New spin on Homo Naledi research
Laboratories around the world confirm that Homo Naledi lived about 300 000 years ago
THE dating process which has placed Homo Naledi’s age at about 300 000 years may well have turned archaeology in Africa on its head. Six dating methods, involving 20 researchers in 10 laboratories on four continents, were used to determine the true age of the hominid species, which rose to prominence two years ago.
Following the 2015 announcement of the discovery of the fossilised remains of Homo Naledi, by Wits University’s Professor Lee Berger, scientists worldwide criticised the fact that such fossils had not been dated.
Yesterday, Berger’s team revealed Homo Naledi was between 236 000 to 335 000 years old.
The announcement, carried in the international journal eLife, and made at the Cradle of Humankind centre at Maropeng, revealed a new “mystery”.
The surprisingly young age of the Homo Naledi species, which lived at the site of the Cradle of Humankind, had resulted in a “whodunnit”, Berger said, raising questions about whether humans in southern Africa were the first hominids to use tools.
Sub-Saharan Africa has many tools from about 300 000 years ago at archaeological sites, such as sharp blades that could have been used to make spears.
These tools were always assumed to have been created and used by humans.
But there are no fossils to show humans were in southern Africa at
that time, despite the presence of tools from that period.
The dating of Homo Naledi meant that when archaeologists examined the sites where Stone Age tools were found, they needed to ask whether the tools were created by humans or Homo Naledi, Berger and colleagues said.
“Archaeologists have classically said [these tools are from modern humans]. But right now, the best possible fossil evidence in that time frame in which the tools were created [points to] Homo Naledi,” Berger said. “What we do know is that a lot of archaeology exists from that time period, but there isn’t a great deal of fossil evidence for modern humans.
“As scientists we have to use the best evidence in front of us, and not just fairytales.”
Determining Homo Naledi’s age was not easy, as there was the possibility of damaging the fossils.
Another difficulty was that the cave in which Homo Naledi was found had no fossilised animals or plants with which to do age comparisons, Professor Paul Dirks, of James Cook University, who headed up the dating project, said.
To solve the mystery, scientists dated the cave, the stones there and geometrical formations the fossils were found in, using more than one method.
Laboratories in Europe, Australia and South Africa were used.
In an almost unprecedented move, scientists sent the same samples of teeth to different international laboratories, who used the same dating method, Electron Spin Resonance, without the scientists knowing they were working on the same project.
This was to see if they received similar results, and added to the rigorousness of the tests.