The scientific team that made headlines in 2015 by unearthing a previously unknown ancient human relative says its latest discoveries could change the way we look at human evolution.
The findings, which are being published this week in the scientific journal ELife, include the discovery of a second chamber of fossils of the small-brained hominin Homo Naledi -- and the surprisingly young age of the fossils.
‘Young’ bones
The bones found in these fossil-rich caves northeast of Johannesburg were originally thought to be more than 2 million years old, making them a candidate as a possible human ancestor -- maybe even, some in the scientific community mused, the elusive “missing link” between higher apes and humans.
However, independent tests of the first group of fossils put them between 236,000 and 335,000 years old, which means that they lived at the same time as ancient humans. Scientists say they believe this species originated much earlier, and survived for more than 2 million years.
The team’s leader, paleoanthropologist Lee Berger of Johannesburg’s University of the Witwatersrand, said that could mean some artifacts and actions attributed only to early humans -- things like tools, adornments and burial of the dead -- might not be our work after all.
“That date corresponds with when most archeologists and paleoanthropologists -- and genetics -- is suggesting we see the rise of modern humans,” he said. “And a lot of people argue that that rise was right here in southern Africa. But now there’s another species here. Everything is very complex from this moment onward.”
The ‘Chamber of Secrets’
Scientists also hailed the discovery, just 100 meters from the original cave where fossils were found, of a similar narrow, hard-to-access chamber containing remains -- raising the tantalizing possibility that Naledi may have methodically disposed of its dead.
“This likely adds weight to the hypothesis that Homo naledi was using dark, remote places to cache its dead,” said anthropologist John Hawks of the University of Wisconsin-Madison. “What are the odds of a second, almost identical, occurrence happening by chance?”
Among the cache of fossils in the second chamber, Berger says, is a nearly complete adult skull, which scientists nicknamed Neo -- the SeSotho word for “gift.”
“Neo gives us a real look at what the body and face of this incredible new species looks like. It tells us we were a little bit wrong,” he said. “We had guessed there was a little bit more nose. Actually Homo Naledi has a little flatter, even more primitive face than we thought, which is one of the reasons we placed it further back in the family tree of relatedness to early hominids. It’s clear that parts of Homo Naledi from Neo are very, very, very primitive, amongst the most primitive we’ve seen in hominids. And other parts are surprisingly advanced. They, in fact, are comparable mostly with us, as humans.”
A ‘Golden Age’
Hawks, an author on all three of this week’s scientific papers, says this discovery could start a new era in his field.
“There is so much unexplored territory out there; there are so many discoveries yet to be made that we’re now just beginning what I think is the golden age,” he told VOA. “We’re going to see more chambers like this, more fossil discoveries, and they’re going to tell us things we don’t expect to see now.”