A new oviraptorid theropod fossil from the Upper Cretaceous of Southern China with implications for oviraptorosaurian systematics and palaeobiogeography

Abstract Oviraptorosauria have long attracted our interest with their bizarre skulls and unique behaviours. Among oviraptorosaurs, Oviraptoridae exhibits exceptional diversity in eastern Asia, with southern China yielding abundant fossil material in recent years. However, insufficient description in some previous studies led to ambiguity on comparative morphology, which hinders further study of their diversity. Here we describe a new nest-associated oviraptorid specimen from the Upper Cretaceous of Ganzhou, Jiangxi, southern China. The new fossil not only adds data to the posture of oviraptorids atop the nest, but also provides important osteological information for understanding the taxonomy of Huanansaurus ganzhouensis Lü et al., 2015 and Corythoraptor jacobsi Lü et al., 2017, the fossils of which came from the same locality and horizon as the new specimen. Our in-depth analysis suggests that C. jacobsi, H. ganzhouensis, and the new specimen are best regarded to represent a single species. Furthermore, we built a significantly expanded phylogenetic dataset covering as many morphological variations among oviraptorosaurs as possible, particularly in light of recent discoveries including the new fossil described herein. Analysis based on this new dataset produced some novel results on oviraptorosaur evolution and palaeobiogeography, especially finding endemic southern China clades in two main subfamilies of Oviraptoridae. Detailed morphological work and more phylogenetic data are still needed for finally revealing oviraptorosaur disparity and evolution.