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Scansoriopterygidae (meaning "climbing wings") is an extinct group of climbing and gliding maniraptoran dinosaurs. Scansoriopterygids are known from four well-preserved fossils, representing three species, unearthed in the Tiaojishan Formation fossil beds (dating to the mid-late Jurassic Period) of Liaoning and Hebei, China. ''Scansoriopteryx heilmanni'' (and its likely synonym ''Epidendrosaurus ninchengensis'') was the first non-avian dinosaur found that had clear adaptations to an arboreal or semi-arboreal lifestyle–it is likely that they spent much of their time in trees. Both specimens showed features indicating they were juveniles, which made it difficult to determine their exact relationship to other non-avian dinosaurs and birds. It was not until the description of ''Epidexipteryx hui'' in 2008 that an adult specimen was known. In 2015, the discovery of another, larger adult specimen belonging to the species ''Yi qi'' showed that scansoriopterygids were not only climbers but also had adaptations that could have been used for gliding flight. ==Description== Scansoriopterygids are among the smallest dinosaurs known. The juvenile specimens of ''Scansoriopteryx'' are the size of house sparrows, about 16 centimeters long, while the adult type specimen of ''Epidexipteryx'' is about the size of a pigeon, about 25 centimeters long (not including the tail feathers).〔Zhang, F., Zhou, Z., Xu, X., Wang, X. and Sullivan, C. (2008). "A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers", Supplementary Information. ''Nature'', 455: 46pp. PMID 18948955〕 Scansoriopterygids differentiate from other theropod dinosaurs in part by their extremely long third fingers, which were longer than the first and second digits of the hand. In all other known theropods, the second finger is the longest. At least one species, ''Yi qi'', also had a long "styliform" bone growing from the wrist, which, along with the third finger, helped support a bat-like wing membrane used for gliding. This use of a long finger to support a wing membrane is only superficially similar to the wing arrangement in pterosaurs.〔 Other features shared within the group include short and high skulls with down turned lower jaws and large front teeth, and long arms. Tail length, however, varied significantly among scansoriopterygids. ''Epidexipteryx'' had a short tail (70% the length of the torso), anchoring long tail feathers, while ''Scansoriopteryx'' had a very long tail (over three times as long as the torso) with a short spray of feathers at the tip. All three described scansoripterygid specimens preserve the fossilized traces of feathers covering their bodies.〔〔Czerkas, S.A., and Yuan, C. (2002). "An arboreal maniraptoran from northeast China." Pp. 63-95 in Czerkas, S.J. (Ed.), ''Feathered Dinosaurs and the Origin of Flight.'' The Dinosaur Museum Journal 1. The Dinosaur Museum, Blanding, U.S.A. (PDF abridged version )〕〔Zhang, F., Zhou, Z., Xu, X., Wang, X., & Sullivan, C. (2008). "A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers." ''Available from Nature Precedings'', (PDF full text ).〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Scansoriopterygidae」の詳細全文を読む スポンサード リンク
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