Cultural and human dynamics in southern Arabia at the end of the Middle Paleolithic

International audienceThe Arabian Peninsula has long been considered as a region devoid of long-term human settlement until the Holocene period, as a result of drastic climatic changes throughout the Pleistocene. It might be expected that the area was deserted during hyper-arid and arid periods, and populated by new migrant groups during humid events, according to a " push and pull " phenomenon. Although this scenario may be perfectly valid for a large part of the Peninsula, a set of recent data points to the persistence of populations in several regions, which may have served as refugia for human groups who developed their own technological traditions. Such a scenario is suggested by: (1) The succession of dense human occupations under arid conditions between ca. 60 and 50 ka, in the Wadi Surdud basin, a small sedimentary basin in the foothills of the Yemeni Western Highlands. This archaeological site complex encompasses several successive human settlements characterized by a Middle Paleolithic tradition which significantly differs from the Middle Paleolithic and Middle Stone Age contemporaneous traditions from neighboring regions; (2) The regional diversity of the Middle Paleolithic throughout the Saharo-Arabian arid belt during MIS 3, expressed by an array of local techno-typological facies that likely relate to distant and disconnected source regions where populations contracted when climate worsened. Together with a set of high-resolution archaeological contexts recently discovered in the Arabian Peninsula and dated to MIS 5, these data suggest that the major human expansion waves which occurred in the region during the Upper Pleistocene are correlated with the wet phases of MIS 5, while populations probably contracted into a few refugia areas at the beginning of MIS 3