Tuesday, January 26, 2010

Microraptor A Glider

Model tests of gliding with different hindwing configurations in the four-winged dromaeosaurid Microraptor gui. 2010. D.E. Alexander et al. PNAS, published online before print January 25.

Credit: University of Kansas
A new flight model based on casts of the original bones and the preserved impressions of feathers of Microraptor support the argument that flight originated with ‘tree-down’ gliders.
The fossils also show that an essentially sprawling posture was a plausible hind-limb wing position to provide stable flight with gliding parameters better than those of modern "flying lemurs."

The competing "biplane posture" advanced by other researchers suggested that an upright stance provided for successful glides. But the research team argues that this stance required an impossibly heavy head to maintain a proper center of gravity. Furthermore, the presence of seven-inch-long flight feathers on the feet would prohibit any extended stay on the ground. Thus, Microraptor must have been completely arboreal.

"We decided that we would take the skeleton we had, put wings on it from the feather pattern and show that it could fly," said Burnham. "If others think that it was a terrestrial runner, they should make a model and put it on a treadmill and show that it could run with those long feathers on its hind legs."

Successful flight tests were conducted in the open air and under more controlled conditions at KU. A video of some of the tests is available HERE

Indeed, the team's work provides such strong support for the trees-down model for the origin of avian flight that the alternative terrestrial (ground up) origin now may be abandoned [right – good luck with that! Ed.]. link