pterodactyloids

Caulkicephalus trimicrodon, an ornithocheirid pterosaur from the Early Cretaceous (~130 mya) of the Isle of Wight, carrying around a flapling in a similar manner to modern crocodiles.

We still know very little about the life cycle and reproduction of pterosaurs. The few known fossilized eggs had leathery shells, and may have been left buried in sand or vegetation. Baby pterosaurs (“flaplings”) seem to have been superprecocial, highly developed and possibly even capable of flight very soon after hatching.

Whether any actual parental care took place is also a mystery. So this is a rather speculative idea — but still adorable.

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Nemicolopterus crypticus: A baby pterosaur, or just small?

Size: 10 inches (25 centimeters) from wingtip to wingtip.

Time Period: The Aptian stage of the Early Cretaceous Period.

Locale: The Jiufotang Formation of China.

Name: The generic name means “forest-dwelling wing,” in reference to the animal’s presumed forest habitat. The specific name means “hidden.”

Pterosaurs astonish us humans because they were strange prehistoric creatures that lived in the sky. They looked a bit like birds, but were incredibly foreign in comparison to our feathered friends. Most astonishing of all is the size of some pterosaurs. Animals like Hatzegopteryx and Aerotitan grew to sizes never seen in other flying animals. However, not all pterosaurs were as huge and macho as the azhdarchids. Some were pretty tiny.

One such “ptiny pterosaur” is Nemicolopterus, a Chinese pterodactyloid that is currently identified as the smallest pterosaur of all. However, there might not be as much truth to this as you’d think. The fossil specimen is actually smaller than any (excepting a choice few) hatchling pterosaur, but it isn’t fully grown. Darren Naish has argued that, since pterosaurs are able to be out and about from an early age, bone fusion and ossification can occur very quickly. Factoring this into our catalog of Jiufotang faunal assemblages, we can guess that Nemicolopterus may be a hatchling of the genus Sinopterus, a decently sized tapejarid from the same area. 

All that discussion aside, there are some concrete conclusions to be made about this little fellow. Nemicolopterus is toothless, and may be an intermediate between the ornithocheiroids and dsungaripteroids. Though Nemicolopterus isn’t the best representative of its relatives’ size, some of its relatives may have evolved into the aforementioned macho pterosaurs (such as Aerotitan).

We can also confidently assert that we know just about where Nemicolopterus lived. Since this pterosaur demonstrates adaptions for grasping tree branches, it may have hunted for insects and lived in the canopy of a forest. Though most pterosaurs are known from marine sediments, and would have probably caught fish in the sea and landed on nearby structures to eat and mate, it’s clear that Nemicolopterus was found in the continental interior of its area, making it one of the few pterosaurs known to live in such a habitat. Other inland pterosaurs include Quetzalcoatlus, a “Ptexan pterosaur” whose inland habitat was originally given as evidence that it was a vulture-like scavenger. Tapejaridae, the family that Sinopterus (Nemicolopterus’s presumed adult version) belongs to, also shows similar adaptions despite the fact that some were marine.

So, though Nemicolopterus may have only been a juvenile specimen of Sinopterus, it’s still interesting. It might make us reconsider our phylogenetic assignments of other small pterosaurs, and it is one of the few inland pterosaurs discovered thus far. As we have piece together the puzzle of pterosaur “ptylogeny (okay, I tried),” we find that a bit more investigation may be required to correctly determine the identity of some flying reptiles, even our forest-dwelling pal.

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Genus: Pterodaustro

…an extinct genus of pterodactyloid pterosaurs that lived in Early Cretaceous South America. This genus is noted for its tooth comb, which means it likely waded in water and filter fed like modern flamingos. It probably mashed hard crustaceans with its small teeth on its upper jaw. It was once thought that Pterodaustro was pink due to its diet like a flamingo, however recent studies show that only members of Neoaves can absorb those pigments and it was unlikely that any pterosaur was pink. Analysis of Pterodaustro’s  scleral rings indicate that it might have been nocturnal and it might have lived like nocturnal anseriform birds.

Phylogeny

Animalia-Chordata-Reptilia-Pterosauria-Ctenochasmatidae-Ctenochasmatinae-Pterodaustro

Images: Mark Witton and Gadfium

Pterorhynchus wellnhoferi, a ‘rhamphorhynchoid' pterosaur from the Middle Jurassic of China (~164 mya). With a wingspan of around 85cm (33”), it was probably comparable in size to a modern barn owl.

It’s known from a nearly complete specimen, with preserved soft tissue such as wing membranes, hair-like pycnofibers, a prominent head crest, and a distinctive saw-toothed tail vane.

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Aerotitan sudamericanus: Air Nomads.

Size: Though it’s too fragmentary to definitely ascertain this animal’s size, its wingspan was probably at least 16.4 feet (5 meters) in width.

