Late last month, researchers in South Africa uncovered the earliest known dinosaur-nesting site. The site dates back 190 million years, according to research published in the Proceedings of the National Academy of Science (PNAS).

According to the Jan. 22 issue of PNAS, the discovery was made within the fossil-rich Gate Highlands National Park, located in Free State, Republic of South Africa, by paleontologist Robert Reisz, a professor of biology at the University of Toronto.

“The significance [of this finding] is the early date of nesting behaviors,” said John Wahlert, chair and professor of biology at Baruch College. Researchers from the site claim that these new nests are more than 100 million years older than the previously thought oldest dinosaur-nesting site.

According to PNAS, at the time of the research publication, Reisz had located ten nests, each with up to 34 eggs, along with “fascinating evidence of complex reproductive behaviours.”

Reisz graduated from McGill University with his B.Sc. in 1969, M.Sc. in 1971, and Ph.D in 1975.  Since then, he has conducted fieldwork across the globe, specifically in North America, Africa, and Europe.  This recent discovery stands next to some of Reisz’s other notable excavations, including the oldest known bipedal reptile, and the oldest known diapsid reptile.

Evidence suggests that there are more eggs to be found in the area, according to Reisz, but they have just yet to be discovered and are covered by tons of rock.

These newly uncovered nests contain clutches of eggs of theMassospondylus dinosaur. Many of these fossilized eggs contain embryos.

“It is always interesting to have embryonic stages of fossils,” saidWahlert “They are fragile and very rare.  It allows assessment of how dinosaurs grew.”

Reisz has been studying the site since 2006, following the discovery of a partial egg clutch in a block of siltstone in 1976.  Along with these egg clutch discoveries, evidence is hinting at unknown reproductive behaviors that have also been revealed.

According to the researchers, evidence suggests that dinosaur nests were highly organized, suggesting mothers may have arranged them carefully after she laid them. Evidence also shows that hatchlings have lingered at nesting sites and almost doubled in size, revealing tiny footprints.

Chantelle Janse van Rensburg, a student at the University of Pretoria in South Africa, grew up in the area and is familiar with the Province’s high fossil density, even recalling a time in her childhood when she and her brother found a fossilized egg in her uncle’s backyard.

“I think it is fantastic that we keep making such wonderful discoveries in South Africa. The country as a whole has so much to offer in every sense of the natural world,” said van Rensburg in an interview.  “Onwards to discovering the next amazing fossil.”