The climate history of the major dryland zones of the world, such as the Saharo-Arabian Desert belt, plays a key role in the dispersal of early humans through these intermittently inhospitable regions. Here, we assess the relative intensity of Late Quaternary humid phases in northern Arabia through lithological, geochemical, palaeoecological and geochronological analysis of three sediment sequences in the Nefud Desert. Two sequences are marl beds that accumulated in perennial, groundwater-fed lake systems during two distinct humid phases that occurred in MIS 5e and MIS 5a. The third records sediment accumulation within an ephemeral lake system during the terminal Pleistocene/early Holocene. The altitude of the two MIS 5 deposits indicates that the water table must have reached altitudes of >929 m ASL (MIS 5e) and >922 m ASL (MIS 5a). In contrast, the sedimentary characteristics of the early Holocene sequence imply that, during this interval, the water table was <917 m ASL. These results indicate that, in relative terms, the humid phase of the Holocene was significantly drier than other Late Quaternary humid phases, a conclusion that is consistent with a growing body of evidence from across the Saharo-Arabian Desert belt. These findings are discussed relative to human dispersal/occupation and palaeoclimatic conditions in northern Arabia during Late Quaternary humid phases.

Recent discoveries in Malta and Tunisia provocatively point to a possible web of Mesolithic/Epipalaeolithic sea crossings, encounters, and exchanges that linked continents long before the age of the sail (Lipson et al. 2025; Scerri et al 2025). Determining whether such connections were singular events or sustained episodes is therefore critical to illuminate the scale of early seafaring. Here, we model how patterns of sea-level change impacted land connectivity between Sicily and Malta and predict potential population sizes through time from the Last Glacial Maximum to evaluate whether Mesolithic hunter-gatherers could have persisted on Malta, or if sustained connections would have been required. To achieve this, we use reconstructions of sea-level change and modern bathymetric models to evaluate changes in land size areas and connectivity. We calculate Net Primary Productivity values for a high-resolution palaeoclimate dataset, which we translate to population density by comparisons to ethnographic datasets. Finally, we calculate changes in estimated population sizes through time for Malta and Sicily, as well as minimum distances of sea voyages. Our results show that following disconnection from Sicily, Malta would have been unsuitable to support a viable, persistent forager population, including for the minimum 1000-year timespan of the Maltese Mesolithic record. As a result, only repeated, long-distance sea voyaging can explain the longevity of Mesolithic occupations of Malta, opening up the possibility that other south-central Mediterranean islands were reached and explaining the presence of European hunter-gatherer ancestry in North Africa.

Throughout the Holocene, humans covered the landscape of Arabia in hundreds of thousands of diverse dry-stone structures. These archaeological remains are predominantly funerary structures, enclosures, and camps although they also include ritualised features such as mustatils, all of which form essential components for understanding Neolithic and Bronze Age peninsular societies and their dynamic relationships with the natural environment. Archaeologists typically document these structures by either mapping them in the field or applying manual digitisation within a Geographic Information System (GIS) framework. Such methods are time consuming and can be expensive, especially in the case of field documentation. In order to develop a more time- and cost-effective method for identifying large numbers of stone features, we have tested three pre-trained semantic segmentation Deep Learning models (MA-Net, SegFormer, and U-Net) for semi-automatic feature detection by applying them to satellite imagery of archaeological landscapes in northwestern Saudi Arabia.The results show that, the MA-Net model performed best on averaged metrics, however, the SegFormer model showed more stable metrics during training. We present confusion matrices to show that the SegFormer model is more consistently able to correctly identify stone structures, regardless of structure types, in contrast to the U-Net and MA-Net models. While survey and excavation of these structures is essential for producing fine-resolution data, automated workflows that incorporate remote sensing data can generate the breadth of coverage required for interpreting ancient social landscapes on a wider geographic scale. Such mapping is also critical for defining and protecting cultural heritage across the vast arid landscapes of desert regions such as Arabia and the Sahara.

