page_title: Sinornithosaurus
section_title: Flight/gliding
hierarchical_section_title: Sinornithosaurus / Paleobiology / Flight/gliding
caption_attribution_description: Sinornithosaurus millenii fossil displayed in Hong Kong Science Museum
context_page_description: Sinornithosaurus is a genus of feathered dromaeosaurid dinosaur from the early Cretaceous Period of the Yixian Formation in what is now China. It was the fifth non–avian feathered dinosaur genus discovered by 1999. The original specimen was collected from the Sihetun locality of western Liaoning. It was found in the Jianshangou beds of the Yixian Formation, dated to 124.5 million years ago. Additional specimens have been found in the younger Dawangzhangzi bed, dating to around 122 million years ago.
  Xu Xing described Sinornithosaurus and performed a phylogenetic analysis which demonstrated that it is basal, or primitive, among the dromaeosaurs. He has also demonstrated that features of the skull and shoulder are very similar to Archaeopteryx and other Avialae. Together these two facts demonstrate that the earliest dromaeosaurs were more like birds than the later dromaeosaurs were.
  Sinornithosaurus was among the smallest dromaeosaurids, with a length of about 90 centimetres. In 2010, Gregory S. Paul gave higher estimations of 1.2 metres and three kilogrammes.
context_section_description: The possibility that Sinornithosaurus was capable of gliding has been presented several times, due to its close relation to flying or gliding dromaeosaurs like Microraptor. Chatterjee and Templin 2004 found S. millenii as grouping within dinosaurs with aerodynamic potential for aerial locomotion, an opinion latter also expressed by Darren Naish, while Longrich & Currie 2009 have expressed that it was probably too heavy to fly, though it is worth to note that this latter study was published before the formal description of Changyuraptor, a larger microraptorine with evident flight capacities.
caption: Referred specimen, Hong Kong Science Museum
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