Many of my Fellow Fossils have human offspring, some canine, feline, avian, reptilian, or none at all. But it may give you proud dinosaurs some degree of satisfaction to know that at least one species of theropod—an oviraptorosaur—was recently discovered in fossilized form sitting atop a clutch of eggs, demonstrating classic nurturing behavior.
The fossil was recovered in Ganzhou City, in southern China, amid Cretaceous rocks some 70 million years old. Yes, just like modern birds, the adult oviraptorosaur was found crouched atop at least 24 eggs in different stages of maturity. Dinosaurs, then, may be credited with showing parental concerns!
Paleontologists associated with the discovery hailed it an important first. "Dinosaurs preserved on their nests are rare, and so are fossil embryos. This is the first time a non-avian dinosaur has been found, sitting on a nest of eggs that preserve embryos, in a single spectacular specimen," noted Dr. Shundong Bi, the principal investigator of the excavation and a professor at the Indiana University of Pennsylvania.
According to scientists familiar with the findings, at least seven of the eggs included skeletal remains of unhatched oviraptorid embryos. Because the adult was adjacent to the eggs, evidence suggests that the dinosaur perished during its parental duties.
"This kind of discovery, in essence, fossilized behavior, is the rarest of the rare in dinosaurs," noted Dr. Matthew C. Lamanna, associate curator of vertebrate paleontology, Carnegie Museum of Natural History, and a co-author of the journal article describing the finding. "Though a few adult oviraptoridae have been found on nests of their eggs before, no embryos have ever been found inside those eggs. In the new specimen, the babies were almost ready to hatch, which tells us beyond a doubt that this oviraptorid had tended its nest for quite a long time. This dinosaur was a caring parent that ultimately gave its life while nurturing its young."
Interestingly, while all of the embryos were well along toward hatching, some were more mature than others, offering scientists a new biological insight into this species of theropod.
"It's extraordinary to think how much biological information is captured in just this single fossil. We're going to be learning from this specimen for many years to come" said Dr. Xing Xu, another co-author and a professor at the Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences.
The study appeared in ScienceDirect, published by Science China Press.