Reconstruction of a close-to-hatching oviraptorosaur egg.LIDA XING/ISCIENCE

The embryo has been found inside a fossilized dinosaur egg which sheds light on the link between the behavior of modern birds and dinosaurs.

The embryo, nicknamed ‘Baby Yingliang’, was discovered in the Upper Cretaceous rocks of Ganzhou in southern China, and belongs to a toothless theropod dinosaur or oviraptorosaur. It is one of the most complete dinosaur embryos ever found. Baby dinosaur bones are so small and fragile that they are rarely preserved as fossils. In fact, the fossil suggests that these dinosaurs developed bird-like postures at hatching. The scientists found that the ‘Baby Yingliang’ posture is unique among known dinosaur embryos: its head sits below the body, with its feet on either side, and its back bent along the blunt end of the egg. This posture is similar to that of modern bird embryos and, until now, it had not been found in any dinosaur specimen.

The embryo is estimated to be 27 cm long from head to tail, although the creature lies inside a 17 cm long egg, according to the study led by scientists at the University of Birmingham, the University of Geosciences of China (Beijing), the Yingliang Stone Museum of Natural History, the University of Calgary, the Chinese Academy of Sciences and the University of Edinburgh and which has just been published in the digital magazine iScience.
A unique discovery
“Dinosaur embryos are some of the rarest fossils that exist and most of them are incomplete or with broken bones. Therefore, we are excited about the discovery of ‘Baby Yingliang’, as it is preserved in excellent condition and helps us to answer many questions about the growth and reproduction of dinosaurs with him, “said Fion Waisum Ma, one of the authors and PhD researchers at the University of Birmingham.

For his part, Professor Steve Brusatte, from the University of Edinburgh, said that “this little prenatal dinosaur looks like a bird nestled in its egg, which is further proof that many characteristic features of today’s birds evolved by first time in their dinosaur ancestors. ” The fossil helps answer questions about the growth and reproduction of dinosaurs The 70-million-year-old fossil was acquired in 2000 by Liang Liu, director of the Yingliang Group, and is kept in the Museum of Natural History of Stone in Yingliang, from which it has received its name.