Time Period: The Early Maastrichtian Stage of the Late Cretaceous Period.

Locale: The Allen Formation of Argentina, a place that was also home to Willinakaqe and Austroraptor, the former of which has been covered on this blog.

Name: The generic name means ‘air titan,’ thanks to this animal’s large size and airborne lifestyle. The specific name means ‘of South America,’ because Aerotitan was found in South America.

I’ve mentioned that animals such as Quetzalcoatlus and Hatzegopteryx are macho pterosaurs. These huge creatures were very interesting and were probably also threatening. Here, I report a fairly new one, and the first confirmed azhdarchid from South America, Aerotitan.

This creature is known only from a rostrum, or the part of the head at the end of the beak. It was a toothless animal, and probably had a spearlike beak like its fellow azhdarchids. Its snout was very long and compressed transversely. The animal, like Hatzegopteryx and company, was a semi-terrestrial predator that lived much like a modern-day stork.

The real subject of this post isn’t about Aerotitan itself, it’s about it and the many other azhdarchid taxa that have been assigned. These animals all looked very similar, and are known from similar and fragmentary evidence. This makes me question just how many of these animals were distinct taxa. Here, I propose the theory that, since azhdarchids were such large flying creatures, they could fly from continent to continent and colonize the world without being very distinct taxa. Though this is a bit Paulian in a sense (and I don’t like lumping a bunch of taxa into a genus no matter how convenient it is), this large amount of taxa has always seemed a bit questionable to me. Though I could be wrong, it’s always a little bit tricky to assign taxa.

So, though Aerotitan seems like a distinct taxa, I’ve nursed my misgivings about it for a while now. The truth is, most of the azhdarchids can’t be definitely grouped outside of a single genus. Quetzalcoatlus and Hatzegopteryx, for example, aren’t distinct save for their locations on the globe. Though research might or might not prove me wrong, I can still have my opinion.

Note: I’m sorry that this post is so short. It’s hard to blog about such a poorly-known taxon.

Aerodactylus scolopaciceps by Steven Vidovic:

Aerodactylus scolopaciceps is a pterodactyloid pterosaur from the Solnhofen Plattenkalk of Bavaria, Germany. Aerodactylus was a Jurassic pterosaur, like Pterodactylus. It was in fact synonymous with Pterodactylus until 2014 when Vidovic and Martill erected the genus Aerodactylus for it.

(And yes, it’s named for the Pokémon.)

Nyctosaurus sebulbai by Jaime A. Headden:

No, this isn’t a real animal.

Nyctosaurids are pterosaurs with incredibly long arms, but comparatively short feet. Darren Naish once speculated ([link]) that pterosaurs could attain flightless status in much the same ways as birds do, with reduction of the forelimbs and wing form, developing elongated hindlimbs in azhdarchid-like taxa and thus become giraffe or horse-like “quadrupedasaurs.” I wonder if the selection on the wings for form are so intensive this could ever happen. Indeed, it seems that it would be the feet first to go, the wings second, if ever. What if, instead, we got pterosaurs who walked with their wings, freeing their feet from locomotion?

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For a coastal species, there sure are very few illustrations of Pteranodon around coastal features. It’s always beaches and cliffs, which is why I decided to put these two in a sea cave, perhaps on an adventure of some sorts.

There are also woefully few images of purported female Pteranodon out there, all the attention seems to go to the larger, more spectacularly crested males, while the females are shoved into the background. This clearly doesn’t reflect nature, as female Pteranodon make up 2/3 of all Pteranodon specimens, so surely there should be a lot more of them showing up in palaeoart?

So to shake things up a little, here are two female Pteranodon, without a male in sight, exploring a sea cave.

Lacusovagus magnificens restoration by Mark Witton:

Now, if pterosaur palaeobiogeography floats your boat, finding a chaoyangopterid in Brazil is extremely cool. Chaoyangopterids, y’see, have thus far only been found in the Jehol Group of ChinaLacusovagus, therefore, provides the first record of these guys outside of Asia and suggests that this otherwise poorly-known group were far more widespread than previously realised. It also heightens the faunal similarity between these two localities, suggesting that we should expect pretty similar pterosaur diversity between China and Brazil. All in all, it goes to show that we’ve still got a hell of a lot to learn about pterosaur diversity and biogeography and emphasises just how reliant we are on fossil lagerstätte – sites of exceptional fossil preservation like Crato and Jehol – to tell us what pterosaurs were up to at any given time in their evolutionary history.

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Most primitive species of pterodactyloid discovered in China. Kryptodrakon progenitor is thought to be the ancestral species to the entire clade of flying reptiles that soared over the late cretaceous earth. One of the co-discoverers is the University of South Florida’s own Dr. Brian Andres.