The Flying Reptile Thread- Anything pterosaur related

Fathom wrote: »

Iberodactylus, a new crested pterosaur from the early Cretaceous. Why crest? Evolutionary advantage?

It appears that sexual selection may be behind the crests. Again, Pteranodon was the first crested pterosaur ever discovered, and it was believed at first that the crest served as a sort of rudder; that by turning its head to one side or the other, the animal could alter its course while gliding (this was before Pteranodon was considered capable of powered flight.

Leaving the physics aside, there is a very big problem with this interpretation; adult Pteranodon specimens come in two very distinct morphs. There's the large-sized morph with a large crest and narrow hips, and there's the small-sized morph with a small, round crest and wide hips.



(Image below shows a female Pteranodon skull, on top, and skulls of male Pteranodon longiceps and Pteranodon sternbergi).



It seems reasonable to assume that the small, short-crested ones were females, considering they would've needed wider hips to lay their eggs, and that this morph is twice as abundant as the large crested, narrow hipped one.

So it is obvious that the crest was not a vital flight instrument, but rather a secondary sexual trait. Nowadays, it is believed that Pteranodon were polygynous, with one single male having a small harem of females, as in today's seals and sea lions, and that they would use their superior size and showy crest not only to attract these females, but also to intimidate potential rivals.



This contradicts the popular image, ingrained in our minds by movies and cartoons, of Pteranodon nesting, eagle-style, on top of a mountain or cliff, either as a monogamous pair or just the female. They were socially more complex than that.

It was once believed that crests were a rare thing, found only among some advanced pterodactyls (short-tailed, advanced pterosaurs), but more and more crested pterosaurs have been discovered since, and even some that were originally thought to be crestless, like group-namer Pterodactylus, were found upon closer analysis to have crests made of softer material.



Moreover, crested pterosaurs from the Triassic have now been found, so it seems like crests were actually a frequent characteristic. One can imagine the earlier pterosaurs using their (likely brightly colored) crests like an Anolis lizard uses its colorful dewlap, and that sort of display becoming more elaborate along with their social behavior in many pterosaur groups.



The most spectacular crests do come from Cretaceous pterodactyls, however, such as Tapejara imperator (aka Tupandactylus):



Or the thalassodromids like Thalassodromeus proper and Tupuxuara:



Or the bizarre Nyctosaurus, a relative and contemporary of Pteranodon, which was once thought to use its crest as a sail, quite literally.

Fathom wrote: »

How Were Pterosaurs Adapted for Flight?

Relevant to the video's subject, here's an interesting read about giant pterosaur flight ability:

https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0013982

Our flight range estimates suggest large pterosaurs were likely able to fly considerable distances under anaerobic power after launch to find external sources of lift, owing to their relatively large muscle fractions. This would be aided by their ability to reach high velocities upon takeoff, which would limit the required acceleration during climbout. Therefore, while the largest pterosaurs appear to exceed the size limits for continuous flapping flight by a volant animal, there is no reason to suspect that they could not fly long distances Rather, it is reasonable to expect that so long as giant pterosaurs launched within 1 to 2 kilometres of an external source of lift, they could then stay aloft by transitioning to a soaring-dominated mode of travel after an initial burst of anaerobic power.

There is virtually no indication from the anatomy, biomechanics, aerodynamic performance or depositional contexts of any giant pterosaurs that they had lost their ability to fly. This is particularly so for Pteranodon, an animal with anatomy so skewed towards a glide-efficient wing morphology that its terrestrial capabilities may have been lessened. The case is not so clear-cut for azhdarchids: as pterosaurs living within continental settings and apparently possessing good terrestrial abilities, they meet some criteria that may be expected of a flightless pterosaur. However, like Pteranodon, giant azhdarchids also possess skeletons that function well as flying apparatus and were almost certainly flighted as well.

