It’s hard to imagine a mighty T. rex kneeling delicately above a clutch of eggs, However, new research around a fossil ovoid suggests that this behavior may have been practiced by some dinosaurs. The first non-avalanche dinosaurs (species outside the litter of dinosaurs related to living birds) featuring adult dinosaurs have been described in detail in the science bulletin. What’s more, the embryos were at different stages, indicating that the eggs could hatch at different times, which is usually determined after the parents start encouraging them.
Study author Shundong Bi, a professor at the Indiana University of Pennsylvania, told IFLScience, “This is not the first time an oviraptorid has been found, or these are not the first ovarian embryos.” “But for the first time, an adult was found on top of a fetal egg. It is also the first nesting oviraptorid found outside the Gobi Desert. “
Brooding, seen in chickens that sit on their eggs to incubate them during development, was thought to be an unlikely behavior in non-avialan dinosaurs whose heavy bodies would surely squish their progeny. However, this new fossil found near Ganzhou, China, was the first to be discovered in an avalanche dinosaur preserved on top of an eggshell that still contains embryonic remains. The researchers believe that the presence of an adult in embryonic eggs at a stage of advanced growth provides strong support for the brooding hypothesis in some non-avalanche dinosaurs.
Interestingly, the embryos inside the eggs are at different stages of development, which means that if the eggs could survive, they would hatch at different times. Bi said, “Asynchronous hatching was not very widespread among dinosaurs.” “This phenomenon, known as asynchronous hatching, is a very strange and unusual of living descent of dinosaurs, even in modern birds.”
The researchers say their results prove that the evolution of reproductive biology along the line of birds archosaurs (a large group of vertebrates including dinosaurs and pterosaurs and represented by birds today) was complex and not linear, a growing process that was previously conceived. They give the theoretical idea that some aspects of non-avalanche theropod reproduction may be unique to these dinosaurs and did not eventually go to the avian ancestors who gave birth to modern birds.
Recent research has detailed how the aerial plane feature evolved twice in dinosaurs before the clad image of modern bird ancestors was detailed. This new insight introduces more features of avian dinosaurs and animals that can be shared by their distant cousins.