Not quite two years ago, on October 6, 2013, paleoanthropologist Lee Berger of the National Geographic Society and the University of Witwatersrand in South Africa posted an odd, tantalizing ad on facebook:
Dear Colleagues – I need the help of the whole community and for you to reach out to as many related professional groups as possible. We need perhaps three or four individuals with excellent archaeological/palaeontological and excavation skills for a short term project that may kick off as early as November 1st 2013 and last the month if all logistics go as planned. The catch is this – the person must be skinny and preferably small. They must not be claustrophobic, they must be fit, they should have some caving experience, climbing experience would be a bonus. They must be willing to work in cramped quarters, have a good attitude and be a team player. Given the highly specialized, and perhaps rare nature of what I am looking for, I would be willing to look at an experienced Ph.D. student or a very well trained Masters student, even though the more experience the better (PH.D.’s and senior scientists most welcome). No age limit here either. I do not think we will have much money available for pay – but we will cover flights, accommodation (though much will be field accom., food and of course there will be guaranteed collaboration further up the road). Anyone interested please contact me directly on lee.berger@wits.ac.za copied to my assistant Wilma.lawrence@wits.ac.za . My deadlines on this are extremely tight so as far as anyone can spread the word, among professional groups.
Many thanks
Lee
What Lee Berger needed was a team of experienced excavator/cavers capable of retrieving newly discovered fossils from a small, remote chamber in South Africa’s Rising Star cave system, thirty meters—nearly one hundred feet—below ground level, and eighty meters—two hundred-sixty feet—from the cave entrance. The final approach to the chamber includes a twelve meter drop, forty feet down a chute of jagged rock that at its narrowest is just 18 centimeters—seven inches—wide.
He expected no more than a handful of people could meet requirements like this, but within only a few days, from around the world, he had fifty-seven well-qualified applicants who did. By the second week in October, Lee and his colleagues on the project had selected six women for the advance team of scientists to enter the chamber. By the first week in November, they were at the cave site, setting up camp.
On September 10, 2015, they finally announced to the world what they found.
The Advance Scientists
Despite being near the beginnings of their careers—two with masters degrees, and four in the process of getting PhDs—the women of the advance team brought with them a great mix of interests, backgrounds, and expertise, and significant work experience at archaeological and paleontological sites all over the world. Trowelblazers, a blog devoted to women in archaeology, offered profiles:
As a Ph.D. student at the University of Iowa, she worked with a number of other well-known fossil hominin collections – from specimens of Australopithecus excavated at the South African site of Sterkfontein to Anatomically Modern Humans from sites in Europe and South America. Much of her doctoral research has centered on the evolution, shape, and function of the thorax or ‘trunk’ of the skeleton in our genus, Homo…
[S]he [has] worked on excavations at Lake Baikal in southern Siberia, and at the northernmost archaeological site in the USA: Nuvuk on Point Barrow, Alaska…
Elliott’s research specialism is the archaeology and anatomy of the human skeleton, including forensic anthropology and the archaeology of death and burial… [W]e can learn a lot about people from the study of their bones and teeth: their age, their height and weight, whether they suffered from any illnesses.
Marina’s PhD research uses full body CT scans to explore the relationship between people’s skeletons and their body mass, to check the accuracy of methods currently in use for estimating body mass after death, using the remains of someone’s skeleton.
Elen’s PhD thesis at the Australian National University, Canberra, is on what’s termed the biomechanics of knapping (stone tool-making), focusing in on the shoulder. She looks at the particular muscles that are used when people knap, and will compare the data from modern experiments to the patterns of muscle attachments on ancient hominin bones, hoping to see which fossil species had configurations closest to those of stone-tool makers.
“It’s my dream to spend my life in the dirt.”
… Alia [has worked] at Palaeolithic (earliest stone age) sites around the world including Dmanisi in Georgia, Neumark Nord in Germany and Pinnacle Point in South Africa… [and] one of the most famous hominin fossil sites in the world: Olduvai Gorge, Tanzania.
Her innovative PhD (at University of Wisconsin) involves trying to see if the ancient human relatives living there around 1.8 million years ago were hunting and foraging differently according to the season … [using] a technique called microwear: if animals that the hominins ate died during the dry season rather than the wet, the last food they were eating would vary in texture, and leave particular patterns of tiny scratches on their teeth…
One of Hannah’s main research interests is paleoethnobotany-that is, the study of ancient plant use by people… She’s particularly interested in the domestication of what archaeologists call the Eastern Agricultural Complex, which includes plant species such as sunflower, goosefoot and little barley, all domesticated in the southeastern United States between 4,000-5,000 years ago.
