title: New information on the anatomy of the Chinese Early Cretaceous Bohaiornithidae (Aves: Enantiornithes) from a subadult specimen of Zhouornis hani.
abstract: Enantiornithines are the most diverse avian clade in the Cretaceous. However, morphological specializations indicative of specific ecological roles are not well known for this clade. Here we report on an exquisitely well-preserved specimen from the Lower Cretaceous Jehol Group of northeastern China, which pedal morphology is suggestive of a unique ecological specialization within Enantiornithes. The morphology of the new specimen is largely indistinguishable from that of the holotype of the bohaiornithid enantiornithine Zhouornis hani, albeit the latter is somewhat larger. The new specimen provides important and previously unknown details of the skull of Zhouornis hani, which add to the limited knowledge about the cranial anatomy and evolution of enantiornithines. The information offered by the new specimen also augments our understanding of the postcranial morphology of bohaiornithid enantiornithines, a clade that has been only recently recognized. With the description of this specimen, Zhouornis hani becomes one of the most anatomically complete known enantiornithine species, which will facilitate future morphological studies.
authors.affiliation: Beijing Natural History Museum , Beijing , PR China.
authors.forename: Yuguang
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Institute of Vertebrate Paleontology and Paleoanthroplogy , Beijing , PR China.
authors.forename: Jingmai
authors.initials: J
authors.lastname: O'Connor
authors.affiliation: Beijing Natural History Museum , Beijing , PR China.
authors.forename: Liu
authors.initials: L
authors.lastname: Di
authors.affiliation: Beijing Natural History Museum , Beijing , PR China.
authors.forename: Meng
authors.initials: M
authors.lastname: Qingjin
authors.affiliation: Dinosaur Institute, Natural History Museum of Los Angeles County , Los Angeles, CA , USA.
authors.forename: Trond
authors.initials: T
authors.lastname: Sigurdsen
authors.affiliation: Dinosaur Institute, Natural History Museum of Los Angeles County , Los Angeles, CA , USA.
authors.forename: Luis M
authors.initials: LM
authors.lastname: Chiappe
keywords: Bohaiornithidae; Enantiornithes; Jehol; Mesozoic birds; Pedal morphology; Skull