Anatomy and Flight Performance of the Early Enantiornithine Bird Protopteryx fengningensis: Information from New Specimens of the Early Cretaceous Huajiying Formation of China.

Abstract

The Early Cretaceous (∼131 Million Years Ago) Protopteryx fengningensis is one of the oldest and most primitive enantiornithine birds; however, knowledge of its anatomy has largely been limited to the succinct description of two specimens (holotype and paratype). This study describes two new specimens of P. fengningensis preserving most of the skeleton and plumage, and it therefore adds significantly to understanding the morphology of this important species and the character evolution of enantiornithine birds. The well-preserved plumage of these specimens also affords a quantitative assessment of the flight performance of P. fengningensis. Our aerodynamic considerations indicate that this early enantiornithine was capable of intermittent flight (bounding or flap-gliding), thus marking the earliest occurrence of such energy-saving aerial strategy. Anat Rec, 303:716-731, 2020. © 2019 American Association for Anatomy.