Four-winged dinosaur makes feathers fly
Jeff Hecht
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Long flight feathers adorn the hind legs of Microraptor gui (Image: Xing Xu)
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A stunning set of six fossils discovered in China could rewrite our understanding of how and why birds first took to the sky. The fossils clearly show a small dinosaur that had flight feathers covering its legs, as well as tail and arms, forming an extra pair of wings never before seen by palaeontologists.
News of the find comes just days after scientists published work showing that baby partridges flap their tiny wings to help them climb steep slopes, an insight that may explain why wings first evolved. Together, the two discoveries may represent one the most significant advances in the contentious study of avian evolution for decades.
"We need to be prepared to change some cherished notions" about the evolution of flight, palaeontologist Larry Witmer of Ohio University told New Scientist.
Experts have traditionally been split between two mutually exclusive theories. Flight either began with small, fleet predatory dinosaurs leaping from the ground into the air, or with other animals that learnt to fly whilst jumping to earth from trees. But the new studies reveal a far more complex picture.
Extensive coat
The six new specimens "are potentially as important as Archaeopteryx," the famous feathered fossil discovered in the 1860s. It first alerted scientists to the link between dinosaurs and birds, says Kevin Padian of the University of California at Berkeley.
The Chinese fossils are of a small dinosaur belonging to the Microraptor genus. It is known to be the most primitive dromeosaur, a group of two-legged predatory dinosaurs closely related to birds.
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| The four-winged dinosaur lived 130 million years ago (Artist's impression: Portia Sloan) |
Earlier Microraptor fossils did not preserve feathers. But the best of the six new specimens, thought to belong to a new species, have the most extensive coat of feathers ever seen on a dinosaur.
The animal was presumably light enough to fly - the best-preserved skeleton is just 77 centimetres from the nose to the tip of the long tail. There is "no doubt the new animal is a flying animal," says Xing Xu from the Institute for Vertebrate Paleontology and Paleoanthropology in Beijing, who describes the new fossils in Nature.
Gliding down
Xu describes it as a "four-winged dinosaur". Instead of being capable of powered flight, Xu believes that Microraptor used all four limbs to climb trees, and then glide back down again. But Microraptor gui, as it has been dubbed, is unusual because it has feathers at the ends of its arms and legs that are twice as long as those close to its body.
Usually animals have gliding surfaces that narrow, rather than widen, the further they are from the body. The feathers on the legs are particularly baffling, as they cannot spread wide enough to generate much lift.
Xu suggests they might have served as a stabilizer, but other scientists say we need more time to be sure. "This is so far out of the box that we need to sit back and figure out how this can work," says Witmer.
Journal reference: Nature (vol 421, p 335)
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