Ash Parton

Several hundred Middle Palaeolithic (MP) archaeological sites have now been identified in the Arabian Peninsula. However, the study of lithic raw material properties and related procurement behaviours is still in its infancy. Here we describe raw material procurement and early stage lithic reduction at MP sites in the Jubbah palaeolake basin, in the Nefud Desert, northern Saudi Arabia. We describe the sites identified during our surveys, and we use petrographic studies to demonstrate that MP assemblages were mostly produced from differing forms of ferru-ginous quartzite. These raw materials do not substantially vary in composition, although they are not identical in terms of factors such as grain size and the proportion of iron oxide. We then describe the lithic technology at these sites, with a particular focus on the largest assemblage identified, Jebel Katefeh-12 (JKF-12), which provides detailed information on lithic reduction at a quartzite source. Analyses from this site are then considered together with data from other MP sites in the Jubbah basin, where similar raw material was used. The results indicate that factors such as initial clast size/shape and reduction intensity play important roles in influencing aspects of morphological and technological variability. Our results suggest that incursions of MP populations into northern Arabia were probably temporally limited, as might be expected in a marginal and generally arid region. MP raw material procurement sites provide a highly visible signal of these ephemeral incursions, providing information on the ways that human populations adapted to the challenging conditions of the Saharo-Arabian arid belt.

The early part of Marine Isotope Stage (MIS) 3 (ca. 60–50 ka) is a crucial period for studying human demography and behaviour in southwest Asia, and how these relate to climatic changes. However, the archaeological and palaeoenvironmental records for MIS 3 in critical areas such as the Arabian Peninsula remain poorly developed. Here, we present findings from the Al Marrat basin in the Nefud desert, which provides the first clear evidence for both increased humidity and human occupation of the interior of northern Arabia during early MIS 3. A Middle Palaeolithic assemblage, dated by optically stimulated luminescence to ca. 55 ka, was found stratified within a sequence of relict palustrine deposits indicative of shallow water body formation in the Al Marrat basin. Hominin presence in northern Arabia at this time coincides with the intensification and northward displacement of monsoon rainfall systems during a period of maximum insolation. These findings add to a growing corpus of palaeoenvironmental evidence, which indicates that the Arabian interior was neither arid nor unpopulated during early MIS 3, and that hydrodynamic responses to enhanced moisture availability facilitated demographic expansions into the Arabian interior.

Enzel et al. (2015) reassess sedimentary records of Early to Mid-Holocene lake sites in Arabia based on a reinter-pretation of published multiproxy data and a qualitative analysis of satellite imagery. The authors conclude that these sites represent palaeo-wetland environments rather than palaeolakes and that the majority of the Arabian Peninsula experienced no or, if at all, only a very minor increase of rainfall at that time mainly due to eastward expansion of the East African Summer Monsoon. We disagree with their reassessment and identify several cases where unequivocal evidence for early Late Pleistocene and Early to Mid-Holocene perennial lake environments in Arabia, lasting for centuries to millennia, was neglected by Enzel et al. (2015). Here we summarize findings which indicate the presence of lakes from the sites of Jubbah, Tayma, Mundafan (all Saudi Arabia), Wahalah, Awafi (both UAE), and the Wahiba Sands (Oman), supported by evidence including occurrence of barnacle colonies in living position, remnant bioclastic shoreline deposits, undisturbed varve formation, shallowing-up lacus-trine sequences, various aquatic freshwater, brackish and saline micro-and macrofossils, such as ichnofaunal remains, which are the result of prolonged field-based research. While the precise depth, hydrology and ecology of these water bodies is still not entirely resolved, their perennial nature is indicative of a markedly increased precipitation regime, which, in combination with more abundant groundwater and increased spring outflow in terminal basins fed by charged aquifers, was sufficient to overcome evaporative losses. The palaeolakes' influence on sustaining prehistoric populations is corroborated by the presence of rich archaeological evidence.

