July 08, 2013

Continuity of microblade technology in India since 45ka

An interesting new paper extends continuity of microblade technologies in India to ~45ka, and hence makes it probable that these were introduced by AMH together with the UP colonization of the rest of Eurasia.

I am not sure that the authors' suggestion that early modern humans were "tropically adapted" is certain. Personally, my idea du jour is to derive them from the Saharo-Arabian belt. In any case, as an advocate of "early OOA" (in the sense of pre-UP/LSA), it makes sense to me that modern humans in Eurasia would be initially climate-limited and at a disadvantage vis a vis archaic Eurasians inhabiting regions for which they were maladapted. In my opinion, it was the technological revolution of ~50ka being responsible for the extension of their range at the expense of other Eurasians.

PLoS ONE 8(7): e69280. doi:10.1371/journal.pone.0069280

Continuity of Microblade Technology in the Indian Subcontinent Since 45 ka: Implications for the Dispersal of Modern Humans

Sheila Mishra et al.

We extend the continuity of microblade technology in the Indian Subcontinent to 45 ka, on the basis of optical dating of microblade assemblages from the site of Mehtakheri, (22° 13' 44″ N Lat 76° 01' 36″ E Long) in Madhya Pradesh, India. Microblade technology in the Indian Subcontinent is continuously present from its first appearance until the Iron Age (~3 ka), making its association with modern humans undisputed. It has been suggested that microblade technology in the Indian Subcontinent was developed locally by modern humans after 35 ka. The dates reported here from Mehtakheri show this inference to be untenable and suggest alternatively that this technology arrived in the Indian Subcontinent with the earliest modern humans. It also shows that modern humans in Indian Subcontinent and SE Asia were associated with differing technologies and this calls into question the “southern dispersal” route of modern humans from Africa through India to SE Asia and then to Australia. We suggest that modern humans dispersed from Africa in two stages coinciding with the warmer interglacial conditions of MIS 5 and MIS 3. Competitive interactions between African modern humans and Indian archaics who shared an adaptation to tropical environments differed from that between modern humans and archaics like Neanderthals and Denisovans, who were adapted to temperate environments. Thus, while modern humans expanded into temperate regions during warmer climates, their expansion into tropical regions, like the Indian Subcontinent, in competition with similarly adapted populations, occurred during arid climates. Thus modern humans probably entered the Indian Subcontinent during the arid climate of MIS 4 coinciding with their disappearance from the Middle East and Northern Africa. The out of phase expansion of modern humans into tropical versus temperate regions has been one of the factors affecting the dispersal of modern humans from Africa during the period 200–40 ka.

Link

3 comments:

Grognard said...

Even though the bulk of anthropological poking seems to be in africa the results in asia that do come out are always quite interesting. Like I said in some other post we should probably be looking for "modern" humans where the earliest cities and large populations were, which is along the same belt you point to.

I think they are off about jungle and cold adaptation. By that time it was the brain and culture making the adapations and most people writing articles seem to forget there were NO deserts in most of the areas that are there now. Climate has changed many times and you can't look at what's there today to make a guess, and aside from present times deserts have been largely transient.

terryt said...

"It also shows that modern humans in Indian Subcontinent and SE Asia were associated with differing technologies and this calls into question the 'southern dispersal' route of modern humans from Africa through India to SE Asia and then to Australia".

That has always been one of the problems with the theory. Australian Aborigines did not have any sort of micro-blade technique until as recently as 5-6000 years ago. And the Upper Paleolithic appears to have been introduced to Chian from the north, not via South Asia. The lack of any connection between SE Asian and S Asian technolgies argues strongly in favour of the hill country in the border region as being remarkably impassable, as does the very steep cline in the region between East and South Asian phenotypes.

Grognard said...

Speaking of aboriginies, look at this:

http://discovermagazine.com/2002/aug/featafrica#.UcW3NxbRu7c

Guy sequences old large skulled skeletons that according to out of africa have no explanation at all. Finds they have previously unknown mtDNA. Results discarded out of hand with no further investigation.

Now you can't just make up results for something like that. So if they are not convincing it should be easy to counter them, but simply ignoring them is criminal.