Northeast Africa and Southwest Asia present a rich record of hominin occupations between ca. 100 and 50 thousand years ago (ka) at a critical biogeographic crossroads, with differences in physical landscapes, environmental responses to climate change, and varied population histories contributing to archaeological diversity. Research in Arabia has identified previously unexplained technological heterogeneity amongst stone tool assemblages. To investigate this pattern, we compiled a database of Levallois blank attributes to quantify patterns of variability observed across sites in Northeast Africa, Arabia, and the Levant. A range of alternate explanations for variability within this comparative dataset are explored using Simple Mantel tests and Multiple Matrix regressions including assemblage age, landscape setting, palaeoenvironmental conditions, assemblage size, composition and raw material use, site type, and population history. The results highlight that shape variability in Levallois blanks across the region is best explained by differences in population history. We then train logistical regression models to differentiate the population history associated with Levallois blanks with a >93% agreement rate and apply this model to key Arabian assemblages dating to ca. 55 ka. The results strongly support a Neanderthal attribution. We interpret these findings in the context of wider debates surrounding Neanderthal expansions and a wider role for Arabia in South-West Asian hominin demography.

In the recent past, evolutionarily speaking, every other kind of hominin, from the Neanderthals of western Eurasia to the ‘hobbits’ of Flores, became extinct while our species prospered and spread across the world, from remote islands to high mountains. Understanding how, why, and when this global spread of Homo sapiens occurred is a major question in human evolutionary studies. While there is broad agreement on our African origin and subsequent global expansion, currently fossil, genetic, and archaeological data and perspectives on the details of this process are, if not actively contradictory, then certainly uncomfortable bedfellows. In part, this uncertainty reflects the profound spatial and temporal biases in currently available archaeological, fossil, and genetic samples. However, there are also methodological and theoretical aspects which limit understanding. Two central examples, reviewed in this paper, are the challenges of accurately dating palaeoanthropological sites and the continuing influence of the outdated concept of a ‘Human Revolution’ and the related concept of ‘modernity’, in both cultural and biological forms.

The Maltese archipelago is a small island chain that is among the most remote in the Mediterranean. Humans were not thought to have reached and inhabited such small and isolated islands until the regional shift to Neolithic lifeways, around 7.5 thousand years ago (ka) 1 . In the standard view, the limited resources and ecological vulnerabilities of small islands, coupled with the technological challenges of long-distance seafaring, meant that hunter-gatherers were either unable or unwilling to make these journeys 2–4 . Here we describe chronological, archaeological, faunal and botanical data that support the presence of Holocene hunter-gatherers on the Maltese islands. At this time, Malta’s geographical configuration and sea levels approximated those of the present day, necessitating seafaring distances of around 100 km from Sicily, the closest landmass. Occupations began at around 8.5 ka and are likely to have lasted until around 7.5 ka. These hunter-gatherers exploited land animals, but were also able to take advantage of marine resources and avifauna, helping to sustain these groups on a small island. Our discoveries document the longest yet-known hunter-gatherer sea crossings in the Mediterranean, raising the possibility of unknown, precocious connections across the wider region.

Drylands cover almost half of Earth’s land surfaces, supporting ~30% of the world’s population. The International Panel on Climate Change predicts increasing aridification and expansion of drylands over the course of this century. As we approach new climate states without societal precedent, Earth’s geological past may offer the best tool to understand hydroclimate change under previously, allowing us to elucidate responses to external forcing. Paleo-records from previously warm and high-CO2 periods in Earth’s past, such as the mid-Pliocene (~3 Ma), point towards higher humidity in many dryland regions. Here, we examine desert speleothems from the hyper-arid desert in central Arabia, part of the largest near-continuous chain of drylands in the world, stretching from north-western Africa to the northern China, to elucidate substantial and recurrent humid phases over the past 8 million years. Independent quantitative paleo-thermometers suggest that mean annual air temperatures in central Arabia were approximately between 1 to 5 °C warmer than today. The analyses of the isotopic composition (δ18O and δ2H) of speleothem fluid inclusion waters, representing ‘fossil rainwater’, reveal an aridification trend in Arabia from the Late Miocene to Late Pleistocene during Earth’s transition from a largely ‘ice-free’ northern hemisphere to an ‘ice-age’ world. Together, our data provide evidence for recurrent discrete wetter intervals during past warmer periods, such as the Pliocene. Data-model comparisons allow us to assess the agreement between our paleoclimate data and climate model output using the HadCM3 isotope-enabled model simulations during past ‘warmer worlds’ – namely the mid-Piacenzian warm period (3.264 to 3.025 Ma). To assess the hydroclimate response to external forcing, we examine model output from a series of sensitivity experiments with different orbital configurations allowing us to postulate the mechanisms responsible for the occurrence of humid episodes in the Arabian desert, with potential implications for other dryland regions at similar latitudes. Together, our approach unveils the long-term controls on Arabian hydroclimate and may provide crucial insights into the future variability.

