New Research Shows Early Ancestor May Have Coincided with Modern Humans
Homo naledi’s surprisingly young age opens up more questions on where we come from
05/09/2017
''Neo'' skull from Lesedi Chamber (left) with DH1 Homo naledi skull from Dinaledi
Chamber (right). Homo naledi was alive sometime between 335,000 to 236,000 years ago.Photo Credit: John Hawks, Wits University.
BATON ROUGE – Scientists today announced that the Rising Star Cave system has revealed
yet more important discoveries, only a year and a half after it was announced that
the richest fossil hominin site in Africa had been discovered, and that it contained
a new hominin species named Homo naledi by the scientists who described it.
The age of the original Homo naledi remains from the Dinaledi Chamber has been revealed
to be startlingly young in age. Homo naledi, which was first announced in September
2015, was alive sometime between 335,000 and 236,000 years ago. This places this population
of primitive, small-brained hominins at a time and place that it is likely they lived
alongside Homo sapiens. This is the first time that it has been demonstrated that
another species of hominin survived alongside the first humans in Africa.
The research, published today in three papers in the journal eLife, presents the long-awaited
age of the naledi fossils from the Dinaledi Chamber and announces the new discovery
of a second chamber in the Rising Star cave system, containing additional specimens
of Homo naledi. These include a child and a partial skeleton of an adult male with
a remarkably well-preserved skull.
The new discovery and research was done by a large team of researchers from the University
of the Witwatersrand, or Wits, in Johannesburg, South Africa; James Cook University,
Australia; the University of Wisconsin, Madison; LSU; and more than 30 additional
international institutions have announced two major discoveries related to the fossil
hominin species Homo naledi.
The team was led by Wits Professor Lee Berger, who is a National Geographic Explorer
in Residence. The discovery of a second chamber has led the team to argue that there
is more support for the controversial hypothesis that Homo naledi deliberately disposed
of its dead in these remote, hard to reach caverns.

LSU Department of Geography & Anthropology Assistant Professor Juliet Brophy examined
the teeth of the early human ancestors, which led to the discovery of the new species,
Homo naledi.Photo Credit: Juliet Brophy, LSU.
“My colleagues and I examined the teeth from the second chamber. In particular, we
described the lower left deciduous, or juvenile, second molar, or dm2. We compared
it to the assemblage from the Dinaledi Chamber as well as other specimens in the genus
Homo. The deciduous tooth is nearly identical to that of the teeth from Dinaledi.
Furthermore, the morphology of the juvenile and adult permanent teeth support their
taxonomic designation to H. naledi,” said Juliet Brophy, LSU Department of Geography
& Anthropology assistant professor and co-author of the paper titled, "New fossil remains of Homo naledi from the Lesedi Chamber, South Africa."
The dating of Homo naledi is the conclusion of the multi-authored paper titled, “The age of Homo naledi and associated sediments in the Rising Star Cave, South Africa,” led by Professor Paul Dirks of James Cook University and Wits.
The naledi date is surprisingly recent. The fossil remains have primitive features
that are shared with some of the earliest known fossil members of genus Homo rudolfensis
and Homo habilis, which are species that lived nearly two million years ago. On the
other hand, however, it also shares some features with modern humans. After the description
of the new species in 2015, experts had predicted that the fossils should be around
the age of these other primitive species. Instead, the fossils from the Dinaledi Chamber
are barely more than one-tenth that age.
“The dating of naledi was extremely challenging,” said Dirks, who worked with 19 other
scientists from laboratories and institutions around the world, including labs in
South Africa and Australia, to establish the age of the fossils. “Eventually, six
independent dating methods allowed us to constrain the age of this population of Homo
naledi to a period known as the late Middle Pleistocene.”
The age for this population of hominins shows that Homo naledi may have survived for
as long as 2 million years alongside other species of hominins in Africa. At such
a young age, in a period known as the late Middle Pleistocene, it was previously thought
that only Homo sapiens, or modern humans, existed in Africa. More critically, it is
at precisely this time that researchers see the rise of what has been called “modern
human behavior” in southern Africa – behavior attributed, until now, to the rise of
modern humans and thought to represent the origins of complex modern human activities
such as burial of the dead, self-adornment and complex tools.
