title: Four-winged dinosaurs from China.
abstract: Although the dinosaurian hypothesis of bird origins is widely accepted, debate remains about how the ancestor of birds first learned to fly. Here we provide new evidence suggesting that basal dromaeosaurid dinosaurs were four-winged animals and probably could glide, representing an intermediate stage towards the active, flapping-flight stage. The new discovery conforms to the predictions of early hypotheses that proavians passed through a tetrapteryx stage.
authors.affiliation: Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, P.O. Box 643, Beijing 100044, China. xing_xu@sina.com
authors.forename: Xing
authors.initials: X
authors.lastname: Xu
authors.forename: Zhonghe
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xiaolin
authors.initials: X
authors.lastname: Wang
authors.forename: Xuewen
authors.initials: X
authors.lastname: Kuang
authors.forename: Fucheng
authors.initials: F
authors.lastname: Zhang
authors.forename: Xiangke
authors.initials: X
authors.lastname: Du
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology; D002681:China; D025061:Dinosaurs / Q000033:anatomy & histology* / Q000145:classification / Q000502:physiology; D005241:Feathers / Q000033:anatomy & histology / Q000502:physiology; D005426:Flight, Animal; D005580:Fossils; D008954:Models, Biological; D014921:Wings, Animal / Q000033:anatomy & histology* / Q000502:physiology