Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis

We report fossil evidence of feather structural protein (beta-keratin) from a 130-My-old basal bird (Eoconfuciusornis) from the famous Early Cretaceous Jehol Biota, which has produced many feathered dinosaurs, early birds, and mammals. Multiple independent molecular analyses of both microbodies and associated matrix recovered from the fossil feathers confirm that these microbodies are indeed melanosomes. We use transmission electron microscopy and immunogold to show localized binding of antibodies raised against feather protein to matrix filaments within these ancient feathers. Our work sheds new light on molecular constituents of tissues preserved in fossils.