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4 Posts tagged with the professor_chris_stringer tag
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Finds from Taiwan and Israel shed light – and confusion – on the story of ancient human species.

Find 1: A mysterious jawbone from Penghu, Taiwan

Discovered by chance by fishermen off the coast of Taiwan, an unusually thick and primitive human jawbone shows a challenging mix of features. While no DNA has yet been recovered from the specimen, its characteristics make it difficult to classify into existing groups.

 

The jawbone is short and wide, with a thick body and large teeth. It dates within the last 450,000 years, and most likely within the last 200,000.

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The jawbone, left, and a reconstruction of the jaw, right © Yousuke Kaifu.

 

A partial Homo erectus skull from the Chinese mainland has some large associated teeth and could be 400,000 years old, so the new jawbone may belong to the same group. But it could also be one of the elusive ‘Denisovans’, a group known only by DNA from a fragmentary fossil finger bone and two very large molar teeth in a Siberian cave.

 

Museum human origins expert Prof Chris Stringer said this could be an interesting development:

I have considered the Denisovans as an Asian sister group of the Neanderthals, and like them, derived from Homo heidelbergensis, but if Penghu is indeed a long-awaited Denisovan jawbone, it looks more primitive than I would have expected.

He said of the find:

As the authors note, this enigmatic fossil is difficult to classify, but it highlights the growing and not unexpected evidence of human diversity in the Far East, with the apparent co-existence of different lineages in the region prior to, and perhaps even contemporary with, the arrival of modern humans some 55,000 years ago.

Read the original paper

 

Find 2: The skull of a possible early migrant, from northern Israel

A later and much better-dated specimen, the partial skull of an early modern human from Manot Cave dates to a time of migration out of Africa and interbreeding with Neanderthals. At about 55,000 years old, it sits comfortably in the timeframe estimated for early modern human and Neanderthal interbreeding, 50-60,000 years ago.

 

The skull itself has characteristics indicative of early modern humans, and without DNA it is impossible to say yet whether interbreeding with Neanderthals had an impact on the individual. Nonetheless, Prof Stringer said it is a critical find for examining possible migrant populations:

Manot might represent some of the elusive first migrants in the hypothesised out-of-Africa event about 60,000 years ago, a population whose descendants ultimately spread right across Asia, and also into Europe. Its discovery raises hopes of more complete specimens from this critical region and time period.

Read the original paper

 

Related human origins posts:

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The femur of a man found near Ust'-Ishim, Siberia, has yielded the oldest modern human genome yet recovered.

 

The DNA of the 45,000-year-old man contains Neanderthal DNA in a similar proportion to modern non-African people, as reported in the journal Nature.

When did we meet Neanderthals?

 

Modern humans migrating out of Africa interbred with Neanderthals somewhere in Asia, leaving today's non-African people with an imprint of around two per cent Neanderthal DNA in their genome.

 

However, exactly when this interbreeding occurred was previously unknown. Estimates based on the chunks of Neanderthal DNA present in humans today gave a range of 37,000-86,000 years ago for the interbreeding event, but new data from the ancient Siberian man has considerably narrowed this estimate.

 

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Models of an early modern human (left) and a Neanderthal (right)

 

While the Siberian man had a similar proportion of Neanderthal DNA to living humans, the individual chunks of DNA were more intact. The longer it has been since the interbreeding event, the more the chunks of DNA get broken up and shortened.

 

So, the Siberian man lived closer to the time of the original event than we do, and using the information from his DNA, scientists have estimated the interbreeding occurred between 7,000-13,000 years before he lived; no more than 60,000 years ago.

 

How many times did we leave Africa?

 

The timing of Neanderthal interbreeding has important implications for theories of early human migration out of Africa.

 

Skeletons of early modern humans have been found in the Middle East that date back to 100,000 years ago. One theory states that these bones represent an early dispersal of modern humans into Asia and beyond, reaching Australia and New Guinea. A second dispersal of early humans out of Africa, around 60,000 years ago, would then have spread to Europe and Asia.

 

A second theory states that the Middle Eastern skeletons represent a failed early migration of humans, and that the migration at 60,000 years ago was the one that dispersed people across Asia, Europe and Australasia.

 

However, Museum human origins expert Prof Chris Stringer thinks that the new data from the Siberian man lends more support to the second model.

 

The same stream

 

Modern Australasian people have the same approximate percentage of Neanderthal DNA as other modern non-Africans, so would have been the result of the same interbreeding event, which is now shown to have happened no more than 60,000 years ago.

