Stone age remains of people with a penchant for home-cooked
venison could represent a new human evolutionary line
Ian
Sample,
science correspondent
guardian.co.uk,
Wednesday 14 March 2012 15.11 GMT
A skull, possibly from a new species of human, recovered from Longlin cave in Guangxi province, China. Photograph: Darren Curnoe
The
fossilised remains of stone age people recovered from two caves in
south west China may
belong to a new species of human that survived until around the dawn
of agriculture.
The partial
skulls and other bone fragments, which are from at least four
individuals and are between 14,300 and 11,500 years old, have an
extraordinary mix of primitive and modern anatomical features that
stunned the researchers who found them.
Named the
Red Deer Cave people, after their apparent penchant for home-cooked
venison, they are the most recent human remains found anywhere in the
world that do not closely resemble modern humans.
The
individuals differ from modern humans in their jutting jaws, large
molar teeth, prominent brows, thick skulls, flat faces and broad
noses. Their brains were of average size by ice age standards.
"They
could be a new evolutionary line or a previously unknown modern human
population that arrived early from Africa and failed to contribute
genetically to living east Asians," said Darren
Curnoe,
who led the research team at the University of New South Wales in
Australia.
"While
finely balanced, I think the evidence is slightly weighted towards
the Red Deer Cave people representing a new evolutionary line. First,
their skulls are anatomically unique. They look very different to all
modern humans, whether alive today or in Africa 150,000 years ago,"
Curnoe told the Guardian.
"Second,
the very fact they persisted until almost 11,000 years ago, when we
know that very modern looking people lived at the same time
immediately to the east and south, suggests they must have been
isolated from them. We might infer from this isolation that they
either didn't interbreed or did so in a limited way."
One partial
skeleton, with much of the skull and teeth, and some rib and limb
bones, was recovered from Longlin cave in Guangxi province. More than
30 bones, including at least three partial skulls, two lower jaws and
some teeth, ribs and limb fragments, were unearthed at nearby
Maludong, or Red Deer Cave, near the city of Mengzi in Yunnan
province.
At
Maludong, fossil hunters also found remnants of various mammals, all
of them species still around today, except for giant red deer, the
remains of which were found in abundance. "They clearly had a
taste for venison, with evidence they cooked these large deer in the
cave," Curnoe said.
The
stone age bones are particularly important because scientists have
few human fossils from Asia that are well described and reliably
dated, making the story of the peopling of Asia hopelessly vague. The
latest findings point to a far more complex picture of
human evolution than
was previously thought.
"The
discovery of the Red Deer Cave people shows just how complicated and
interesting human evolutionary history was in Asia right at the end
of the ice age. We had multiple populations living in the area,
probably representing different evolutionary lines: the Red Deer Cave
people on the East Asian continent, Homo floresiensis, or the
'Hobbit', on the island of Flores in Indonesia, and modern humans
widely dispersed from northeast Asia to Australia. This paints an
amazing picture of diversity, one we had no clue about until this
last decade," Curnoe said.
Much
of Asia was also occupied by Neanderthals and another group of
archaic humans called the Denisovans. Scientists learned of the
Denisovans after recovering a
fossilised little finger from
the Denisova cave in the Altai mountains of southern Siberia in 2010.
The
fossils from Longlin cave were found in 1979 by a geologist
prospecting in the area. At the time, researchers removed only the
lower jaw and a few fragments of rib and limb bones from the cave
wall. The rest of the skeleton was left encased in a block of rock,
which sat in the basement of the Yunnan Institute of Cultural Relics
and Archaeology in Kunming, Yunnan, for 30 years. The fossils were
rediscovered in 2009 by Ji
Xueping,
a researcher at the institute, who teamed up with Curnoe to examine
the remains.
"It
was clear from what we could see that the remains were very primitive
and likely to be scientifically important. We had a skilled
technician remove the bones from the rock, and they were glued back
together. Only then was it clear what we had found: a partial
skeleton with a very unusual anatomy," Curnoe said.
The fossils
at Maludong were found in 1989 but went unstudied until 2008.
Lumps of
charcoal uncovered alongside the Longlin fossils were carbon dated to
11,500 years, a time when modern humans in southern China began to
make pottery for food storage and to gather wild rice in some of the
first steps towards full-scale farming.
Marta
Mirazón Lahr,
an evolutionary biologist at Cambridge University, is convinced the
remains are from modern humans. The unusual features, she said,
suggest the Red Deer Cave people are either "late descendants of
an early population of modern humans in Asia" or a very small
population that developed the traits through a process known
asgenetic
drift.
Chris
Stringer,
head of human origins at the Natural History Museum, London, was
similarly sceptical.
"The
human remains from the Longlin Cave and Maludong are very important,
particularly because we do not have much well-described and
well-dated material from the late Pleistocene of China.
"The
fossils are unlike recent populations of modern humans in several
respects, and the mosaic of more archaic features could indicate the
dispersal of a poorly known and more primitive form of modern human
that left Africa before the main exodus at about 60,000 years. This
dispersal could have reached as far as China, surviving there for
many millennia, before disappearing in the last 12,000 years."
But he
added: "There might be another possible explanation for the more
archaic features. Could these alternatively be attributed to gene
flow from a more archaic population that survived alongside modern
humans? In the case of the Longlin Cave and Maludong fossils, the
most likely candidate would be the enigmatic Denisovans who
apparently interbred with the ancestors of modern Australasians
somewhere in south east Asia. Could these Chinese fossils be further
evidence of such hybridisation?"
Republished
from guardian.co.uk
