title: Basal paravian functional anatomy illuminated by high-detail body outline.
abstract: Body shape is a fundamental expression of organismal biology, but its quantitative reconstruction in fossil vertebrates is rare. Due to the absence of fossilized soft tissue evidence, the functional consequences of basal paravian body shape and its implications for the origins of avians and flight are not yet fully understood. Here we reconstruct the quantitative body outline of a fossil paravian Anchiornis based on high-definition images of soft tissues revealed by laser-stimulated fluorescence. This body outline confirms patagia-bearing arms, drumstick-shaped legs and a slender tail, features that were probably widespread among paravians. Finely preserved details also reveal similarities in propatagial and footpad form between basal paravians and modern birds, extending their record to the Late Jurassic. The body outline and soft tissue details suggest significant functional decoupling between the legs and tail in at least some basal paravians. The number of seemingly modern propatagial traits hint that feathering was a significant factor in how basal paravians utilized arm, leg and tail function for aerodynamic benefit.
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: Vertebrate Palaeontology Laboratory, Department of Earth Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.
authors.forename: Michael
authors.identifier: 0000-0002-6149-3078
authors.initials: M
authors.lastname: Pittman
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: Foundation for Scientific Advancement, 7023 Alhambra Drive, Sierra Vista, Arizona 85650, USA.
authors.forename: Thomas G
authors.identifier: 0000-0001-7996-618X
authors.initials: TG
authors.lastname: Kaye
authors.affiliation: Department of Biology, Centre College, 600 West Walnut Street, Danville, Kentucky 40422, USA.
authors.forename: Amanda R
authors.initials: AR
authors.lastname: Falk
authors.affiliation: Department of Geoscience, University of Wisconsin-Madison, Lewis G. Weeks Hall for Geological Sciences, 1215 West Dayton Street, Madison, Wisconsin 53706-1692, USA.
authors.forename: Scott A
authors.initials: SA
authors.lastname: Hartman
authors.affiliation: Key Laboratory of Vertebrate Evolution and Human Origins of Chinese Academy of Sciences, Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, Beijing 100044, China.
authors.forename: Xing
authors.initials: X
authors.lastname: Xu
mesh_terms: D000818:Animals; D001717:Birds / Q000033:anatomy & histology*; D005552:Forelimb / Q000033:anatomy & histology; D006614:Hindlimb / Q000033:anatomy & histology; D007091:Image Processing, Computer-Assisted; D010388:Pelvis / Q000033:anatomy & histology; D012867:Skin / Q000033:anatomy & histology; D013623:Tail / Q000033:anatomy & histology