Preserved Tissue on 2-Million-Year-Old Human Ancestor May be Oldest Skin Ever Found
A team of scientists investigating early human species in an ancient cave near Johannesburg, South Africa, have revealed that preserved tissue found on a 2-million-year-old fossil may be the oldest sample of human skin ever recovered. The finding may reveal new information about the species and about our human origins.
The sample came from the remains of 4ft 2 inch tall male juvenile belonging to the species known as Australopithecus sediba, which were recovered in 2008 within an ancient cave in the Malapa Nature Reserve, situated in the ‘Cradle of Humankind World Heritage Site’. The area is important as nearly a third of the entire evidence for human origins in Africa comes from just a few sites in this region.
The Malapa site, August 2011 site of discovery of Australopithecus sediba. Photo by Lee R. Berger (Wikimedia Commons)
Professor Lee Berger, an anthropologist at the University of Witwatersrand in Johannesburg, who has been leading the excavation, noticed that the skull, which was embedded in cemented rock, had thin layers around it that looked like preserved soft tissue.
The cranium was examined using 3D scanning, microscopy and chemical analysis in an attempt to find out what the thin layers were made of.
“We found out this wasn't just a normal type of rock that they were contained in - it was a rock that was preserving organic material,” said Professor Berger. “Plant remains are captured in it - seeds, things like that - even food particulates that are captured in the teeth, so we can see what they were eating. Maybe more remarkably, we think we've found fossil skin here too.”
Professor Berger, who made his comments in an interview with the Naked Scientists, explained that Australopithecus sediba was first discovered after his son Matthew stumbled upon a fossilised bone in the Malapa Nature Reserve near Johannesburg.
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Matthew Berger moments after the discovery of the clavicle of Australopithecus sediba at the Malapa site. Photo by Lee R. Berger (Wikimedia Commons)
Australopithecus sediba was identified as a new species based on fossil remains from six separate skeletons discovered together at the bottom of the Malapa Cave, where they apparently fell to their death, and have been dated to between 1.977 and 1.980 million years ago.
Berger believes that the recently classified Australopithecus sediba species could very well be the most recent ancestor to the Homo genus. This is based on a number of characteristics, some which are more humanlike that those seen in Homo habilis, considered by many scientists to be the earliest member of our genus. At the same time, Australopithecus sediba also shows similarities to much more primitive primates.
Australopithecus sediba, two fossils of which are shown on the left and right, are thought to have been a transitional species between older Australopithecus, like Lucy in the middle, and later Homo species. Image compiled by Peter Schmid courtesy of Lee R. Berger. (Wikimedia Commons)
Researchers have spent decades trying to trace back the family tree of modern humans. However, the problem comes when new discoveries, such as Berger’s findings in Malapa, do not serve to clarify the picture but rather to muddy the waters even further. Each ancient species appears to have unique combination of traits that make them seem so close and yet so far from being a true human ancestor.
The fact that A. sediba was a completely unknown species until just a few years ago, shows us how much we don’t know and how much more there must be to discover. Berger stresses that our understanding of human evolution is nowhere near complete. We haven't even finished looking at the things we thought we knew, he says.
Featured image: Skull of Malapa hominid 1 (MH1) from South Africa, named "Karabo". The combined fossil remains of this juvenile male is designated as the holotype for Australopithecus sediba. (Wikimedia Commons)