Yi (dinosaur)

Yi is a genus of climbing and gliding dinosaurs from the Jurassic of China. Its only species, Yi qi is known from a single fossil specimen of an adult found in middle or late Jurassicof Hebei, China. It lived about 160 million years ago. 
"Yi" was a small, possibly tree-dwelling (arboreal) animal. Like other of its family, "Yi" had an unusual, elongated third finger. This helped to support a membranous gliding plane (aerofoil) made of skin. 
The gliding planes of "Yi qi" were also supported by a long, bony strut attached to the wrist. This modified wrist bone and gliding membrane is unique among all known dinosaurs, and might have resulted in wings similar in appearance to those of bats.