Birds evolved from gliding four-legged dinosaurs
mongabay.com
September 22, 2006
Birds may have evolved from gliding four-legged dinosaurs according to new research by a University of Calgary paleontologist.
In a paper published in the journal Paleobiology, Department of Biological Sciences PhD student Nick Longrich argues that the earliest known ancestor of modern-day birds flew by "gliding from trees using primitive feathered wings on their arms and legs." His theory flies in the face of the idea that birds first took flight from the ground after a running start.
"The discussions about the origins of avian flight have been dominated by the so-called 'ground up' and 'trees down' hypotheses," Longrich said. "This paper puts forward some of the strongest evidence yet that birds descended from arboreal parachuters and gliders, similar to modern flying squirrels."
Sierra forest. Photo by Rhett Butler
Examining fossils of the dinosaur-like bird Archaeopteryx, Longrich concluded that "the dinosaur's leg feathers have an aerodynamic structure that imply its rear limbs likely acted as lift-generating 'winglets' that played a significant role in flight."
"The idea of a multi-winged Archaeopteryx has been around for more than a century, but it hasn't received much attention," Longrich said. "I believe one reason for this is that people tend to see what they want or expect to see. Everybody knows that birds don't have four wings, so we overlooked them even when they were right under our noses
This is article is a rewritten news release from the University of Calgary.
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