellet-Tinner G, Wroe S, Thompson MB, Ji Q |title=A note on pterosaur nesting behavior |journal=Historical Biology |volume=19 |issue=4 |pages=273–77 |year=2007 |doi=10.1080/08912960701189800|bibcode=2007HBio...19..273G |s2cid=85055204 }}</ref>
A ''Darwinopterus'' specimen showcases that at least some pterosaurs had a pair of functional [[ovaries]], as opposed to the single functional ovary in birds, dismissing the reduction of functional ovaries as a requirement for powered flight.<ref>{{cite journal | last1 = Xiaolin Wang | first1 = Kellner Alexander W.A. | last2 = Cheng | first2 = Xin | last3 = Jiang | first3 = Shunxing | last4 = Wang | first4 = Qiang | last5 = Sayão Juliana | first5 = M. | last6 = Rordrigues Taissa | first6 = Costa Fabiana R. | last7 = Li | first7 = Ning | last8 = Meng | first8 = Xi | last9 = Zhou | first9 = Zhonghe | year = 2015 | title = Eggshell and Histology Provide Insight on the Life History of a Pterosaur with Two Functional Ovaries | journal = Anais da Academia Brasileira de Ciências | volume = 87 | issue = 3| pages = 1599–1609 | doi = 10.1590/0001-3765201520150364| pmid = 26153915| doi-access = free }}</ref> [[File:Rhamphorhynchus_Growth.jpg|thumb|left|Growth series of ''[[Rhamphorhynchus]]'' specimens showing changes throughout life]] Wing membranes preserved in pterosaur embryos are well developed, suggesting that pterosaurs were ready to fly soon after birth.<ref>{{cite journal |vauthors=Wang X, Zhou Z |title=Palaeontology: pterosaur embryo from the Early Cretaceous |journal=Nature |volume=429 |issue=6992 |page=621 |date=June 2004 |pmid=15190343 |doi=10.1038/429621a |bibcode=2004Natur.429..621W|s2cid=4428545 |doi-access=free }}</ref> However, [[tomography]] scans of fossilised ''Hamipterus'' eggs suggests that the young pterosaurs had well-developed thigh bones for walking, but weak chests for flight.<ref name=":1">{{Cite web|url=https://phys.org/news/2017-11-hundreds-pterosaur-eggs-reveal-early.html|title=Pterosaur hatchlings needed their parents, trove of eggs reveals (Update)|website=phys.org|language=en-us|access-date=2020-03-21}}</ref> It is unknown if this holds true for other pterosaurs. Fossils of pterosaurs only a few days to a week old (called "flaplings") have been found, representing several pterosaur families, including pterodactylids, rhamphorhinchids, ctenochasmatids and azhdarchids.<ref name=DU06b/> All preserved bones that show a relatively high degree of hardening (''ossification'') for their age, and wing proportions similar to adults. In fact, many pterosaur flaplings have been considered adults and placed in separate species in the past. Additionally, flaplings are normally found in the same sediments as adults and juveniles of the same species, such as the ''Pterodactylus'' and ''Rhamphorhynchus'' flaplings found in the [[Solnhofen limestone]] of Germany, and ''Pterodaustro'' flaplings from Argentina. All are found in deep aquatic environment far from shore.<ref name=bennett1995>{{cite journal | author = Bennett S. C. | year = 1995 | title = A statistical study of ''Rhamphorhynchus'' from the Solnhofen Limestone of Germany: Year-classes of a single large species | jstor=1306329 | journal = Journal of Paleontology | volume = 69 | issue = 3 | pages = 569–80| doi = 10.1017/S0022336000034946| bibcode = 1995JPal...69..569B | s2cid = 88244184 }}</ref> [[File:Lamberts_Bay_Bird_Island.jpg|thumb|Some pterosaurs may have reproduced in [[bird colony|colonies]] similar to those of modern seabirds]] For the majority of pterosaur species, it is not known whether they practiced any form of parental care, but their ability to fly as soon as they emerged from the egg and the numerous flaplings found in environments far from nests and alongside adults has led most researchers, including Christopher Bennett and David Unwin, to conclude that the young were dependent on their parents for a relatively short period of time, during a period of rapid growth while the wings grew long enough to fly, and then left the nest to fend for themselves, possibly within days of hatching.<ref name=DU06b/><ref name=lifehistory/> Alternatively, they may have used stored yolk products for nourishment during their first few days of life, as in modern reptiles, rather than depend on parents for food.