Once the avian group is determined from the microstrucutre, species identifications can then be made if adequate
pennaceous feathers are available to match with museum collections of voucher specimens.
Apart from paleontologists and creationists, nobody much cares whether those fossils that keep turning up in China really belonged to a dinosaur with
pennaceous feathers.
Feathers derive from a complex process of morphogenesis inside embryonic feather filaments that begins with the formation of barb ridges and terminates with the formation of barbs, free in plumulaceous feathers and regularly joined to a rachis in
pennaceous feathers (Lucas & Stettenheim, 1972; Chuong & Widelitz, 1999; Prum & Dyck, 2003; Sawyer & Knapp, 2003).
The feather was identified as eagle from its size, color, and the coarse texture of the
pennaceous barbs.