These observations do not preclude the existence of flightless pterosaurs, however: it is entirely conceivable that some forms may have abandoned flight given the right environments and selection pressures. In our view, however, the pterosaur lineage closest to abandoning flight may not be giant at all but, rather, the considerably smaller basal pterosaur clade Dimorphodontidae (wingspans of 0.6–1.3 m ). Dimorphodon has been found to be a particularly heavyset pterosaur with relatively high wing loading, attributes found in modern fliers like rails and galliforms that find flight particularly energetically expensive. Given that Dimorphodon also possesses an unusually robust skeleton – including long limbs and well-developed appendages - it was probably also a competent terrestrial (or, more likely, scansorialanimal that spent much of its time grounded. Dimorphodontids therefore possessed characteristics quite conducive to developing flightless habits and there seems little reason to assume that more derived members of this group could not have abandoned flight in the right conditions. We stress, however, that there is currently no evidence that any pterosaurs fully surrendered their flight abilities and, conversely, a wealth of evidence suggesting that all pterosaurs were flighted.

It would appear that giant pterosaurs could reach speeds of over 100 km p/h and possibly stay aloft for days on a row, flying at altitudes of up to 15,000 feet/4.5 km. This would've allowed them to expand their range considerably and even cross entire oceans with relative ease, explaining their worldwide distribution and presence in ancient island environments.
For example, remains of azdharchids are known known from all continents except Antarctica, whereas pteranodontids are known from North America, Asia and north Africa.

Also relevant :pac:

Fathom wrote: »

Just saw sci fi movie Pterodactyl (2005). Story plot was weak. Pterodactyl Fx was cool.

There is no denying their monster appeal.

Flying reptiles were the most important prehistoric creatures featured in Conan Doyle's The Lost World, published in 1912. Interestingly, Pteranodon had already been found in North America, but Doyle's pterosaurs are toothed and never mentioned to have a crest; in the novel, his zoologist characters Professor Challenger and Dr. Summerlee argue about whether the pterosaurs belong to genus Pterodactylus or genus Dimorphodon, which would've been the better known ones at the time. At the end they don´t reach a consensus and refer to them simply as pterodactyls. It is the pterodactyl that gets shipped to London and escapes once there, causing panic.

Then the 1925 film version of the novel featured a Pteranodon, and from that moment on, the vast majority of "pterodactyls" in movies have been either Pteranodon, or a mix between Pteranodon and a rhamphorhynchoid (just add teeth and/or a long tailed to the Pteranodon).



Almost invariably, the "pterodactyl" will have a taste for humans (despite the real Pteranodon being mostly a fish eater), and the ability to grasp people with its feet and carry them away like an eagle (the real thing could not grasp, using its proportionally small feet exclusively to walk and maybe swim, and would've caught all of its food with its jaws). It will also nest on top of a large cliff or mountain, in a bird-like nest, and feed its relatively helpless young with live prey- including humans, of course.





Doyle wrote his pterodactyls as nesting in a colony, thus predicting this behavior long before the fossil record revealed evidence of it, but in most fiction, the "pterodactyl" nests alone, like an ominous, monstrous bird of prey.

It seems very interesting to me that the "pterodactyl" as a movie monster seems to incarnate our fear of being attacked from above and devoured not by pterosaurs, which naturally were long gone by the time our early hominid ancestors evolved, but rather by large raptors. We know thanks to the fossil record that our australopithecine ancestors were being hunted and eaten by large eagles, such as the African crowned eagle. Not surprising when you consider that a) said australopithecines were rather small in size, and b) large African eagles are still known to hunt monkeys, some of them of considerable size. The African Crowned Eagle is considered a specialist in hunting primates, but the Martial and Verreaux eagle are known to take monkeys too.



The African eagles will carry prey to a nest to feed their chicks. Skulls of human infants have been found in nests of African crowned eagles at certain points in recent history and there is a case of an African boy (I don´t remember the country) being attacked and badly mauled by a crowned eagle on the way to school. As the eagle was a juvenile and there were no nests around, it was concluded that the attack had been predatory. In captivity, Crowned eagles seem to have their predatory instinct triggered by small children's movements and voices.

So it may be that we humans are subconsciously wired to to fear aerial attacks by large, winged predators because at some point, it was a very real danger; so we fulfill our "need" for scary flying monsters by imagining harpies, dragons, pterodactyls... maybe even hostile UFOs!

Rubecula wrote: »

possibly but why did folks develop a fear of spiders moths etc?

