The fossil of a dinosaur perched on an egg nest with embryos inside was unearthed in a first discovery of this kind that sheds light on how the creatures hatched their chicks.
The skeletal remains of an oviraptorosaur – a bird-like beast that roamed the Earth more than 66 million years ago – have been found in 70-million-year-old rocks dug in Ganzhou, China, according to a report published in Science Bulletin.
The partially preserved feathered dinosaur had incubated a nest of 24 eggs, seven of which contained the skeletal remains of developing babies, paleontologists say in the report.
The innovative finding is a sign that oviraptorosaurs have been nesting like their current avian cousins, rather than guarding egg claws like alligators and other reptiles.
“This type of discovery – essentially fossilized behavior – is the rarest of the dinosaurs,” said Matthew Lamanna of the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania, who wrote the study in a press release. “Although several adult oviraptorids have been found in the nests of their eggs before, no embryos have ever been found inside these eggs.”
Scientists have ruled out the possibility that the dinosaur died during egg laying due to the late stage of the embryos. They also probed the eggs with an oxygen isotope, which showed that they were incubated at high temperatures, just like newborn birds.
The researchers also found that the embryos were at different stages of development, suggesting the presence of “asynchronous hatching” – an incubation method that could have evolved in oviraptorid dinosaurs and some birds over time.
“This dinosaur was a caring parent who eventually gave his life while caring for his cubs,” Lamanna concluded in the report.
Other researchers have hailed the discovery of fossils as a discovery of Jurassic proportions.
“It’s amazing to think how much biological information is captured in this single fossil alone,” Xing Xu’s vertebrate paleontology at the Chinese Academy of Sciences in Beijing said in a press release. “We will learn from this specimen for many years to come.”
The report does not mention how big the fossilized dinosaur or its eggs were, but oviraptorosaurs ranged from a turkey to a larger one than an elephant.