Fossil feathers from the Colli Albani volcanic complex (Late Pleistocene, Central Italy) preserved in zeolites

Fossil feathers are usually preserved as carbonaceous films and impressions in lacustrine and marine sediments, or embedded in amber, but rarely mineralized. We report mineralized plumage of a griffon vulture preserved in an ash-rich pyroclastic deposit from the Late Pleistocene Colli Albani volcanic complex (Rome, Italy). Feathers are preserved in three dimensions, with preservation of tissue ultrastructures such as melanosomes and the surrounding feather cortex. These tissue ultrastructures are mineralized in nanocrystalline zeolite, a mode of preservation not previously reported in fossil soft tissues. We propose that zeolitization of the host rock promoted the precipitation of nanocrystalline zeolite within feather structures, possibly controlled by local pH conditions (i.e., within the immediate vicinity of the carcass) and the presence of Si-Al-rich fluids during early diagenesis. Our study suggests that terrestrial volcanic settings have the potential for remarkably high fidelity preservation of soft tissue ultrastructure in diverse ancient organisms.