Extraordinary: they discover the fossil of a dinosaur sitting in its nest of eggs

Paleontologists have found remains in southern China World’s first dinosaur specimen to be found sitting in egg nest with fossilized babies.

The fossil in question is that of an ovirraptorsaurus, a group of theropod dinosaurs looking like birds who prospered during the Cretaceous period, the third and final period of the Mesozoic era (commonly called the “The Age of Dinosaurs”) which extended from 145 to 66 million years ago.

The new specimen was recovered from the rocks of the Upper Cretaceous, about 70 million years old, in the town of Ganzhou, in Jiangxi province.

“Dinosaurs kept in their nests are rare, as are fossil embryos. This is the first time that a non-avian dinosaur has been found, sitting in an egg nest that preserves embryos, in a single spectacular specimen, ”explained the doctor. Shundong Bi, Yunnan University and first author, cited by Science China Press.

The fossil consists of an incomplete skeleton of a large oviraptor, presumably adult, crouching in a bird hatching posture on a clutch of at least 24 eggs. At least seven of these eggs retain partial bones or skeletons embryos of oviraptorids without hatching inside.

The late stage of development of the embryo and the proximity of the adult to the eggs strongly suggest that the latter died while hatching its nest, like their modern bird cousins, rather than laying their eggs or simply protecting their crocodile-style nest, as was sometimes proposed for the few other oviraptorid skeletons found above the nests.

“This type of discovery, essentially fossilized, is the rarest of the rare among dinosaurs”, explained the co-author Matthew C. Lamanna, from the Pittsburg Natural History Museum.

“Although some adult oviraptorids have already been found in the nests of their eggs, embryos have never been found in these eggs. In the new specimen, the babies were almost ready to hatch, which no doubt tells us that this oviraptorid had been nesting for some time. This dinosaur was a loving father who ultimately gave his life by feeding his young. “, he stressed.

The team also performed isotopic analyzes of oxygen indicating that the eggs were incubated at high temperatures similar to those of birds, which further strengthens the hypothesis that the adult died while raising its nest.

In addition, although all embryos are well developed, some seem to have been more mature than others, which in turn suggests that the eggs in the same nest might have hatched at slightly different times. This feature, known as asynchronous hatching, seems to have evolved independently in oviraptorids and some modern birds.

Another interesting aspect of the new oviraptorid specimen is that the adult keeps a group of pebbles in his abdominal region. These are almost certainly gastroliths, or “stomach stones,” rocks that would have been deliberately swallowed to help the dinosaur digest its food.

This is the first time that indisputable gastroliths have been discovered in an oviraptorid. And, as such, these stones may provide new information about the diet of these animals.

Europa Press