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Thursday, May 8, 2008

Aterian and the coastal migration model


It seems that Aterian, the North African paleolithic culture (attributable to Homo sapiens), occupies the whole range of dates between c. 85,000 BP to the Epipaleolithic, when new waves (Iberomaurusian, Capsian) may have arrived from Spain and Sudan.

Recently these findings have been confirmed by archaeological research at Taforalt, Morocco, that have yielded some of the oldest known ornaments, competing for that title with Skuhl cave (Palestine) and Oued Djebanna (Algeria).



Aterian tools

Fine so far. But there is a problem: the deepest genetic layer in North Africa seems to be mtDNA haplogroup U6, that is related with other U clades of West, Central and South Eurasia. This clade is believed to have arrived to North Africa with the earliest human colonists, much like its "sisters" U5 and U8a seem to have arrived to Europe too. But, while European early sapiens colonization may date to 48-40,000 BP, not being in contradiction with the mainstream model of colonization of Eurasia from a single out of Africa migration c. 75-60,000 BP, the Aterian very old C14 dates do.

And there is nothing between Aterian and the Epipaleolithic that can explain that.

So I am starting to question the coastal migration model too, or at least the dates attributed to it.

No hardcore conclussions yet but what if... the OOA event happened much earlier, maybe c. 120,000 BP, and had a westward branch via the Levant that ended up in North Africa? There are certainly H. sapiens remains in the Levant that are date c. 100,000 BP (though they are believed to have been replaced by Neanderthals, that are dated to c. 60,000 BP).

In South Asia (key area for Eurasian prehistory) archaeology can hardly differentiate between pre-sapiens and sapiens technologies. The divide between Middle and Upper UP is placed, somewhat arbitrarily, at c. 30,000 BP (much later than in Central and West Eurasia) and human or hominin remains are very scarce anyhow. But, like in West Asia, disconinued blade tools (preluding UP somewhat) are occasionally found with much older dates. In West Asia this was (more or less consistently) attributed to Neanderthals but it is very unlikely that the findings of India can be attributed to them too.

Check for instance Petraglia et al., 2007: Middle Paleolithic Assemblages from the Indian Subcontinent Before and After the Toba Super-Eruption:


We provide here firm chronological evidence that hominins were present in the Jurreru River valley, south India, immediately before and after the YTT eruption. Analyses of the archaeological industries recovered from the site indicate a strong element of technological continuity between the pre- and post-Toba assemblages. Together with the presence of faceted unidirectional and bidirectional bladelike core technology, these pre- and post-Toba industries suggest closer affinities to African Middle Stone Age traditions (such as Howieson's Poort) than to contemporaneous Eurasian Middle Paleolithic ones that are typically based on discoidal and Levallois techniques (Fig. 3). The coincidence of (i) evidence of hominins flexible enough to exhibit continuity through a major eruptive event, (ii) technology more similar to the Middle Stone Age than the Middle Paleolithic, and (iii) overlap of the Jwalapuram artifact ages with the earlier end of the most commonly cited genetic coalescence dates (21–23) may suggest the presence of modern humans in India at the time of the YTT event. This interpretation would be consistent with a southern route of dispersal of modern humans from the Horn of Africa (24); the latter, however, will remain speculative until other Middle Paleolithic sites in the Indian subcontinent and Arabian Peninsula (25) are excavated and dated.



Jwalapuram tools

And also:
- Modern Human Origins and the Evolution of Behavior in the Later Pleistocene Record of South Asia, by Hanna V.A. James and Michael D. Petraglia, 2005 (no link found).
- J.B. Harrod, Synopsis of the Paleolithic of India (PDF).

From this last paper (a list of Indian Paleolithic sites with brief descriptions), I specially noticed two sites from before the Toba event that show blade creation. One (Hokra 1-a and Gurha, Thar Desert, Rajasthan) is not dated but the other (Patpara, Middle Son Valley) has a C14 date of at least 100,000 BP. Blade based tools are also found after the Toba event in several sites that may be dated since c. 45,000 BP.

But even if the earlier blade industries are not really consolidated UP (like happens with Levantine Jabroudian, where stone blades were made long before UP apparently by Neanderthals without continuity), presence of anatomically modern humans does not need to be related to them anyhow (in fact that is the case in may other parts of the World). And the technoligical continuity in India an the very early dates of Sapiens-made Aterian in North Africa, strongly suggest an out-of-Africa event much earlier than Toba eruption. Maybe c. 100,000 BP. There was a warm peak (a more favorable climate probably) c. 105,000 BP that could account for such migration maybe.

6 comments:

Manjunat said...

In West Asia this was (more or less consistently) attributed to Neanderthals but it is very unlikely that the findings of India can be attributed to them too.

Why not? What about Homo Heidelbergensis?

Maju said...

Maybe because there are no known Neanderthal remains from South Asia?

I don't know if Heidelbergensis was capable of such developements but, in any case, they would probably be separated culturally from Neanders.

Also Neanderthal presence in the Levant has dates of c. 60,000 (over dates of c. 100,000 for H. sapiens), while these tools are much older, with dates above 100,000 BP.

Just very unlikely, not impossible anyhow.

...

In any case, weren't you the one arguing against the coastal migration model recently? (And I the one insisting in its validity?) :D

Manjunat said...

Maybe because there are no known Neanderthal remains from South Asia?

As you have already mentioned before, forget about Neanderthals even Sapiens remains around 60000-70000BP have not be found in South Asia.

However, there was a news in National Genographic that Hiedelbergensis roamed around in South Asia 250000 thousands years ago. How about them evolving culturally to produce tools similar to that of Neanderthals(who I supppose are evolved Hiedelbergensis) and Sapiens?


