From the Guardian: Hidden fossil, flying dragon.

Around 120m years ago, as the dinosaurs neared the climax of their dominion, high above their heads an extraordinary creature flitted from tree to tree. The bizarre lizard, named the "flying dragon" by its Chinese discoverers, glided using a flap of skin spread over eight ribs.

The find is remarkable because almost all gliding species, such as "flying" frogs and squirrels, use a membrane spread between their toes or between their body and legs to generate lift. Only two other species evolved the rib-gliding tactic. Xianglong zhaoi is also the first lizard fossil with gliding ribs to be found. [continue]