The fossilized remains of a dinosaur sitting on a nest of eggs, complete with embryos preserved inside, have been excavated in China, a study reports.
The find – a world first – is an oviraptorosaur, one of a group of bird-like theropod dinosaurs that flourished 130-66 million years ago, during the Cretaceous Period.
Experts say the specimen in question has been found in 70-million-year-old rocks excavated near the train station in Ganzhou City, Jiangxi Province.
The adult oviraptorosaur was partially preserved brooding over the clutch of at least 24 eggs, at least seven of which contained skeletal remains from the unhatched young.
The late development of the embryos allowed paleontologists to rule out the possibility that the adult had died while laying its eggs.
Instead, the find suggests that oviraptorosaurs incubated their nests like their modern-day cousins - rather than just guarding their nests in the manner of a crocodile.
This was supported by oxygen isotope analyzes of the eggs, which showed that they hatched at high temperatures, much like modern bird eggs.
The fossilized remains of a dinosaur sitting on a nest of eggs, complete with embryos preserved inside, have been excavated in China, a study reports.
The adult oviraptorosaur was partially conserved brooding over the clutch of at least 24 eggs, at least seven of which contained skeletal remains from the unhatched young. Picture: a photo of the fossilized specimens, left and for illustration right
“This kind of discovery – essentially petrified behavior – is the rarest of the rare in dinosaurs,” said paper author and vertebrate paleontologist Matthew Lamanna of the Carnegie Museum of Natural History in Pittsburgh, Pennsylvania.
“Although a few adult oviraptorids have been found on nests of their eggs before, no embryos have ever been found in those eggs.”
“In the new specimen, the babies were almost ready to hatch, which tells us no doubt that this oviraptorid has been taking care of its nest for a long time.”
“This dinosaur was a caring parent who eventually gave his life while nursing its young,” he concluded.
Analysis of the fossil embryos revealed that, while all were well developed, some had reached a more mature stage than others, suggesting that if they had not been buried and fossilized, they would likely have hatched at slightly different times.
This trait – referred to as “ asynchronous hatching ” by experts – appears to have evolved independently in oviraptorid dinosaurs and some modern birds, the researchers explained.
The team also found a cluster of pebbles preserved in the adult oviraptorid’s abdominal region, which they said are gastroliths, or “ stomach stones, ” that would have been ingested to help the dinosaur digest its food.
This is the first time that verified gastroliths have been found preserved in a fossilized oviraptoride and thus may lead to new insights into their diet.
The late development of the embryos allowed paleontologists to rule out the possibility that the adult had died while laying its eggs. Instead, the find suggests that oviraptorosaurs incubated their nests like their modern-day cousins - rather than just guarding their nests in the manner of a crocodile. Pictured, an exploded diagram of the adult oviraptorosaurus skeleton (with preserved bones in white) brooding on its egg clutch
Analysis of the fossil embryos (shown) revealed that while all were well developed, some had reached a more mature stage than others, suggesting that if they had not been buried and fossilized, they would likely have hatched at slightly different times.
“It is extraordinary to consider how much biological information is contained only in this one fossil,” said paleontologist Xing Xu of the Chinese Academy of Sciences in Beijing.
“We will learn from this specimen for many years to come,” he added.
The full findings of the study are published in the journal Science Bulletin.
The specimen in question was found in 70-million-year-old rocks excavated near the train station in Ganzhou City, Jiangxi Province.