2-Million-Year-Old Human Ancestor Preserved Tissue Maybe the oldest skin ever discovered
The remains of six skeletons are believed to have uncovered fossilised skins of an ancient human ancestor, who lived two million years ago.
Anthropologists believe they have found the preserved skin tissue of an early human species known as Australopithecus sediba in an ancient cave near Johannesburg, in South Africa.
It could be the oldest example of human soft tissue to ever be found and is set to reveal new details about what this now-extinct species of human was like. Scientists who have been leading the excavation, which began with the discovery of the remains of a 4ft 2 inch tall male juvenile in 2008, believe they have also found the remains of the ancient humans’ last meals still preserved in their teeth.
Professor Lee Berger, an anthropologist at the University of Witwatersrand in Johannesburg, who has been leading the excavation, said: ‘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.
‘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, discovered the first remains of Australopithecus sediba in 2008 after his son Matthew stumbled upon a fossilised bone in the Malapa Nature Reserve near Johannesburg.
They later excavated an almost complete skull, together with shoulder bones, a hand, wrist bones and ankle bones. Professor Berger announced the discovery to the world in 2010. He described the early human as a new species that he called Australopithecus sediba and is thought to be a transitional species between earlier Australopithecus species and early Homo species.
However, the discovery has been controversial, with some anthropologists insisting that the remains do not belong to a new species at all, but are in fact a combination of several different early humans.
But since 2010, Professor Berger and his team have unearthed the remains of five other individuals at the Malapa site, including two almost complete skeletons along with a variety of animal fossils.
These, he insists, have helped to confirm the attribution of Australopithecus sediba as a unique species. The researchers believe the site was once an ancient cave that perhaps contained a pool of water that attracted a range of animals that fell in. The cave later collapsed, preserving everything down there.
On two fragments of hominid skull excavated from the ground, however, Professor Berger and his team noticed an unusual surface. Embedded in the cemented rock, known as breccia, that surrounded the cranial remains of the original fossil and a second found at the site were some small, thin layers that looked like preserved soft tissue. Professor John Hawks, an anthropologist at the University of Wisconsin Madison who is helping lead the project, said: ‘They do not appear to be skin impressions within the matrix, they appear to be thin layers that are a different substance from the surrounding matrix.
‘In the initial CT-scanning of the MH1 cranium, team members noticed an area where the matrix surrounding the skull appeared irregular.
As they prepared this out, it became clear that the breccia itself had pulled away from the cranium across a small region, and the breccia had a thin layer of material at its surface there. This is not the outer table of the bone – which is intact in the corresponding area – nor is it apparently an impression of the bone. An additional section of possible soft tissue emerged as the female MH 2 mandible was prepared.
‘Upon magnification, these pieces do appear to have a structure.’
The team have been using 3D scanning, microscopy and chemical analysis in an attempt to examine the samples. The researchers also hope to find out whether, if it is soft tissue, it had been dried or soaked in water as it was preserved in the rock. The remains of plants and insects have also been found preserved in the cement-like breccia alongside the skeletons. It is thought that sediment in the bottom of a pool of water may have helped to protect the organic material from bacteria that would have caused them to rot and break down.
Professor Berger and his team are now trying to create a live laboratory on top of the site so they can continue working on the fossils while they are still in the ground without damaging them. The laboratory will also have a platform that will allow members of the public to look down into the site where the remains are being excavated. Professor Berger said he had no idea how many more individuals they may find at the site. Speaking to Naked Scientists said: ‘That’s why we’re building this laboratory over the top that we’ve begun excavation.
‘But so far, what is exposed on the surface have been two main skeletons and at least the remains of 4 other individuals that we found so far. But every time we open up a little bit of rock here and move a little bit of dirt, we see someone new. We’re introduced to another one of these people that died 2 million years ago.
‘The cave is like a big swimming pool that you’d fill up with concrete throwing bones intermediately into it and in this case, some of those and in fact, quite a lot of them were skeletons of this early human ancestor species.’ He added that his team were still attempting to piece together exactly how these species fit into the evolutionary history of humans.
He said that the skeletons they found have many features similar to Homo – such as the shape of their pelvis, hand and teeth, but they also have quite primate-like features too. Professor Berger added: ‘They walk on two legs. They would probably only be standing about 1.3 metres tall. They have also been more lightly built. They would’ve been quite skinny.
‘They had longer arms than we do, more curved fingers. So, they’re clearly climbing something. They also would’ve moved a little different. Their hips were slightly different than ours and their feet are slightly different.
‘So, their gait would’ve probably been a more rolling type gait, slightly different from the more comfortable long-distance stride we had. As they got closer to you, you’d be struck by for the most obvious thing which would be, their heads are tiny.’