With its origins in the late 18th and early 19th century, the question of what drove the late Quaternary megafauna extinctions remains one of science’s most enduring and hotly contested debates. Once strictly the domain of archaeologists and paleontologists, the topic has attracted growing interest from other disciplines in recent decades, particularly ecologists and conservation biologists, who view these extinctions as a lens through which to inform contemporary conservation and ecosystem management strategies. Alongside this expansion, the field has seen increasing use of advanced analytical and statistical methods. Yet despite these developments, scientific opinion remains deeply divided over the cause(s) of these extinctions. Each year dozens of papers on the topic are published and along with these review articles that cover the debate or certain aspects of it. However, these reviews tend to reflect the viewpoints of their authors. Recognizing this limitation, the present study aimed to offer a more objective, data-driven overview of the field by conducting a systematic review and analysis of the literature. Specifically, we sought to: (1) trace the development of the megafauna extinction debate to understand how it has evolved over time; (2) identify key thematic and conceptual foci within the literature; and (3) use this synthesis of historical trends and interdisciplinary variation to propose a forward-looking research agenda that encourages greater engagement, discussion, integration, and collaboration across fields. Our analysis reveals strong disciplinary divides, uneven temporal and spatial research coverage, and persistent uncertainty over extinction causes. Despite recent major methodological advances, the field remains fragmented, underscoring the need for a research agenda that fosters interdisciplinary collaboration, expands field and legacy studies, as well as species-specific approaches, and integrates cutting-edge scientific and statistical techniques.

The study of Levallois points is important as it combines themes relating to Levallois technology in general (such as cognitive evolution, standardisation, and cultural transmission) with discussions on the specific function of stone tools (for example, the notion of points as spear tips). Many Levantine Middle Palaeolithic assemblages feature a strong focus on Levallois point production. Traditionally, this phenomenon has been studied from a typological perspective, while more recent technological approaches have added layers of understanding, such as the recognition of the frequently recurrent Levallois character of point production in the area. Likewise, use-wear and residue analyses have led to changing perceptions of the function of Levallois points. Here we explore how two quantifiable aspects of Levallois points - cross-section angles and lateral angles - relate to the morphology of Levallois points. By combining experimental knapping with an analysis of Levallois points from Yabroud I, Syria, we show that the obliqueness of lateral preparatory removals has a significant impact on the morphology of Levallois points, particularly in terms of the feature of a Concorde-shaped profile. Likewise, we show that the lateral edge angle influences the length of the points produced. Not only does this study improve of our understanding of Levallois points, but it highlights the importance of angles in studying lithic technology. We emphasize that this study aims to investigate the impact of oblique preparatory removals on the morphology of Levallois points generally, through an initial case study of one assemblage, allowing future multivariate analysis of multiple assemblages to test our hypotheses.

The hydroclimate change in the hot and arid Arabian Desert under anthropogenic global warming is a subject of ongoing discussions. Climate models project rising mean annual temperatures coupled with decreasing precipitation averaged over Saudi Arabia with regional variance (Almazroui, 2020). Stable isotope analysis on a combined speleothem record from central Arabia revealed recurring local humid periods during globally warmer intervals over the past ~8 million years (Markowska et al., in review). The speleothem record showed a long-term drying trend towards present, which may potentially be controlled by temperature change. The present study aims to reconstruct mean annual air temperatures (MAATs) of central Arabia during humid periods. These temperatures provide valuable benchmark data for past and future climate models in a region where terrestrial climate archives are scarce. Recent advances in speleothem-based paleothermometry facilitate extracting robust MAATs. We present data from several independent paleothermometers: Fluid inclusion isotopes (de Graaf et al., 2020), TEX86 (Meckler et al., 2021; Wassenburg et al., 2021), fluid inclusion microthermometry (Krüger et al., 2011), and dual clumped isotopes (Bajnai et al., 2020). These reconstructions show that recurrent wet intervals during the Miocene to Pleistocene in the Arabian Peninsula occurred at warmer than modern MAATs. We note, however, that temperature is not the only driver of humidity in the Arabian Peninsula and that both dry and humid periods likely existed under a warmer than today’s climate. Therefore, these observations cannot directly be interpreted as indicator that anthropogenic global warming will lead to future wet conditions in Saudi Arabia. Overall, we provide novel quantitative paleoclimate parameters that can inform climate model experiments leading to improved predictions for future climate scenarios.

