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

Ashok K. Singhvi,Naveen Chauhan,Darren Curnoe,Sheila Mishra

doi:10.1371/journal.pone.0069280

Ashok K. Singhvi, Naveen Chauhan + Show 2 more

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https://doi.org/10.1371/journal.pone.0069280

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Abstract

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.

Highlights

The period between ~200 ka when the earliest modern humans are found in Africa [1] and ~ 40 ka when the last archaic populations disappeared [2], is complex and variable
We suggest that the Indian Subcontinent during MIS 5 times was occupied by a population derived from Homo erectus adapted to the Indian environment from Lower Pleistocene times onwards
If modern humans were able to spread into the Indian Subcontinent during MIS 4 times, we should expect that some microblade sites in the Indian Subcontinent should date even earlier than Mehtakheri, as this technology disappeared from South and East Africa around 60 ka or later [22]

Summary

Introduction

The period between ~200 ka when the earliest modern humans are found in Africa [1] and ~ 40 ka when the last archaic populations disappeared [2], is complex and variable. If modern humans were able to spread into the Indian Subcontinent during MIS 4 times, we should expect that some microblade sites in the Indian Subcontinent should date even earlier than Mehtakheri, as this technology disappeared from South and East Africa around 60 ka or later [22].

Materials and Methods

Findings

Discussion and Conclusions