<ref name=bennett1995/> Fossilised ''Hamipterus'' nests were shown preserving many male and female pterosaurs together with their eggs in a manner to a similar to that of modern [[seabird]] [[Bird colony|colonies]].<ref name=":0" /><ref>{{Cite web|url=https://phys.org/news/2014-06-3d-pterosaur-eggs-parents.html|title=First 3D pterosaur eggs found with their parents|website=phys.org|language=en-us|access-date=2020-03-21}}</ref> Due to how underdeveloped the chests of the hatchlings were for flying, it was suggested that ''Hamipterus'' may have practiced some form of parental care.<ref name=":1" /> However, this study has since been criticised.<ref>{{Cite journal|doi = 10.1098/rspb.2019.0409|title = Prenatal development in pterosaurs and its implications for their postnatal locomotory ability|year = 2019|last1 = Unwin|first1 = David Michael|last2 = Deeming|first2 = D. Charles|journal = Proceedings of the Royal Society B: Biological Sciences|volume = 286|issue = 1904|pmid = 31185866|pmc = 6571455}}</ref> Most evidence currently leans towards pterosaur hatchlings being [[Precociality|superprecocial]], similar to that of [[megapode]] birds, which fly after hatching without the need of parental care. A further study compares evidence for superprecociality and "late term flight" and overwhelmingly suggests that most if not all pterosaurs were capable of flight soon after hatching.<ref>{{Cite journal|doi = 10.1038/s41598-021-92499-z|title = Powered flight in hatchling pterosaurs: Evidence from wing form and bone strength|year = 2021|last1 = Naish|first1 = Darren|last2 = Witton|first2 = Mark P.|last3 = Martin-Silverstone|first3 = Elizabeth|journal = Scientific Reports|volume = 11|issue = 1|page = 13130|pmid = 34294737|pmc = 8298463|bibcode = 2021NatSR..1113130N}}</ref> A later study suggested that while smaller-bodied pterosaurs were most likely superprecocial or precocial, owing to the consistent or decreasing wing aspect ratio during growth, certain large-bodied pterosaurs, such as ''Pteranodon'' showed possible evidence of their young being [[altricial]], due to the fast rate the limb bones closest to the body grew compared to any other element of their skeleton after hatching. Other factors mentioned were the limits of soft shelled eggs and the size of the pelvic opening of large female pterosaurs.<ref>{{Cite journal |last1=Yang |first1=Zixiao |last2=Jiang |first2=Baoyu |last3=Benton |first3=Michael J. |last4=Xu |first4=Xing |last5=McNamara |first5=Maria E. |last6=Hone |first6=David W. E. |date=2023-07-26 |title=Allometric wing growth links parental care to pterosaur giantism |journal=Proceedings of the Royal Society B: Biological Sciences |language=en |volume=290 |issue=2003 |article-number=20231102 |doi=10.1098/rspb.2023.1102 |issn=0962-8452 |pmc=10354479 |pmid=37464754}}</ref><ref>{{Cite web |last=Bristol |first=University of |title=July: Pterosaurs parents {{!}} News and features {{!}} University of Bristol |url=https://www.bristol.ac.uk/news/2023/july/pterosaurs-parents.html |access-date=2023-08-22 |website=www.bristol.ac.uk |date=19 July 2023 |language=en-GB}}</ref>
Growth rates of pterosaurs once they hatched varied across different groups. In earlier, long-tailed pterosaurs ("[[rhamphorhynchoid]]s"), such as ''Rhamphorhynchus'', the average growth rate during the first year of life was 130% to 173%, slightly faster than the growth rate of [[alligator]]s. Growth in these species slowed after sexual maturity, and it would have taken more than three years for ''Rhamphorhynchus'' to attain maximum size.<ref name=lifehistory>{{Cite journal | last1 = Prondvai | first1 = E. | last2 = Stein | first2 = K. | last3 = Ősi | first3 = A. | last4 = Sander | first4 = M. P. | editor1-last = Soares | editor1-first = Daphne | title = Life history of ''Rhamphorhynchus'' inferred from bone histology and the diversity of pterosaurian growth strategies | doi = 10.1371/journal.pone.0031392 | journal = PLOS ONE | volume = 7 | issue = 2 | article-number = e31392 | year = 2012 | pmid = 22355361 | pmc = 3280310| bibcode = 2012PLoSO...731392P | doi-access = free }}</ref> In contrast, the later [[pterodactyloid]] pterosaurs, such as ''[[Pteranodon]]'', grew to adult size within the first year of life. Additionally, pterodactyloids had ''determinate growth'', meaning that the animals reached a fixed maximum adult size and stopped growing.<ref name="bennett1995"/>