The Saharo-Arabian Desert is one of the largest biogeographical barriers on Earth, impeding dispersals between Africa and Eurasia, including movements of past hominins. Recent research suggests that this barrier has been in place since at least 11 million years ago 1 . In contrast, fossil evidence from the late Miocene epoch and the Pleistocene epoch suggests the episodic presence within the Saharo-Arabian Desert interior of water-dependent fauna (for example, crocodiles, equids, hippopotamids and proboscideans) 2–6 , sustained by rivers and lakes 7,8 that are largely absent from today’s arid landscape. Although numerous humid phases occurred in southern Arabia during the past 1.1 million years 9 , little is known about Arabia’s palaeoclimate before this time. Here, based on a climatic record from desert speleothems, we show recurrent humid intervals in the central Arabian interior over the past 8 million years. Precipitation during humid intervals decreased and became more variable over time, as the monsoon’s influence weakened, coinciding with enhanced Northern Hemisphere polar ice cover during the Pleistocene. Wetter conditions likely facilitated mammalian dispersals between Africa and Eurasia, with Arabia acting as a key crossroads for continental-scale biogeographic exchanges.

Knowledge about environmental change and the evolutionary history of hominins in Arabia has been rapidly developing over the last two decades. Interdisciplinary research on humans and environments across the vast and heterogenous landmass of the Arabian Peninsula remains, however, highly spatially uneven. Here we present the results of archaeological, hydro-geological, and palaeontological research in inland northeastern Arabia, a poorly studied area with diverse landscape features including caves, palaeorivers, and chert outcrops. Hominin use of the landscape appears to be sparse in comparison to other regions of Arabia, though archaeological evidence spanning from the Lower Palaeolithic to the historic era was identified, including finds from the Middle Palaeolithic, which is the most well represented period. The caves of inland northeast Arabia contain a rich record of past climate change in the form of speleothems, as well as abundant faunal assemblages. Our survey results highlight the significant potential of these records to cast light on environmental, faunal, and cultural changes over time while demonstrating regional variation across Arabia.

Among growing indications of human occupation in the coastal regions of southern and southeastern Arabia extending into the Neolithic and beyond, this study introduces new archaeological evidence, namely bifacial arrowheads and trihedral points, suggesting human presence at the Saruq Al-Hadid site in the fringe of Rub' Al Khali during the mid-Holocene period. Human activities in the site are dated to the 'Dark Millennium' and Bronze Age. We suggest that Contexts 10 and 8 are an extension of the activities of the Horizon IV, located 20 m to the West. This is evidenced by the similarity in the simple reduction strategies applied in both to produce microliths, which are dated in both as well to the Wadi Suq and Late Bronze Age periods. However, there is a notable difference in bone density, with Horizon IV exhibiting higher density. Moreover, the almost complete absence of end products in Contexts 10 and 8 contrasts with their prevalence in Horizon IV. And the absence of final products in Contexts 10 and 8, with their high percentage in the Horizon IV. Taken together, these indications, coupled with the low density of lithics in Contexts 10 and 8 as well as those unearthed in area F, suggest that Horizon IV was the focal point of activities during the Wadi Suq period and the Late Bronze Age.