In any case, weren't you the one arguing against the coastal migration model recently? (And I the one insisting in its validity?) :D


I haven't changed my opinion. What makes you think so? In fact, arguing for Neanderthals or Hiedelbergensis in South Asia around 70000 BP, makes my case stronger for non coastal migration model.

Were you not the one to suggest there were Neanderthals in Central Asia therefore C clan taking that root to SE Asia is highly unlikely?

Maju said...

However, there was a news in National Genographic that Hiedelbergensis roamed around in South Asia 250000 thousands years ago. How about them evolving culturally to produce tools similar to that of Neanderthals(who I supppose are evolved Hiedelbergensis) and Sapiens?

Well, it's always a possibility - yet 100 KY ago is much closer to the date of the first known Indian Sapiens than to the date of the last known Heidelbergensis.

And, I'm not just thinking in terms of South Asia anyhow. Would it have been only because of the doubts regarding the South Asian late Paleolithic, I would probably have never written this post.

It was North African Aterian what made me think, together with the known presence of Sapiens in West Asia c.100 KYBP and the issues surrounding South Asia.

We have:

1. First known Sapiens out of sud-Saharan Africa in Palestine c. 100 KYBP. They were apparently replaced by Neanderthals later on.

2. Second known Sapiens out of sud-Saharan Africa in North Africa c.85 KYBP. Apparently continuous presence till the Epipaleolithic. Apparently carrier of haplogroup U6, that still makes up a good deal of North African genetics.

And then, only then, I wondered. Does that mean a Western route for dispersion of Humans in Eurasia or what? And then I pondered the issues of South Asian late Paleolithic, with technologies related with Africa Middle Stone Age (believed Sapiens), not just after Toba explosion... but also before.

I also pondered that is difficult to explain the dispersion of Y-DNA macrohaplogroups F and C without considering South Asia as the place of their main dispersal. MtDNA U could live without India maybe but again, one step above India appears as the place with the highest R diversity, as well as M.

It's nearly impossible to consider the genetics of Eurasia, North Africa, Oceania and America without India as intermediate step between Africa and them.

So that's my hypothesis right now: early migration to South Asia, followed by rapid spread out, specially towards West Asia and North Africa, where remains document earliest human presence.

Not sure what happened in the East, though. Archaeology is again an issue regarding East and SE Asian human arrivals. There is nothing like what is found in India or the West so early. But after Toba event anyhow, the area should have been cleaned of most archaic hominins (except Flores man maybe), leaving a lot of room for newer arrivals.

I haven't changed my opinion. What makes you think so? In fact, arguing for Neanderthals or Hiedelbergensis in South Asia around 70000 BP, makes my case stronger for non coastal migration model.

I don't see how. But guess your hypothesis (or rather "anti-hypothesis", as you are not proposing any alternative model so far) has the weakness of being only regionally focused.

When you look to all Eurasia, you see clarly that only South Asia has enough diversity for the root clades (except for D maybe) to be the origin of the spread. Only in South Asia you find high R and M diversity, C* and F*, and only South Asia, as origin or intermediate step, can explain the spread of K from Australia to Europe.

West Asia cannot. (Though I'm not sure about mtDNA N right now).

Were you not the one to suggest there were Neanderthals in Central Asia therefore C clan taking that root to SE Asia is highly unlikely?

I don't remember using this logic. I know that there were Neanders in Central Asia at some point but I don't see how this may relate with C travelling to SE Asia via the coasts of the Indian Ocean and/or the inner routes of the Indian subocntinent.

Manjunat said...

I don't remember using this logic.

Be consistent, Maju.

Ren's words:

Also put in doubt is the theory made by geneticists that Central Asia was a main corridor of Modern human migration that turned west and east. It seems that Central Asia was not free of Neanderthals for Modern Humans to thrive in.


And Your comment:

That's more interesting in fact. It seems to strongly support the "coastal migration" theory.

Maju said...

And?! *eyes wide open*

...strongly support the "coastal migration" theory

I still don't get how Neanderthals in Uzbekistan could block the road to Burma . AFAIK they are in totally opposite directions.

Thanks for the reference but I'm not saying in it what you claim I'm saying. Or I do not follow your logic around that in any case.

What I was saying then was: if Central Asian corridor is less likely (competition by other hominins), then the Coastal Migration model becomes even more likely. Just that.

It may be thought as an argument to question the migration of Sapiens Westward into West Asia and North Africa if anything, but:

1. Neanders arrived only late to Asia (c. 60 KYBP are the dates for Palestine) and were there for little time before what seems indications of H. Sapiens displacing them again.

2. They were not the border cops and there was no electrified wall anywhere. They just could not guarantee that modern humans would not pass and settle near them maybe. If they had different strategies, if Sapiens were for instance more into fishing trouts and Neanders into hunting mammouths (exaggerating a bit, I reckon), they could even have lived side by side.

And in fact this possibility is what has Zilhao (against) and Mellars (in favor) yelling at each other in the latest release of PaleoAnthropology.

There's no strong direct evidence of such neighbourhood (if we accept Zilhao's criticisms of earlier archaeologists - basically he's calling them fraudsters) but there is strong indirect evidence: Chatelperronian correlates best, not with typical Aurignacian (nor Mousterian either) but with Levantine early UP (Emirian). Chatelperronian is quite clearly an aculturation of Neanders by UP Sapiens' influences, even if we can't know the details on how that happened.

Anyhow, I'm (again) talking more than was strictly necessary. Sorry.