Tuesday, May 9, 2017
Mercyhurst University anthropologist Heather Garvin, Ph.D., a member of the international team of scientists that discovered a new species of human ancestor in South Africa called Homo naledi a year and a half ago, plays a pivotal role in identifying a new set of remains from the Rising Star cave system.
The research, published today in two papers in the journal eLife (elifesciences.org), presents the long-awaited age of the naledi fossils from the Dinaledi Chamber and announces the new discovery of a second chamber – the Lesedi Chamber – in the Rising Star cave system, containing additional specimens of Homo naledi. These include a child and a partial skeleton of an adult male with a remarkably well-preserved skull that scientists have named “Neo”.
For her part, Garvin, a co-author on one of the papers, was charged with estimating Neo’s brain size using 3D scans. As a young scientist with degrees in anthropology, zoology, biological and forensic anthropology, and functional anatomy and evolution, Garvin’s research in human skeletal variation and macro‐ and micro‐evolutionary events continues to play an important part in her role as a member of the scientific team.
“The brain size came out to 610cc, which is larger than the other two Homo naledi skulls from the Dinaledi chamber (which were 465 and 560cc), but still less than half our brain size,” Garvin said. “Overall, Neo appears to be a larger male, but all of the features on the skull and the rest of the bones indicate that these fossil remains are also Homo naledi.”
The archaeologists on the team still support the hypothesis that Homo naledi was using the cave system to deposit their dead, she added.
Other research released today indicates the original Homo naledi remains from the Dinaledi Chamber were startlingly young in age. Homo naledi, which was first announced in September 2015, was alive sometime between 335 and 236 thousand years ago. This places this population of more primitive, small-brained hominins at a time and place alongside much more human-like species of Homo. This is the first time that it has been demonstrated that another species of hominin survived alongside the first archaic humans in Africa.
“To me, both the date and additional fossil remains are amazing additions to the enigmatic story of Homo naledi,” Garvin said. “To have a fossil hominin with such a mixture of primitive (ape-like) and derived (human-like) features running around so recently in our timeline proves that there's much more to the story of our evolutionary past than we may have assumed.”
Garvin said the evolution of our human lineage was not a simple linear process; rather, there were likely numerous off-shoots of species.
“The combination of the smaller-brain size in this relatively recent hominin species and mysterious deposition in this cave system also leads to a number of questions regarding possible culture in these smaller-brained ancestors,” Garvin said. “It's these questions that continue to drive the science.”
The Rising Star Expedition is expected to continue as many more fossils remain to be unearthed and more questions are yet to be answered, Garvin said.
Garvin earned her master’s degree in biological and forensic anthropology from Mercyhurst, and her doctorate from Johns Hopkins University.