ABSTRACT Analysis of plant‐wax biomarkers from sedimentary sequences can enable past environmental and hydrological reconstruction and provide insights into past hominin adaptations. However, biomarker preservation in desert contexts has been considered unlikely given the sparse nature of the vegetation within the landscape. Here we evaluate the preservation of n ‐alkanes and fatty acids collected from four depositional sequences associated with archaeological contexts in the Nefud Desert, Saudi Arabia, and the Thar Desert, India. Pleistocene and Holocene samples were selected to understand the effects of age on preservation. The results of molecular distribution patterns and indices, particularly the high carbon preference index and average chain length, show the preservation of plant‐wax biomarkers in both the Holocene and Pleistocene desert sequences, while δ 13 C values and organic content provide insights into the vegetation contributing to the plant‐wax organic pool. This study provides a baseline for understanding human–environment interactions and for reconstructing changes in arid land habitats of relevance to hominins during the Quaternary.

Recent advances in interdisciplinary archaeological research in Arabia have focused on the evolution and historical development of regional human populations as well as the diverse patterns of cultural change, migration, and adaptations to environmental fluctuations. Obtaining a comprehensive understanding of cultural developments such as the emergence and lifeways of Neolithic groups has been hindered by the limited preservation of stratified archaeological assemblages and organic remains, a common challenge in arid environments. Underground settings like caves and lava tubes, which are prevalent in Arabia but which have seen limited scientific exploration, offer promising opportunities for addressing these issues. Here, we report on an archaeological excavation and a related survey at and around Umm Jirsan lava tube in the Harrat Khaybar, north-western Saudi Arabia. Our results reveal repeated phases of human occupation of the site ranging from at least the Neolithic through to the Chalcolithic/Bronze Age. Pastoralist use of the lava tube and surrounding landscape is attested in rock art and faunal records, suggesting that Umm Jirsan was situated along a pastoral route linking key oases. Isotopic data indicates that herbivores primarily grazed on wild grasses and shrubs rather than being provided with fodder, while humans had a diet consistently high in protein but with increasing consumption of C3 plants through-time, perhaps related to the emergence of oasis agriculture. While underground and naturally sheltered localities are globally prominent in archaeology and Quaternary science, our work represents the first such combined records for Saudi Arabia and highlight the potential for interdisciplinary studies in caves and lava tubes.

Monumental rectangular stone structures called mustatils are an important emerging feature of the Holocene archaeological record of northwestern Arabia. To date, few have been excavated, with available radiocarbon dates suggesting an age range of ca. 5400–4200 BC. Here we present a rigorous spatial analysis to identify the patterning and landscape context of 169 mustatils in the southern and western margins of the Nefud Desert. This included: (1) a systematic survey of satellite imagery to identify mustatils; (2) viewshed analysis to examine location and landscape visibility; (3) a point process model to understand how diverse environmental and landscape variables affect mustatil locations; (4) mark correlation function to assess spatial patterning of mustatils based on their size. Results indicate that mustatil locations are determined most by proximity to water (likely locations of enhanced surface water occurrence under the enhanced humidity of the Mid-Holocene), on east facing slopes, close to rocky areas, at elevations between 880 and 950 masl, and on or near topographic ridges (positive topographic position index). Viewshed analysis showed that mustatils are preferentially located in areas that have good views, but not the best that are available, indicating complex landscape positioning that balances a range of topographic and behavioural factors. Using a rank permutation method with size (length) of mustatils as a proxy for labour mobilization we show that mustatils within clusters are not arranged hierarchically based on size, and were likely built by non-stratified groups of people. Our analyses show that people were choosing multiple factors when deciding where to build mustatils, and that the distribution of mustatils may relate to different groups of people resulting in the construction of complex ritual landscapes. As one of the earliest examples of large-scale monumental stone structure construction in global prehistory, understanding mustatils can enlighten us on human-environment interaction during the Neolithic.

Levallois points are a prominent part of many Levantine Middle Paleolithic assemblages. They are either produced intentionally or incidentally by the Levallois core reduction technique and are of a generally similar shape, although the degree to which they were used as specialized tools has been questioned. Here, we examine Levallois points using geometric morphometric analyses to assess the range of shape variation in this artifact type. We then compare Levallois point shape variation and symmetry to a sample of Late Pleistocene-aged Folsom projectile points from North America. Folsom are highly standardized projectile points that current evidence suggests were primarily used for hunting ancient bison. Our results indicate that Levallois points are more variable and asymmetrical than Folsom and therefore more generalized than Folsom. Differences in manufacturing technique, hafting, and delivery system when used as weapons are posited as playing roles in the differences in shape and symmetry that we document.