title: A nearly modern amphibious bird from the Early Cretaceous of northwestern China.
abstract: Three-dimensional specimens of the volant fossil bird Gansus yumenensis from the Early Cretaceous Xiagou Formation of northwestern China demonstrate that this taxon possesses advanced anatomical features previously known only in Late Cretaceous and Cenozoic ornithuran birds. Phylogenetic analysis recovers Gansus within the Ornithurae, making it the oldest known member of the clade. The Xiagou Formation preserves the oldest known ornithuromorph-dominated avian assemblage. The anatomy of Gansus, like that of other non-neornithean (nonmodern) ornithuran birds, indicates specialization for an amphibious life-style, supporting the hypothesis that modern birds originated in aquatic or littoral niches.
authors.affiliation: Institute of Geology, Chinese Academy of Geological Sciences, 26 Baiwanzhuang Road, Beijing 100037, People's Republic of China.
authors.forename: Hai-Lu
authors.initials: HL
authors.lastname: You
authors.forename: Matthew C
authors.initials: MC
authors.lastname: Lamanna
authors.forename: Jerald D
authors.initials: JD
authors.lastname: Harris
authors.forename: Luis M
authors.initials: LM
authors.lastname: Chiappe
authors.forename: Jingmai
authors.initials: J
authors.lastname: O'connor
authors.forename: Shu-An
authors.initials: SA
authors.lastname: Ji
authors.forename: Jun-Chang
authors.initials: JC
authors.lastname: Lü
authors.forename: Chong-Xi
authors.initials: CX
authors.lastname: Yuan
authors.forename: Da-Qing
authors.initials: DQ
authors.lastname: Li
authors.forename: Xing
authors.initials: X
authors.lastname: Zhang
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Lacovara
authors.forename: Peter
authors.initials: P
authors.lastname: Dodson
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ji
mesh_terms: D000818:Animals; D001717:Birds / Q000033:anatomy & histology* / Q000145:classification* / Q000502:physiology; D001842:Bone and Bones / Q000033:anatomy & histology*; D002681:China; D004777:Environment; D005241:Feathers / Q000033:anatomy & histology; D005269:Femur / Q000033:anatomy & histology; D005426:Flight, Animal; D005580:Fossils; D006614:Hindlimb / Q000033:anatomy & histology; D006811:Humerus / Q000033:anatomy & histology; D008124:Locomotion; D010802:Phylogeny; D013131:Spine / Q000033:anatomy & histology; D014034:Toes / Q000033:anatomy & histology; D014867:Water; D014921:Wings, Animal / Q000033:anatomy & histology
chemical_list: D014867:Water