A 2021 study indicates that pterosaur juveniles of larger species increasingly took the roles previously occupied by adult small pterosaurs.<ref name="Smith et al 2021"/>
===Daily activity patterns=== Comparisons between the [[scleral ring]]s of pterosaurs and modern birds and reptiles have been used to infer daily activity patterns of pterosaurs. The pterosaur genera ''[[Pterodactylus]]'', ''[[Scaphognathus]]'', and ''[[Tupuxuara]]'' have been inferred to be [[Diurnality|diurnal]], ''[[Ctenochasma]]'', ''[[Pterodaustro]]'', and ''[[Rhamphorhynchus]]'' have been inferred to be [[nocturnal]], and ''[[Tapejara (pterosaur)|Tapejara]]'' has been inferred to be [[cathemeral]], being active throughout the day for short intervals. As a result, the possibly fish-eating ''Ctenochasma'' and ''Rhamphorhynchus'' may have had similar activity patterns to modern nocturnal seabirds, and the filter-feeding ''Pterodaustro'' may have had similar activity patterns to modern [[Anseriformes|anseriform]] birds that feed at night. The differences between activity patterns of the [[Paleobiota of the Solnhofen Formation|Solnhofen]] pterosaurs ''Ctenochasma'', ''Rhamphorhynchus'', ''Scaphognathus'', and ''Pterodactylus'' may also indicate [[niche partitioning]] between these genera.<ref>{{cite journal|author1=Schmitz, L. |author2=Motani, R. |year=2011 |title=Nocturnality in Dinosaurs Inferred from Scleral Ring and Orbit Morphology |journal=Science |volume=332 |issue= 6030|pages= 705–08|doi=10.1126/science.1200043 |pmid=21493820 |bibcode=2011Sci...332..705S|s2cid=33253407 }}</ref>
==Cultural significance== {{anchor|In popular culture}} [[File:Pterosaurs on South Bank.jpg|thumb|''Quetzalcoatlus'' models in [[South Bank]], created by Mark Witton for the Royal Society's 350th anniversary]] Pterosaurs have been a staple of popular culture for as long as their cousins the dinosaurs, though they are usually not featured as prominently in films, literature, or other art. While the depiction of dinosaurs in popular media has changed radically in response to advances in paleontology, a mainly outdated picture of pterosaurs has persisted since the mid-20th century.<ref name=honepterosaurculture/> [[File:When Dinosaurs Ruled the Earth (1970) trailer - Rhamphorhynchus 2.png|thumb|left|Scene from ''[[When Dinosaurs Ruled the Earth]]'' depicting an outsized ''[[Rhamphorhynchus]]'']] The vague generic term "pterodactyl" is often used for these creatures. The animals depicted in fiction and pop culture frequently represent either ''[[Pteranodon]]'' or (non-pterodactyloid) ''[[Rhamphorhynchus]]'', or a fictionalized hybrid of the two.<ref name=honepterosaurculture>Hone, D. (2010). [http://www.pterosaur.net/popular_culture.php "Pterosaurs In Popular Culture."] {{Webarchive|url=https://web.archive.org/web/20210502201531/http://www.pterosaur.net/popular_culture.php |date=2021-05-02 }} ''Pterosaur.net'', Accessed 27 August 2010.</ref> Many children's toys and cartoons feature "pterodactyls" with ''Pteranodon''-like crests and long, ''[[Rhamphorhynchus]]''-like tails and teeth, a combination that never existed in nature. However, at least one pterosaur ''did'' have both teeth and a ''Pteranodon''-like crest: ''[[Ludodactylus]]'', whose name means "toy finger" for its resemblance to old, inaccurate children's toys.<ref name=MFDB00>Frey, E., Martill, D., and Buchy, M. (2003). "A new crested ornithocheirid from the Lower Cretaceous of northeastern Brazil and the unusual death of an unusual pterosaur" in: Buffetaut, E., and Mazin, J.-M. (eds.). ''Evolution and Palaeobiology of Pterosaurs''. ''Geological Society Special Publication'' '''217''': 56–63. {{ISBN|1-86239-143-2}}.</ref> Pterosaurs have sometimes been incorrectly identified as (the ancestors of) [[bird]]s, though birds are [[Theropoda|theropod]] dinosaurs and not descendants of pterosaurs.
