Paleontologists in China have found an oviraptorosaur fossil that sits on an egg nest. By itself that is an amazing and rare find, but this fossil is unique in that the eggs still retain evidence of the unseen generation. inside.
“Here we report first [non-avian] dinosaur fossil known for preserving an adult skeleton at the top of an egg cluster containing an original residue, ”said authors research paper published in Science Bulletin. Found in China, the fossil broadens our understanding of oviraptorosaur behavior and biology, while at the same time providing further evidence that non-bird dinosaurs used bird-like breeding behaviors.
Oviraptorosaurs, also known as oviraptors, have been so named due to early paleontological misunderstanding of similar fossils. The name means “egg thief,” but these dinosaurs were not thieves, as oviraptorosaurs were later shown to be the rightful owners of fossil eggs often found next to what is left of them. skeleton.
In fact, fossils of oviraptorosaurs nesting with their eggs have previously been found. What is new here is that there is still evidence in the dino eggs about the inner embryos. It is worth noting that embryos inside oviraptor eggs have been found before, but only on their own. A famous example is the “Baby LouieFossil, found in Henan, China, back in the 1990s.
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Oviraptorosaurs were highly successful theropod dinosaurs of the Cretaceous period. They varied greatly in size, with some of the largest weighing up to 2,425 pounds (1,100 kilograms).). Common features include feathers, long neck, wings, and beaks. These non-bird dinos were very much like birds, like modern ostriches. When nesting, these animals would lay their eggs in an almost perfect circle, laying their large eggs in a very orderly fashion.
The newly described fossil, named LDNHMF2008, was hauled from the Nanxiong Creation near Ganzhou railway in Jiangxi district of southern China. The fossil dates back to the end of the Cretaceous period, about 70 million years ago. It preserves the remains of a medium-sized adult oviraptorosaur, with its skull and other skeletal features missing. The animal apparently died while in a nesting position.
These fossil bones were found along with a “worry-free shearing” of at least 24 eggs, “some broken, revealing original bones,” the study authors wrote. The researchers, led by Shundong Bi from Indiana University in Pennsylvania and Xing Xu from the Chinese Academy of Sciences, donated the eggs to the fossil species Macroolithus yaotunensis.
Oviraptorosaur nests that contain so many eggs at once are uncommon, and appear to be altering large poaching with real “egg thieves”. ”
Microscopic analysis of the fossils showed that some embryos were at late stages of development, and were about to give birth. These authors took as possible evidence that oviraptors were actively invading their nests, and not just protecting them, as some paleontologists have profited.
“In the new sample, the babies were almost ready for birth, which tells us without a doubt that this oviraptorid had kept its nest a long time ago,” said Matthew Lamanna, a paleontologist at Home- Carnegie Natural History museum and co-author of the new study, he said in a statement. “This dinosaur was a caring parent who eventually gave his life while raising his young. ”
Other evidence confirmed this explanation, namely an oxygen isotope study showing that the eggs were incubated at high temperatures, similar to birds around 97 to 100 degrees Fahrenheit (36 to 38 degrees Celsius). Interestingly, the eggs were found at different stages of development, meaning that they hatched at different times. This is mentioned asynchronous birth, a genetic wonder seen in modern birds. The authors could not give a reason for the asynchronous skin, but they did reveal a plausible situation, as they write in their study:
“As in ostriches, oviraptorosaurs would have begun to enter the nest immediately after the eggs were laid, so that the lower eggs, which were laid earlier, would, injured for the same time as the tall eggs. However, the upper eggs would have been laid earlier than the lower eggs because, as they were closer to the breeding adult, they would have received more heat from this person than the eggs. lower, so the primroses in them would have grown faster. ”
Finally, the scientists also found a handful of stones in the abdominal area of the dino. These rocks are probably gastroliths, which animals swallow to help with digestion. This is the first time such a thing has been recorded in an oviraptorosaur, and a possible hint of diet. That admits there’s a ton of new look for single fossils, though it’s amazing.
“It’s amazing to think how much biological information will be captured in this one fossil,” said Xu. “We are going to learn from this sample for many years to come.”