This study investigates hydrological responses to climatic shifts using sediment flux data derived from two dated palaeolake records in south-east Arabia. Flux values are generally low during the early Holocene humid period (EHHP) (∼9.0–6.4k cal a BP) although several short-lived pulses of increased detrital input are recorded, the most prominent of which is dated between ∼8.3 and 7.9k cal a BP. The EHHP is separated from the mid-Holocene humid period (MHHP) (∼5.0–4.3k cal a BP) by a phase of increased sediment flux and aridity, which began between ∼6.4 and 5.9k cal a BP and peaked between ∼5.2 and 5.0k cal a BP. The termination of the MHHP is marked by a phase of high detrital sediment flux between ∼4.3 and 3.9k cal a BP. While long-term shifts in climate are most likely linked to changes in the summer position of the Intertropical Convergence Zone and associated Indian and African monsoon systems, it is noted that the abrupt, short-term phases of aridity observed in both records are coeval with intervals of rapid climate change globally, which triggered non-linear, widespread landscape reconfigurations throughout south-east Arabia.

The dispersal of human populations out of Africa into Arabia was most likely linked to
episodes of climatic amelioration, when increased monsoon rainfall led to the activation of drainage systems, improved freshwater availability, and the development of regional vegeta- tion. Here we present the first dated terrestrial record from southeast Arabia that provides evidence for increased rainfall and the expansion of vegetation during both glacial and inter- glacial periods. Findings from extensive alluvial fan deposits indicate that drainage system activation occurred during Marine Isotope Stage (MIS) 6 (ca. 160–150 ka), MIS 5 (ca. 130–75 ka), and during early MIS 3 (ca. 55 ka). The development of active freshwater systems during these periods corresponds with monsoon intensity increases during insolation maxima, sug- gesting that humid periods in Arabia were not confined to eccentricity-paced deglaciations, and providing paleoenvironmental support for multiple windows of opportunity for dispersal out of Africa during the late Pleistocene.

The Arabian Peninsula is situated at an important crossroads for the movement of Pleistocene human populations out of, and into, Africa. Although the timings, routes and frequencies of such dispersals have not yet been confirmed by genetic, fossil or archaeological evidence, expansion into Arabia would have been facilitated by humid periods driven by incursions of monsoon rainfall, potentially from both Indian Ocean and African monsoon systems. Here we synthesise terrestrial and marine core palaeoclimatic data in order to establish the spatial and temporal variability of humid periods in Arabia between late Marine Isotope Stage (MIS) 7 and 3. Incursions of monsoon rainfall occurred during periods of insolation maxima at ca. 200e190, 170, 155, 130e120, 105e95, 85e75 and 60e55 ka, providing multiple ‘windows’ of favourable climatic conditions that could have facilitated demographic expansion through Arabia. Strong summer monsoons are generally associated with mid-high latitude interglacials, however, enhanced monsoon convection also brought rainfall into Arabia during global glacial phases, possibly due to a strengthened winter monsoon and a greater influence of southern hemispheric temperature changes. Key periods for dispersal into northern regions of Arabia correspond with the synchronous intensifica- tion of both eastern Mediterranean and monsoon rainfall systems at insolation maxima during MIS 7 and MIS 5, which may have facilitated demographic connectivity between the Levant and the Arabian interior. Environmental conditions throughout southern and southeast regions were also favourable to expansion during these times, although strong monsoons in these regions during MIS 6 and MIS 3 suggest further opportunities for demographic expansion and exchange. Terrestrial and marine evidence show that during early MIS 3 (ca. 60e50 ka), a strengthened monsoon led to the activation of interior drainage systems and increased productivity in coastal zones, indicating that favourable environmental conditions existed along both coastal and interior routes at that time.

Current fossil, genetic, and archeological data indicate that Homo sapiens originated in Africa in the late Middle Pleistocene. By the end of the Late Pleistocene, our species was distributed across every continent except Antarctica, setting the foundations for the subsequent demographic and cultural changes of the Holocene. The intervening processes remain intensely debated and a key theme in hominin evolutionary studies. We review archeological, fossil, environmental, and genetic data to evaluate the current state of knowledge on the dispersal of Homo sapiens out of Africa. The emerging picture of the dispersal process suggests dynamic behavioral variability, complex interactions between populations, and an intricate genetic and cultural legacy. This evolutionary and historical complexity challenges simple narratives and suggests that hybrid models and the testing of explicit hypotheses are required to understand the expansion of Homo sapiens into Eurasia.

