Microraptor (Greek, μίκρος, mīkros: "small"; Latin, raptor: "one who seizes") is a genus of small, four-winged dromaeosaurid dinosaurs. Numerous well-preserved fossil specimens have been recovered from Liaoning, China. They date from the early Cretaceous Jiufotang Formation (Aptian stage), 120 million years ago.

Like Archaeopteryx, Microraptor provides important evidence about the evolutionary relationship between birds and dinosaurs. Microraptor had longpennaceous feathers that formed aerodynamic surfaces on the arms and tail but also, surprisingly, on the legs. This led paleontologist Xu Xing in 2003 to describe it as a "four-winged dinosaur" and to speculate that it may have glided using all four limbs for lift. Two species have been named, M. zhaoianus and M. gui, though further study has suggested that all of the specimens belong to a single species, which is properly called M. zhaoianus.Cryptovolans, initially described as another four-winged dromaeosaur, is usually considered be a synonym of Microraptor.^[1]

Microraptor was among the most abundant non-avian dinosaurs in its ecosystem, and is represented by more fossils than any other dromaeosaurid, with possibly over 300 fossil specimens represented across various museum collections.^[2]

With adult specimens ranging 77–90 centimetres long (2.53–3.0 ft) and with a weight estimated up to 1 kilogram (2.2 lb), Microraptor was among the smallest known dinosaurs.^[3][4] Aside from its extremely small size, Microraptor was among the first non-avian dinosaurs discovered with the impressions of feathers and wings. Three specimens of M. zhaoianus have been described in detail, in addition to two specimens of M. gui and three specimens of M. sp. described by Xu and colleagues in 2003, from which most feather impressions are known. Unusual even among early birds and feathered dinosaurs, Microraptor is one of the few known bird precursors to sport long flight feathers on its feet as well as its forearms and hands. Their bodies had a thick covering of feathers, with a diamond-shaped fan on the end of the tail (possibly for added stability during flight). Xu et al. (2003) compared the longer plumes on Microraptor's head to those of the Philippine Eagle. Bands of dark and light present on some specimens may indicate color patterns present in life. Several anatomical features found in Microraptor, such as a combination of unserrated and partially serrated teeth with constricted 'waists', and unusually long upper arm bones, are shared with both primitive avians and primitive troodontids. Microraptor is particularly similar to the basal troodontidSinovenator; in their 2002 description of two M. zhaoianus specimens, Hwang et al. note that this is not particularly surprising, given that both Microraptorand Sinovenator are very primitive members of two closely related groups, and both are close to the deinonychosaurian split between dromaeosaurids and troodontids.^[5]