Recent studies demonstrate that many avialan features evolved incrementally prior to the origin of the group,but the presence of some of these features,such as bird-like brooding behaviours,remains contentious in non-...Recent studies demonstrate that many avialan features evolved incrementally prior to the origin of the group,but the presence of some of these features,such as bird-like brooding behaviours,remains contentious in non-avialan dinosaurs.Here we report the first non-avialan dinosaur fossil known to preserve an adult skeleton atop an egg clutch that contains embryonic remains.The preserved positional relationship of the adult to the clutch,coupled with the advanced growth stages of the embryos and their high estimated incubation temperatures,provides strong support for the brooding hypothesis.Furthermore,embryos in the clutch are at different developmental stages,suggesting the presence of asynchronous hatching—a derived feature even among crown-group birds—in non-avialan theropods.These findings demonstrate that the evolution of reproductive biology along bird-line archosaurs was a complex rather than a linear and incremental process,and suggest that some aspects of non-avialan theropod reproduction were unique to these dinosaurs.展开更多
基金supported by the Double First-Class Joint Program of Yunnan Science and Technology Department and Yunnan University (2018FY001-005)the China-Myanmar Joint Laboratory for Ecological and Environmental Conservation+2 种基金the University of Hong Kong Faculty of Science RAE Improvement Fundsupported by the CNRS Program INSU INTERRVIEthe National Natural Science Foundation of China(41688103)。
文摘Recent studies demonstrate that many avialan features evolved incrementally prior to the origin of the group,but the presence of some of these features,such as bird-like brooding behaviours,remains contentious in non-avialan dinosaurs.Here we report the first non-avialan dinosaur fossil known to preserve an adult skeleton atop an egg clutch that contains embryonic remains.The preserved positional relationship of the adult to the clutch,coupled with the advanced growth stages of the embryos and their high estimated incubation temperatures,provides strong support for the brooding hypothesis.Furthermore,embryos in the clutch are at different developmental stages,suggesting the presence of asynchronous hatching—a derived feature even among crown-group birds—in non-avialan theropods.These findings demonstrate that the evolution of reproductive biology along bird-line archosaurs was a complex rather than a linear and incremental process,and suggest that some aspects of non-avialan theropod reproduction were unique to these dinosaurs.
