New Scientist - USA (2019-07-13)

(Antfer) #1
13 July 2019 | New Scientist | 11

HOMO SAPIENS lived in Greece
210,000 years ago. The finding
rewrites human prehistory,
suggesting our ancestors migrated
out of Africa – and reached
Europe – earlier than we thought.
The evidence comes from
Apidima cave in southern Greece.
Two hominin skulls, both missing
their lower jaws, were discovered
in the cave in the 1970s. They were
thought to be from Neanderthals,
who lived in Europe long before
modern humans arrived.
Katerina Harvati at the
University of Tübingen in
Germany and her colleagues have
now taken a closer look. They CT-
scanned the skulls and compared
their shapes to other hominin
specimens. As expected, one of the
skulls was from a Neanderthal. But
to their surprise, the other didn’t
fit the Neanderthal mould, and was
instead from a modern human.
The next step was to find out
how old the skulls were. This was
difficult, because they were found
encased in a block of hardened
mud and rocks stuck to the cave
ceiling. “This means that they did
not come from the same context
as any material excavated from
the cave floor,” says Harvati.
So Harvati’s team turned to
uranium-thorium dating, which
estimates the age of an object by
tracking the decay of radioactive
elements. This found the
Neanderthal skull to be 170,
years old. But the human skull was
significantly older: 210,000 years
old. “This age makes it older than
any other accepted Homo sapiens
specimen outside of Africa,” says
Harvati (Nature, DOI: 10.1038/
s41586-019-1376-z).
In the early 2000s, most
anthropologists agreed that Homo
sapiens arose in Africa 200,
years ago and that everyone of
recent non-African descent came
from a group that left Africa about

60,000 years ago, with Europe
reached 45,000 years ago.
However, this story is being
revised. Fossils from modern
humans found in Morocco date
to 315,000 years ago, pushing back
the age of our species. A jawbone
found in an Israeli cave is 177,
years old, meaning humans
roamed beyond Africa earlier.
There are also putative modern
humans in China at similarly early
times, but these are disputed.

Before these discoveries,
the Apidima find would have
been a shock, but “nothing
surprises us any more”, says
Fred Spoor of London’s Natural
History Museum.
Mathieu Duval at Griffith
University in Nathan, Australia,
points out that the uranium-
thorium dating method gives
the minimum age of the fossils,
meaning the skulls could be
even older.
Key findings must now be
reconsidered, says Eleanor Scerri
at the Max Planck Institute for
the Science of Human History
in Jena, Germany. For instance,
65,000-year-old cave art from
Spain has been attributed to the
Neanderthals, as modern humans
were assumed to be absent from
Europe. “Those assumptions can’t
be made now,” she says.

The human skull at Apidima
does make sense of a puzzle.
Famously, humans and
Neanderthals interbred about
50,000 years ago, leaving all
people of recent non-African
descent with a small amount of
Neanderthal DNA in their cells.
But it also seems they interbred
over 200,000 years ago, giving
Neanderthals human DNA. This
made no sense if they lived on
separate continents, but the
Apidima skull suggests they
overlapped and so could have met.
In separate research, Adam
Siepel of Cold Spring Harbor
Laboratory in New York and his
colleagues have reanalysed
modern human and Neanderthal
DNA using a new technique. They
found that the early interbreeding
occurred between 300,000 and
200,000 years ago (bioRxiv,
doi.org/c72w). The two studies
are “consistent in that respect”,
he says.
It remains clear that humans
evolved in Africa, says Scerri. “The
oldest fossils are still in Africa and
they’re 100,000 years older than
these,” she says.
However, Scerri says there may
have been multiple dispersals
out of Africa, perhaps enabled
by a greening of the Sahara and
Arabian deserts, which happens
every 100,000 years.
Scerri and her colleagues
promote African multiregionalism:
the idea that there were many
ancient human populations living
in Africa, which were sometimes
isolated and sometimes
connected. It now seems this web
of populations extended beyond
Africa. “We have this sort of
human patchwork of very small
populations,” she says. ❚

Human evolution

Michael Marshall

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Skull rewrites our history


Our species was in Europe 165,000 years earlier than thought


The ancient skull
was found along this
Greek coastline

This cave contained
a 210,000-year-old
modern human skull
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