With Mother's Day around the corner, paleontologists have just discovered the remains of a dinosaur mother who died with two eggs still inside of her, according to a report in the journal Cretaceous Research.
The discovery marks the first time that fossilized eggs have been found so close—in this case, inside—the skeletal remains of an alvarezsaurid dinosaur, an enigmatic family of small, long-legged running dinos. They had a bird-like skull, tiny teeth-carrying jaws, hefty but short forearms and enormous claws.
This particular species is now called Bonapartenykus ultimus, in honor of José Bonaparte, who discovered the first alvarezsaurid in Patagonia in 1991.
According to paleontologist Martin Kundrát of Uppsala University, in Sweden, this latest alvarezsaurid is one of the largest members of its dino family. The adult mom would have measured at least 8.5 feet long. She and her species represent the last survivors of their kind from Gondwana, the southern landmass in the Mesozoic Era.
"This shows that basal alvarezsaurids persisted in South America until Latest Cretaceous times," Kundrát was quoted as saying in a press release.
Numerous eggshell fragments near the mother dino indicate that "at least some of the eggs were incubated and contained embryos at an advanced stage of their development," according to the researchers. Two eggs were in the mother dinosaur's oviducts when she perished.
"They were close to being laid, but the female didn't make it," Kundrát told LiveScience.
It's a mystery as to how she died.
Yet another finding from these remains is the first evidence of fungal contamination of dinosaur eggs. The scientists spotted it using scanning electron microscopy. The fungal remains looked like "unusual fossilized objects inside of the pneumatic canal (air pocket) of the eggshells," Kundrát said.
Photo 1: A reconstruction of Bonapartenykus; Credit: Gabriel Lio.
Photo 2: A Bonapartenykus egg. It has a unique eggshell microstructure, according to the scientists. Credit: Fernando Novas.