Switching from research on dinosaurs to ancient human fossils is an uncommon transition in his field.
But it was Dr Roberts’ involvement in the discovery of important early ape fossils in Tanzania, and his interest in the geology of the East Africa Rift, that led to him becoming a lecturer at South Africa’s University of the Witwatersrand in 2005. Here he met fellow geologist Professor Paul Dirks.
Over the past decade, the two have worked together in the field in locations from Zimbabwe to South Africa, and ultimately in Australia. After Professor Dirks moved to Australia to take up a position at JCU, Dr Roberts himself moved there in 2010, relocating to Townsville.
Working in remote locations is not always smooth sailing. Dr Roberts remembers one field season in 1999 in the southern Sahara of Mali, where for five weeks he and a group of scientists had to be guarded by soldiers against banditry and potential kidnapping, and got into some hairy situations along the way.
“It’s one of the wildest, most remote places I've ever been,” he says.
But the real contrast between these other expeditions and the Rising Star dig in South Africa, is the sheer volume of fossils.
“In East Africa, people get excited when they find one tooth,” says Dr Roberts. “Here, you’re tiptoeing from rock to rock, and everywhere there’s bone. It was cool and humbling, after many years of very little fossils, to see that and to try and put it into context.”