Fig. 1.

SEM images of the sample from pennaceous feather attached to the right forelimb of Anchiornis compared with barbules of a black flight feather from the extant chicken G. gallus, showing that feathers of Anchiornis are preserved as 3D filaments. In some regions, melanosomes are embedded within the matrix as in extant feathers, but the microstructure of Anchiornis feathers differs from that of extant feathers, which could be caused by compression and degradation during the fossilization. (A–D) SEM images of a feather from Anchiornis; (C and D) High-magnification images of the boxed areas in B; melanosomes are indicated by yellow arrows. (E and F) SEM images of an extant feather from the chicken G. gallus; (F) High-magnification images of the boxed area in E.