The Dating Game
The team used a combination of optically stimulated luminescence dating of sediments
with Uranium-Thorium dating and paleomagnetic analyses of flowstones to establish
how the sediments relate to the geological timescale in the Dinaledi Chamber.
Direct dating of the teeth of Homo naledi, using Uranium series dating, or U-series,
and electron spin resonance dating, or ESR, provided the final age range. The scientists
used double blinds wherever possible, said Professor Jan Kramers of the University
of Johannesburg, a uranium dating specialist. Hannah Hilbert-Wolf, a geologist from
James Cook University who also worked on the Dinaledi Chamber, noted that it was crucial
to figure out how the sediments within the Dinaledi Chamber are layered, in order
to build a framework for understanding all of the dates obtained.
“Of course we were surprised at the young age, but as we realized that all the geological
formations in the chamber were young, the U-series and ESR results were perhaps less
of a surprise in the end,” said Professor Eric Roberts, from James Cook University
and Wits, who is one of the few geologists to have ever entered the Dinaledi Chamber,
due to the tight 18cm-wide constraints of the entrance chute.
Marina Elliott, exploration scientist at Wits and one of the original “underground
astronauts” on the 2013 Rising Star Expedition, says she had always felt that the
naledi fossils were “young.”
“I’ve excavated hundreds of the bones of Homo naledi, and from the first one I touched,
I realized that there was something different about the preservation, that they appeared
hardly fossilized,” she said.
Homo naledi’s Significant Impact
In an accompanying paper led by Berger titled, “Homo naledi and Pleistocene hominin evolution in subequatorial Africa,” the team discusses the importance of finding such a primitive species at such a time
and place. They noted that the discovery will have a significant impact on the interpretation
of archaeological assemblages and understanding which species made them.
“We can no longer assume that we know which species made which tools or even assume
that it was modern humans that were the innovators of some of these critical technological
and behavioral breakthroughs in the archaeological record of Africa,” Berger said.
“If there is one other species out there that shared the world with modern humans
in Africa, it is very likely there are others. We just need to find them.”
John Hawks of the University of Wisconsin-Madison and Wits University, an author on
all three papers, said, “I think some scientists assumed they knew how human evolution
happened, but these new fossil discoveries plus what we know from genetics, tell us
that the southern half of Africa was home to a diversity that we’ve never seen anywhere
else.”
“Recently, the fossil hominin record has been full of surprises, and the age of Homo
naledi is not going to be the last surprise that comes out of these caves I suspect,”
Berger said.
A New Chamber and Skeleton
In a third paper published at the same time in eLife titled, “New fossil remains of
Homo naledi from the Lesedi Chamber, South Africa,” the team announces the discovery
of a second chamber within the Rising Star cave system, which contains more remains
of Homo naledi.
“The chamber, which we have named the Lesedi Chamber, is more than 100 meters from
the Dinaledi Chamber. It is almost as difficult to access, and also contains spectacular
fossils of naledi, including a partial skeleton with a wonderfully complete skull,”
said Hawks, who is the lead author on the paper describing the new discovery.
Fossil remains were first recognized in the chamber by Rick Hunter and Steven Tucker
in 2013, as fieldwork was underway in the Dinaledi Chamber. The name “Lesedi” means
“light” in the Setswana language. Excavations in the Lesedi Chamber began later, and
would take nearly three years.
No easy access

Explorers inside the Rising Star cave system included (left to right) Mathabela Tsikoane, Maropeng Ramalepa, Dirk van Rooyen, Steven Tucker (seated) and Rick Hunter (seated).
Photo Credit: Marina Elliott, Wits University.
Access to the Lesedi Chamber is only slightly easier than the Dinaledi Chamber, said
Elliott, who was the lead excavator of the fossils from the new locality. After passing
through a squeeze of about 25 cm, there is a descent along vertical shafts before
reaching the chamber. While slightly easier to get to, the Lesedi Chamber is, if anything,
more difficult to work in due to the tight spaces involved. Hawks points out that
while the Lesedi Chamber is “easier” to get into than the Dinaledi Chamber, the term
is relative.
“I have never been inside either of the chambers, and never will be. In fact, I watched
Lee Berger being stuck for almost an hour, trying to get out of the narrow underground
squeeze of the Lesedi Chamber,” Hawks said. Berger eventually had to be extracted
using ropes tied to his wrists.