Spiders I can understand, as our ancestors would've coexisted with large, potentially dangerous arachnids, and would surely have encountered them while foraging for insects, roots and other food sources in the forest floor or the savannah.

Consider the African baboon spiders, for example; large, aggressive, and venomous enough to cause pain and illness for several days in modern humans, so who knows what effect it would've had on smaller bodied hominins? This spider is still found in the same regions that saw our ancestors evolve.



But I do admit I cannot understand people who are scared of moths :pac:

Tracks and feces of "Jurassic flamingo" pterosaurs found

https://sciglow.com/archaeology/filter-feeding-pterosaurs-were-the-flamingos-of-the-late-jurassic/

The pterosaurs known as ctenochasmatids (comb-mouths) filled a niche similar to that of today's flamingoes, and include such strange creatures as Pterodaustro.

Interesting article on how giant pterosaurs could fly/get so big. Relevant to previous posts in which we discussed the possibility of birds reaching similar sizes. This article would seem to suggest otherwise, if quadrupedal posture and launching was actually the key to the pterosaur's giant size.

https://www.scientificamerican.com/article/pterosaurs-were-monsters-of-the-mesozoic-skies/?utm_medium=social&utm_content=organic&utm_source=facebook&utm_campaign=SciAm_&sf219675129=1&fbclid=IwAR27P08tFqx1DoH_sz1OqrNLgovFtb4H9HqSvF06cBkNa9qL2At2FWx5t3s

New pterosaur Ferrodraco from Australia:

https://www.nationalgeographic.com/science/2019/10/new-iron-dragon-pterosaur-found-australia/?cmpid=org=ngp::mc=social::src=facebook::cmp=editorial::add=fb20191003science-irondragonpterosaur::rid=&sf220751964=1&fbclid=IwAR1JYHW44FjNr2Mn0cDh_BllSC-rmCLFz5UTmOj3M-iUbAucbEsfo_OgiTw

Albadraco, a new (?) azhdarchid pterosaur from Transylvania. Very fragmentary, as per usual, so maybe it could be a juvenile Hatzegopteryx?

https://www.sciencedirect.com/science/article/pii/S0195667119301016#undfig1

Rhamphorhynchoid trackway found in France, a first; proves these long-tailed pterosaurs were quadrupedal, like pterodactyloids.

https://www.sciencedirect.com/science/article/abs/pii/S0016699520300024

This was predicted by French illustrator Riou who drew a quadrupedal Rhamphorhynchus (and its tracks) in 1863.

Plesioteuthis fossil with embedded Rhamphorhynchus tooth is first proof that these pterosaurs hunted squid, and not always succesfully:

https://www.sciencenews.org/article/squid-fossil-offers-rare-record-pterosaur-feeding-behavior?fbclid=IwAR2E51rNYzyiR8NZwD7csqbDRACD_r4FTl0Ewmt-twO4ryHujJ5hx2-jOUQ

Paleontologist Michael Habib of the University of Southern California in Los Angeles says he suspects the squid was far too large for the pterosaur to haul out of the water. “The pterosaur was lucky that the tooth broke off,” says Habib, who was not involved with the study. “A squid of that size could probably have pulled it under.”

On the crest structure and soft tissue from Tupandactylus (formerly known as Tapejara imperator).

Free PDF:

https://www.biorxiv.org/content/10.1101/2020.02.06.937458v1.full.pdf

Tupandactylus is the largest member of the tapejarid family and one of the weirdest pterosaurs known. It is known from several well preserved specimens. Its diet has been subject to debate, with some suggesting a frugivorous lifestyle, like an oversized toucan; however, this paper sort of implies it may have been a predator/scavenger with an oversized nasal cavity similar to today's turkey vulture.

Remains of Anhanguera and Ornithocheirus found in Morocco. Both pterosaurs were previously known only from South America and Europe. This adds to the evidence that large pterosaur forms had huge geographical distributions due to their ability to fly long distances over both land and sea.

https://phys.org/news/2020-03-fossil-clues-reptiles-sahara-million.html?fbclid=IwAR040zV62dGZ0qdw63-_hwP8v-p8JMYPntrbDI6-9u76QyKmEWcGPnohVAk