The mechanics of the pterosaur flight

How could they grow so huge?

Contrary to what you might think, the giant pterosaurs of the late‪ Cretaceous could go ballistic in a second. This is because contrary to your another misconception, birds don’t take off as much using their wings as their legs.

A big bird needs strong legs to launch itself, but the lower part of the body becomes a dead weight when the bird flies. It’s this flaw in the overall bird design that keeps the birds small and not some physical law that postulates that big things can’t fly.

The pterosaur quadrupedal take-off relied on all four limbs in the manner of the vampire bat. Developing the upper part of the body and forelimbs was thus beneficial for both take-off and flight. There was no trade-off between launch and flight involved. And this is why pterosaurs‬ could grow gigantic

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“Island Hateg”, by Sergey Krasovskiy (~atrox1)

HatzegopteryxBalaur and some kind of unlucky nodosaurid

“The authors estimated the size of Hatzegopteryx by comparing the humerus fragment, 236 mm (9.3 in) long, with that of Quetzalcoatlus, of which specimen TMM 41450-3 has a 544 mm (1 ft 9.4 in) long humerus. Observing that the Hatzegopteryx fragment presented less than half of the original bone, they established that it could possibly have been "slightly longer” than that of Quetzalcoatlus. They noted that the wing span of the latter had in 1981 been estimated at eleven to twelve metres, while earlier estimates had strongly exceeded this at fifteen to twenty metres. From this they concluded that an estimate of a twelve meter wing span for Hatzegopteryx was conservative “if its humerus was indeed somewhat longer than that of Q. northropi”. In 2003 they moderated the estimates to a close to twelve metres wing span and an over 2.5 m (8 ft 2 in) skull length.[3] In 2010 Mark Witton e.a. stated that any appearance that the Hatzegopteryx humerus was bigger than TMM 41450-3 had been caused by a distortion of the bone after deposition and that the species thus likely had no larger wingspan than Quetzalcoatlus, today generally estimated at ten to eleven metres.[4]Wikipedia.

More Pterosaurs! I wanted to play with analogous displays and coloring with this guy.I also added a dash of reptile in there just for good measure.

*DISCLAIMER: I’m not a paleo artist. So the exploration of  sexual dimorphism, displays, crests, waddles, patterns, etc  are purely speculatory but feel free to start your sentences with “technically, actually, scientifically, or the ever favorite looks like David Peters ” in 3,2,1

The Hateg basin wing, Hatzegopteryx (2002)

Phylum : Chordata
Class : Reptilia
Order : Pterosauria
Family : Azhdarchidae
Genus : Hatzegopteryx
Species : H. thambema

  • Late Cretaceous (70 - 66 Ma)
  • 11 m wingspan and 100 kg (size)
  • Hunedoara county, Romania (map)

Hatzegopteryx poses a puzzle worthy of a TV detective show. To judge from this reptile’s incomplete remains, including pieces of its skull and humerus, Hatzegopteryx may have been the largest pterosaur that ever lived, with a wingspan possibly approaching 40 feet (compared to “only” 35 feet or so for the biggest known pterosaur, Quetzalcoatlus). Even the skull of Hatzegopteryx was gigantic, one reconstruction pegging it at over ten feet long, which would count as the biggest noggin of any non-marine creature in earth’s history.

So what’s the mystery? Well, apart from the elusive nature of Hatzegopteryx’s fossil remains–it’s a tricky business to reconstruct an extinct animal from only a handful of bones–there’s the fact that this pterosaur lived on Hatzeg Island, which was isolated from the rest of Europe during the late Cretaceous period. The dinosaurs that lived on Hatzeg Island, most notably Telmatosaurus and Magyarosaurus, were much smaller than their mainland contemporaries, an example of “insular dwarfism” (that is, creatures on small islands tend to evolve to small sizes, so as not to outgrow the available resources). Why would such a huge pterosaur have lived on an island populated by dwarf dinosaurs? Until more fossil evidence is uncovered, we may never know the answer for sure.

sauropolis-princeps asked:

How bout' a breakdown on the biggest thing to ever take to the skies? Quetzalcoatlus! (or possibly hatzegopteryx)

The pterosaurs in general are one of my favorite types of animal, but since you asked, I’m going to talk about the biggest - which also, coincidentally, happens to be the best.

Quetzalcoatlus - named after Quetzalcoatl, the benevolent feathered serpent god of Aztec mythology - was perhaps the largest flying animal of all time.  Seriously, I can’t stress this enough.  Here’s a size comparison with a human and a giraffe.

This animal was so gargantuan that serious doubt has been cast on whether or not it could actually fly.  No one is certain, however, for a couple reasons:

  • It’s incredibly difficult to calculate how much pterosaurs this large weighed, since no comparable animal exists today.  Estimates range from 150 to 500 pounds, which could impact the possibility of flight in a variety of ways.
  • The biomechanics of pterosaur flight are notoriously poorly understood.  Their anatomies are not directly comparable to any flying animals alive today, and an exact model of pterosaur flying abilities has never been successfully created.

This has led to an incredibly widespread array of theories as to Quetzalcoatlus’ aerial capabilities, ranging from “it was completely flightless” to “it could fly for a straight week at 80 miles an hour”.  Personally, I feel like the reality is somewhere in between.  If you ask me, Quetzalcoatlus was probably capable of flight, but probably spent most of its time on the ground.  Speaking of which…

Quetzalcoatlus’ lifestyle is also a subject of debate.  Early reconstructions portray it living a seabird-like lifestyle, but this is unlikely; Quetzalcoatlus lived in an arid inland environment, and lacked the necessary adaptations for skimming or diving.  More modern reconstructions, like the one above, portray it feeding like a ground hornbill, foraging in the grass for smaller vertebrate prey.  And by “smaller vertebrates”, I mean “dinosaurs, probably”.

Quetzalcoatlus has since been discovered to belong to an entire family of gargantuan pterosaurs, known as the “azdarchids”, after the Persian mythical creature Azi Dahaka.  They were some of the last pterosaurs, but were extremely successful, and lived on every continent throughout the Late Cretaceous.

One of these animals was found in Romania, and named Hatzegopteryx, after the Hateg Basin in which its fossils were discovered.  However, based on closer inspection of its bones, Hatzegopteryx may or may not be the same animal as Quetzalcoatlus, a native of the United States.  This may or may not prove that Quetzalcoatlus was some sort of globe-trotting power-flyer.  It’s too soon to say.

Honestly, that’s part of what makes Quetzalcoatlus - and the pterosaurs in general - so interesting.  It’s such an iconic image of the Age of Dinosaurs, but we know extremely little about it.  Even professional paleontologists know comparatively little about Quetzalcoatlus, in comparison with some of the dinosaurs that lived in the same place and time.

Keep an eye on this blog for a much longer, more in-depth post that might help shine a light on the mysteries of pterosaur evolution…

A pair of Eurazhdarcho trailing behind a lone Hatzegopteryx, snatching up anything that’s disturbed by the larger azhdarchid.

I just had to draw something involving these two after I read the TetZoo article on them, since I always think niche partitioning and how similar genera adapt to different lifestyles and such is really neat.

Please excuse the shoddy “plants”.

I made this my 6th All Your Yesterdays submission just for kicks.