An excavation at a site in South Africa by U.S., Canadian, Australian and South African researchers has unearthed the 190-million-year-old nesting site of the prosauropod dinosaur Massospondylus, revealing clutches of eggs, many with embryos, as well as tiny dinosaur footprints that suggest hatchlings remained at the nesting site long enough to at least double in size.
"This research project, which has been ongoing since 2005, continues to produce groundbreaking results and excavations continue. First it was the oldest dinosaur eggs and embryos, now it is the oldest evidence of dinosaur nesting behavior," researcher Bruce Rubidge at South Africa's University of the Witwatersrand said in a release Monday.
The dinosaur nesting ground is more than 100 million years older than previously known nesting sites, researchers said.
Ten nests have been discovered at several levels of the site, suggesting these early dinosaurs returned repeatedly to this location, and likely assembled in groups to lay their eggs, the oldest known evidence of such behavior in the fossil record, they said.
"Even though the fossil record of dinosaurs is extensive, we actually have very little fossil information about their reproductive biology, particularly for early dinosaurs," David Evans, curator of Vertebrate Palaeontology at the Royal Ontario Museum, said.