World’s first preserved dinosaur sits on nest of eggs with petrified babies

The fossil in question is that of an oviraptorosaurus, a group of bird-like teropod dinosaurs that thrived during the Cretaceous, the third and last period of the Mesozoic Period (commonly known as the ‘Age of Dinosaurs’) that stretched from 145 . to 66 million years ago. The new sample was recovered from the top chalk-obsolete rocks, about 70 million years old, in Ganzhou City in Jiangxi Province in southern China.

“Dinosaurs kept in their nests are rare, and so are fossil embryos. This is the first time a non-bird dinosaur has been found sitting in a nest of eggs that keep embryos in one. spectacular specimen, “explains dr. Shundong. Bi.

The fossil consists of an incomplete skeleton of a large, presumably adult oviraptoride crouched in a bird-like breeding position over a coupling of at least 24 eggs. At least seven of these eggs retain bones or partial skeletons of unbroken oviraptorous embryos inside. The late stage of development of the embryos and the proximity of the adult to the eggs strongly indicate that the latter died during the incubation of its nest, such as its modern cousins ​​and birds, rather than laying its eggs or simply its nest crocodile to protect – style, as sometimes suggested for the few other oviraptorite skeletons found on top of nests.

“This kind of discovery, essentially petrified behavior, is the rarest of the rare in dinosaurs,” explains dr. Lamanna. “Although a few adult oviraptorides have been found in their eggs before, no embryos have ever been found in the eggs. In the new specimen, the babies were almost ready to hatch, which no doubt tells us that this oviraptoride was prone to The eggs. dinosaur was a caring parent who eventually gave his life while raising his young. ‘

The team also conducted oxygen isotope analyzes suggesting that the eggs were incubated during high, bird-like temperatures, further supporting the hypothesis that the adult perished during nesting. Although all embryos were well developed, it appears that some were more mature than others, again indicating that oviraptorid eggs would hatch in the same clutch at slightly different times. This trait, asynchronously hatching, appears to have developed independently in oviraptorids and some modern birds.

Another interesting aspect of the new oviraptorite sample is that the adult preserves a group of pebbles in its abdominal region. These are almost certainly gastrolytes, or ‘stomach stones’, rocks that would be deliberately swallowed to help the dinosaur digest its food. This is the first time that undoubted gastrolytes occur in an oviraptoride, and as such, these stones can provide new insights into the diets of these animals.

Dr. Xu says, “It’s extraordinary to think how much biological information is just captured in this single fossil. We’ll be learning from this sample for many years to come.”

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See the article:

Bi, S., Amiot, R., de Fabrègues, CP, Pittman, M., Lamanna, MC, Yu, Y., Yu, C., Yang, T., Zhang, S., Zhao, Q. and Xu , X., 2020. An oviraptoride stored on top of an embryo-bearing egg clutch sheds light on the reproductive biology of non-avialan-teropod dinosaurs. Science Bulletin. 2020, https: //doi.org /10.1016 /j.scib.2020.12.018.