Abstract

Among all of the dinosaurs, the Late Cretaceous oviraptorosaurs, in addition to troodontid dinosaurs, boast the best fossil records ranging from numerous eggs and embryos, seven clutch–adult associations, highly organized egg clutches, two gravid adults and possible colonial nesting grounds, to plenty of species described from skeletons from East Asia. These well-preserved fossils provided insights into the reproductive biology, ecology, behaviour and developmental biology of oviraptorid dinosaurs, contributing to several groundbreaking palaeontological discoveries in the last decade. Some of them received further support, while the others remain controversial, indicating that a comprehensive, rigorous re-examination using all available evidence is required. In a recent review, oviraptorosaurs were considered as an intermediate stage in moving towards the modern avian reproduction, whose reproductive biology can be inferred based on the avian model. With the new insights generated from the shell histology of several embryo-containing eggs and evidence from previous studies, this study offers a synthetic view of the reproductive biology of the Late Cretaceous oviraptorosaurs, illuminating the peculiar reproductive biology of oviraptorosaurs. In conclusion, oviraptorosaurs had an essentially unique reproductive biology lacking modern analogies. Thus, simply applying either avian or reptilian models to infer the biology of extinct animals appears inappropriate in the case of oviraptorosaurs.