Pterosaurs were used in fiction in Sir Arthur Conan Doyle's 1912 novel ''[[The Lost World (Doyle novel)|The Lost World]]'' and its [[The Lost World (1925 film)|1925 film adaptation]]. They appeared in a number of films and television programs since, including the 1933 film ''[[King Kong (1933 film)|King Kong]]'', and 1966's ''[[One Million Years B.C.]]'' In the latter, animator [[Ray Harryhausen]] had to add inaccurate bat-like wing fingers to his stop motion models in order to keep the membranes from falling apart, though this particular error was common in art even before the film was made. [[Rodan]], a fictional giant monster (or ''[[kaiju]]'') which first appeared in the 1956 film ''[[Rodan (film)|Rodan]]'', is portrayed as an enormous irradiated species of ''Pteranodon''.{{sfn|Berry|2005|p=452}}<ref name=Thomas2020>Thomas, H.N. (2020). [https://jgeekstudies.org/2020/07/05/the-one-born-of-fire-a-pterosaurological-analysis-of-rodan "The One Born of Fire: a pterosaurological analysis of Rodan"]. ''Journal of Geek Studies'' '''7''': 53–59.</ref> Rodan has appeared in multiple Japanese [[Godzilla (franchise)|''Godzilla'' films]] released during the 1960s, 1970s, 1990s, and 2000s, and also appeared in the 2019 American-produced film ''[[Godzilla: King of the Monsters (2019 film)|Godzilla: King of the Monsters]]''.<ref name=Thomas2020/><ref>{{cite web|last=Gonzales|first=Dave|url=https://www.thrillist.com/entertainment/nation/best-godzilla-movies-monster-fights|title=A Monster-Sized Breakdown of Every Insane 'Godzilla' Movie|date=October 12, 2016|website=[[Thrillist]]|access-date=July 11, 2019}}</ref><ref>{{cite web|last=Sharf|first=Zack|url=https://www.indiewire.com/2018/12/godzilla-king-of-the-monsters-trailer-mothra-rodan-1202026840/|title='Godzilla: King of the Monsters' Trailer Turns Mothra, Rodan, and More Into Epic Spectacle |format=video|date=December 10, 2018|website=[[IndieWire]]|access-date=July 11, 2019}}</ref> [[File:Paleoart_reconstruction_of_Vesperopterylus.png|thumb|''[[Versperopterylus]]'' is one of the only pterosaurs with grasping feet, despite popular depictions of them on many pterosaurs]] The [[Nazg%C3%BBl#Steeds|Fell Beast]]s of [[J.R.R. Tolkien]]'s ''[[Lord of the Rings]]'' are often understood as "pterosaur-like", although Tolkien himself did deny they were actual pterosaurs. After the 1960s, pterosaurs remained mostly absent from notable American film appearances until 2001's ''[[Jurassic Park III]]''. Paleontologist Dave Hone noted that the pterosaurs in this film had not been significantly updated to reflect modern research. Errors persisting were teeth while toothless ''Pteranodon'' was intended to be depicted, nesting behavior that was known to be inaccurate by 2001, and leathery wings, rather than the taut membranes of muscle fiber required for pterosaur flight.<ref name=honepterosaurculture/> Petrie from ''[[The Land Before Time]]'' (1988), is a notable example from an animated film.<ref>{{cite book |last1=Mansour |first1=David |title=From Abba to Zoom A Pop Culture Encyclopedia of the Late 20th Century |date=2005 |publisher=Andrews MacMeel Publishing |page=272}}</ref>
