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Archaeopteryx leg feathers in new Paleobiology
From: Ben Creisler bh480@scn.org
In case this paper has not been mentioned yet:
Longrich, Nick, 2006. Structure and function of hindlimb
feathers in Archaeopteryx lithographica
Paleobiology 32(3):. 417?431
This study examines the morphology and function of
hindlimb plumage in Archaeopteryx lithographica. Feathers
cover the legs of the Berlin specimen, extending from the
cranial surface of the tibia and the caudal margins of
both tibia and femur. These feathers exhibit features of
flight feathers rather than contour feathers, including
vane asymmetry, curved shafts, and a self-stabilizing
overlap pattern. Many of these features facilitate lift
generation in the wings and tail of birds, suggesting that
the hindlimbs acted as airfoils. A new reconstruction of
Archaeopteryx is presented, in which the hindlimbs form
approximately 12% of total airfoil area. Depending upon
their orientation, the hindlimbs could have reduced stall
speed by up to 6% and turning radius by up to 12%.
Presence of the ?four-winged? planform in both
Archaeopteryx and basal Dromaeosauridae indicates that
their common ancestor used fore- and hindlimbs to generate
lift. This finding suggests that arboreal parachuting and
gliding preceded the evolution of avian flight.