Researchers excavate the Tam Pa Ling cave in Laos, where
skeletal evidence of “the earliest” modern humans in Asia was discovered.
The skull – which you can see in the
reconstruction here on the right – is undoubtedly from a modern human and is
claimed by the authors to provide the earliest compelling evidence for modern
humans in East Asia.
Well it might, but then again, it
might not.
Asia occupies one-third of the
planet’s land area and contains two-thirds of the world’s human population.
Yet, we still know so little about human origins in the area – it’s almost a
crime!
Just when did the founders of modern
Asia enter the region after exiting Africa? Who did they look like? Stone Age
Africans, or recent Asians?
Disturbing
evidence
We know the Cave of Monkeys seems to
have been disturbed, as the entire upper half of the soil has been washed out,
replaced with a substantially younger soil. Within less than one metre, the age
goes from 51,000 years to 2,700 years old (a difference of more than 48,000
years).
Another concern with the dating is
that the age estimates are somewhat out of sequence and in conflict.
Site of Tam Pa Ling, in northern
Laos.
There are dates on sand grains in
the cave of 48,000 years a good two metres below the skull’s recovery unit and
a date of 46,000 years 20cm below it. The authors themselves state that dates
from sand grains “should provide a result close to the ‘true’ burial age".
Yet the skull is dated directly,
using a different method, to about 63,000 years old, but with large errors.
Dates using the radiocarbon method are also out of order (inverted), suggesting
the soils have been disturbed once they were formed.
These apparent conflicts would need
to be resolved before claims for the oldest modern human can be accepted.
If Demeter and colleagues are
correct in their dating assessment, this find shows the earliest humans in the
area were extremely modern-looking: not like early modern humans in Africa, nor
West
Asia, and nothing like the Red
Deer Cave people described
by myself, Ji Xueping and others earlier this year.
It would also show that very
modern-looking humans had settled widely across Asia by about 50,000 years ago.
First
dates
This is important because some much
younger humans – such as the remains we dubbed the Red Deer Cave people from
southwest China – are very archaic looking.
Skull of the Red Deer Cave people. Darren
Curnoe
The Tam Pa Ling skull has the
distinctive features of a modern human, but is too incomplete to allow an
assessment of whether it resembles recent East Asian people.
It also lacks the many archaic
features we described for the Red Deer Cave people from southwest China.
I was surprised to read that Demeter
and co-workers essentially ignored our Red Deer Cave people finds.
In a one-liner, they simply
dismissed our work as irrelevant, without providing any valid reason for doing
so.
As the team co-leader for that
discovery, I think they missed a golden opportunity to consider the diversity
that existed in the late Ice Age of the region as well as to better understand
the complexity of human population history at the time.
Placing the Tam Pa Ling skull into a
broader context will be crucial to establishing its importance to human
evolution.
While the Tam Pa Ling discovery holds great
promise in its potential to tell us about the early origins of recent East
Asians, more work will need to be done to provide a solid case. Did our Asian
story just get more complicated? It seems so. An article published this week in
the Proceedings of the National Academy of Sciences by Fabrice Demeter and
co-workers describes a new modern human skull from Tam Pa Ling (Cave of the
Monkeys) in Laos believed to be between 63,000 and 46,000…
Photos by Duringer
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