Fig. 3.

Elemental maps of the ultrastructure of various fossil feathers compared with that of an extant feather of G. gallus in TEM images. Both extant and fossil feathers show similar elemental compositions of the melanosomes and surrounding matrix. With the exception of Anchiornis, the surrounding matrix does not show a high concentration of sulfur. TEM image and corresponding elemental maps of feather from the chicken G. gallus (A–E), Anchiornis (F–J), Dromaeosauridae indet. (K–O), Eoconfuciusornis (P–T), Yanornis (U–Y), and the isolated Oligocene feather (Z–AD). Boxes show areas selected for elemental mapping. Maps of nitrogen are red, maps of sulfur are green, maps of copper are blue, and maps of calcium are purple. (Scale bars: 1 µm.)