Matthew Diebel

USATODAY

Homo sapiens – that’s us and our direct ancestors, and long thought to be pretty much the only show in town for hundreds of thousands of years – had a rival cousin as recently as 236,000 years ago, according to South African scientists.



The species, Homo naledi, was discovered in caves near Johannesburg in 2013, and the researchers have now announced that some of the bones are less than a quarter of a million years old, which would mean that the primitive humans – who had much smaller brains than homo sapiens – were running around in Africa at the same time as our direct forebears.

And not only that, but Homo naledi also appear to have engaged in the relatively advanced practice of burying their dead.

In three studies published in the journal eLife on Tuesday, the team, led by Professor Lee Berger of the University of the Witwatersrand in Johannesburg, said it had also discovered a second cave in in South Africa's Rising Star cave system containing remains of other Homo naledi, which included one of the most complete skeleton of the species ever found as well as the bones of a child.

“This is a humbling discovery for science,” said Berger, a paleoanthropologist. “It's reminding us that the fossil record can hide things … we can never assume that what we have tells the whole story.”

The study also concluded that the discovery of the second, more remote, chamber reinforced the team’s belief that Homo naledi buried the bodies of the deceased in their communities, considered to be a sophisticated custom.

In a statement, John Hawks, another researcher on the studies, said that the discovery of the second set of remains "adds weight to the hypothesis that Homo naledi was using dark, remote places to cache its dead. What are the odds of a second, almost identical occurrence happening by chance?"

Hawks said the team believes that members of the species purposefully placed their dead in the chamber, a behavior would indicate raised intelligence and a developed culture.

The second cave, known as the Dinaledi (“star” in the local language), was so difficult to access that the team had to use an all-women cadre of petite spelunkers to enter it, the Washington Post reported.

After the naledi species was revealed in 2015, it had been expected that the remains would be about 2 million years old, at which time other human ancestors, such as Homo rudolfensis and Homo habilis, were wandering around Africa. According to the science website Phys.org, experts had predicted that the fossils should be from around the same era; instead, DNA analysis found that the remains in the caves are about a tenth of that age.

In one of its papers, Berger’s team also make the claim that the naledi emerged about 2 million years ago, just about when the Homo genus was getting started and was around long enough to be on the continent with near-modern humans.

The discoveries have encouraged other scientists to rethink human evolution.

Rick Potts, director of the Human Origins Program at the Smithsonian Institution's National Museum of Natural History, told the Washington Post that the discovery should prompt people to question the familiar image of a stooped chimp-like creature evolving into an upright, modern human.

“We've had for so long this view that human evolution was a matter of inevitability represented by that march, that progress,” he told the paper. “But now that narrative of human evolution has become one of adaptability. There was a lot of evolution and extinction of populations and lineages that made it through some pretty tough times, and we're the beneficiary of that.”