Climatic changes in Arabia are of critical importance to our understanding of both monsoon variability and the dispersal of anatomically modern humans (AMH) out of Africa. The timing of dispersal is associated with the occurrence of pluvial periods during Marine Isotope Stage (MIS) 5 (ca. 130e74 ka), after which arid conditions between ca. 74 and 10.5 ka are thought to have restricted further migra- tion and range expansion within the Arabian interior. Whilst a number of records indicate that this phase of aridity was punctuated by an increase in monsoon strength during MIS 3, uncertainties regarding the precision of terrestrial records and suitability of marine archives as records of precipitation, mean that the occurrence of this pluvial remains debated. Here we present evidence from a series of relict lake deposits within southeastern Arabia, which formed at the onset of MIS 3 (ca. 61e58 ka). At this time, the incursion of monsoon rainfall into the Arabian interior activated a network of channels associated with an alluvial fan system along the western flanks of the Hajar Mountains, leading to lake formation. Multiproxy evidence indicates that precipitation increases intermittently recharged fluvial systems within the region, leading to lake expansion in distal fan zones. Conversely, decreased precipitation led to reduced channel flow, lake contraction and a shift to saline conditions. These findings are in contrast to the many other palaeoclimatic records from Arabia, which suggest that during MIS 3, the latitudinal position of the monsoon was substantially further south and did not penetrate the peninsula. Addi- tionally, the occurrence of increased rainfall at this time challenges the notion that the climate of Arabia following MIS 5 was too harsh to permit the further range expansion of indigenous communities.

Located at the crossroads between Africa and Eurasia, Arabia occupies a pivotal position for human migration and dispersal during the Late Pleistocene. Deducing the timing of humid and arid phases is critical to understanding when the Rub' al-Khali desert acted as a barrier to human movement and settlement. Recent geological mapping in the northern part of the Rub' al-Khali has enabled the Qua- ternary history of the region to be put into a regional stratigraphical framework. In addition to the active dunes, two significant palaeodune sequences have been identified. Dating of key sections has enabled a chronology of dune accretion and stabilisation to be determined. In addition, previously published optically stimulated luminescence (OSL) dates have been put in their proper stratigraphical context, from which a record of Late Pleistocene dune activity can be constructed. The results indicate the record of dune activity in the northern Rub' al-Khali is preservation limited and is synchronous with humid events driven by the incursion of the Indian Ocean monsoon.

The Empty Quarter (or Rub' al Khali) of the Arabian Peninsula is the largest continuous sandy desert in
the world. It has been known for several decades that Late Pleistocene and Holocene deposits, representing
phases of wetter climate, are preserved there. These sequences have yielded palaeontological
evidence in the form of a variety of vertebrate and invertebrate fossils and have been dated using various
radiometric techniques. However, evidence for human presence during these wetter phases has until
now been ephemeral. Here, we report on the first stratified and dated archaeology from the Empty
Quarter, recovered from the site of Mundafan Al-Buhayrah (MDF-61). Human occupation at the site,
represented by stone tools, has been dated to the later part of Marine Isotope Stage (MIS) 5 using
multiple luminescence dating techniques (multigrain and single grain OSL, TT-OSL). The sequence consists
primarily of lacustrine and palustrine sediments, from which evidence for changing local environmental
conditions has been obtained through analysis of fossil assemblages (phytoliths and nonmarine
molluscs and ostracods). The discovery of securely-dated archaeological material at ~100 to
80 ka in the Empty Quarter has important implications for hypotheses concerning the timing and routes
of dispersal of Homo sapiens out of Africa, which have been much debated. Consequently, the data
presented here fill a crucial gap in palaeoenvironmental and archaeological understanding of the
southern Arabian interior. Fossils of H. sapiens in the Levant, also dated to MIS 5, together with Middle
Palaeolithic archaeological sites in Arabia and India are thought to represent the earliest dispersal of our
species out of Africa. We suggest that the widespread occurrence of similar lithic technologies across
southern Asia, coupled with a growing body of evidence for environmental amelioration across the
Saharo-Arabian belt, indicates that occupation of the Levant by H. sapiens during MIS 5 may not have
been a brief, localized ‘failed dispersal’, but part of a wider demographic expansion.

