[ad_1]
The old nest belongs to medium-sized oviraptors; this is known from the fact that one parent has survived in the nest. The skeleton of this ostrich-like theropod crouched over two dozen eggs, at least seven of which were about to hatch and still contained embryos.
Such a scene is a completely unprecedented find and provides the first solid evidence that dinosaurs were doting parents who incubated eggs over a long period of time.
“Such a discovery, an example of largely fossilized behavior, is the rarest of the rarest dinosaur finds,” said paleontologist Matt Lamanna of the Carnegie Museum of Natural History in the United States. “And while several nests have been found with eggs containing adult oviraptors in the past, embryos have never been found within those eggs.”
Since the 1980s, paleontologists have discovered numerous dinosaur nests that contain fossilized eggs. In some rare cases, parental skeletons have even been found found in eggs. However, to date it has been problematic to accurately identify animal behavior based on these fossils. While the oviraptor parents appear to have migrated into nests, it may also have been that these dinosaurs died while laying or storing eggs, rather than necessarily incubating them. This would be more like the way crocodiles manage their nests, rather than modern birds.
The new specimen was found in the Nanxiongo Formation in Ganzhou, southern China, a region famous for having the world’s largest collection of fossilized dinosaur eggs. But the new find is unlike anything scientists have been able to find before.
In no other finding was the connection between the parents of dinosaurs and eggs so close. The body of an adult oviraptor has been kept “very close to the eggs”, with almost (or no) sediment between them.
At least seven eggs show embryos, including fossilized bones, whose shape is recognizable.
In one of the eggs, scientists predict the presence of the entire skeleton with vertebrae, ribs, humerus, femur and tibia.
By analyzing the oxygen isotopes of these embryos, the researchers found that their implicit incubation temperature corresponded to the body temperature of their parents, somewhere between 30 and 38 degrees Celsius.
“This dinosaur was a loving father or mother who finally gave his life to protect his cubs,” says the scientist.
Interestingly, not all embryos have the same level of development. This suggests that the same egg laying could have hatched at different times; Until now it was thought that this trait appeared much later, and this only happened to some birds.
Most modern birds wait until all the eggs have been laid before hatching, sometimes both the mother and the father, and this results in a synchronous transition.
Although oviraptors could also wait for all the eggs to be laid, the study authors say that the upper eggs may have been closer to the hatching adult animal, allowing them to develop faster. But that’s just a theory: more data will be needed for scientists to figure out why some eggs hatch earlier than others.
The sex of the adult oviraptor is still up for debate.
As if all this reproductive information wasn’t enough, this amazing fossil also allows us to look at the possible diet of oviraptors. For the first time, scientists have found small stones in the stomach of this type of dinosaur, which were probably ingested to facilitate digestion; these stones act as ‘stomach teeth’, crushing the food that enters here.
“It is remarkable to realize how much biological information is recorded in this fossil,” said paleontologist Xing Xu of the Beijing Institute of Paleontology and Paleoanthropology. “We will learn from this copy for many years to come.”
The study was published in the scientific journal Science Bulletin.
Prepared under Science Alert.
