Beijing Natural History Museum , Beijing , PR China.
Institute of Vertebrate Paleontology and Paleoanthroplogy , Beijing , PR China.
PeerJ. 2014 May 29;2:e407. doi: 10.7717/peerj.407. eCollection 2014.
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.
反鸟类是白垩纪最具多样性的鸟类分支。然而，这个分支中特定生态角色的形态特化并不为人所知。在这里，我们报告了一个来自中国东北下白垩统热河群的保存精美的标本，其足部形态暗示了反鸟类中一种独特的生态特化。新标本的形态与渤海鸟型反鸟类周氏鸟的模式标本基本相同，尽管后者稍大一些。新标本提供了周氏鸟头骨的重要且以前未知的细节，增加了我们对反鸟类颅解剖结构和进化的有限认识。新标本提供的信息也增加了我们对最近才被认识的渤海鸟型反鸟类后肢形态的理解。随着该标本的描述，周氏鸟成为了最具解剖完整性的已知反鸟类之一，这将有助于未来的形态学研究。
