title: Molecular evidence of keratin and melanosomes in feathers of the Early Cretaceous bird Eoconfuciusornis.
abstract: Microbodies associated with feathers of both nonavian dinosaurs and early birds were first identified as bacteria but have been reinterpreted as melanosomes. Whereas melanosomes in modern feathers are always surrounded by and embedded in keratin, melanosomes embedded in keratin in fossils has not been demonstrated. Here we provide multiple independent molecular analyses of both microbodies and the associated matrix recovered from feathers of a new specimen of the basal bird Eoconfuciusornis from the Early Cretaceous Jehol Biota of China. Our work represents the oldest ultrastructural and immunological recognition of avian beta-keratin from an Early Cretaceous (∼130-Ma) bird. We apply immunogold to identify protein epitopes at high resolution, by localizing antibody-antigen complexes to specific fossil ultrastructures. Retention of original keratinous proteins in the matrix surrounding electron-opaque microbodies supports their assignment as melanosomes and adds to the criteria employable to distinguish melanosomes from microbial bodies. Our work sheds new light on molecular preservation within normally labile tissues preserved in fossils.
authors.affiliation: Key Laboratory of Economic Stratigraphy and Palaeogeography of the Chinese Academy of Sciences, Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences Nanjing 210008, China; yhpan@nigpas.ac.cn zhouzhonghe@ivpp.ac.cn mhschwei@ncsu.edu.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Pan
authors.affiliation: Department of Biological Science, North Carolina State University, Raleigh, NC 27695.
authors.forename: Wenxia
authors.initials: W
authors.lastname: Zheng
authors.affiliation: Department of Biological Science, North Carolina State University, Raleigh, NC 27695.
authors.forename: Alison E
authors.initials: AE
authors.lastname: Moyer
authors.affiliation: Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
authors.forename: Jingmai K
authors.initials: JK
authors.lastname: O'Connor
authors.affiliation: Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
authors.forename: Min
authors.identifier: 0000-0001-8506-1213
authors.initials: M
authors.lastname: Wang
authors.affiliation: Institute of Geology and Paleontology, Linyi University, Linyi City, Shandong 276005, China.|Shandong Tianyu Museum of Nature, Pingyi, Shandong 273300, China.
authors.forename: Xiaoting
authors.initials: X
authors.lastname: Zheng
authors.affiliation: Institute of Geology and Paleontology, Linyi University, Linyi City, Shandong 276005, China.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Wang
authors.affiliation: Department of Biological Science, North Carolina State University, Raleigh, NC 27695.
authors.forename: Elena R
authors.initials: ER
authors.lastname: Schroeter
authors.affiliation: Key Laboratory of Vertebrate Evolution and Human Origins of the Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China; yhpan@nigpas.ac.cn zhouzhonghe@ivpp.ac.cn mhschwei@ncsu.edu.
authors.forename: Zhonghe
authors.initials: Z
authors.lastname: Zhou
authors.affiliation: Department of Biological Science, North Carolina State University, Raleigh, NC 27695; yhpan@nigpas.ac.cn zhouzhonghe@ivpp.ac.cn mhschwei@ncsu.edu.|North Carolina Museum of Natural Sciences, Raleigh, NC 27601.
authors.forename: Mary H
authors.initials: MH
authors.lastname: Schweitzer
mesh_terms: D000818:Animals; D005075:Biological Evolution; D001717:Birds / Q000033:anatomy & histology*; D005241:Feathers / Q000648:ultrastructure*; D005580:Fossils / Q000648:ultrastructure*; D007633:Keratins; D020460:Melanosomes
chemical_list: D007633:Keratins
keywords: ChemiSTEM; Early Cretaceous; immunogold; keratinous protein; melanosome