Microraptor gui, a little dinosaur with four feathered limbs, may have glided through the air like a biplane, with its wings paired in parallel, say palaeontologists.
If the hypothesis is correct, it would be the only known example of a living creature employing such a flight mechanism. The microraptor fossil was found in China (see Four-winged dinosaur makes feathers fly) and measures just 77 centimetres from the nose to the tip of its long tail. It dates from 125 million years before biplanes were invented.
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Researchers originally suggested that Microraptor spread both arms and legs to the sides of its body to form two pairs of gliding wings. But palaeontologist Sankar Chatterjee of Texas Tech University in Lubbock, US, says that would have been aerodynamically inefficient and that Microraptor鈥檚 legs could not be splayed sideways.
No choice
He says the dinosaur instead folded its legs under its body like modern raptors catching prey, with its long leg feathers sticking out to the side. The asymmetric foot feathers must have had their narrow side facing forward to smooth the flow of air around the leg.
鈥淥nce you do this, you have no other choice but the biplane design,鈥� Chatterjee told 快猫短视频. This creates a second set of wings below the body and behind the arm wings, which is 鈥渁 more anatomically and aerodynamically stable configuration鈥�, he believes.
Gregory Paul, a palaeontologist not involved in the study, is unconvinced by the theory, although he allows the model is plausible. Although fossils clearly show flight feathers, their orientation 鈥� critical to understanding their role in flight 鈥� remains unclear.
鈥淲e don鈥檛 know what they鈥檙e doing with those hind feathers,鈥� Paul told 快猫短视频. He thinks Microraptor used its hind wings only for gliding, folding them out of the way for powered flight. Clearer fossil finds may provide a definitive answer.
Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0609975104)