Peixotto recently completed her MA in Public Anthropology at the American University, where she became involved with the Great Dismal Swamp Landscape Study. The Great Dismal Swamp – which straddles the Virginia-North Carolina border – sounds spectacularly uninviting, … just getting to the field sites could be challenging… It was this very inaccessibility that in the 17th-19th Centuries turned the Great Dismal Swamp into a refuge for escaped slaves, and a key part of the Underground Railroad. Up to 50,000 ‘maroons’ – as the escaped slaves were known – are now thought to have lived in hidden communities within the Great Dismal Swamp, but the necessary secrecy surrounding their existence means that very little is known about them.
Update: Video interviews with the members of the advance team about their experiences with Rising Star are available here: Lindsay Hunter, Marina Elliott, Elen Feuerriegel, Alia Gurtov, Hannah Morris, Becca Peixotto.
Letting the Whole World In
The usual practice in paleontology is for discoverers to tightly control access to their fossils for years or even decades. This makes it difficult, sometimes impossible, for other researchers to verify claims made about the material, or to correct mistakes in interpretation when those occasionally happen. Lee Berger believes strongly in the benefits of open science, of sharing access to fossils and data, and in the insights that emerge when people with a richness of backgrounds and expertise come together to consider what exactly it is that they’re holding in their hands.
He also loves the excitement and sense of engagement that being open generates, not only in the direct participants, but in those of us who thrill at what they’re doing.
Knowing that most of them could never reach the fossil chamber, he and a sixty-member team put together a command center outside the entrance and ran multiple cable lines deep into the cave, providing power for lighting, and networking for video cameras and computers, all along the passage and into the chamber itself.
The Rising Star Expedition began with a facebook ad to recruit the select team who would excavate the fossils. Then, for three weeks in real-time, it shared itself with the world at @RisingStarExped on twitter, with posts and video interviews with team members on the Rising Star Expedition blog at National Geographic, and in skype sessions with middle school and high school students around the world.
Announcing the discovery of Homo naledi, September 10, 2015, Johannesburg, South Africa, Lee Berger:
[36:43]
This is a great moment for us. It is a moment that was perhaps two years in the making, for some of you who may follow our adventures since November of 2013, but in fact, it’s ninety years in the making. Ninety years of exploration here in South Africa for human origins. Begun by the greats like Professor Dart, carried on by great scientists like Professor Brain and Professor Tobias. We stand on the shoulders of giants as we look for these extraordinary finds that are revealing information about, not just our origins, but the origin of our species.
This story began in 2013 … with what was called the Rising Star Expedition. …[W]e felt this was an opportunity to perhaps bring this discovery, perhaps for the only time, of a fossil hominid to the world. And with the assistance of National Geographic and the university, we streamed live and tweets and social media, entertaining classrooms around the world as our “underground astronauts” would come out and speak to children. We enjoyed an experience of sharing a moment of exploration that I think touched us all.
We had not gone into that cave with an expectation of that extraordinary discovery; we’d gone in with the idea of recovering one fossil. That turned into multiple fossils; it turned into the discovery of multiple skeletons and multiple individuals. And so by the time of the end of that remarkable 21-day experience, we had discovered the largest assemblage of fossil human relatives ever discovered in the history of the continent of Africa.
[…] In November 7 we put a sixty-person expedition into the field. On November 10, after laying three and a half kilometers of communication cables and fiber optics, we began recovering fossils…
[42:17]
And then the work began after that—the work of analysis—for we were faced with perhaps the greatest assemblage ever seen of fossil hominid remains, and we knew that we could not do it in a normal way. We had been fortunate to be working on Australopithecus [sediba], had an experienced team that worked on high impact discoveries for the previous five years, published in all major journals, and even they were overworked.
They could not keep up with what was coming out of that extraordinary site. And so, together with the senior members of the team, we designed a new way of looking at this material. We brought to South Africa, with the assistance of the National Research Foundation and Wits University, early career scientists—those who had their fingers on the most current datasets, those who had their fingers on the most current technology. We brought thirty of them and combined this into a sort of superteam, in a workshop in May of 2014. And it was in that incredible collaborative, open experience that the fossils you are going to see described today began to take on life, because contrary to what many people believe, bones do not speak for themselves. It requires extraordinary minds, technology, intuition—it requires human beings—to study them.
One of the benefits of being a National Geographic Society Explorer-in-Residence is that when Lee Berger first saw photos from the Rising Star fossil chamber and realized there was something quite special there (of course, not yet knowing just how special), he could go to the Society and ask for support. Along with funding, they provided a video team to document the entire expedition as it happened.
The result of that effort is Dawn of Humanity, a Nova/National Geographic Special program. It has been freely available for streaming on the PBS website since the day Homo naledi was announced, and was broadcast nationally on PBS on Wednesday, September 16. It doesn’t just document the expedition; it places the discovery of naledi in the context of nearly one hundred years of fossil discoveries, including what people have read into these fossils, and taken them to be telling us about our deepest nature as human beings.
