Wikipedia
Scansoriopteryx
Scansoriopteryx ("climbing wing") is a genus of avialan dinosaur. Described from only a single juvenile fossil specimen found in Liaoning, China, Scansoriopteryx is a sparrow-sized animal that shows adaptations in the foot indicating an arboreal (tree-dwelling) lifestyle. It possessed an unusual, elongated third finger which may have supported a membranous wing. The type specimen of Scansoriopteryx also contains the fossilized impression of feathers.
Most researchers regard this genus as a synonym of Epidendrosaurus, with some preferring to treat Scansoriopteryx as the junior synonym, though it was the first name to be validly published.