Few could carve out a dream vocation that involves digging for dinosaurs across the world and uncovering African hominid fossils of staggering significance, but geologist Dr Eric Roberts hasn’t had just any old career.
Getting into South Africa’s Rising Star cave system – the site of the most exciting hominid discovery of recent decades – is no simple task.
Head of Geoscience at James Cook University (JCU), Associate Professor Eric Roberts first experienced this in 2013 when, after a challenging climb through a series of caverns, he lowered himself down a narrow 12-metre chute into the fossil-bearing Dinaledi Chamber.
“The fracture pinches to about 18 cm, which is pretty much my limit,” the geologist admits.
“During my first trip into the Dinaledi Chamber, I was so full of nervous excitement, I tried to go down too fast, and got really stuck in a diagonal squeeze. When I tried to pull myself back up, my pants got caught, and I ended up ripping the back pockets off.”
Despite the claustrophobia and bruising, the effort was well worth it, says Dr Roberts, who is one of very few scientists to have made it down the chute and into the final chamber.
It was here that a new member of the Homo genus was discovered – a species with an unusual mix of modern human and ape-like features, named Homo naledi. Few important new hominid fossils had come from South Africa in the previous 60 years, so the find, reported in 2015, rocked the scientific world.
The incredible fossil trove – now up to 2,000 elements from perhaps 18 individuals – has more than doubled South Africa’s entire hominid fossil tally.
Working with JCU Professor Paul Dirks, Dr Roberts has helped uncover the geological context explaining the circumstances in which these fossils were found. Last year, the pair were co-authors on a paper revealing the fossils to be less than 335,000 years old, showing that Homo naledi lived in Africa alongside early members of our own species.
According to Dr Roberts, his role in this astounding palaeoanthropological find owes itself in part to the serendipity of him being small and adventurous enough to squeeze into the chamber. Many other remarkable turns in his career, he says, have been the result of him being in the right place at the right time.
“It's an amazing career, and something I totally stumbled into.”
Dr Roberts is responsible for uncovering the geological context that explains how and why important fossil sites came to be. This includes piecing together how old the fossils are; what their environments were like when they were alive; and how and why they may have died.
A self-described “geologist to the stars”, he’s worked on digs with such celebrity scientists as National Geographic explorer Professor Lee Berger of Homo naledi fame; Montana-based dinosaur scientist and advisor on the Jurassic Park films, Jack Horner; and Canadian palaeontologist Scott Sampson, host of US kids’ show, Dinosaur Train.
It was working alongside Sampson and other heavyweight palaeontology experts in Madagascar on a pioneering expedition in 1996 that gave Dr Roberts – then an undergraduate at Cornell College in the US – his first taste of a palaeontological dig.
Being involved in the discovery of the massive skull of a carnivorous dinosaur called Majungasaurus “was the defining experience of my early career”, he says. “I've never been to a place with quite as much excitement as that first field season in Madagascar.”
Dr Roberts adds that in the early days, he’d never seriously considered a research career, but “being a part of that team, and feeling the thrill of discovery and wonder associated with unearthing a new species of dinosaur was inspiring”.
“Indeed, that summer resulted in so many important discoveries, I still get excited thinking about what else is out there to find,” he says.
And find more fossils he did.
Dr Roberts estimates that his geological work has seen him co-author more than 25 academic papers describing new dinosaurs and other extinct creatures from locations as far flung as Tanzania, Mali, and Antarctica.
He credits an undergraduate professor for pushing him to consider graduate school, which ultimately led to him to pursuing a PhD studying the geology of the then-unknown Kaiparowits Formation in Utah.
Dr Roberts took on the role of lead geologist for the Kaiparowits Basin Project, started by Sampson, which has since resulted in the discovery of numerous new dinosaurs, including several tyrannosaurs and new ceratopsian relatives of Triceratops, such as Kosmoceratops, Utahceratops, and Nasutoceratops.
As a PhD candidate at the University of Utah, Dr Roberts had a habit of sneaking off with colleagues Patrick O’Connor and Nancy Stevens to the Great Rift Valley region of East Africa to hunt for dinosaurs there, too.
“Initially, my PhD advisor didn't know,” he says. “But eventually she found out, and allowed me to do it. I did that work in Tanzania concurrently with my PhD.”
Both dinosaur projects have continued to this day, alongside his hominid work in South Africa, which all results in Dr Roberts being frequently away from his Townsville base.
In the past few years, his work on what has come to be known as the Rukwa Rift Basin Project has resulted in the description of two new long-necked dinosaurs: both 20-metre-long giant sauropods named Rukwatitan and Shingopana.
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.”
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Find out more about Dr Eric Roberts' discoveries at World Science Festival Student Day.
Feature image: Kumiko/Flickr