‘Hidden dragon’ fossil from China fill ancient evolutionary gap

Millions of years ago, dinosaurs may have ruled the Earth, but the skies were dominated by flying reptiles called pterosaurs, some of whom reached the size of a modern fighter jet. In a study published this week, paleontologists report discovering the progenitor to the largest of these massive flyers, filling in a large evolutionary gap in the process.

From the fossil record that scientists have been able to uncover, pterosaurs — or 'winged lizards' — first appeared on Earth over 200 million years ago, during the Triassic period. They were fairly small back then, at least compared to the gargantuan pterodactyloids that were around in the later Jurassic period, and their evolution towards bigger species apparently stemmed from several changes to their anatomy over time. Fossil specimens of early pterosaurs showed smaller heads with toothy mouths, and short, stumpy 'pinky' fingers on their 'hand' that limited wing shape and size. Later, larger pterodactyloids had bigger heads, no teeth and extremely long 'ring' fingers. It was these longer fingers that allowed their wing shape to change and grow larger, to give them a better advantage in the skies, and the ability to develop into larger species.

Now, a group of paleontologists that examined portions of a pterosaur fossil discovered in China's Gobi desert in 2001 are reporting that their find is the oldest pterodactyloid specimen ever found, extending their fossil record back 5 million years, to around the boundary between the middle and late Jurassic, 163 million years ago. The newly-named species, called Kryptodrakon progenitor, only had a wing-span of about 4-½ feet, but as its name suggests, it was the progenitor of all of these larger pterodactyloids.

"This guy is the very first pterodactyloid — he has the last features that changed before the group radiated and took over the world," said Brian Andres, a paleontologist at the University of South Florida and co-author of the study, according to LiveScience.

Not only has this specimen filled in a rather large evolutionary gap, but it has also revealed that this species very likely lived over land, like later pterodactyloids, rather than along coastal or over marine environments, like its earlier relatives did.

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Although the pterodactyl is popularly portrayed as 'the flying dinosaur' of prehistoric Earth, pterodactyls are just one specific genus of pterodactyloidea — which is one of the branches of pterosaurs that populated Earth up until the late Jurassic — and pterosaurs aren't actually dinosaurs (both are their own order or 'clade' in the animal kingdom). However, several other branches on the 'tree' are so like the pterodactyl that scientists refer to them, collectively, as pterodactyloids.

As for this new pterodactyloid, its name 'Kryptodrakon progenitor' — which means 'ancient hidden dragon' — was chosen because the 2000 film Crouching Tiger, Hidden Dragon was filmed in the area that the fossil specimen was discovered.

(Image courtesy: Reuters)

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