September 18, 2015
Lucas Delezene was only 15 years old when he discovered what he wanted to do with his life. His mother took him to the library after school as she had done so many times before. Delezene aimlessly wandered through the biology and nature sections as he always did, until he came across a book he had never read before: “Origins Reconsidered” by Richard Leakey. This was his first introduction to biological anthropology.
“The book stuck with me enough that when I was accepted into college I wrote a letter to my soon-to-be freshman roommate that Richard Leakey was my favorite anthropologist,” said Delezene with a smile. “I was such a dork.”
After receiving degrees in both biology and anthropology from Emory University in Atlanta, Delezene became the assistant professor of biological anthropology at the University of Arkansas. But it was in the spring of 2014 that Delezene encountered the opportunity that would change his career forever.
Delezene had already heard about the discovery of over 1,500 bones in a small cave outside of Johannesburg, but he didn’t think much of it, telling himself it was for someone else to work on. But after seeing posts splattered across his Facebook page about the assembly of an international team of scientists to work together to analyze the fossils found and identify the species, Delezene decided to apply.
“Lucas was an easy pick,” said Dr. Steve Churchill, professor of evolutionary anthropology at Duke University, and a senior scientist on the project. “He was a young, bright guy, early in his career and we knew he could bring in cutting-edge techniques that the senior scientists had never used.”
Over 60 scientists were brought together from across the globe, all with different specialties, but all very early in their careers. These scientists spent two years examining the 15 near complete skeletons that had been excavated from the site, trying to identify the species.
The scientists were split into different anatomical teams based on their specialties by Professor Daryl de Ruiter, a professor of anthropology at Texas A&M University.
As an expert on dental evolution, Delezene was put in charge of what he referred to as “the tooth team,” a group of about five scientists who examined only the teeth of the species. There was also a cranial team, hand team, leg team and so forth. Each team would spend their days examining their different specialties, and then they would all meet together in the evenings to discuss their observations.
“Me and the other senior scientists tried to stay away when they would get together to discuss their findings,” said de Ruiter. “We didn’t want to influence them, we wanted to see how the younger scientists researched differently from us.”
Delezene continued to teach at the U of A during the school year and would travel to South Africa for months at a time in the summers. All of the fossils are kept near the original site, so Delezene created replicas of the teeth so he could continue his research from Fayetteville.
He also explained that it was not simply the teeth that indicated a new species, but the way the skeleton went together as a whole. Some of the teeth he examined were similar to fossil records, but the small brain size, or curled fingers or short legs all belonging to the same body was like nothing ever found.
“I spent every free moment I had examining every fossil tooth I could get my hands on, trying to match it the dental anatomy of a known human ancestor,” said Delezene. “But there was nothing exactly like it.”
Together, the entire research team agreed this creature was unlike anything they had ever seen. On Sept. 11, senior scientists announced the new species and gave it the name Homo naledi.
This is the largest and most significant discovery of early human ancestors ever made on the continent of Africa, Delezene said. Though surprisingly, these fossils were found less than 900 yards from some of the most well known fossil hunting territories in South Africa.
“It’s a reminder to me to keep an open mind and to be a little less confident about some of the things that I thought about the fossil record,” Delezene said. “And working with the material has reinvigorated my passion for studying the human past.”
Now that the discovery and announcement of a new species has been done, the research will need to go even more in depth. For now, excavation of fossils from the cave has stopped. Scientists want to answer the questions they still don’t know the answers to such as age and diet before bringing out any new fossils.
Delezene also explained that the team wants to leave some of the fossils in the ground for future generations to excavate themselves. As technology continues to develop and anthropology evolves, the scientists want later generations to be able to make their own conclusions about the new species.
One of the first things researchers are still trying to identify is how these bodies got into this small cave in the first place. In similar caves located not far from the site, it is common to see bite marks on bones, animal fossils and other evidence that these people were dragged into a cave by a wild animal. However, Homo naledi showed no such traits.
“These bones were found all cramped in one small crevice with no tools, no animals, nothing,” Delezene said. “Just complete human skeletons, which might suggest a burial ground of sorts.”
However, Delezene was quick to clarify his interpretation of the perceived burial ground. Burying the dead is a habit exclusively done by humans. The skeletons they’ve put together indicate a brain size one-third the size of a human’s today, making it doubtful the species would have been advanced enough to have a ritual for the dead. Delezene theorizes the possibility of foul play or a massacre leading to the dumping of dozens of bodies. Though with a smile he clarified again, this is just his theory.
For the remainder of the school year, Delezene and Professor Peter Ungar, chair of the UA anthropology department, will work together to attempt to reconstruct the diet of this species.
In summer 2016, Delezene is looking forward to returning to South Africa with one of his collaborators, Professor Matthew Skinner of the University of Kent. Together, Delezene and Skinner will assemble a completely new team of young scientists to join the project to give a new perspective on the findings.