China discovered rare dinosaur embryos from 66 million years ago

The researchers wrote that a clutch of subspherical dinosaur eggs was recently discovered while blasting for a construction project in the Upper Cretaceous red beds (Hekou Formation) of the Ganzhou Basin, Jiangxi Province, China. "At least two of the eggs contain identifiable hadrosauroid embryos, described here for the first time," the researchers wrote in the study.

The Yingliang Stone Natural History Museum in East China's Fujian Province, where the embryo is presently held, has called the specimen the "Ying Baby," and the egg is an ellipsoid with a diameter of around 9 centimeters. One of the most important new pieces of information this discovery gives on dinosaur development is that the tiny size of both the egg and embryo implies that duck-billed dinosaurs had small eggs and late body development as a primordial feature.

Back in December 2021, the same team uncovered a branch of embryo fossils, including an oviraptorosaur embryo fossil. As researchers further examine the embryo fossils, which are incredibly rare finds as most fade away inside their eggshells, they could provide valuable information for the study of the reproductive development, behavior, evolution, and paleoecology of dinosaurs, which became extinct around 66 million years ago. With more than 700 recognized extinct dinosaur species, there is still much to uncover.