The current paucity of Pleistocene vertebrate records from the Arabian Peninsula e a landmass of over 3 million km 2 e is a significant gap in our knowledge of the Quaternary. Such data are critical lines of contextual evidence for considering animal and hominin dispersals between Africa and Eurasia generally, and hominin palaeoecology in the Pleistocene landscapes of the Arabian interior specifically. Here, we describe an important contribution to the record and report stratigraphically-constrained fossils of mammals, birds and reptiles from recent excavations at Ti's al Ghadah in the southwestern Nefud Desert. Combined U-series and ESR analyses of Oryx sp. teeth indicate that the assemblage is Middle Pleistocene in age and dates to ca. 500 ka. The identified fauna is a biogeographical admixture that consists of likely endemics and taxa of African and Eurasian affinity and includes extinct and extant (or related Pleistocene forms of) mammals (. alba) and reptiles (Varanidae/Uromastyx sp.). We infer that the assemblage reflects mortality in populations of herbivorous animals and their predators and scavengers that were attracted to freshwater and plant resources in the inter-dune basin. At present, there is no evidence to suggest hominin agency in the accumulation of the bone assemblages. The inferred ecological characteristics of the taxa recovered indicate the presence, at least periodically, of substantial water-bodies and open grassland habitats.

The animal species depicted in the rock art of Shuwaymis, Saudi Arabia, provide a record of Holocene climatic changes, as seen by the engravers. Of 1903 animal engravings, 1514 contained sufficient detail to allow identification with confidence. In addition, the stratigraphy of the engravings and the depiction of domesticates provide a broad chronological framework that allows a division into images created during the Holocene humid phase and animals represented after the onset of desert conditions. Despite the large sample size, only 16 animal species could be identified, which represents an extraordinarily narrow species spectrum. Comparison with the scarce faunal record of the Arabian Peninsula shows that all larger animals that are thought to have been present in the area were also depicted in the rock art. The contemporaneous presence of at least four large carnivores during the Holocene humid phase suggests that prey animals were abundant, and that the landscape consisted of a mosaic of habitats, potentially with thicker vegetation along the water courses of the wadis and more open vegetation in the landscape around them. Community Earth System Models (COSMOS) climate simulations show that Shuwaymis was at the northern edge of the African Summer Monsoon rainfall regime. It is therefore possible that Shuwaymis was ecologically connected with southwestern Arabia, and that an arid barrier remained in place to the north, restricting the dispersal of Levantine species into Arabia.

The Pleistocene archaeological record of the Arabian Peninsula is increasingly recognized as being of great
importance for resolving some of the major debates in hominin evolutionary studies. Though there has been
an acceleration in the rate of fieldwork and discovery of archaeological sites in recent years, little is known
about hominin occupations in the Pleistocene over vast areas of Arabia. Here we report on the
identification of five new Middle Palaeolithic sites from the Nejd of central Arabia and the southern
margins of the Nefud Desert to the north. The importance of these sites centers on their diversity in terms
of landscape positions, raw materials used for lithic manufacture, and core reduction methods. Our
findings indicate multiple hominin dispersals into Arabia and complex subsequent patterns of behavior
and demography.

Freshwater availability is critical for human survival, and in the Saharo-Arabian desert belt repeated fluctuations between aridity and humidity over the Quaternary mean the distribution of freshwater was likely a primary control upon routes and opportunities for hominin dispersals. However, our knowledge of the spatio-temporal distribution of palaeohydrological resources within Arabia during MideLate Pleistocene episodes of climatic amelioration remains limited. In this paper we outline a combined method for remotely mapping the location of palaeodrainage and palaeolakes in currently arid regions that were formerly subject to more humid conditions. We demonstrate the potential of this approach by mapping palaeochannels across the whole Arabian Peninsula, and palaeolakes and marshes for select regions covering c. 10% of its surface. Our palaeodrainage mapping is based upon quantitative thresh- olding of HydroSHEDs data, which applies flow routing to Digital Elevation Model (DEM) data, while our palaeolake mapping uses an innovative method where spectral classification of Landsat Thematic Mapper (TM) imagery is used to detect palaeolake deposits within endorheic (closed) basins, before modelling maximum lake extents by flooding the basin to the level of the elevation of the highest detected deposit. Field survey in the Nefud desert and the Dawadmi and Shuwaymis regions of Saudi Arabia indicates accuracies of 86% for palaeodrainage mapping, and 96% for identifying former palae- olake basins (73% accuracy of classification of individual deposits). The palaeolake mapping method has also demonstrated potential for identifying surface and stratified archaeological site locations, with 76% of the surveyed palaeolake basins containing archaeological material, including stratified Palaeolithic archaeology. Initial examination of palaeodrainage in relation to archaeological sites indicates a relationship between mapped features and previously recorded Palaeolithic sites. An example of the application of these data for period-specific regional palaeohydrological and archaeological re- constructions is presented for a region of Northern Saudi Arabia covering the southern Nefud desert and adjacent lava fields.

