Eggs and gizzards

It was all but confirmed that the oviraptor was brooding due to several factors. The first was the proximity of its body to the eggs — a space so small as to prevent even sediment from creeping in, and the second was the oxygen isotopes of the bones and the embryos displaying a similar temperature.

“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,” explains Lamanna. “This dinosaur was a caring parent that ultimately gave its life while nurturing its young”.

One egg even contained a complete skeleton of the baby oviraptor — an unbelievable find in itself.

“[The] embryos in the clutch are at different developmental stages, suggesting the presence of asynchronous hatching—a derived feature even among crown-group birds—in non-avialan theropods,” write the discoverers of the dinosaur in their corresponding paper.

Simultaneous hatching is a strategy that involves the work of both the mother and father taking turns to ensure all eggs reach the same temperature. Non-simultaneous hatching is thought to have originated, as the authors describe, at a much later date, and from a different group of birds. The new fossil suggests this behavior was not a linear evolutionary development.

Yet more discoveries were made when small stones were discovered within the fossilized stomach of the oviraptor, suggesting it may have swallowed them to aid in digestion. Some modern birds have gizzards, an old organ that contains gravel into which go seeds and other ruffage to be broken down.

“It’s extraordinary to think how much biological information is captured in just this single fossil,” says paleontologist Xing Xu from the Institute of Vertebrate Paleontology and Paleoanthropology in Beijing. “We’re going to be learning from this specimen for many years to come”. WaL