The Flying Reptile Thread- Anything pterosaur related

Rubecula wrote: »

If they had lasted I think we would have made use of them much like we have done with horses (and other beasts of burden)

We may not have even invented aeroplanes, or else invented them a lot sooner.?

Except that unlike horses, these guys were carnivorous... and potentially capable of eating a small human :eek:

I wonder what would we think of marabou storks (storks in general I guess) if they didn´t exist today and we knew them only by their fossils. I can totally see scientists suggesting that they were fligthless based on their weird proportions and large size:

Allkauren, a new Jurassic pterosaur from Argentina

http://www.sci-news.com/paleontology/allkauren-koi-argentina-04145.html


Shows intermediate traits between long-tailed rhamphorhynchoids and short-tailed pterodactyls.

A variety of new pterosaurs from Morocco

Including pteranodontids and nyctosaurids. Mostly just fragments.
http://www.eartharchives.org/articles/pterosaurs-maintained-high-diversity-until-the-end/
Interesting graphic tho. Avisaurus is pretty impressive for a Mesozoic bird. Looks about eagle-sized!

https://www.livescience.com/62662-largest-pterosaur-jawbone-transylvania.html

Quetzalcoatlus relative found in southern France

https://www.naturalsciences.be/en/news/item/17106/?fbclid=IwAR1PxCfxVdhMQmeMIbHxOMXQDmmUW6AqGDMzs7z3siR12j44CO8qwGWb2rQ

Clues reveal how baby pterosaurs grew up

https://www.livescience.com/63871-how-pterosaurs-grew-up.html

Pterosaurs had... feathers???

https://www.nature.com/articles/s41559-018-0728-7?fbclid=IwAR2wtt7fuOg5-LtduK5eh0JlMlEIds0A4Vgp5zcaBpx916kVqIv67nS-9VA

Pterosaur trackway found in Poland. Apparently the trackmakers were large for Jurassic standards.

https://www.sciencedirect.com/science/article/pii/S0031018218310162

Seazzadactylus, a new Triassic pterosaur. Unusual teeth apparently.

https://peerj.com/articles/7363/

Fathom wrote: »

Is the a threshold of weight to length of wingspan for flying reptiles? Wing composition a factor too (feathers? Or?). Shorter wingspans don't fly.

There has been much debate about the limits of pterosaur size/flight ability. There was a time, for example, when the iconic Pteranodon (with a wingspan of about 7 m) was believed to be the absolute limit for any flying creature.



Even then, there were plenty of scientists who refused to believe such an enormous animal was capable of powered flight; instead, they suggested that it would only glide by throwing itself from high cliffs, and that it would use the small claws on its wings to climb back up.

Pteranodon was discovered in 1870 (being not only the largest pterosaur found at the time, but also the first found outside of Europe, and the first one known to have been toothless). It remained the largest known flying creature until 1971, when an even bigger pterosaur was found in Texas:



This one was named Quetzalcoatlus and assumed to have similar proportions to Pteranodon, which gave it a wingspan of 12-15 m. So Pteranodon was apparently not the upper limit for flying animals after all.

Quetzalcoatlus also posed an interesting puzzle. Pteranodon was thought to glide over sea currents like an albatross, and it was believed that these very particular conditions were what had allowed it to become so large. But Quetzalcoatlus came from inland deposits away from the sea, so this was an animal that flew over vast plains and forests, and presumably the terrain here was flat so, there were no cliffs to jump from.

It also seemed rather unlikely that a pterosaur this size would survive among the likes of Tyrannosaurus rex without being able to take off from the ground. Scientists then suggested that Quetzalcoatlus was probably a scavenger that fed on the scraps of giant theropod's kills- like a giant vulture, despite the fact that it had a long, straight, edentulous jaw that didn´t seem particularly well suited for dealing with large carcasses.

As time went on, more complete remains of Quetzalcoatlus-like pterosaurs were found around the world, allowing for a better understanding of its anatomy. It turns out, Quetzalcoatlus was part of a family- known as the azhdarchids ("dragons"), which had proportionally short wings, incredibly elongated necks and huge heads, and were seemingly better suited for walking and perhaps even running on the ground than other pterosaurs. Pteranodon, for example, with its tiny hind legs and extremely long wings, would've been capable but not particularly agile on the ground. Quetzalcoatlus and its azhdarchid kin however seemed well prepared for a mostly terrestrial lifestyle.



This has led to our current concept of azhdarchids as predators of small to medium-sized prey, caught not on the wing but by walking, like modern day marabou storks or ground hornbills. The relatively short wings and very long neck and beak do resemble those of said birds.

Naturally some paleontologists have expressed doubts that such weirdly proportioned giants were flyers at all, but they are a minority. The fact that the pterosaurs coexisted with the likes of tyrannosaurs and dromeosaurs, and that azhdarchids were found all across the globe (including places that were islands during the Cretaceous), does suggest that they must have been able to fly, even if they spend the majority of their time on the ground.



Of course, the relatively short wing model means that even Quetzalcoatlus has been downsized from 12-15 m to about 9-11 m. Even then, it and other giant azhdarchids currently have no rivals among flying creatures.



I personally don´t think there's anything weird about azhdarchids being able to fly even with those strange proportions. Many birds today have such huge heads and necks that you wouldn´t think, by looking at their skeletons, that they would be able to fly, yet we see them do it all the time.





I think maybe weight would be a more important factor when limiting the flying capabilities of giant pterosaurs. Despite its great size, Quetzalcoatlus had relatively light bones. Its weight is estimated at about 200-250 kg, which is a very large animal in absolute terms, but paperweight when you consider it would be about the size of a giraffe when standing on all fours. An adult giraffe can weigh over 1 ton.



On the other hand, some fragmentary remains from Romania seemingly come from much more robust azhdarchids. Since Romania was an island back then- known as Hateg island- populated by dwarved versions of mainland dinosaurs, and these giant azhdarchids are believed to have been the apex predators in such island, there is a possibility that they were flightless or nearly fightless, since they would face presumably no competition or threat from giant theropods, and there would be no need to fly anymore. But we need more complete skeletons to be sure.

Until now, no pterosaur has been confirmed as flightless.

As for wing composition, pterosaurs did not have feathers (or at least, flight feathers); their wings were composed by a single elongated digit (equivalent to our pinky), and a membrane of skin and muscle and other components (including unique fibres for strengthening and support, and a copious network of blood vessels). In some pterosaurs, even the respiratory system seemingly extended its air sacs into the wing membranes. Overall, the wing structure of all pterosaurs known thus far seems pretty consistent.

So they weren´t like bird wings at all, and they were a lot more complex structurally than the simple kite-like structure imagined by early paleontologists.

Iberodactylus, a new crested pterosaur from the early Cretaceous

https://www.nature.com/articles/s41598-019-41280-4