How Pterosaurs Got Their Wings

How Pterosaurs Got Their Wings

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Language: English

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one night about 230 million years ago a reptilian predator stalked the desert in what's now Scotland the critter could probably fit in the palm of your hand but it was a hunter nonetheless they relied on its massive eyes to find prey in the darkness like insects and small vertebrates it's known today as sclera ma CLIs and it was really well adapted to life in the desert it's long legs and feet carried it across the sand without sinking and when they had eaten its fill it curled up with some other members of a species to sleep the day away in the shadows of the dunes today most fossils of Sparrow Makos are found curled up
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together suggesting they were buried by dune collapses and entombed with these little bug hunters is an evolutionary key because even though it had no wings sclera McClure's had some features that linked it with another group of mysterious reptiles the pterosaurs some scientists think that the relationship between pterosaurs and sclera maquas is pivotal for understanding some of the greatest evolutionary mysteries about pterosaurs like where they came from and how they developed the ability to fly but when pterosaurs first took flight you could say that it marked the beginning of the end for the winged reptiles because strangely enough the
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power of flight and the changes that are brought about may ultimately have led to their downfall to unravel the mystery of pterosaur origins we have to start by figuring out what they're related to and this is quite a puzzle because pterosaurs had very fragile bones this made them light in the air but it also meant that they didn't fossilized very well and because they were highly specialized for flight they lost some of the features that could tell us who they're related to most paleontologists consider pterosaurs to be a type of orcas or a group that includes dinosaurs and crocodiles among other things and
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many experts also consider pterosaurs to be closer to dinosaurs than they are to crocodiles part of a grouping called unearth 'dear ins or bird line darkest ores but while pterosaurs are hard to place in relation to other animals it's pretty easy to place them together as a group all pterosaurs look like pterosaurs with unusually large skulls extra-long fingers and of course fully developed wings one of the oldest pterosaurs currently known is u dimorphodon from the Late Triassic of Europe and it belongs to one of the two main groups of pterosaurs a group called REM for ring codes these pterosaurs were generally on the smaller side and often had longer
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tails and had differentiated teeth and they were distinct from the other group of pterosaurs known as the pterodactyl oins those pterosaurs typically had shorter tails longer wrist bones Crest's and either simple teeth or no teeth at all the pterodactyl eggs would go on to include the largest animal that ever flew Quetzalcoatlus but of course the RAM foreign codes were also fully equipped for flying with complete wings and membranes that ran the length of their legs but for each group the fossil record doesn't tell us much about where they came from which leads us to the next big mystery surrounding pterosaurs how did they develop the ability to fly
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in the first place well pterosaurs probably didn't go from having no wings to having full wings in a single evolutionary leap so when it comes to hell pterosaurs got their wings there are three general theories the first theory suggests that the ancestors of pterosaurs lived in trees and got around by jumping from branch to branch this is called the arboreal leaping theory which sounds kind of fun and to suggest that pterosaur ancestors may have had a bit of membrane on their arms that helped them glide for short distances then this advantage might have selected for a larger partial wing that would have let them go a little farther and then eventually the same pressures would lead to the membrane becoming a
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full wing but other scientists think the ancestors of pterosaurs might have been falling rather than jumping this theory known as the arboreal parachute model suggests that like some lizards today pterosaur ancestors could have scrambled around in trees and then fallen down to the next branch if they were threatened this again would have been safer with skin connecting their arms and legs so that invention could have led to larger and larger membranes until wings but not all theories have the earliest pterosaurs living in trees there's also the ground-up theory which suggests that they were terrestrial and bipedal so in
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this model the feeding habits of pterosaur ancestors might have involved running and jumping to catch things like flying insects in which case having partial wings could have helped them jump higher to catch their prey and eventually winged jumping could have turned into flight so which theory works best the pterosaurs come from bipedal running ancestors or quadrupedal ancestors that lived in trees to answer that we need to go back to square OMA CLIs Square and walk less wasn't a pterosaur I mean probably but based on its physical features most studies classify sclera buckless as an early or northa dieren one of those bird line
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darker sores that includes the pterosaurs which kind of makes sense because Clara maquas had a lot of traits in common with pterosaurs it had shoulder blades that were a lot like those of pterosaurs with long bony projections where our muscles attached now sclera maquas couldn't fly but as easy to see how these features could have been adapted by an early flying pterosaur it also had four long toes really big but lightly built head a square pelvis and very small fibula or lower leg bones all traits found in pterosaurs so even the square ma class itself wasn't the pterosaur ancestor many paleontologists think that
