Flying reptile fossil bridges evolutionary gap between two groups of pterosaurs

Wednesday, October 14, 2009

WASHINGTON - A team of international scientists has identified a new type of flying reptile, which bridges the evolutionary gap between two groups of pterosaurs.

Pterosaurs, flying reptiles, also known as pterodactyls, dominated the skies in the Mesozoic Era, the age of dinosaurs, 220-65 million years ago.

Scientists have long recognized two different groups of pterosaurs: primitive long-tailed forms and their descendants, advanced short-tailed pterosaurs some of which reached gigantic size.

These groups are separated by a large evolutionary gap between the smaller, ancient pterosaurs and more modern ones, which grew to gargantuan proportions and, unlike their ancestors, could walk.

This gap, identified in Charles Darwin’s time, looked as if it would never be filled. Now, details of a new pterosaur fit exactly in the middle of that gap.

Christened Darwinopterus, meaning Darwin’s wing, the name of the new pterosaur honours the 200th anniversary of Charles Darwin’s birth.

More than 20 fossil skeletons of Darwinopterus, some of them complete, were found earlier this year in north-east China in rocks dated at around 160 million years old.

This is close to the boundary between the Middle and Late Jurassic and at least 10 million years older than the first bird, Archaeopteryx.

The long jaws, rows of sharp-pointed teeth and rather flexible neck of this crow-sized pterosaur suggest that it might have been hawk-like, catching and killing other contemporary flying creatures.

These included various pterosaurs, tiny gliding mammals and small, pigeon-sized, meat-eating dinosaurs that, aided by their feathered arms and legs had recently taken to the air, and would later evolve into birds.

“Darwinopterus came as quite a shock to us,” explained David Unwin, part of the research team and based at the University of Leicester’s School of Museum Studies.

“We had always expected a gap-filler with typically intermediate features such as a moderately elongate tail - neither long nor short - but the strange thing about Darwinopterus is that it has a head and neck just like that of advanced pterosaurs, while the rest of the skeleton, including a very long tail, is identical to that of primitive forms,” he added.

According to Dr Unwin, “The geological age of Darwinopterus and bizarre combination of advanced and primitive features reveal a great deal about the evolution of advanced pterosaurs from their primitive ancestors.”

“Our new pterosaur is great, because it jumps right in that gap that we’ve known about,” he said. (ANI)

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