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 …