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something like it was probably what ancestral pterosaurs looked like so the next question is did sera McClure's live in the trees or on the ground well its body gives us some important clues its back legs were much longer than its front legs and a head a long tail it seemed to have walked on its toes instead of the flats of its feet and its fingers weren't very long so it didn't have the grasping ability that many treating animals have you know what in some ways it kind of looked like a jerboa a little modern mammal that gets around the desert by hopping like a kangaroo so square ma CLIs was likely terrestrial and either hop terrain along the ground
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and it wasn't alone other early unearthed adherents have also been interpreted as small jerboa like animals so the terrestrial ancestor fits perfectly with the ground up theory right episode done good bye everybody yeah now there's actually lots of evidence to suggest that even if their ancestors were bipedal pterosaurs themselves were quadrupedal they have shoulder joints that are oriented for walking on all fours and the weird tracks are left behind are all quadrupedal so little sclera buckless appears to have been a bipedal ancestral cousin of a quadrupedal group some
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scientists think that when their wings became large and heavy enough early pterosaur started to walk on four feet so they didn't fall on their faces but many other scientists think that there was something between a bipedal ancestor and the pterosaurs something that was arboreal and quadrupedal that hasn't been found in the fossil record yet so the evolution of pterosaurs is still foggy but what we do know is that over there 150 million years of existence pterosaurs only became more well adapted for flight they probably had unidirectional airflow just like modern birds do making them very efficient at breathing even while flying and some
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pterosaurs also had weird little feathers and even though pterosaurs were all lightly built the later pterosaurs were even lighter they had more air chambers in their bones and fewer vertebrae all of these things and more help pterosaurs conquer the skies eventually fact is for the first hundred million years or so of their existence pterosaurs weren't very diverse the earliest ones were just all little bug eaters but around 125 million years ago they started to change it became dramatically more diverse nearly doubling in the number of species they grew traffic and crests and began hunting
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fish and other vertebrates instead of just bugs familiar species like Pteranodon and the largest creature to ever fly Quetzalcoatl as' took over the skies what happened to make them so diverse a little evolutionary pressure from another group related to those early ornithol earrings birds birds begin to show up in the fossil record during the late Jurassic period around 160 million years ago so birds and pterosaurs coexisted for 60 million years and it wasn't until after birds evolved that pterosaur started to move out of their nisha of tiny flying bug eaters in fact some fossil formations like the jehovah
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pin china preserve lots of different birds and pterosaurs together each of which ate slightly different things in slightly different environments but one of the things that pterosaurs did best was something that bodybuilders know a bit about getting big pterosaurs gruta sizes that birds couldn't reach the biggest birds of the Late Cretaceous like Ava Soros and the wing spans no more than 2 metres across but pterosaurs like Quetzalcoatlus reached at least 11 metres these larger sizes allowed pterosaurs to conquer ecological niches that weren't available to birds like flying long distances over the open ocean in search of food
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so pterosaurs and birds coexisted peacefully until things changed we've all seen this movie by now the end of the Cretaceous period some 66 million years ago was marked by the extinction event that wiped out the non-avian dinosaurs but the animals that did survive had something in common they were all pretty small being small meant mammals and birds could live on less food a helpful trait in a post-impact world but pterosaurs had grown bigger and bigger to find roles where they could hold their own against the birds are the Late Cretaceous they all had wing spans between two and ten metres meaning the smallest pterosaur at the time of the extinction
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event was about the size of a bald eagle so in the end and may have been that their size impressive as it was doomed them to extinction perhaps just perhaps if they'd stayed on the ground or remained the size of little sclera ma CLIs pterosaurs would still be around sharing our skies today with birds [Music] okay so what do you think the pterosaurs acquired the ability to fly by living in trees or on the ground did they jump to catch air or did they fall let us know in the comments which hypothesis you support and why show your work always got to give a shout out to this month's
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intelligence Patrick Seyfert Jake Hart John Davison ting and Steve bill pledge your support at patreon.com slash yawns and become an Ian ight and also thanks for joining me in the Constantine Haza studio if you like what we do here then subscribe at youtube.com slash yawns [Music]

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