A farmer in China unearthed the eggs, roughly half a metre long, on his land some 30 years ago. A scientific paper on the fortuitous find was published Tuesday in the open-access journal Nature Communications.
University of Alberta paleontologist Philip Currie has been studying the eggs since 1993. In 2015, Currie, accompanied by the farmer who first collected them, returned to the discovery site in north-central China’s Henan province.
“It was the most astounding thing. The whole area had been ripped up by enormous equipment terracing the mountainsides to plant walnut trees,” Currie recalled in a news release.
“The one slope remaining was where these giant eggs came from, and we found shells from the same specimen three decades later.”
Currie said he and an international team of paleontologists thought they were tyrannosaur eggs at first.
“But when we saw the embryo, it screwed everything up.”
After examining the skull, the researchers concluded the animal was related to feathered caenagnathids or oviraptorosaurs from Alberta.
Oviraptorosaur translates to “egg thief” because specimens have often been found near nests and their jaws are adapted for eating eggs.
But recently the name has been found to be inaccurate, as the beasts were actually protecting their own offspring from predators.
Currie said the nest found in China was incomplete. It only contained between six and nine eggs, whereas a normal oviraptorosaur nest would have 30 to 40 spread three metres across in a ring formation.
The mother would have situated herself in the middle to protect her progeny.
“She would have been able to stretch her arms out protectively over the eggs. This might have been the reason these animals developed the long feathers behind their arms to ensure the eggs were covered.”
The giant eggs are still tiny in relation to the creature’s adult size. The animal’s bones indicate it would have weighed two tonnes once fully grown.
Currie said it was lucky such well-preserved eggs were found.
“You need exactly the right conditions. If there’s even a little bit of acidity in the soil, the eggs will just dissolve,” he said.
“Add that to the fact that eggs are delectable little meals for scavengers, and there are a lot of reasons why finding dinosaur eggs and embryos is extremely rare.”