PDA

View Full Version : Homo Sapiens in Arabia by 85,000 years ago



Angela
10-04-18, 17:01
See: Huw S. Groucutt et al
"Homo Sapiens in Arabia by 85,000 years ago"
https://www.nature.com/articles/s41559-018-0518-2

"Understanding the timing and character of the expansion of Homo sapiens out of Africa is critical for inferring the colonization and admixture processes that underpin global population history. It has been argued that dispersal out of Africa had an early phase, particularly ~130–90 thousand years ago (ka), that reached only the East Mediterranean Levant, and a later phase, ~60–50 ka, that extended across the diverse environments of Eurasia to Sahul. However, recent findings from East Asia and Sahul challenge this model. Here we show that H. sapiens was in the Arabian Peninsula before 85 ka. We describe the Al Wusta-1 (AW-1) intermediate phalanx from the site of Al Wusta in the Nefud desert, Saudi Arabia. AW-1 is the oldest directly dated fossil of our species outside Africa and the Levant. The palaeoenvironmental context of Al Wusta demonstrates that H. sapiens using Middle Palaeolithic stone tools dispersed into Arabia during a phase of increased precipitation driven by orbital forcing, in association with a primarily African fauna. A Bayesian model incorporating independent chronometric age estimates indicates a chronology for Al Wusta of ~95–86 ka, which we correlate with a humid episode in the later part of Marine Isotope Stage 5 known from various regional records. Al Wusta shows that early dispersals were more spatially and temporally extensive than previously thought. Early H. sapiens dispersals out of Africa were not limited to winter rainfall-fed Levantine Mediterranean woodlands immediately adjacent to Africa, but extended deep into the semi-arid grasslands of Arabia, facilitated by periods of enhanced monsoonal rainfall."

Commentary:

https://theconversation.com/our-fossil-finger-discovery-points-to-earlier-human-migration-in-arabia-94670

https://www.gnxp.com/WordPress/2018/04/09/arabia-as-africa-across-the-sea/?utm_source=dlvr.it&utm_medium=twitter

IronSide
10-04-18, 17:12
The question is, did they contribute ancestry to modern people or not? why is it difficult to have aDNA from Arabia?

Razib seems to suggest they were Basal Eurasians.

bicicleur
10-04-18, 17:39
The question is, did they contribute ancestry to modern people or not? why is it difficult to have aDNA from Arabia?

Razib seems to suggest they were Basal Eurasians.

Lots of stone tools are found all over Arabia, but not human remains, which perished.
Bone can be carbondated, stone tools can't.
Dating the stratification is also problematic in the shifting desert sands.
Most of the stone tools are undated.
But many tools belong to the Nubian Complex and we have a date of 106 ka by thermolumiscence of such tools found on the Dhofar highlands.
IMO it was haplogroup BT that brought the Nubian complex to Arabia during the Eemian, after the preceding glacial maximum.

markozd
10-04-18, 17:47
Lots of stone tools are found all over Arabia, but not human remains, which perished.
Bone can be carbondated, stone tools can't.
Dating the stratification is also problematic in the shifting desert sands.
Most of the stone tools are undated.
But many tools belong to the Nubian Complex and we have a date of 106 ka by thermolumiscence of such tools found on the Dhofar highlands.
IMO it was haplogroup BT that brought the Nubian complex to Arabia during the Eemian, after the preceding glacial maximum.

Good thinking, it could also explain how one group of incipient Eurasians (i. e. the Basal Eurasian ghost) could have avoided Neandertal gene flow which surely mainly occurred in the Levant & adjacent West Asia.

Angela
11-04-18, 16:01
Some commentary:
https://arstechnica.com/science/2018/04/saudi-arabian-fossil-find-puts-finger-on-the-story-of-human-dispersal/?comments=1