The exquisitely preserved dinosaur embryo tucked inside an egg like a child chicken has been unearthed in southern China. This provides an “unprecedented glimpse” into dinosaur growth.
The posture of the embryo resembles modern bird embryos close to hatching.
“This dinosaur embryo inside its egg is one of the most beautiful fossils I have ever seen,” paleontologist and examine writer Steve Brusatte on the University of Edinburgh stated.
Most of the other non-avian dinosaur embryos discovered to date are incomplete and their skeletons disjointed, but this fossilized egg contains one of the most complete non-avian dinosaur embryos found yet. It suggests tucking behaviour might have evolved prior to the origin of modern birds.
The almost-complete skeleton measuring roughly 23.5 cm (9.3 inches) from head to tail is curled up inside the elongated fossilized egg, which is nearly a whole 7 cm (2.7 inches) shorter than the embryo.
The embryo’s clawed forelimbs are nestled on either side of its skull, which is tucked towards the base of its looping tail. This tucking posture was thought to be unique to birds, which bend their bodies and tuck their heads under a wing to ready themselves for hatching.
While the precise developmental stage of the embryo, named ‘Baby Yingliang’, is not known, and the relationship between tucking and hatching is still uncertain for extinct theropods. This rare specimen preserved in superb detail provides some cracking insights into dinosaur development and evolution.
The embryo lay in a posture distinct from their more distant dinosaur cousins, long-necked sauropodomorphs, and very similar to chicken embryos days before they hatch.