The presence of a second chamber, distant from the first, containing multiple individuals
of Homo naledi and almost as difficult to reach as the Dinaledi Chamber, gives an
idea of the extraordinary effort it took for Homo naledi to reach these hard-to-get-to
places, said Hilbert-Wolf.
“This likely adds weight to the hypothesis that Homo naledi was using dark, remote
places to cache its dead,” Hawks said. “What are the odds of a second, almost identical
occurrence happening by chance?”
So far, the scientists have uncovered more than 130 hominin specimens from the Lesedi
Chamber. The bones belong to at least three individuals, but Elliot believes that
there are more fossils yet to be discovered. Among the individuals are the skeletal
remains of two adults and at least one child. The child is represented by bones of
the head and body and would likely have been under 5 years of age. Of the two adults,
one is represented by only a jaw and leg elements, but the other is represented by
a partial skeleton, including a mostly complete skull.
Meeting naledi
The team describes the skull of the skeleton as spectacularly complete.
“We finally get a look at the face of Homo naledi,” said Peter Schmid of Wits and
the University of Zurich, who spent hundreds of hours painstakingly reconstructing
the fragile bones to complete the reconstruction. The skeleton was nicknamed “Neo”
by the team, chosen for the Sesotho word meaning “a gift.”
“The skeleton of Neo is one the most complete ever discovered, and technically even
more complete than the famous Lucy fossil, given the preservation of the skull and
mandible,” Berger said.
The specimens from the Lesedi Chamber are nearly identical in every way to those from
the Dinaledi Chamber, a remarkable finding in and of itself.
“There is no doubt that they belong to the same species,” Hawks said.
The Lesedi Chamber fossils have not been dated yet, as dating would require destruction
of some of the hominin material.
“Once described, we will look at the way forward for establishing the age of these
particular fossils,” Dirks said.
Elliot aded, however, that as the preservation and condition of the finds are practically
identical to that of the naledi specimens from the Dinaledi Chamber, the team hypothesizes
that their age will fall roughly within the same time period.
Berger believes that with thousands of fossils likely remaining in both the Lesedi
and Dinaledi Chambers, there are decades of research potential.
“We are going to treat ongoing extraction of material from both of these chambers
with extreme care and thoughtfulness and with the full knowledge that we need to conserve
material for future generations of scientists, and future technological innovations,”
he said.
Fifty-two scientists from 35 departments and institutions were involved in the research.
Wits Vice-Chancellor and Principal Professor Adam Habib said, “The search for human
origins on the continent of Africa began at Wits, and it is wonderful to see this
legacy continue with such important discoveries.”
“The National Geographic Society has a long history of investing in bold people and
transformative ideas,” said Gary E. Knell, president and CEO of the National Geographic
Society, a funder of the expeditions that recovered the fossils and established their
age. “The continued discoveries from Lee Berger and his colleagues showcase why it
is critical to support the study of our human origins and other pressing scientific
questions.”
Public Display
The original fossils of this exciting new discovery, as well as Homo naledi fossils
from the first Rising Star Expedition will be put on public display at Maropeng, the
Official Visitor Center for the Cradle of Humankind World Heritage Site on Thursday,
May 25. This exhibit of the largest display of original fossil hominin material in
history, form part of an exhibition called “Almost Human.” This exhibition will be
housed in The Gallery. This state-of-the-art exhibition space was built as part of
the Gauteng Government Infrastructure Upgrade Project. Maropeng is getting ready to
receive thousands of visitors wanting to the see the exhibition and the new fossils.
In 2015, when Homo naledi was first put on display, some 3,500 visitors per day made
their way to Maropeng.
“It was an extraordinary thing to experience,” said Michael Worsnip, managing director
of Maropeng. “It was something like a pilgrimage – a wonderful celebration of our
heritage as a country, a continent and a planet.”
Additional Links:
“The age of Homo naledi and associated sediments in the Rising Star Cave, South Africa,” eLife: http://dx.doi.org/10.7554/eLife.24231
“New fossil remains of Homo naledi from the Lesedi Chamber, South Africa,” eLife: http://dx.doi.org/10.7554/eLife.24232
“Homo naledi and Pleistocene hominin evolution in subequatorial Africa,” eLife: http://dx.doi.org/10.7554/eLife.24234
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