File:Feather Sinornithosaurus.jpg

Summary
Figure 11. Filamentous integumental structure of Sinornithosaurus millenii with compound structures composed of multiple filaments. These structures exhibit two types of branching structure unique to avian feathers: the filaments are joined in a basal tuft, and the filaments are joined at their bases in series along a central filament. a, Arrows indicate the distal tips of some component filaments. b, Illustrated reconstruction of the appendage showing the positions of the observed filaments (lines) and the inferred outline of the appendage (shading). Asterisk, the proximal end of the appendage. The curved position of the appendage reveals its compound structure. Each filament converges on the centre of the appendage at its base. Scale bar, 5 mm (From: Xu et al. 2001).