Scientists find oldest fossils of dinosaurs living in a herd

A vast trove of fossils unearthed in Argentina’s southern Patagonia region is offering the oldest-known evidence that some dinosaurs thrived in a complex and well-organized herd structure, with adults caring for the young and sharing a communal nesting ground.

Scientists said on Thursday the fossils include more than 100 dinosaur eggs and the bones of about 80 juveniles and adults of a Jurassic Period plant-eating species called Mussaurus patagonicus, including 20 remarkably complete skeletons.

The animals experienced a mass-death event, probably caused by a drought, and their bodies were subsequently buried by wind-blown dust, the researchers said.

“It is a pretty