World's most complete dinosaur embryo discovered

After three years of detailed research, scientists discovered the most complete dinosaur embryo scientifically recorded in the world so far in a dinosaur egg fossil. This research was also published in the international scientific journal "iScience" on December 22, 2021.

A team of scientists from China, Britain and Canada has spent three years studying a dinosaur embryo perfectly preserved in a fossil egg. The fossil was found in the Late Cretaceous strata of Ganzhou, Jiangxi Province in southern China and is currently housed in the Yingliang Stone Natural History Museum in Fujian Province.

The fossil, which is between 72 and 66 million years old, belongs to a toothless theropod dinosaur and is the most complete dinosaur embryo ever recorded by science. The embryo is in a pristine state, not much disturbed by fossilization, and clearly shows what it was like when it was alive. The individual is estimated to be 27 centimeters long from head to tail, curled up in a 17-centimeter-long egg fossil. The Yingliang Stone Natural History Museum in Fujian Province nicknamed the specimen "Yingliang Beibei."

Yingliang Beibei was identified as an oviraptorosaur based on its short, toothless skull. Oviraptorosaurs are a group of feathered theropod dinosaurs known from Cretaceous strata in Asia and North America that are closely related to modern birds. Their varied beak shapes and body shapes likely allowed them to have a wide range of diets, including herbivores, omnivores, and carnivores.

The research team found that the preservation posture of Yingliang Beibei is unique among known dinosaur embryos, with its head under the body, its feet on both sides, and its back curled up along the blunt end of the egg. This posture is similar to that of modern bird embryos, and has never been found in dinosaur embryo fossils before.

Birds are known to perform a series of contracted postures shortly before hatching, where they bend their bodies and tuck their heads under their wings. Embryos that fail to complete these postures are more likely to fail to hatch and die.

By comparing Yingliang Beibei with other theropod dinosaurs, long-necked sauropod dinosaurs and bird embryos, the research team proposed that the contraction behavior originally thought to be unique to birds may have evolved from theropod dinosaurs tens of millions or hundreds of millions of years ago. The discovery of more embryo fossils is extremely important for further testing this hypothesis. According to experts, this major scientific discovery provides new and important scientific understanding of the growth, development and reproduction of dinosaurs.

Source: People's Daily Client (Liu Xiaoyu, Jiang Zichen, Liu Qing), Science and Technology Daily, CCTV News Client

Editors of this issue: Hu Hongjiang, Jiang Chuan