Epidendrosaurus ningchengensis
"upon branch lizard from Ningcheng County"

     Named for the county in China where is was discovered, and for its apparent arboreal lifestyle, Epidendrosaurus was described around the same time as the very similar looking Scansoriopteryx. For a while there was discussion over whether these two "aye-aye dinosaurs" (so called for their very long third finger) were actually the same species. The question is still open, but new dating methods for the formation in which Epidendrosaurus was found seem to indicate that it lived in the Middle Jurassic, well before the Early Cretaceous Scansoriopteryx. The phylogenetic position of the aye-aye dinosaurs (scansoriopterygids) is still rather uncertain as both known specimens are juvenile, but they probably were some type of avialan, sitting on a very primitive branch of the bird family tree.

     The Epidendrosaurus reconstructed here is a sub-adult, with near fully developed wings. It is using its unusually long thirds finger to grip the trees as it climbs, and its tail as a woodpecker-like brace. The long leg feathers are speculative, based on the much more elaborate hind wings found in some dromaeosaurs, probably close relatives to the scansoriopterygids.