August 9, 2014
As a paleoanthropologist, I study the human fossil record in order to understand human evolution. I am currently spending a little over three weeks in South Africa working in the “Rising Star Workshop” led by Prof. Lee Berger of the University of the Witwatersrand in Johannesburg. To my knowledge, this workshop (the brainchild of Prof. Berger) is the first of its kind. Its purpose is to bring together a large (30+ people) international team of scientists to analyze the over 1,700 dental, cranial, and postcranial (i.e., bones of the trunk and limbs) pieces of fossil hominins (“hominins” are those animals more closely related to us than to chimpanzees) recovered from the Rising Star Cave System in the Cradle of Humankind World Heritage Site, northwest of Johannesburg, in 2013. The researchers here with me in Johannesburg are from all over the world – daily I interact with scholars from Italy, Spain, Ethiopia, Australia, England, Switzerland, Tanzania, China, Canada, and of course, the US and South Africa. What makes the Rising Star Workshop so unique is that most of these colleagues are early-career scientists – i.e., advanced graduate students and recently-minted PhDs. My task as one of the senior scientists on the project is to provide guidance and advice to the junior researchers, with the ultimate goal being a group of papers describing the Rising Star fossil hominins that will appear in major peer-reviewed journals. More importantly, these junior scholars will be first authors on the vast majority of the contributions.
The workshop experiment is a huge success – the excitement in the fossil vault is palpable as we all pore over these fossil human remains, each of us focused on our anatomical specializations, but also “cross-fertilizing” by sharing ideas and data with scientists working on different parts of the analysis. The Rising Star Cave fossils are currently of uncertain species assignation and of unknown date, but they are remarkable in that they represent so many remains of multiple individuals that accumulated over a seemingly short period of time (and many more fossils remain in the cave, awaiting future excavation – the 1,700 fossils we are currently studying all come from a one-meter-by-one-meter square with a cumulative depth of ca. 20 cm).
The workshop is also the first step toward changing the culture of paleoanthropology. Too often in my field, scientists hide fossil discoveries away for decades at a time, refusing access to all but a few of their closest friends and associates. This is antithetical to good science. Professor Berger, who has now discovered more fossil hominins than anyone else in South Africa, has for several years now had a completely “open-door” policy allowing anyone who wants to see the fossils access to study them, and we also promise to publish our findings, along with reams of raw data, within the year, facilitating further inquiry into human evolution. South Africa is a relatively new area of study for me, since my traditional line of research since the 1990s revolves around the Neandertals and the earliest modern humans who succeed them in Europe (the so-called “Cro-Magnons” – see the report below on the French site of Regourdou). But in 2010 I was invited by Prof. Berger to come to South Africa to study fossil material from the then newly-discovered site of Malapa – two million year-old hominin fossils that were classified as a new species of the genus Australopithecus – Australopithecus sediba. With the volume of the new Rising Star material, it is likely that I will be spending more and more time in South Africa in the future!
August 9, 2014
This has been a busy summer for me! I have just now returned from my second field excursion, this one in France, where I was working in the Neandertal site of Regourdou. Regourdou is located in the beautiful Dordogne Region of southwestern France, an area of limestone cliffs, rock shelters, caves, scenic river valleys, and shady forests. It is also a region famous for its Paleolithic sites, with hundreds of sites featuring cultural remains left behind by (and bones of) Neandertals and early modern humans – these latter humans are colloquially known as “Cro-Magnons” - named after the site of Cro-Magnon, in the town of Les Eyzies (where I and the team stayed).
A little background may be warranted on the site of Regourdou. The site, located outside the small town of Montignac, ca. 11 miles from Les Eyzies, was discovered in 1954 by French farmer Roger Constant. Mr. Constant couldn’t help but notice all of the thousands of visitors lining up to see the cave art in Lascaux Cave, which had been discovered in 1940, and was located just a stone’s throw from his property. Mr. Constant had found a natural “chimney” leading down into a deep cavern on his own property, and thought that if he dug his own entrance into Lascaux, he could get “a piece of the action” and charge admission to visitors. He never did find the back entrance to Lascaux, but he did find many fossilized bear bones, including several bear skulls, and in 1957, he found a partial skeleton of a Neandertal. As a result, Regourdou is one of the sites that fed into the notion of Neandertals having “Bear Cults” where they cached bear skulls in special “religious” chambers in caves. Noted French paleoanthropologists François Bordes, Jean Piveteau, Eugène Bonifay, and Bernard Vandermeersch participated in extensive excavations at the site in the 1960s.
Mr. Constant died in 2002, and his niece Michelle now owns the property and runs the visitor center, restaurant, and small museum associated with the site, which now resembles a giant hole in the ground, and has a neighboring “zoo” with live brown bears (again, taking advantage of the notion of Neandertal “Bear Cults”). She has also encouraged researchers to come back to do more work at the site, which has been largely abandoned by scientists since the 1960s. One of my friends and colleagues, whom I have known since we were both graduate students back in the early 1990s, is Dr. Bruno Maureille of the University of Bordeaux. Michelle invited Bruno to reopen the site, and he in turn invited me to participate in a joint project to start new excavations at Regourdou. Our objectives are: 1.) to categorize the nature of the site. In other words, is it a Neandertal living site, or could it instead be some kind of hole into which Neandertals fell and died – a kind of natural trap? 2.) to redate the site using new technologies. Based on dates on material previously recovered at Regourdou, the site is thought to be too old to date with radiocarbon. However, a relatively new dating method, optically-stimulated luminescence, could provide an accurate absolute date for the site, and tell us how old the site is. It is possible, based on the presence of warm-weather fauna, that the site dates to the last interglacial, ca. 120,000 years ago, which would make it among the earliest Neandertal sites known. Finally, 3.) we hope to recover the cranium of the Regourdou I individual. This individual is represented by a mandible (lower jaw), clavicles, vertebrae, ribs, and sternum, arm and hand bones, pelvic bones, and some of the lower limb and foot bones, but its cranium was never recovered. Dr. Maureille and I are convinced it is still there, and we hope to find it.
This year was a cleanup year; excavations will begin in earnest in the summer of 2015. For now, our team is breaking up large pieces of rock (using jackhammers, pick-axes, hammers, and in some cases, explosives) from a sterile (i.e., no artifacts or fossil bones are found in it) layer. Once the pieces of rock are small enough, we use a system of buckets on pulleys to haul the material out of the site. Members of our team also used old photographs and modern scanning technology to pinpoint where the 1963 datum point lay. A datum point is a 3D point in space chosen by archaeologists, to which all recovered artifacts are referred; e.g., the center of recovered bone “A” lies 250 cm below datum, 400 cm E of datum, and 200 cm S of datum). We verified the position of the datum point just last week!
To sum up, this last year was the best field season I have ever had as a researcher, and I am excited about future work in both countries, as well as the possibility of involving Tulane students in my field research.