Bristle Scale As a Predecessor of Protofeather and Feather

The bristle scale is a skin appendage recognized in the ornithiscian dinosaurs Daurosaurus olovus and Kulindapteryx ukureica from the Kulinda locality (Transbaikalia, Russia). Morphologically, the bristle scale is a horn plate immersed in the dermis, with strands (bristles) diverging from its external edge. It is assumed that the filamentous protofeather of dinosaurs is the monobristle variant of the bristle scale and avian feather results from its tubular spatial modification. The bristle scale is considered to be intermediate between the reptilian scale and avian feather.