title: Seeking carotenoid pigments in amber-preserved fossil feathers.
abstract: Plumage colours bestowed by carotenoid pigments can be important for visual communication and likely have a long evolutionary history within Aves. Discovering plumage carotenoids in fossil feathers could provide insight into the ecology of ancient birds and non-avian dinosaurs. With reference to a modern feather, we sought chemical evidence of carotenoids in six feathers preserved in amber (Miocene to mid-Cretaceous) and in a feather preserved as a compression fossil (Eocene). Evidence of melanin pigmentation and microstructure preservation was evaluated with scanning electron and light microscopies. We observed fine microstructural details including evidence for melanin pigmentation in the amber and compression fossils, but Raman spectral bands did not confirm the presence of carotenoids in them. Carotenoids may have been originally absent from these feathers or the pigments may have degraded during burial; the preservation of microstructure may suggest the former. Significantly, we show that carotenoid plumage pigments can be detected without sample destruction through an amber matrix using confocal Raman spectroscopy.
authors.affiliation: 1] Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA [2].
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Thomas
authors.affiliation: Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024-5192, USA.
authors.forename: Paul C
authors.initials: PC
authors.lastname: Nascimbene
authors.affiliation: Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA.
authors.forename: Carla J
authors.initials: CJ
authors.lastname: Dove
authors.affiliation: Division of Invertebrate Zoology, American Museum of Natural History, New York, NY 10024-5192, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Grimaldi
authors.affiliation: Department of Vertebrate Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20013-7012, USA.
authors.forename: Helen F
authors.initials: HF
authors.lastname: James
mesh_terms: D018647:Amber / Q000737:chemistry*; D000818:Animals; D005075:Biological Evolution; D002338:Carotenoids / Q000378:metabolism*; D003116:Color; D025061:Dinosaurs / Q000378:metabolism*; D005241:Feathers / Q000378:metabolism*; D005580:Fossils / Q000033:anatomy & histology*; D010858:Pigmentation / Q000502:physiology*; D011309:Preservation, Biological / Q000379:methods
chemical_list: D018647:Amber; D002338:Carotenoids