greek wing genus included largest known flying reptiles metres existed late cretaceous geological period north_america present day kansas alabama nebraska wyoming fossil specimens found specimens known science preserved nearly complete articulated skeletons important animal community dinosaur definition belong order nonetheless frequently featured dinosaur media strongly associated general public description species extremely represented fossil record allowing detailed descriptions anatomy analysis life history specimens identified half complete researchers good information anatomy animal fossil material known includes male female specimens age groups possibly species size adult specimens major species divided distinct size classes smaller class specimens small rounded head wide pelvic canals wider larger size class size pelvic canal probably allowed laying eggs indicating smaller adults females larger size class representing male individuals narrow large probably display adult male largest largest flying animals known late 20th century giant discovered wingspan average adult male metres adult females smaller averaging metres wingspan largest specimen measured metres larger specimen known formation wingspan metres specimen belong distinct genus species specimens found crushed fossils exist detailed description animal methods estimate mass large male specimens meters unreliable producing wide range estimates low kilograms high kilograms review size estimates published researchers demonstrated largest estimates certainly incorrect given total volume body correct animal principally comprised aluminium considered methods researchers obtained smaller mass estimates equally flawed produced scaling modern animals bats birds size despite fact vastly different body proportions soft tissue anatomy living animal skull unlike earlier similar birds solid bony margins projected base jaws long slender ended thin sharp points upper jaw longer lower jaw upper jaw curved upward normally attributed upward curving specimen corresponding widening tip tip known specimen level suggests extremely long unique form specimen led assign distinct genus distinctive characteristic crest consisted skull bones projecting upward backward skull size shape varied number factors including age sex species older species described date placed distinct genus vertical crest broad forward projection descendants evolved narrower backward projecting crest females species smaller bore small rounded probably mainly display structures functions skeleton distinguishing characteristics set apart include narrow spines plate like bony strengthening hip relatively short tail fused long rod entire length tail long wingspan centimetres largest males evolution fossils known primarily central united_states broadly defined existed million years late early stages cretaceous period genus present layers upper surveyed distribution dating fossils formation demonstrating existed million years ago existed million years ago possible species named known member kansas wyoming dating million years ago early 1990s bennett noted major present formation precisely separated time little overlap gross overall similarity suggested probably represent single evolutionary lineage lasting million years words species present time likelihood direct ancestor species biology ecology range environment specimens assigned found deposits formation slightly younger deposits formation alive area covered large inland sea known famous fossils collected formations extend far south kansas united_states canada specimens specimens found southern half formation kansas wyoming despite fact numerous fossils found contemporary parts formation canada specimens found strongly suggests natural geographic range covered southern habitat extend farther north fossils belonging possibly found gulf_coast east_coast united_states example bone fragments delaware come incomplete definite identification remains japan tentatively attributed distance known western interior habitat makes identification unlikely shared sky giant compared common species rare making fossils formation common early toothed bird likely animals males compete association females lived primarily offshore nest away land based predators feed far shore fossils found locations time hundreds kilometres coastline surface sea populated primarily invertebrates squid life apart basal fish included sea turtles diving bird common marine reptiles genera including marine reptiles known fed reported stomach contents containing bones likely fossils terrestrial found chalk suggesting animals died shore washed sea specimen appears shark flight wing shape suggests flown like modern day based fact high aspect ratio wingspan chord length similar compared spend long stretches time sea fishing use flight pattern called dynamic soaring exploits vertical gradient wind speed near ocean surface travel long distances aid occur open ocean way land flight depended soaring like long winged probably required occasional active rapid burst studies wing loading strength wings weight body indicate capable substantial flight contrary earlier suggestions big like probably took standing position long leverage vaulted air rapid leap energy generated wings occurred animal cleared ground followed rapid stroke generate additional lift complete launch air diet diet known included fish fish bones found stomach area fish found jaws specimen numerous specimens preserve fragments fish scales near indicating fish majority diet taken invertebrates traditionally researchers suggested taken fish water low soaring flight probably based assumption animals water surface likely water fish swimming flying small female reached depth centimetres long bill neck floating surface reached greater depths diving water air like modern long winged bennett noted head neck shoulders heavily built diving birds suggested dive folding wings like modern crest function notable skull crest function crest subject debate explanations focused blade like backward pointed crest male ignored wide range variation age sex fact vary rules practical functions use mating displays display probably main function crest functions secondary scientific interpretations crest function began proposed possibilities aerodynamic muscle attachment point suggested crest anchored large long jaw muscles admitted function explain large size bennett agreed assessment crest large variable muscle attachment site suggested secondary function crest long reducing need heavy neck muscles control orientation head wind tunnel tests showed crest function effective degree bennett noted hypothesis focuses long male larger small existed females bennett found females effect male negative effect balance head fact movement required neck control balance suggested crest served rudder idea embraced later researchers researcher suggested crest supported