The Arabian Peninsula is a key region for understanding hominin dispersals and the effect of climate change on prehistoric demography, although little information on these topics is presently available owing to the poor preservation of archaeological sites in this desert environment. Here, we describe the discovery of three stratified and buried archaeological sites in the Nefud Desert, which includes the oldest dated occupation for the region. The stone tool assemblages are identified as a Middle Palaeolithic industry that includes Levallois manufacturing methods and the production of tools on flakes. Hominin occupations correspond with humid periods, particularly Marine Isotope Stages 7 and 5 of the Late Pleistocene. The Middle Palaeolithic occupations were situated along the Jubbah palaeolake-shores, in a grassland setting with some trees. Populations procured different raw materials across the lake region to manufacture stone tools, using the implements to process plants and animals. To reach the Jubbah palaeolake, Middle Palaeolithic populations travelled into the ameliorated Nefud Desert interior, possibly gaining access from multiple directions, either using routes from the north and west (the Levant and the Sinai), the north (the Mesopotamian plains and the Euphrates basin), or the east (the Persian Gulf). The Jubbah stone tool assemblages have their own suite of technological characters, but have types reminiscent of both African Middle Stone Age and Levantine Middle Palaeolithic industries. Comparative inter-regional analysis of core technology indicates morphological similarities with the Levantine Tabun C assemblage, associated with human fossils controversially identified as either Neanderthals or Homo sapiens.

In Arabia the transition to a Neolithic economy is thought to be characterised by a shift to mobile pastoralism, rather than the traditional icons of the Neolithic such as sedentism and crop cultivation. However, in the absence of detailed archaeological research, the Early Holocene prehistory of central, northern and northwestern Saudi Arabia remains largely unknown. Here we use the engraved rock art recorded on 254 panels in Shuwaymis, Ha’il Province, and in particular depictions of hunting and herding scenes, to identify evidence on the character of the Neolithic transition in the region. Due to high levels of erosion it was not possible to carry out spatial analysis of the sites. However, the content and stratigraphic relationship of hunting and herding panels, re-engraving events, and cultural markers related to human figures were analysed. The results show that the engravings can be divided into an exclusive hunting period, where equids are frequently being hunted. Domestic cattle are often placed over and integrated into existing hunting scenes by re-engraving parts of the scene and turning hunting figures into herding figures. Cultural markers associated with human depictions such as headdresses and possible penis sheaths continue across both periods. The evidence in the rock art indicates that herding was adopted by local hunters. Moreover, the rock art shows that herders identified with the depicted hunters and that ibex hunting remained part of the image repertoire, and potentially of the subsistence economy, throughout the Holocene.