In most media appearances, pterosaurs are depicted as [[piscivore]]s, not reflecting their full dietary variation. They are also often shown as aerial predators similar to [[Bird of prey|birds of prey]], grasping human victims with talons on their feet. However, only the small [[anurognathid]] ''[[Vesperopterylus]]'' and small [[wukongopterid]] ''[[Kunpengopterus]]''<ref name="Zhouetal2021">{{Cite journal|last1=Zhou |first1=X. |last2=Pêgas |first2=R. V. |last3=Ma |first3=W. |last4=Han |first4=G. |last5=Jin |first5=X. |last6=Leal |first6=M. E. C. |last7=Bonde |first7=N. |last8= Kobayashi |first8=Y. |last9=Lautenschlager |first9=S. |last10=Wei |first10=X. |last11=Shen |first11=C. |last12=Ji |first12=S. |title=A new darwinopteran pterosaur reveals arborealism and an opposed thumb |year=2021 |journal=[[Current Biology]] |volume= 31|issue=11 |pages=2429–2436.e7 |doi=10.1016/j.cub.2021.03.030 |pmid=33848460 |doi-access=free |bibcode=2021CBio...31E2429Z }}</ref> are known to possess prehensile feet and hands respectively; all other known pterosaurs have flat, plantigrade feet with no opposable toes, and the feet are generally proportionally small, at least in the case of the Pteranodontia.<ref name="myths" />
==See also== {{Portal|Reptiles|Dinosaurs|Evolutionary biology|Paleontology}} * [[Flying and gliding animals]] * [[Graphical timeline of pterosaurs]] * [[List of pterosaur-bearing stratigraphic units]] * [[List of pterosaur genera]] * [[Phylogeny of pterosaurs]] * [[Pterosaur Beach]] * [[Pterosaur size]] * [[Timeline of pterosaur research]]
== Explanatory notes == {{notelist}}
==References== {{Reflist}}
==Sources== * {{cite book |last=Berry |first=Mark F. |year=2005 |title=The Dinosaur Filmography |publisher=McFarland & Company |isbn=978-0-7864-2453-5}} * {{cite book |last=Wellnhofer |first=Peter |year=1991 |title=The Illustrated Encyclopedia of Pterosaurs: An Illustrated Natural History of the Flying Reptiles of the Mesozoic Era |publisher=Crescent Books |isbn=978-0-517-03701-0}} * {{cite book |last=Witton |first=Mark |year=2013 |title=Pterosaurs: Natural History, Evolution, Anatomy|publisher=Princeton University Press |isbn=978-0-691-15061-1}}
==External links== {{Commons category|Pterosauria}} {{Wikisourcecat|Pterosaurs}} * [http://pterosaur.net/index.php Pterosaur.net] {{Webarchive|url=https://web.archive.org/web/20210502201619/http://pterosaur.net/index.php |date=2021-05-02 }}, multi-authored website about all aspects of pterosaur science * [http://www.pterosaur.co.uk/ The Pterosaur Database] {{Webarchive|url=https://web.archive.org/web/20120716092155/http://www.pterosaur.co.uk/ |date=2012-07-16 }}, by Paul Pursglove * [https://dipbsf.uninsubria.it/paleo/kellner.htm "Comments on the phylogeny of the pterodactyloidea"], by Alexander W. A. Kellner (technical)
{{Avemetatarsalia|state=autocollapse}} {{Pterosauria|state=autocollapse}} {{fins, limbs and wings}} {{Taxonbar|from=Q179204}} {{Authority control}}
[[Category:Pterosaurs| ]] [[Category:Reptile clades]]