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China’s Feathered Dinosaurs
The grasping hand and
flight apparatus of Confuciusornis
CLOSE WINDOW
for how a grasping hand evolved into a flying hand.
The ancestral theropod dinosaur had three functional fingers in the hand: the thumb, index and middle fingers.
Birds retain these three fingers, although they support flight rather than grasping. We have long wondered how
dinosaurs made the transition from a grasping to a flying hand, and Confuciusornis gives us new insight into that
problem. Confuciusornis still has fully functional raptorial claws on its thumb and middle fingers, but its index
finger—the finger that supports the flight feathers—is composed of broad, flat bones and a reduced claw.
As with other basal maniraptors, the thumb and middle fingers converge on one another while grasping in
Confuciusornis, enabling its hand to support flight while still retaining some grasping ability.