The Neolithic peopling of Arabia is a subject of increasing debate, as different scenarios are proposed to describe the relatively sudden appearance of seemingly homogeneous archaeological sites throughout the south of the Peninsula during the Early Holocene. Such sites are identified by the co-occurrence of a laminar core reduction strategy with its supposed fossile directeur, the " Fasad point. " This techno-typological package has been used by some to link these sites with an expansion of pastoralists from the Levant. A recent study of blade technologies in Southern Arabia, however, demonstrates a large degree of internal variability within these reduction strategies, whilst an interregional study of Fasad points reveals this artifact category to be both time-transgressive and morpho-metrically variable across parts of Southern Arabia. Archaeological findings from al-Hatab Rockshelter in Dhofar, Oman go further to challenge the notion of an expansion originating in the Levant and spreading across Southern Arabia. Here we demonstrate that an indigenous occupation with a blade technology and tanged points pre-dates the 'Levantine expansion' by at least four millennia. Based on the lithic assemblage from al-Hatab, we argue the Arabian Late Palaeolithic developed locally in Southern Arabia, forming part of the previously defined Nejd Leptolithic tradition. The evidence from al-Hatab in conjunction with recent genetic findings indicates that some groups in Southern Arabia have persisted there since the Late Paleolithic ca 13,000 years ago, if not earlier. Résumé : Le peuplement néolithique de l'Arabie est devenu le sujet de nombreux débats, alors que différents scénarios ont été proposés pour expliquer l'apparition soudaine de sites archéologiques apparemment homogènes à travers le sud de la péninsule au cours de l'Holocène ancien. Ces sites sont identifiés par la concomitance d'une stratégie de débitage laminaire avec son fossile directeur supposé : la « pointe de Fasad ». Cet assemblage typo-technologique est utilisé pour relier ces sites à l'expansion de pasteurs venus du Levant. Une étude technologique récente sur le débitage laminaire d'Arabie du Sud a cependant montré une forte variabilité parmi ces stratégies de débitage, alors qu'une étude interrégionale des « pointes de Fasad » révèle que ce type est à la fois trans-chronologique et de morphométrie différente suivant les régions d'Arabie. Les découvertes archéologiques dans l'abri d'al-Hatab, dans le Dhofar (Oman), contredisent le scénario d'une origine levantine, démontrant l'existence d'une occupation indigène qui possédait une technologie laminaire et des pointes pédonculées, et qui précédait « l'expansion levantine » de plusieurs millénaires. Dans cet article, nous utilisons l'assemblage lithique d'al-Hatab pour définir une nouvelle industrie au sein du Paléolithique récent d'Arabie du Sud, qui se développe localement et appelée le Hatabien. Les vestiges provenant d'al-Hatab, ainsi que les données génétiques, suggèrent que des groupes en Arabie du Sud ont perduré sur place depuis le Paléolithique récent, il y a 10 000 à 15 000 ans.

Despite the numerous studies proposing early human population expansions from Africa into Arabia during the Late Pleistocene, no archaeological sites have yet been discovered in Arabia that resemble a specific African industry, which would indicate demographic exchange across the Red Sea. Here we report the discovery of a buried site and more than 100 new surface scatters in the Dhofar region of Oman belonging to a regionally-specific African lithic industry - the late Nubian Complex - known previously only from the northeast and Horn of Africa during Marine Isotope Stage 5, ,128,000 to 74,000 years ago. Two optically stimulated luminescence age estimates from the open-air site of Aybut Al Auwal in Oman place the Arabian Nubian Complex at ,106,000 years ago, providing archaeological evidence for the presence of a distinct northeast African Middle Stone Age technocomplex in southern Arabia sometime in the first half of Marine Isotope Stage 5.

The dispersal of Homo sapiens out of Africa has been extensively researched across several disciplines. Here we review the evidence for spatial and temporal variability in lithic (stone tool) technologies relative to the predictions of two major hypotheses: 1) that a single successful dispersal occurred 60-50 thousand years ago (ka), marked by a trail of geometric/microlithic technologies, and 2) that multiple dispersals occurred, beginning much earlier (probably in Marine Isotope Stage [MIS] 5), associated with Middle Palaeolithic technology in its early phase. Our results show that Late Pleistocene geometric/ microlithic technologies exhibit significant temporal and regional differences between each other. These differences suggest independent, convergent origins for these technologies, which are likely to have been repeatedly re-invented. In contrast, we identify similarities between East African lithic technologies from MIS 8 onwards and Middle Palaeolithic assemblages as far east as India by MIS 5. That this constellation of technological features e particularly an emphasis on centripetal Levallois reduction reflecting inter- changeable preferential and recurrent methods, along with particular retouched forms such as points e transcends ecologies and raw material types suggests that it is unlikely to entirely reflect technological convergence (analogy). Our results indicate an early onset of multiple dispersals out of Africa. The hy- pothesis of an early onset to successful dispersal is entirely consistent with the possibility of further subsequent (post-MIS 5) dispersals out of Africa. Testing such hypotheses through quantified compar- ative lithic studies and interdisciplinary research is therefore likely to significantly advance under- standing of the earliest H. sapiens dispersals.

