"Skinny anthropologists, biologists, cavers, not afraid of confined spaces." When Professor Lee Berger, who found the fossil of Australopithicus sediba in 2008, put out this call on social media, people thought he was joking.
In the next few days, a group of professional cavers and scientists – all women, chosen specifically because they had a chest measurement of less than 18cm – will begin excavating a new site in the Cradle of Humankind, Berger told journalists in Johannesburg on Wednesday.
Berger, who was earlier this year named National Geographic explorer in residence describes the fossil find as "significant".
"We do not know as yet what species of hominin we have found, and we will not speculate … We are going to find what comes out as it comes out," he said.
Discovered by exploration team leader Pedro Boshoff and his two assistants, slim-physiqued Steve Tucker and Rick Hunter discovered the fossils in an underground cave.
But it is about 30m below the surface, and only people with a bust size of 18cm or less could fit.
Berger put a call out to social media, and within 10 days had a list of 57 qualified candidates, only six of which were chosen.
"These are highly trained scientists with caving experience from the US, Canada and Australia, who are currently in South Africa preparing for the excavation," he said.
The cavers will be extracting the fossils from the site and transporting them out of the cave.
The expedition, at what is called Rising Star Cave, is a partnership with the University of Witwatersrand and National Geographic.
The expedition is expected to take three weeks, a process that was accelerated because the fossils are "exposed", Berger said. However, he refused to speak about the location, the species of the fossils, and implored the journalists and the public to be patient.