Scientists have found a 70 million year-old fossilized dinosaur sitting on a nest of its eggs that contain fossilized embryos.
"Dinosaurs preserved on their nests are rare, and so are fossil embryos," says co-lead researcher Shundong Bi, professor at Indiana University of Pennsylvania and research associate at Carnegie Museum of Natural History (CMNH). "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." The dinosaur and its offspring were found in China's Jiangxi Province.
From the Carnegie Museum of Natural History:
The fossil in question is that of an oviraptorosaur, a group of bird-like theropod dinosaurs that thrived during the Cretaceous Period, the third and final time period of the Mesozoic Era (commonly known as the 'Age of Dinosaurs') that extended from 145 to 66 million years ago. CMNH's famous "Chicken from Hell," Anzu wyliei, is another type of oviraptorosaur. However, whereas Anzu is part of the largely North American oviraptorosaur subgroup Caenagnathidae, the new fossil is a member of another major subgroup, the Oviraptoridae, which has thus far been found only in Asia. The new specimen was recovered from uppermost Cretaceous-aged rocks, some 70 million years old, in Ganzhou City in southern China's Jiangxi Province.
The fossil consists of an incomplete skeleton of a large, presumably adult oviraptorid crouched in a bird-like brooding posture over a clutch of at least 24 eggs. At least seven of these eggs preserve bones or partial skeletons of unhatched oviraptorid embryos inside. The late stage of development of the embryos and the close proximity of the adult to the eggs strongly suggests that the latter died in the act of incubating its nest, like its modern bird cousins, 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.
"This kind of discovery—in essence, fossilized behavior—is the rarest of the rare in dinosaurs," explains [CMNH co-interim director and lead dinosaur paleontologist Matt] Lamanna. "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."
image: Shundong Bi, Indiana University of Pennsylvania