The 26-year-old Brisbane-born paleoanthropologist has a background in caving and rockclimbing, of excavating fossils in mine shafts, a solid grasp of anatomy and is small enough to fit through the tiny crevices that sit between between the surface and what turned out to be a treasure trove of bones.

For someone who started her PhD with the expectation it "wouldn't go anywhere", Ms Feuerriegel has found herself at the centre of a find that could change our understanding of human evolution.

In 2013, Ms Feuerriegel and five other scientists spent three weeks in the hot and damp Dinaledi chamber in the Rising Star cave system, 50 kilometres north west of Johannesburg.

The cave's measurements are enough to make the average surface-dweller squirm.

The excavators had to walk, climb and squeeze through 80 metres of cave to reach the fossil chamber 30 metres below ground. Some thoroughfares were shorter than a 30 centimetre ruler. "It helps if you're not intrinsically claustrophobic to begin with," Ms Feuerriegel said. "Going into squeezes and things, I actually find kind of comforting, it's kind of like entering the womb of the earth."

In a paper published earlier this month the scientists, led by Professor Lee Berger, presented the results of their expedition; more than 1500 fossils, 15 individuals and one new member of the human lineage. Homo naledi's hips, and torso are more apelike – with shoulders designed for climbing – while its lower body is more human, its feet nearly identical to ours. The skull is less than half of the size of modern humans, but its hands suggest it may have been using tools.

The announcement of a species that could be a missing piece in the puzzle of human evolution immediately attracted criticism from other scientists who questioned H. naledi's claim to new species-hood.

But this was a discovery for the modern age. "Lee [Berger] had a vision when he started to put together the Rising Star expedition, he realised the opportunity he had to really turn the tide on paleoanthropology as a discipline," Ms Feuerriegel said.

The expedition was live-tweeted. The paper was published with eLife, a peer-reviewed but open-access journal. The team has also published downloads of the fossils and are actively encouraging doubters to print the models in 3D and study them.

For a discipline that is historically insular and its discoveries highly-guarded, what Mr Berger and the team did with their results was a big upset. "It's magnificent, it's exactly the kind of change that paleoanthropology needed to have," Ms Feuerriegel said. "In terms of research and progress in the field, those [traditional] kinds of behaviours and attitudes are really counterproductive."

Since publishing their results, there has been another attitude that bothers Ms Feuerriegel and her five underground colleagues. From the 60 people who applied to excavate on this expedition, the chosen six who had the required combinations of skill and size also happened to be women.

The fact has simultaneously made role models of the group and caused frustration through the resulting focus on gender and body shape. But Ms Feuerriegel worries that criticism of that focus can undermine the importance of publicising that women do this kind of work.

"It's important that our achievements as women become more public. It sets the stage for very young girls to go into fields like this, without having to worry about discrimination or their own capabilities, because there's this legacy of women who have done this work before. And they've done it really, really well," she said.