Upper Paleolithic cultural diversity in the Iranian Zagros Mountains and the expansion of modern humans into Eurasia

The Persian plateau served as hub for Homo sapiens after the main out of Africa dispersal

A combination of evidence, based on genetic, fossil and archaeological findings, indicates that Homo sapiens spread out of Africa between ~70-60 thousand years ago (kya). However, it appears that once outside of Africa, human populations did not expand across all of Eurasia until ~45 kya. The geographic whereabouts of these early settlers in the timeframe between ~70-60 to 45 kya has been difficult to reconcile. Here we combine genetic evidence and palaeoecological models to infer the geographic location that acted as the Hub for our species during the early phases of colonisation of Eurasia. Leveraging on available genomic evidence we show that populations from the Persian Plateau carry an ancestry component that closely matches the population that settled the Hub outside Africa. With the paleoclimatic data available to date, we built ecological models showing that the Persian Plateau was suitable for human occupation and that it could sustain a larger population compared to other West Asian regions, strengthening this claim.

The discovery of an in situ Neanderthal remain in the Bawa Yawan Rockshelter, West-Central Zagros Mountains, Kermanshah

Neanderthal extinction has been a matter of debate for many years. New discoveries, better chronologies and genomic evidence have done much to clarify some of the issues. This evidence suggests that Neanderthals became extinct around 40,000–37,000 years before present (BP), after a period of coexistence with Homo sapiens of several millennia, involving biological and cultural interactions between the two groups. However, the bulk of this evidence relates to Western Eurasia, and recent work in Central Asia and Siberia has shown that there is considerable local variation. Southwestern Asia, despite having a number of significant Neanderthal remains, has not played a major part in the debate over extinction. Here we report a Neanderthal deciduous canine from the site of Bawa Yawan in the West-Central Zagros Mountains of Iran. The tooth is associated with Zagros Mousterian lithics, and its context is preliminary dated to between ~43,600 and ~41,500 years ago.

Bayesian luminescence dating at Ghār-e Boof, Iran, provides a new chronology for Middle and Upper Paleolithic in the southern Zagros

Ghār-e Boof is a Paleolithic cave site in Iran well known for its rich early Upper Paleolithic Rostamian assemblages. The site is located on the edge of the Dasht-e Rostam plain in the southern Zagros. Recent excavations by the members of the Tübingen-Iranian Stone Age Research Project at Ghār-e Boof also recovered well-stratified Middle Paleolithic assemblages. Here, we provide the first detailed luminescence chronology for the Middle and Upper Paleolithic of the site. More generally, our work is the first luminescence chronology for a Middle and Upper Paleolithic site in the Zagros Mountains region in Iran. The luminescence ages for the Upper Paleolithic of Ghār-e Boof agree with published ¹⁴C dates. We applied Bayesian models specifically designed for luminescence dating using the R package 'BayLum' to incorporate the well-established stratigraphic constraints, as well as the published ¹⁴C ages with our optically stimulated luminescence (OSL) ages to improve the precision of the chronological framework. The Bayesian chronology shows a significantly improved precision of the OSL ages in particular for the upper part of the sequence where ¹⁴C ages were available. The Bayesian OSL ages for the Rostamian horizons, archaeologicalhorizon (AH) III (a-b-c), and AH IV, fall in the range of 37-42 ka (68% credible interval [CI]). Moreover, we determined a series of dates between 45 and 81 ka (68% CI) for the Middle Paleolithic strata from AH IVd to AH VI. Our results point to a demographic shift in the populations responsible for the Middle Paleolithic and the Rostamian within three millennia. This major technological change accompanied by the rise of symbolic artifacts such as personal ornaments, may or may not reflect a replacement of Neanderthals by modern humans. While we are confident that the Rostamian was made by modern humans, available information does not allow us to be sure who made the local Middle Paleolithic.