New_Scientist_May_27_2017

NEWS & TECHNOLOGY
Did we split from chimps in Europe?
The ancestor of all early humans may have been an eastern European
Colin Barras
THE last common ancestor
we share with chimps
might have lived in the east
Mediterranean – not in East
Africa as is generally assumed.
This bold conclusion comes
from a study of Greek and
Bulgarian fossils, suggesting that
the most mysterious of all ancient
European apes was actually a
human ancestor, or hominin.
However, other researchers
remain unconvinced by the claim.
Go back 12 or more million
years and Europe was an ape’s
paradise. But, some 10 million
years ago, environmental
conditions there changed
and apes became largely
confined to Africa, where they
eventually split into gorillas,
chimpanzees and humans.
At least, that’s what most
researchers think happened.
But, in 2012, Nikolai Spassov at
the National Museum of Natural
History in Sofia, Bulgaria, and his
colleagues reported the discovery
of an ape tooth from Bulgaria
that was just 7 million years old.
It was, they said, the youngest
European ape fossil yet found.
Spassov and his colleagues –
including Madelaine Böhme at
the University of Tübingen in
Germany and David Begun at the
University of Toronto, Canada –
now think the tooth belongs to an
ape calledGraecopithecus, which
clung on in Europe long after
other apes had disappeared from
the continent. What’s more, the
team says,Graecopithecus was no
ordinary ape – it was a hominin.
Other than the Bulgarian
tooth,Graecopithecus is known
from just one fossil jawbone
found near Athens in 1944.
With so little fossil material,
Graecopithecus is the most poorly
PAINTING BY CHICAGO-BASED ARTIST VELIZAR SIMEONOVSKI ACCORDING TO SCIENTIFIC INSTRUCTIONS OF MADELAINE BÖHME AND NIKOLAI SPASSOV
known of all European apes.
This is not helped by the Greek
jawbone, nicknamed El Graeco,
having a heavily worn surface.
Now Spassov and his colleagues
have used a micro-CT scanner to
peer into the jawbone of El Graeco,
and found that the roots of one
of the premolars are “fused”
together in an unusual way. “This
condition is so far only known to
occur regularly in hominins – prehumans
and humans,” Spassov
says.“It is extremely rare in recent
chimps.”There are also hints from
the jaw thatGraecopithecus
had relatively small canines.
Together, the two features suggest
Graecopithecus may have been a
hominin (PLoSOne, doi.org/b7gb).
The team has also investigated
the local geology and found
thatGraecopithecus lived in
exactly the sort of dry, savannahlike
environment traditionally
thought to have driven early
hominin evolution (PLoSOne,
doi.org/b7gc).
Furthermore, geological dating
techniques suggest it was alive
“Our last common ancestor
with chimps may have
livedinwhatisnowGreece
and Bulgaria, not Africa”
between 7.25 and 7.18 million
years ago – which means
Graecopithecus slightly predates
the oldest potential hominin
found in Africa:Sahelanthropus is
between 7 and 6 million years old.
–One day this will be a resort–
Putting the pieces of the
puzzle together, the team thinks
hominins might have split from
the chimp evolutionary lineage in
the eastern Mediterranean a little
earlier than 7.25 million years ago.
In other words, our last common
ancestor with chimps may have
been an eastern European.
David Alba at the Catalan
Institute of Palaeontology in
Barcelona, Spain, says there is
value to the new work: it provides
convincing anatomical evidence
thatGraecopithecus is different
from other ancient apes found in
Europe – something that wasn’t
clear from earlier studies.
But he is less convinced by the
idea that the tooth roots alone can
confirm thatGraecopithecus is a
hominin. He says study co-author
David Begun has been arguing for
20 years that the great apes first
appeared in Europe. “It is not
surprising at all that Begun is
now arguing that hominins as
well originated in Europe.”
Sergio Almécija at George
Washington University in
Washington DC says it is
important to bear in mind
that primates seem prone
to evolving similar features
independently.“Single characters
are not reliable to make big
evolutionary [claims],” he says.
Ultimately, however, the early
human fossil record is so poorly
known that it’s impossible to
definitively dismiss the new
claims, says Alba. “Of course,
it is possible that hominins first
evolved in Europe. However,
evidence favouring this view
is anecdotal at best,” he says.
Likewise,Graecopithecus might
be a hominin, he says, but that
can only be confirmed if more
fossils are found.
Spassov is optimistic. “We are
working on that,” he says. ■
6|NewScientist|27May2017