On 15 August 2008, nine-year-old Matt Berger tripped over a fossil that would lead to one of the most important discoveries in the history of human evolution.

The young adventurer had been exploring the Cradle of Humankind, in South Africa, with his father Lee, a paleoanthropologist.

"I didn't really know what was happening. I was just there for fun. But my dad was so excited. So obviously that made me excited too," said Matt.

The fossil turned out to be from a new species of hominid called Australopithecus sediba.

Matt speaks to Vicky Farncombe about his memories of the day.

(Photo: Matt Berger, son of Prof Lee Berger, found the fossil of a new hominid species that lived 1.95 million years ago. Credit: Foto24/Gallo Images via Getty Images)