Climate models are potentially useful tools for addressing human dispersals and demographic change. The Arabian Peninsula is becoming increasingly significant in the story of human dispersals out of Africa during the Late Pleistocene. Although characterised largely by arid environments today, emerging climate records indicate that the peninsula was wetter many times in the past, suggesting that the region may have been inhabited considerably more than hitherto thought. Explaining the origins and spatial distribution of increased rainfall is challenging because palaeoenvironmental research in the region is in an early developmental stage. We address environmental oscillations by assembling and analysing an ensemble of five global climate models (CCSM3, COSMOS, HadCM3, KCM, and NorESM). We focus on precipitation, as the variable is key for the development of lakes, rivers and savannas. The climate models generated here were compared with published palaeoenvironmental data such as palaeolakes, speleo- thems and alluvial fan records as a means of validation. All five models showed, to varying degrees, that the Arabia Peninsula was significantly wetter than today during the Last Interglacial (130 ka and 126/ 125 ka timeslices), and that the main source of increased rainfall was from the North African summer monsoon rather than the Indian Ocean monsoon or from Mediterranean climate patterns. Where available, 104 ka (MIS 5c), 56 ka (early MIS 3) and 21 ka (LGM) timeslices showed rainfall was present but not as extensive as during the Last Interglacial. The results favour the hypothesis that humans potentially moved out of Africa and into Arabia on multiple occasions during pluvial phases of the Late Pleistocene.

The dispersal of Homo sapiens out of Africa has been extensively researched across several disciplines. Here we review the evidence for spatial and temporal variability in lithic (stone tool) technologies relative to the predictions of two major hypotheses: 1) that a single successful dispersal occurred 60–50 thousand years ago (ka), marked by a trail of geometric/microlithic technologies, and 2) that multiple dispersals occurred, beginning much earlier (probably in Marine Isotope Stage [MIS] 5), associated with Middle Palaeolithic technology in its early phase. Our results show that Late Pleistocene geometric/microlithic technologies exhibit significant temporal and regional differences between each other. These differences suggest independent, convergent origins for these technologies, which are likely to have been repeatedly re-invented. In contrast, we identify similarities between East African lithic technologies from MIS 8 onwards and Middle Palaeolithic assemblages as far east as India by MIS 5. That this constellation of technological features – particularly an emphasis on centripetal Levallois reduction reflecting interchangeable preferential and recurrent methods, along with particular retouched forms such as points – transcends ecologies and raw material types suggests that it is unlikely to entirely reflect technological convergence (analogy). Our results indicate an early onset of multiple dispersals out of Africa. The hypothesis of an early onset to successful dispersal is entirely consistent with the possibility of further subsequent (post-MIS 5) dispersals out of Africa. Testing such hypotheses through quantified comparative lithic studies and interdisciplinary research is therefore likely to significantly advance understanding of the earliest H. sapiens dispersals.

The dispersal of human populations out of Africa into Arabia was most likely linked to episodes of climatic amelioration, when increased monsoon rainfall led to the activation of drainage systems, improved freshwater availability, and the development of regional vegetation. Here we present the first dated terrestrial record from southeast Arabia that provides evidence for increased rainfall and the expansion of vegetation during both glacial and inter- glacial periods. Findings from extensive alluvial fan deposits indicate that drainage system activation occurred during Marine Isotope Stage (MIS) 6 (ca. 160–150 ka), MIS 5 (ca. 130–75 ka), and during early MIS 3 (ca. 55 ka). The development of active freshwater systems during these periods corresponds with monsoon intensity increases during insolation maxima, suggesting that humid periods in Arabia were not confined to eccentricity-paced deglaciations, and providing paleoenvironmental support for multiple windows of opportunity for dispersal out of Africa during the late Pleistocene.

