A group of scientists have discovered a new type of flying reptile from the dinosaur age.
Named the Darwinopterus, the creature was one of many kinds of pterosaurs, or pterodactyles, which dominated the skies in the Mesozoic era 220-65 million years ago.
It was identified by a group of researchers from the University of Leicester and the Geological Institute in Beijing.
The discovery also provided the first clear evidence of an unusual and controversial type of evolution, they said.
It is thought to fill the evolutionary gap between two types of pterosaurs — primitive long-tailed forms and their descendants, advanced short-tailed pterosaurs, some of which reached gigantic size.
The researchers said the groups were separated by a large evolutionary gap, identified in Charles Darwin’s time, which looked as if it would never be filled - until now.
Details of the new pterosaur, published today in the journal Proceedings of the Royal Society B: Biological Sciences, fits exactly in the middle of that gap.
More than 20 fossil skeletons of Darwinopterus, some of them complete, were found earlier this year in north-east China in rocks dated around 160 million years old.
This is close to the boundary between the Middle and Late Jurassic periods and at least 10 million years older than the first bird, Archaeopteryx, the researchers said.
With long jaws, rows of sharp-pointed teeth and a flexible neck, the crow-sized reptile is thought to have been hawk-like, catching and killing other flying creatures.
Its prey included various pterosaurs, tiny gliding mammals and small pigeon-sized, meat-eating dinosaurs which, helped by feathered arms and legs, had recently taken to the air and would later evolve into birds.
The new discovery was christened Darwinopterus, meaning Darwin's wing, to honour the 200th anniversary of Darwin's birth and the 150th anniversary of the publication of his famous book On The Origin Of Species.
Doctor David Unwin, from the University of Leicester’s School of Museum Studies, who was part of the research team, said today: “Darwinopterus came as quite a shock to us.
“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 said the geological age of Darwinopterus and its bizarre combination of advanced and primitive features revealed a lot about the evolution of advanced pterosaurs from their primitive ancestors.
“First, it was quick, with lots of big changes concentrated into a short period of time,” he said.
“Second, whole groups of features — termed modules by the researchers — that form important structures such as the skull, the neck, or the tail, seem to have evolved together.
“But, as Darwinopterus shows, not all these modules changed at the same time.
“The head and neck evolved first, followed later by the body, tail, wings and legs.
“It seems that natural selection was acting on and changing entire modules and not, as would normally be expected, just on single features such as the shape of the snout, or the form of a tooth.
“This supports the controversial idea of a relatively rapid ‘modular’ form of evolution.”
Despite the discovery, the research team warned today that much more work is needed to substantiate the idea of “modular evolution”.
But if true, they said it could help explain not just how primitive pterosaurs evolved into more advanced forms, but other cases among animals and plants where “rapid large-scale” evolution must have taken place.
Dr Unwin added: “Frustratingly, these events, which are responsible for much of the variety of life that we see all around us, are only rarely recorded by fossils.
"Darwin was acutely aware of this, as he noted in The Origin Of Species, and hoped that one day fossils would help to fill these gaps.
“Darwinopterus is a small but important step in that direction.”
PA