On September 10, 2015, scientists formally announced that a new species of hominin had been discovered in the Rising Star cave system in northern South Africa. But the discovery was far from a secret: the team had previously tweeted their field season live. They called the species gay naledi-for “star” in the local Sotho-Tswana languages.
What do scientists know so far about gay naledi comes from more than 2,000 fossil fragments that make up 21 individuals—both male and female adults and infants—from three different parts of the Rising Star’s cave system. The species is estimated to be between 236,000 and 335,000 years old, based on various dating methods. For a science that can count the bones of a number of entire fossil hominids with the fingers of one hand, it is unprecedented to find so many fossils of one species in one place.
Of gay nalediNewfound celebrity in paleoanthropology, project leaders and paleoanthropologists Lee Berger and John Hawks were smart enough to turn the situation into an opportunity to challenge the industry status quo. The National Geographic-backed Rising Star project pushed a new set of social mores and practices around data openness that allowed researchers to move through the gay naledi material in an efficient, timely and professional manner. And in retrospect, many factors have placed Rising Star in a good position to trigger a shift toward more open-access practices in paleoanthropology.
“We have an open invitation for colleagues to check our work,” Lee Berger explains to Ars. “And they can do this because we’ve made open collaboration such an important part of Rising Star.” He was silent for a minute and then continued. “I think we’re broadening what science, for paleoanthropology, means, because people can see the site and fossils for themselves to test their conclusions. The data is available.”
The cradle of humanity
The story of gay naledi actually begins millions of years before the Rising Star expedition ever set up camp some 40 miles outside of Johannesburg in South Africa’s Gauteng province.
Caves in that area of South Africa form as water seeps through the cracks and crevices of the region’s dolomite rock and the rock slowly erodes, forming underground caverns of all shapes and sizes. As water flows through these caves, it leaves behind deposits of calcium carbonates — easily recognizable as concrete-hard breccias or slab-like deposits of stream rock found along cave walls. In the Rising Star cave system, this resulted in a network of chambers, including those where researchers have recovered gay naledi fossils.
For scientists piecing together the story of South Africa’s ancient environments and evolution, these caves act as time capsules. For centuries, plant and animal remains (not to mention humanoids) have been found in the caves. Enough hominid bones were found that in 1999 that region of northern South Africa — and all of its fossil-filled caves — was designated a 180-square-mile UNESCO World Heritage Site called the Cradle of Humankind, dedicated to the paleoanthropological history of humanity.
These bones entered the cave through a number of routes. For example, rodents drag bones into caves and have done so for millennia. Water from underground sources can move bones from where an animal died to another place in the cave system. While these caves are incredible resources for finding fossils, it’s anything but easy to understand how those fossils appear in their current locations — to be discovered and excavated by modern scientists.
From caves to Facebook and Twitter
In August 2013, University of Witwatersrand Professor Lee Berger hired Pedro Boshoff to survey caves in the Cradle of Humankind, mapping fossil deposits. Boshoff, a caver, expanded his team to include Rick Hunter and Steven Tucker. Cavers had been in the Rising Star system since the 1970s and, armed with a 1985 map as a guide, Tucker and Hunter began exploring systematically.
“I started in the Rising Star cave system in 2011 as a member of the Speleological Exploration Club,” Steven Tucker explained via email. “It has always been one of my favorite caves, looking for new and explored areas. By mid-2013 I had spent over a hundred hours there.”
Tucker and Hunter found that they could squeeze through a rather daunting, unassigned 18-centimeter trench in the cave, so they squirmed through it. Once through the slot and after pushing their way down, Tucker and Hunter found themselves in a final room with an inordinate amount of fossils. (“When we first saw the lower jaw, we thought, maybe this was the last guy to come to the room and not make it,” Hunter joked during an interview.) When they showed Berger pictures of the fossils, interest was aroused to say the least.
In the photos, Berger could see that there was new damage to the bones, probably from other cavers who didn’t know what they were walking on. After consulting with colleagues, Berger decided it was wise and necessary to dig up the fossils, properly map their context, and do it quickly to avoid further damage. Obtaining the appropriate permits and with the support of: National Geographic, Berger began assembling a team that would have the requisite science and caving background needed to do the job. He started by writing a vacancy.
“Should I just email this to my colleagues and ask them to distribute it the normal way?” Berger wrote in his 2016 bestseller about the expedition, become human. “I suspected there were probably no more than a handful of people in the entire world who fit the description and were available at such short notice.” Berger decided to post the message to Facebook and from there it quickly ripped through the Twitterverse. The underground team consisted of six women with extensive archaeological and caving experience – Marina Elliott, K. Lindsay Hunter no Eaves, Elen Feuerriegel, Alia Gurtov, Hannah Morris and Becca Peixotto.
“It took me 45 minutes to get to the Dinaledi room the first time,” said Marina Elliot, a biological anthropologist at the University of Witwatersrand and the project’s current field director. “When I finally jumped out of the parachute and glided down the final corridor to the Dinaledi room, I could see that the floor was littered with bits of bone, and the stalactites around me shimmered with the light cast around by my headlight. was mind-blowing.” Elliott paused, then laughed, “I expect it’s what Howard Carter’s team felt when they opened King Tut’s grave.”
The November 2013 field season was set up to run as a salvage archaeological project. The point was to excavate in the Dinaledi room (as the space was called) – to get in, get the fossils, document the context, and get out. When Marina Elliott and Becca Peixotto first reached the room, they began marking fossils on the cave’s surface. Their count was over 300 fragments. “Well, we took off our shoes and socks to make sure we didn’t damage anything,” Elliott clarified. “The fossils were – are – incredibly fragile.”
“We use toothpicks for digging,” explains Peixotto. “We’re moving one grain of sediment at a time, looking at everything.” The team of archaeologists also use brushes and Tupperware containers to excavate and transport fossils to the surface — a curious combination of Dollar Store gear with the advanced technology of cameras, cables and the Internet. The latter was there to let the aboveground support team in the “command center” monitor the excavations via a live feed and carefully document the recovery of the fossils. “We also use porcupine quills, which are perfect for the sediments,” Elliott offered cheerfully, confidently. “And sometimes we just have to wait for porcupines to leave the caves before we can get in.”
While the team was excavating, a curious pattern began to emerge. All the fossils were bones of hominins. In caves with fossil hominids, it is not uncommon to find non-human bones, indicating that other animals at some point used the caves and died there, or that natural forces, such as water, could have carried the bones to where they were discovered. But at Rising Star, there were no fossils of other species. Unexpectedly, “Lee took me aside at one point to ask if we were just digging up the hominin material and skipping other stuff for later,” Elliott recalls. “I assured him we were digging everything up. There was just nothing but the humanoids.”
Over the course of the first field season, all the excavators — underground astronauts, a term the media used — took turns. Because it was so difficult to slip into the Dinaledi room, the shifts were extended from 1-2 hours to 3-4 hours, in order to maximize the output of the time spent reaching the fossils. The fossils were mapped and bagged. Sediment was collected to be screened later in the lab. The entire season lasted three weeks and Twitter was captivated the entire time, followed by updates from #RisingStar.
The popular press following major fossil finds is nothing new. When the famous Lucy fossil was discovered in the Afar region of Ethiopia in November 1974, its discoverer, Donald Johanson, held a press conference in Addis Ababa on December 21 to introduce Lucy to the media, well before the fossil was published in the academic literature. Many fossil finds offer the opportunity to engage the general public. Before Rising Star, however, there had been no excavation of fossil hominids immediately shared around the world.