A sample of Dinaledi skeletal specimens recovered from the cave. Source: Wikimedia Commons
A team of archaeologists in South Africa has found a new species of hominid with a tiny brain, opening the door to a new way of examining humanity’s ancient ancestors.
Modern humanity, or Homo sapiens, is currently the only living species in its genus. As recently as 20,000 years ago, other species belonged to the genus Homo. These extinct species, our immediate ancestors and their close relatives, are referred to as ‘hominins’ (1). Sites in Tanzania and the Olduvai Gorge have remnants of the oldest hominin remains, including footprints estimated at 3.6 million years old (2).
A group of archeologists led by Lee Berger have found a strange set of hominin fossils in the Dinaledi Chamber in the Rising Star cave system in South Africa (1).This discovery of 15 individuals, consisting of 1,550 bones, represents the largest fossil hominin find on the African continent. While similar to those of other extinct species, these fossils are unique in their diminutive skull size and jaw shape (1). This newly discovered species has been dubbed Homo naledi after the cave where it was found; “naledi” means “star” in the local South African language Sesotho.
A series of narrow passageways, tight fractures, and steep climbs eventually leads to the fossil-bearing Dinaledi Chamber in the cave. Once there, archeologists excavated fossils from soft clay-rich sediments that had collected in the chamber over time. However, the vague age of the fossil site complicates matters when examining bones. The fossils could be a direct ancestor of humanity, or could be anywhere from 20,000 to 2 million years old.
The assemblage in the cave is unusual because of the large number of fossils discovered so close together in a single chamber deep within the cave system (1). While initial evidence indicates deliberate body disposal in the single location, the true reason is still unknown. Paul Dirks has formulated multiple different explanations as to how the bones came to rest where they did, ranging from Homo Naledi simply living in the caves to predators bringing in their remains for a safe meal from competitors (1).
Scientists believe there are potentially thousands of remains of the
A sample of Dinaledi skeletal specimens recovered from the cave. Source: Wikimedia Commons
newly discovered species hidden within the cave. By examining the passages further, Berger and his team hope to determine whether multiple species of humans lived there over time, or if Homo Naledi coexisted with the larger brained Homo sapiens.
References:
- Dirks, Paul HGM, Lee R Berger, Eric M Roberts, et al. 2015 Geological and Taphonomic Context for the New Hominin Species Homo Naledi from the Dinaledi Chamber, South Africa. eLife 4. http://elifesciences.org/lookup/doi/10.7554/eLife.09561, accessed September 20, 2015.
- University of Colorado Anschutz Medical Campus. (2015, September 10). Ancient ancestor of humans with tiny brain discovered: Homo naledi raises intriguing questions about our evolutionary past. ScienceDaily. Retrieved September 20, 2015 from www.sciencedaily.com/releases/2015/09/150910084610.html
Image notes: “Homo naledi skeletal specimens” by Lee Roger Berger research team – http://elifesciences.org/content/4/e09560. Licensed under CC BY 4.0 via Commons – https://commons.wikimedia.org/wiki/File:Homo_naledi_skeletal_specimens.jpg#/media/File:Homo_naledi_skeletal_specimens.jpg