Recently a team of researchers published the discovery of a dinosaur embryo from between 72 and 66 million years ago inside a fossilized egg. How extraordinary is this discovery? Since when have we been finding dinosaur eggs?
Although the first documented finds of dinosaur eggs were in the 1920s, we now know that there was a first find that occurred nearly a century earlier. Only, back then they weren’t considered to be dinosaur eggs. That first finding appears documented in 1859 in a memoir written by the French priest and naturalist Jean-Jacques Poech, presented in the bulletin of the Geological Society of France. In this report, Poech describes fossils in the geological formations that he considers to be Tertiary in a transect between the towns of Fossat and Allières, and mentions the discovery of some eggs that he considered to belong to a large bird . Interestingly, since we now know that birds are dinosaurs, we can consider that he was not so far off the mark…
The first documented find of dinosaur eggs, their discoverers being fully aware, occurred in 1923, within one of the American Museum of Natural History’s expeditions to Mongolia led by naturalist and adventurer Roy Chapman Andrews . In 1921, the first expedition started. And in April 1922 they found the first fossils, including the discovery of the primitive ceratopsian dinosaur that would be described in 1923 as Psittacosaurus. And of course, considering this first expedition a complete success, they returned many more times and their findings were truly historic. This is how in the summer of 1923 they returned to this area. And this time the To begin with, they found a multitude of skeletons of the ceratopsian dinosaur Protoceratops , whose find included individuals from newborns to adults. Until this moment little was known about the growth of dinosaurs, and suddenly very important information about their life and growth was obtained. But what was even more historic was the discovery of dinosaur eggs for the first time. And organized in sets in what were their nests. The team surmised that they must be Protoceratops eggs, since this dinosaur was so abundant and they had even found hatchlings.
Associated with some of these eggs they found the remains of a toothless theropod dinosaur with a beak. Fossilization was considered to have been caught “red-handed” preying on the nests, and was given the name Oviraptor philoceratops (egg thief with a taste for “horned faces”). Their redemption came late in the 20th century, when similar eggs and a relative of Oviraptor were found hatching them.
Dinosaur egg finds can be even more extraordinary. In 1997, in Neuquén, Argentina, paleontologists Luis M. Chiappe and Rodolfo Coria found a huge expanse of land covered with the shells and eggs of sauropod dinosaurs . It was even possible to verify that their producers were titanosaur sauropods by the discovery of fossil bones of embryos in these eggs.
And it is that for decades discoveries of shells, eggs, nests and embryonic bones have accumulated all over the planet. And in very close places. This is the case of the nests with titanosaur eggs found in Loarre, in Huesca. Or the Poyos deposit in Guadalajara. In Lourinha, Portugal, embryonic bones of the theropod dinosaur Lourinhanosaurus have even been found associated with a nest with eggs. And it is that the exotic and distant places do not have the exclusive of this type of finds.
Today there is a whole subdiscipline of study of these extraordinary remains within Paleontology, Paleoology. And many people continue to work in this field for decades.
Despite the discovery of many dinosaur eggs and nests in the last 100 years, the articulated embryos found inside the egg are not abundant. And that is why this recent fossil embryo has been around the world. An oviraptorosaur that never hatched, articulated and exceptionally preserved inside its egg, from the Late Cretaceous of southern China. And that even allows us to observe that these dinosaurs adopted a posture similar to the chicks of birds when it is almost time to hatch.
References:
Xing, L. Et al. 2021. An exquisitely preserved in-ovo theropod dinosaur embryo sheds light on avian-like prehatching postures. iScience, DOI: https://doi.org/10.1016/j.isci.2021.103516
Carpenter, K. 1999. Eggs, Nests, and Baby Dinosaurs: A Look at Dinosaur Reproduction (Life of the Past), Indiana University Press
Mateus, I. et al.1998. Upper Jurassic theropod dinosaur embryos from Lourinhã (Portugal). Memoirs of the Lisbon Academy of Sciences, 37, 101–110.
