World's first preserved dinosaur atop nest with fossilised embryos found in China

The fossil consists of a skeleton of an oviraptorid crouched over a clutch of at least 24 eggs

In what is a first in the world of palaeontology, a group of scientists in the Ganzhou City of China have uncovered a preserved dinosaur brooding its nest containing fossilised embryos.

The fossil, described as rare by the scientists who discovered them, is of an oviraptorosaur, a group of bird-like theropod that thrived during the Cretaceous period, which extended some 145 to 66 million years ago, a release by the Carnegie Museum of Natural History said.

"Dinosaurs preserved on their nests are rare, and so are fossil embryos. This is the first time a non-avian dinosaur has been found, sitting on a nest of eggs that preserve embryos, in a single spectacular specimen,” Dr Shundong Bi, professor at Indiana University of Pennsylvania and research associate at CMNH, and one of the authors of the discovery that was published in Science Bulletin, is quoted as saying.

The fossil consists of an incomplete skeleton of a large oviraptorid crouched in a bird-like brooding posture over a clutch of at least 24 eggs. At least seven of these eggs preserve fossilied bones or partial skeletons of unhatched oviraptorid embryos inside.

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Oxygen isotope analyses on the nest indicate that the eggs were incubated at high, bird-like temperatures. Additionally, the development of the embryos suggests that the dinosaur died while incubating its nest, rather than laying its eggs or simply guarding its nest crocodile-style, as has sometimes been proposed for the few other oviraptorid skeletons that have been found atop nests, the release said.

Additionally, although all embryos were well-developed, some appear to have been more mature than others, which in turn suggests that oviraptorid eggs in the same clutch might have been hatched at slightly different times.

“This kind of discovery—in essence, fossilised behaviour—is the rarest of the rare in dinosaurs,” said Dr Matt Lamanna, one of members o the research team. “Though a few adult oviraptorids have been found on nests of their eggs before, no embryos have ever been found inside those eggs. In the new specimen, the babies were almost ready to hatch, which tells us beyond a doubt that this oviraptorid had tended its nest for quite a long time. This dinosaur was a caring parent that ultimately gave its life while nurturing its young.”