membrane skin connecting backward pointing crest neck increasing surface area effectiveness rudder rudder hypothesis account females upward pointing backward pointing crest bennett found capacity rudder crest provide nearly directional force simply maneuvering wings suggestion crest air brake animals turn heads order slow suffers similar problem additionally rudder air brake explain large variation exists crest size adults suggested large species heat exchange allowing absorb shed heat regulate body temperature account crest size body size evidence extra blood vessels crest purpose large wings filled blood vessels served purpose effectively ruled best supported hypothesis crest function sexual display consistent size variation seen fossil specimens females juveniles small males large elaborate variable sexual variation adult specimens divided distinct size classes small large large size class half times larger small class small class twice common large class size classes lived alongside researchers previously suggested represent different species showed differences consistent concept represent females males species sexually larger size class preserve large upward backward pointing smaller size class small triangular larger evidence second crest extended long low tip seen smaller specimens sex different size classes determined pelvic bones contrary expected smaller size class large wide set pelvic bones bennett interpreted indicating birth canal eggs pass concluded small size class small triangular represent females larger large specimens represent males note overall size crest size corresponds age immature specimens known females males immature males small similar adult females large developed males reached large adult size making sex immature specimens difficult establish partial remains fact females appear outnumbered males suggests modern animals size related sexual sea lions males competing association groups consisting large numbers females similar modern competed establish territory rocky offshore largest largest males gaining territory having success mating females male competition visual dominance rank symbols display rituals taking place physical competition males hypothesis correct likely male played little young behavior found males modern animals father offspring time terrestrial main article ground movement historically terrestrial especially subject debate today researchers agree thanks largely discovery possibility aquatic swimming discussed briefly papers bennett discovery history found outside europe fossils found late cretaceous deposits western kansas chalk beds deposited large shallow sea north american continent specimens consisted partial wing bones tooth prehistoric fish marsh mistakenly believed belong new known point teeth marsh named find assigning known smaller european genus marsh collected wing bones large realizing specimen marsh named north american meaning western wing finger description new specimen named additional species based size differences largest specimen far smallest marsh rival unearthed specimens large north american based specimens cope named new species attempt assign large european genus accidentally created entirely new genus cope paper naming species published days marsh paper resulted dispute fought published literature names priority obviously species cope conceded marsh names priority maintained distinct species genus marsh named previously evaluation later scientists supported marsh case found cope assertion larger distinct species incorrect wing bones collected marsh cope early 1870s skull found hill river kansas usa fossil collector working marsh second smaller skull soon discovered showed north american different european species lacked teeth marsh recognized major difference describing specimens distinguished previously known genera order entire absence teeth marsh recognized characteristic new genus coined wing tooth marsh reclassified previously named north american species larger skull referred new species named additional species based wing bone pelvic bone soon realized mistake classified specimen separate genus named influential studies 20th century published conducted thorough analysis known specimens published good photographs illustrations best specimens early 1990s published major papers reviewing anatomy taxonomy life history fossils assigned discovered sweden classification valid species researchers consider species aside differences males females described post skeletons little variation species specimens bodies wings essentially identical species traditionally recognized valid type species species differ shape crest adult males described possibly angle certain skull bones preserved skull fossils extremely rare researchers use rock layer formation fossil found determine species identity cases known species upright crest lower jaw meters feet long collected described lower portion older considered bennett direct ancestor later species fossils identifiable found exclusively lower layers fossils exclusively upper layers fossil lacking skull identified based position column early fossil finds precise data location recorded rendering fossils showing phylogenetic placement genus alternate classifications subtle variations specimens researchers assigned single genus species distinguished mainly shape crest classification forms varied researcher researcher published paper arguing forms different placed distinct named disused species preoccupied miller named species named subgenus species combination prominent researchers late 20th century including adopt names continued place species single genus researcher revisited classification followed miller opinion differences species great place different genera placed genus named miller skull specimen bennett previously considered large male argued specimen crest preserved similar specimen millions years younger known assigned new species numerous specimens known formation time period suggested belong species lack identify disused species number additional species named 1870s considered junior synonyms valid species best supported type species based preserved specimen including known skull found individual wingspan valid species include possibly larger wingspan originally estimated considered bennett question validity probably synonymous known species key distinguishing characteristic marsh noted lack teeth jaw fragment found world tended attributed late nineteenth early twentieth centuries resulted species great deal confusion taxon like dinosaur label remains distinguished absence teeth species dubious ones known based sexual variation juvenile characters reclassified number times 1970s erected hold combinations confusing taxonomy include notable authors discussed aspects include species renamed respectively list species synonyms status names listed follow survey bennett noted
Pteranodon