Fossils of early human ancestors from a South African cave are 3.4 million to 3.6 million years old -- making them a million years older than previously suspected and shaking up the way researchers understand human origins and evolution.

This new date makes the Sterkfontein Cave fossils older than the famed Lucy fossil (also known as Dinkinesh) from Ethiopia. Found in 1979, Lucy represented the species Australopithecus afarensis and lived 3.2 million years ago.

The freshly dated fossils also belong to the genus Australopithecus, an ancient hominin that was initially thought to live 2 million to 2.6 million years ago. Researchers used a new technique to date the sediments of the Sterkfontein Caves, which are part of the Cradle of Humankind UNESCO World Heritage Site, about 30 miles (50 kilometers) northwest of Johannesburg.

The caves included in this network have revealed details about human and environmental evolution that span about 4 million years.

The site is home to a treasure trove of fossils that help tell the story of human evolution -- a story that seems to shift with each discovery