title: The colour of fossil feathers.
abstract: Feathers are complex integumentary appendages of birds and some other theropod dinosaurs. They are frequently coloured and function in camouflage and display. Previous investigations have concluded that fossil feathers are preserved as carbonized traces composed of feather-degrading bacteria. Here, an investigation of a colour-banded feather from the Lower Cretaceous Crato Formation of Brazil revealed that the dark bands are preserved as elongate, oblate carbonaceous bodies 1-2 microm long, whereas the light bands retain only relief traces on the rock matrix. Energy dispersive X-ray analysis showed that the dark bands preserve a substantial amount of carbon, whereas the light bands show no carbon residue. Comparison of these oblate fossil bodies with the structure of black feathers from a living bird indicates that they are the eumelanin-containing melanosomes. We conclude that most fossil feathers are preserved as melanosomes, and that the distribution of these structures in fossil feathers can preserve the colour pattern in the original feather. The discovery of preserved melanosomes opens up the possibility of interpreting the colour of extinct birds and other dinosaurs.
authors.affiliation: Department of Geology and Geophysics, Yale University, New Haven, CT 06520, USA.
authors.forename: Jakob
authors.initials: J
authors.lastname: Vinther
authors.forename: Derek E G
authors.initials: DE
authors.lastname: Briggs
authors.forename: Richard O
authors.initials: RO
authors.lastname: Prum
authors.forename: Vinodkumar
authors.initials: V
authors.lastname: Saranathan
mesh_terms: D000818:Animals; D001717:Birds; D003116:Color; D025061:Dinosaurs; D005241:Feathers / Q000648:ultrastructure; D005580:Fossils; D008543:Melanins / Q000302:isolation & purification; D020460:Melanosomes / Q000648:ultrastructure
chemical_list: D008543:Melanins