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furculum n.(pl. -la ) = furcula.

furfur

The feathers attached to the arms and the tail evidently possess the structures of “ modern feathers “ , which consisting of the central shafts ( rachis ) and parallel barbs . dromaeosaurids are unusual group of maniraptoran theropods . they share many similar or the same features with archaeopteryx or other primitive birds , such as : u - shaped furcula , uncinate process , laterally facing glenoid of shoulder girdle , comparatively long forelimb , large semilunate carple , retroverted pubis , ascending process of astragalus , and “ modern feathers “ with rachis and barbs etc . these facts indicate not only that dromaeosaurids had developed many bird - like characters in course of the advanced maniraptorans toward birds , but also that there seemed to be the co - evolutionary trend between the feathers and the skeletal bones 奔龍類是一類較為特殊的手盜龍類( maniraptora ) ,它具有許多與始祖鳥archaeopteryx甚至其它早期鳥類相似或接近的特征,主要表現在:叉骨u形與始祖鳥和孔子鳥類的相同,背肋鉤狀突在孔子鳥類和個別反鳥類中也存在,肩臼窩絕大部分指向側方類似于始祖鳥,肩胛骨與烏喙骨間的夾角非常接近90也和始祖鳥的相似,前肢從比例上講顯得較長,大的半月形腕骨使肘部能向側方折過來,恥骨伸向后下方,距骨上升突與原始鳥類中的為同源結構,羽毛已有顯著的分化且具備了現代羽毛的基本結構等等。