title: Elemental characterisation of melanin in feathers via synchrotron X-ray imaging and absorption spectroscopy.
abstract: Melanin is a critical component of biological systems, but the exact chemistry of melanin is still imprecisely known. This is partly due to melanin's complex heterogeneous nature and partly because many studies use synthetic analogues and/or pigments extracted from their natural biological setting, which may display important differences from endogenous pigments. Here we demonstrate how synchrotron X-ray analyses can non-destructively characterise the elements associated with melanin pigment in situ within extant feathers. Elemental imaging shows that the distributions of Ca, Cu and Zn are almost exclusively controlled by melanin pigment distribution. X-ray absorption spectroscopy demonstrates that the atomic coordination of zinc and sulfur is different within eumelanised regions compared to pheomelanised regions. This not only impacts our fundamental understanding of pigmentation in extant organisms but also provides a significant contribution to the evidence-based colour palette available for reconstructing the appearance of fossil organisms.
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Williamson Research Centre for Molecular Environmental Science, M13 9PL, UK.|University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.
authors.forename: Nicholas P
authors.initials: NP
authors.lastname: Edwards
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Williamson Research Centre for Molecular Environmental Science, M13 9PL, UK.|University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.
authors.forename: Arjen
authors.initials: A
authors.lastname: van Veelen
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Williamson Research Centre for Molecular Environmental Science, M13 9PL, UK.|University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Anné
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.|College of Charleston, Department of Geology and Environmental Geosciences, Charleston, SC, 29424, USA.
authors.forename: Phillip L
authors.initials: PL
authors.lastname: Manning
authors.affiliation: Stanford PULSE Institute, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
authors.forename: Uwe
authors.initials: U
authors.lastname: Bergmann
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Williamson Research Centre for Molecular Environmental Science, M13 9PL, UK.|University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.
authors.forename: William I
authors.initials: WI
authors.lastname: Sellers
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.|College of Charleston, Department of Geology and Environmental Geosciences, Charleston, SC, 29424, USA.
authors.forename: Victoria M
authors.initials: VM
authors.lastname: Egerton
authors.affiliation: Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA 94025, USA.
authors.forename: Dimosthenis
authors.initials: D
authors.lastname: Sokaras
authors.affiliation: Linac Coherent Lightsource, SLAC National Accelerator Laboratory, Menlo Park, CA, 94025, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Alonso-Mori
authors.affiliation: Department of Chemistry, Fujita Health University, School of Health Sciences, Toyoake, Aichi 470-1192, Japan.
authors.forename: Kazumasa
authors.initials: K
authors.lastname: Wakamatsu
authors.affiliation: Department of Chemistry, Fujita Health University, School of Health Sciences, Toyoake, Aichi 470-1192, Japan.
authors.forename: Shosuke
authors.initials: S
authors.lastname: Ito
authors.affiliation: University of Manchester, School of Earth and Environmental Sciences, Williamson Research Centre for Molecular Environmental Science, M13 9PL, UK.|University of Manchester, School of Earth and Environmental Sciences, Interdisciplinary Centre for Ancient Life, Manchester M13 9PL, UK.
authors.forename: Roy A
authors.initials: RA
authors.lastname: Wogelius