The Arabian Peninsula is situated at an important crossroads for the movement of Pleistocene human populations out of, and into, Africa. Although the timings, routes and frequencies of such dispersals have not yet been confirmed by genetic, fossil or archaeological evidence, expansion into Arabia would have been facilitated by humid periods driven by incursions of monsoon rainfall, potentially from both Indian Ocean and African monsoon systems. Here we synthesise terrestrial and marine core palaeoclimatic data in order to establish the spatial and temporal variability of humid periods in Arabia between late Marine Isotope Stage (MIS) 7 and 3. Incursions of monsoon rainfall occurred during periods of insolation maxima at ca. 200e190, 170, 155, 130e120, 105e95, 85e75 and 60e55 ka, providing multiple ‘windows’ of favourable climatic conditions that could have facilitated demographic expansion through Arabia. Strong summer monsoons are generally associated with mid-high latitude interglacials, however, enhanced monsoon convection also brought rainfall into Arabia during global glacial phases, possibly due to a strengthened winter monsoon and a greater influence of southern hemispheric temperature changes. Key periods for dispersal into northern regions of Arabia correspond with the synchronous intensifica- tion of both eastern Mediterranean and monsoon rainfall systems at insolation maxima during MIS 7 and MIS 5, which may have facilitated demographic connectivity between the Levant and the Arabian interior. Environmental conditions throughout southern and southeast regions were also favourable to expansion during these times, although strong monsoons in these regions during MIS 6 and MIS 3 suggest further opportunities for demographic expansion and exchange. Terrestrial and marine evidence show that during early MIS 3 (ca. 60e50 ka), a strengthened monsoon led to the activation of interior drainage systems and increased productivity in coastal zones, indicating that favourable environmental conditions existed along both coastal and interior routes at that time.

The interpretation of Acheulean landscape use through the analysis of artefact distributions over a range of environmental settings is vital for understanding early hominin behaviour. Such approaches have been successfully applied in areas such as East Africa and South Africa, where long-term and sustained archaeological research has led to the development of robust environmental frameworks within which to analyse hominin land-use patterns. Much less is known about Acheulean hominin behaviour in the Arabian Peninsula, which is increasingly being recognised as an important area for studying early hominin dispersals and adaptations to new environments. To address this lacuna, we have undertaken the first multi-scale systematic survey of Acheulean occupation evidence at Dawadmi, in the centre of the Arabian Peninsula. Specifically, we carried out systematic transect surveys over a large andesite dyke at Saffaqah, on which the majority of 26 known Acheulean sites are associated, as well as across narrow drainage channels, desert pavements and hills located within 5 km of the dyke. Survey transects also crossed neighbouring dykes and adjacent landscape units with a 25 20 km area. Our surveys at Saf- faqah have led to the discovery of 14 new Acheulean sites. Initial lithic analyses reveal differences be- tween sites in terms of typology, but further work on the assemblages is required to determine if these differences are behavioural or a product of post depositional processes. A broad regional survey was undertaken to identify the full extent of Acheulean activity around Dawadmi. This led to the discovery of a further 22 sites. There is a strong correspondence between Acheulean sites and fine-grained andesite dykes, which were major lithic raw material sources. No Acheulean sites in the study area were found away from dykes or their adjacent landscape units. Based on dyke distributions, the geographic range of Acheulean activity is estimated to be 100 55 km, making Dawadmi one of the largest Acheulean landscapes in the world.

Archaeological, geoarchaeological and geochronological research at the Terminal Pleistocene/Early Holocene
sites of al-Hatab, Ghazal and Khamseen Rockshelters help to elucidate our understanding of the
Late Palaeolithic occupation of the South Arabian Highlands. The stone tools found at these sites are
attributed to the Nejd Leptolithic tradition; an autochthonous lithic culture found across Dhofar (Oman).
The artifact-bearing deposits excavated within these rockshelters have been chronologically constrained
by optically stimulated luminescence dating, while sedimentological analyses help to establish site
formation processes. Together, these methods provide a chronological anchor for some Nejd Leptolithic
archaeological findspots across Dhofar. The archaeological evidence from surface and stratified sites
indicates a technological continuum across the shifting climatic regimes of the Terminal Pleistocene/
Early Holocene. This technological continuity points to possible population persistence within one of the
posited South Arabian refugia.