Here are a few things that caught my eye during the program, but that either weren’t noted or were not really explained. (The first two are things I remember from following the expedition on social media as it happened. The third is based on something else.)
Several times we see a team member use a handheld device with a circle of flashing LED lights on it, pointing it at fossils, and moving it around much as you might move your head to look at something from slightly different directions to get a better sense of what you’re seeing. This is an Artec Eva™ high resolution 3D scanner. By recording a scene from multiple angles, it creates a 3D image that can later be rotated and tilted to allow the scene to be viewed from different perspectives. The physical context in which a fossil is found—where it’s located, how it’s positioned relative to things near it, and so on—can be critical for understanding how these beings’ remains came to be where they are. So before a fossil is removed, its entire visible context is photographed, and a detailed 3D scan of the scene is made.
You will also notice that at some point the women have begun to go barefoot when in the fossil chamber. They entered the chamber the first day expecting to find only the typical fragmentary remains of a single individual. As they began to work—and understand, the chamber has a dirt floor, these fossils are embedded in dirt and clay, not rock—they realized there were fossils absolutely everywhere: lying on the surface of the dirt, sticking out of the dirt, out of sight just under the dirt, fossils underneath other fossils, and more fossils underneath them. There was no way to take a step anywhere and guarantee they weren’t accidentally crushing something they couldn’t feel through their shoes. So. Barefoot.
When they finally bring up the fragment of cranium on the last day of excavation [beginning at 1:26:32 in the program], they find it includes part of the brow ridge above and to the outside of the left eye, and they can see that the brain case across the front of the skull, just behind the eyes, is fairly broad, and rounded at the sides. The immediate conclusion is that this individual belongs to our genus, Homo [1:33:00]. According to the narrator, “Large orbital ridges with indentations behind them would indicate australopith. Smaller brow ridges with evidence of a more rounded skull would say Homo.” [1:33:34] But they don’t say why those shapes are significant, beyond mere association.
In John Hawk’s superb MOOC, Human Evolution: Past and Future, John, Lee Berger, and Steve Churchill, examine the fossils and reconstructed skeleton of Australopithecus sediba (about which, more below), in a three-part hour-long session for Week 3 of the course.
In the video “In the Lab with A. sediba: Part 1”, they take a few minutes (beginning at 14:57) to examine the skull of MH-1, the A. sediba type specimen. Lee compares it with a reconstruction of Mrs. Ples, one of the best-preserved skulls of Australopithecus africanus. The difference just behind the eyes (“post-orbital”) is striking. In sediba, uncommonly for an australopith, the skull is broad behind the eyes, not pinched in at the sides. This aspect of its skull is very Homo-like, even though the sediba skeleton as a whole is significantly closer to Australopithecus than to Homo, which is why it’s assigned to that genus.
MH-1 (left) and Mrs. Ples (right). Source: video capture at time 15:52, from “In the Lab with A. sediba: Part 1”, Human Evolution: Past and Future.
Lee Berger [15:37]:
And when you look at a specimen like this—I’d like to turn around behind us and grab an Australopith, a very famous one; this isn’t the original, obviously, this is Mrs. Ples—and place them side by side, and I think you can very quickly see some of those really important features we were looking at.
Notice the lack of post-orbital constriction that is present right here [in sediba]. … When you see an australopith morphology, like this [Mrs. Ples], that’s what they look like. Something has happened up here [in sediba] and something really important is happening up here to shift that morphology into what—although it’s microscopic in size and this is a very small brain, it’s 420 cubic centimeters—something important has shifted there in a really important part of anatomy.
(I ‘d love to just embed the thing, but unlike many of the course’s videos, this one isn’t available on youtube. They’re all available at the course website, but to access them you have to create a login account at Coursera and enroll in the course, both of which are free.)
In species of Australopithecus other than sediba, the skull is significantly pinched in at the temples, so that the front of the brain is narrow. If I understand what he’s saying here, the fact that it’s so much broader in sediba suggests that, in that species, something important has begun to happen in the part of the brain known as the prefrontal cortex, and the prefrontal cortex
“…has been implicated in planning complex cognitive behavior, personality expression, decision making, and moderating social behavior. The basic activity of this brain region is considered to be orchestration of thoughts and actions in accordance with internal goals.” (Wikipedia, retrieved 2015.09.11)
Homo naledi‘s cranium is similarly broad. Although its brain is small overall, only about a third the size of a modern human and about the same as an australopith, this noticeable widening of the prefrontal cortex, together with the human-like character they had already seen in other important parts of its anatomy, is the reason they could confidently say that H. naledi belongs in the genus Homo as part of the human lineage.
We Have Not Understood What We Were Walking On
Homo naledi was discovered two years ago, in 2013. Five years earlier, Lee Berger had discovered another rich fossil site, Malapa, only a few miles from Rising Star. That site yielded Australopithecus sediba; like Homo naledi, a previously unknown species.