 

This means that modern Australasians cannot be the descendants of an early migration out of Africa, but from the same migration 60,000 years ago that also spawned modern Europeans and Asians. As Prof Stringer says:

While it is still possible that modern humans did traverse southern Asia before 60,000 years ago, those groups could not have made a significant contribution to the surviving modern populations outside of Africa which contain evidence of interbreeding with Neanderthals.

 

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Stencils of hands and figurative drawings of animals in Indonesian caves show that expressive art existed in southern Asia and Europe at the same time.


A team of Australian and Indonesian researchers dated art in several caves on the Indonesian Island of Sulawesi and found that some were at least 35,000 years old.

 

Advanced cave art depicting animals and people has been found in sites across Europe, with some dated to around 35,000 years old, but this is the first time that art of this age has been identified in southern Asia.

 

Art out of Africa

 

The finding challenges a traditional view that palaeoart originated in Europe as simple geometric designs and evolved there into expressive and figurative art.

 

40,000 years ago, Europe and southeast Asia were at nearly opposite ends of the Palaeolithic world, following two main migration routes out of Africa some 20,000 years before. Advanced cave art in both these places suggests that art originated before early modern humans reached Europe, spreading out of Africa with them.

 

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Modern hand stencils created in the style of ancient cave paintings at our Science Uncovered event.

 

Artistic roots and routes

 

Museum human origins expert Prof Chris Stringer thinks this is a blow to the view that art in southern Asia or Australia would be younger than that in Europe, and had either developed by the spread of ideas from Europe, or by independent developments of artistic expression after modern humans settled in those regions.

 

I think these exciting discoveries allow us to move away from Eurocentric ideas on the development of figurative art to consider the alternative possibility that such artistic expression was a fundamental part of human nature 60,000 years ago, when modern humans not only occupied most of Africa but were beginning to disperse out towards Europe and the Far East.

 

I predict that even older examples of cave art will be discovered on Sulawesi, and in mainland Asia, and ultimately in our African homeland dating to more than 60,000 years ago.

The research team that dated the Indonesian art think that similar art found in southeast Asia and northern Australia could be the same age, expanding the range of early human artistic expression.

 

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A group of bones discovered ten years ago in Indonesia were determined to be a new human species that lived about 17,000 years ago. The only skull, with very small proportions, earned the species the ‘hobbit’ nickname.

 

Now, a new paper suggests that the hobbit is just an individual with Down syndrome, but Museum human origins expert Prof Chris Stringer doubts the conclusions.

 

The find, on the island of Flores, included bones from several individuals, but only one had a complete skull and leg bones, from which the original calculations of height and brain capacity were made.

 

Standing at approximately 1.06m (3.5ft) tall and with a brain only a third of the size of modern humans, the bones seemed to belong to a new species, which was named Homo floresiensis.

 

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A copy of the Homo floresiensis skull.
Credit: Ghedoghedo, Wikimedia Creative Commons.

 

A new analysis of the skull and thigh bones, published this week in a paper in the journal Proceedings of the National Academy of Sciences USA (PNAS), suggests that these estimates are too low, and a slightly bigger individual actually lies within the range of modern humans with Down syndrome.

 

The authors support their claims with other evidence, including the asymmetry of the skull, a condition common in modern individuals with Down syndrome. They conclude this one individual had a developmental disorder, and all the remains were in fact modern humans.

 

Still a new species?

 

However, Prof Stringer is sceptical of the conclusions. Although there are no other complete skulls, there is another jaw that has similar proportions and characteristics.

 

Both appear to have no chin, instead showing internal bony reinforcements similar to those found in prehuman fossils from at least two million years ago. This feature is not found in Down syndrome. The wrist bones of two individuals also show features previously unknown in humans from the last one million years, further indicating a unique species.

 

Weight of evidence

 

New human species are often difficult for the scientific community to accept, especially from so few bones. Prof Stringer, however, sees parallels between the stories of H. floresiensis and the Neanderthals, originally described from a single site:

A number of pathological conditions were advanced to explain away the distinctive morphology of the Neander Valley skeleton, but other finds gradually forced the acceptance of the Neanderthals as a distinct and extinct human group.

Prof Stringer acknowledges that more H. floresiensis individuals are needed to establish the range of sizes and shapes there may have been, but he thinks this new analysis does not shake the foundations of the species:

In my view this paper does not provide a sound basis to challenge the basic conclusion that a primitive human-like species persisted on the island of Flores within the last 100,000 years.