It’s been a good week for pterosaur discoveries. Just as one team of researchers has announced that dwarf-like, cat-sized pterosaurs flew in the skies of the Late Cretaceous Earth 77 million years ago, another has revealed that a perfect intermediary between the earliest and final pterosaur forms has been dug up in Patagonia.
Publishing their work in the journal PeerJ, the team note that the cranial remains were in such an excellent state of preservation that it was clear they belonged to a brand-new variety of pterosaur that dates back to the late Early Jurassic, around 183 million years ago. This means that this flying monster, with a wingspan of perhaps several meters, predated the appearance of the famous Stegosaurus by about 30 million years.
Using CT (X-ray) scans on the three-dimensionally preserved skull, the team were able to check in unprecedented detail whether or not it was new to paleontology, and as it turns out, it belongs to a completely new genus, not just its own species. It has been named Allkauren koi, which is the native Tehuelche words for “ancient brain”.
Pterosaurs – which are flying lizards and not, as many often cite, dinosaurs – have been around since the Late Triassic, around 228 million years ago, but they started out quite small, with wingspans no larger than a meter (3.3 feet) or so. By the time of the Late Cretaceous, about 100 million years ago, they were far bigger, with one giraffe-sized example having an 11-meter (33-foot) wingspan, equivalent to that of a small plane.
The newly discovered A. koi, therefore, is smack bang in the middle of this evolutionary lineage, which makes it a great example of how developed pterosaurs were between their very small and very large size limits.
“Allkaruen… shows an intermediate state in the brain evolution of pterosaurs and their adaptations to the aerial environment,” study co-author Diego Pol, a paleontologist at the National Scientific and Technical Research Council (CONICET) in Argentina, said in a statement. “As a result, this research makes an important contribution to the understanding of the evolution of all of pterosaurs.”
Restoration of Campylognathoides, one of the earliest types of pterosaur. ?????/Wikimedia Commons; Public Domain
Pterosaurs can feed quite differently, with some dip-feeding by skimming over water and occasionally poking their head beneath the waves, and with others stalking the land and picking up vertebrate prey. Some have teeth and some do not. As this is a newly found genus, and its skull was the only well-preserved part found, much about its lifestyle is unknown at present.
Generally speaking, two major body plans have been recognized for pterosaur-like powered flight. The first is from the short-tailed pterodactyls, and the second is from the long-tailed rhamphorhynchoids, an ambiguous, pterosaur-like group. The general anatomy and the structures of their brains were quite different, and A. koi’s transitionary braincase (finally) fills the enigmatic gap between the two.
Over 150 species of pterosaur are currently known to science. They were incredibly diverse creatures, and perhaps most strikingly, they coexisted with the earliest birds, the direct descendants of some non-avian dinosaurs.
We all know how the story goes – assisted by the rise of mammals and massive climate-changing volcanic eruptions, an asteroid slammed into the planet 66 million years ago, taking the non-avian dinosaurs and pterosaurs with them, among others. Mammals and crocodiles stole the land from the Tyrannosaurs, and birds thieved it from the pterosaurs – and the rest, as they say, is history.
A reconstruction of the Quetzalcoatlus, one of the largest genus of pterosaur. Mark Witton and Darren Naish/Wikimedia Commons; CC BY 3.0
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