A reappraisal of Boluochia zhengi (Aves: Enantiornithes) and a discussion of intraclade diversity in the Jehol avifauna, China

Abstract

A careful reappraisal of the only known specimen of the poorly understood fossil enantiornithine bird Boluochia zhengi reveals numerous morphological similarities that suggest this taxon is closely related to the well-known Longipteryx chaoyangensis, and so is assignable to the most diverse recognized clade of Early Cretaceous enantiornithines, the Longipterygidae. This new study of the holotype of B. zhengi reveals new longipterygid synapomorphies and expands our knowledge of the temporal and geographical ranges and diversity of the clade. We suggest that the trophic specialization that characterizes longipterygids may have been a major factor contributing to the success of this clade.

Keywords:

• Enantiornithes
• Ornithothoraces
• Longipterygidae
• Boluochia
• Longipteryx
• Jehol

Acknowledgements

We thank Xinzhen Liu for preparing casts of the holotype of Boluochia zhengi for study and Wei Gao for photographing the specimen. Thanks go to Gareth Dyke for comments during the manuscript stage, and Jerry Harris and one other reviewer for comments on an earlier version of this manuscript. This project has been supported by the National Natural Science Foundation of China (40121202), National 973 Project (TG20000077706).