Both naledi and sediba included surprising mixes of human-like and australopith-like qualities in their skeletons, and were surprisingly different from each other in the ways they were and weren’t human-like.
Both were discovered in well-explored areas where people had been hunting fossils for nearly a hundred years; discovered precisely by setting out to look for fossils in places where it was thought there was nothing left to find.
And both were discovered through a combination of planning, persistence, and luck. In the case of naledi, the luck was when one of the two cavers canvassing sites for Lee Berger dropped himself down into a narrow crevice to allow his fellow caver to get past him, noticed there was nothing under his feet, and realized it might lead to another chamber. In the case of sediba, it was when Lee’s nine year old son, Matthew, running after his dog, tripped on a log and landed right next to the rock that contained the first sediba fossil, a collarbone.
Lee Berger calls it “the backyard syndrome,” the way a place can become so familiar that it’s hard to see the things that are hiding in plain sight. By the late 1990s, that was the situation in which he felt paleoanthropology had become stuck. If you know that fossils of human relatives are so exceedingly rare that they’ve pretty much all been found, why bother to look?
In 2011, at National Geographic Live!, Lee told the story of how in 1997, determined to break out of that state, he began looking for fossils in places he thought he knew well. He used what at the time was an amazing, cutting-edge technology: a hand-held GPS system with an accuracy of 15 meters, and just-released high resolution satellite photos from NASA with a resolution of thirty meters per pixel. He then set about finding and exploring previously unknown cave sites and fossil sites.
By 2007, there was Google Earth, and it led him to a tiny, never-before-visited cave site called Malapa. He let his son Matthew tell what happened next.
Matthew Berger [14:57]
I’m Matthew Berger, I’m twelve years old, and this is the lightning-struck tree where I discovered one of the coolest things in the world.
What happened was my dad had found this site two weeks before, and he had said he had found some antelope fossils at it, so he wanted to take me out to see if I could find anything.
So two weeks later we came out with myself, my dog Tau, and his colleague Job Kibii, and we came to the site and he said, “Go look for fossils.” So I ran off down the path trying to catch my dog Tau, and as I was running, I tripped over a log in the middle of the path, and as I was tripping I saw a fossil sticking out of a rock, right next to this tree. And when I got up to dust all the dirt off myself, I picked up the rock and there was the clavicle of a hominid sticking out. But at first, I didn’t know it was a clavicle. I though it was a antelope fossil. So I called my dad over and about five meters away he started swearing, and I was like, “What did I do?” and he’s like, “Nothing, nothing, you found a hominid!”
And I was pretty shocked, but I wasn’t as shocked as I would be when it actually got released, because I never knew it was gonna be that big, I just thought it was gonna be just another fossil find.
This was a previously unknown species, Australopithecus sediba, and Malapa proved to be one of the richest hominid fossil sites ever discovered … until 2013 and Rising Star.
Lee Berger [27:30]
We have not explored this planet. We have not understood what we were walking on. We must take the technology of the 21st century, we must take this lethargy of the idea that we have found all the cool stuff, and we must prepare everyone in this world for discovery. We must teach the children that there’s more out there—because there is.
Links
Berger, Lee R., et al. “Homo naledi, a new species of the genus Homo from the Dinaledi Chamber, South Africa.” eLife 4 (2015): e09560.
Dirks, Paul HGM, et al. “Geological and taphonomic context for the new hominin species Homo naledi from the Dinaledi Chamber, South Africa” eLife 4 (2015): e09561.
National Geographic, This Face Changes the Human Story. But How? Cover story. September 10, 2015.
Rising Star Expedition blog, (1) most recent posts first, (2) In chronological order, oldest posts first.
Berger, Lee, Excavating in the Dinaledi Chamber. Facebook post. September 21, 2015. Describes how they recorded the original locations of everything they removed, given that traditional archaeological methods of doing that—string grids and theodolite photography—were unusable in the chamber. (I saw this facebook post just as I was about to post this article. He talks about using the 3D scanner, and even mentions the barefoot protocol.)
Mead, John. Rising Star Interview Dr. Lee Berger & Dr. John Hawks. YouTube. September 10, 2015. A 33-minute interview, posted the day of the Homo naledi announcement, in which they discuss extensively why they concluded that the remains in the chamber were put there deliberately, and the implications of that for how we understand ourselves, our earliest human relatives, and the lineage that led to us.
Mead, John. Rising Star Interviews with the members of the advance team: Marina Elliott, Elen Feuerriegel, Alia Gurtov, Lindsay Hunter, Hannah Morris, Becca Peixotto. YouTube. Summer 2015. They talk about their experiences with the Rising Star project, prior to the announcement of Homo naledi on September 10. Good stuff.