Recently , a series of the feathered dinosaurs have been found from the jehol biota of western liaoning , northeast china , which give extremely strong evidences of the theropod hypothesis of bird origin and of the cursorial hypothesis of the avian flight origin . but the origin and early evolution of feathers have still been unanswered . in late 2000 , a well - preserved specimen of dromaeosaurids was excavated from the early cretaceous jiufotang formation of shangheshou , suburb of chaoyang city , western liaoning 2000年，辽西朝阳市上河首早白垩世九佛堂组地层中，发现了一件保存完好的长有羽毛的奔龙类化石，这是继北票四合屯、朝阳下三家子、凌源大王杖子之后长羽毛奔龙化石在辽西的又一次发现，为解决奔龙类的系统关系、羽毛的起源及早期演化提供了重要的实物资料。
