Human interactions with tropical environments over the last 14,000 years at Iho Eleru, Nigeria

The Ihò Eléérú (or Iho Eleru) rock shelter, located in Southwest Nigeria, is the only site from which Pleistocene-age hominin fossils have been recovered in western Africa. Excavations at Iho Eleru revealed regular human occupations ranging from the Later Stone Age (LSA) to the present day. Here, we present chronometric, archaeobotanical, and paleoenvironmental findings, which include the taxonomic, taphonomic, and isotopic analyses of what is the only Pleistocene faunal assemblage documented in western Africa. Our results indicate that the local landscape surrounding Iho Eleru, although situated within a regional open-canopy biome, was forested throughout the past human occupation of the site. At a regional scale, a shift from forest- to savanna-dominated ecotonal environment occurred during a mid-Holocene warm event 6,000 years ago, with a subsequent modern reforestation of the landscape. Locally, no environmental shift was observable, placing Iho Eleru in a persistent forested “island” during the period of occupation

Paleo-ENSO influence on African environments and early modern humans

Our results identify the prime driver of climate variation in Africa’s low latitudes over the past 620 ky—the key time frame for the evolution of our species. Warming and cooling of the tropical Pacific Ocean paced by insolation changes modulated the tropical Walker circulation, driving opposing wet–dry states in eastern and western Africa. We show that the effects of glacial/interglacial cycles were not the predominant source of environmental change in most of the continent. Africa’s environmental patchwork driven by low-latitude climate processes should therefore be a critical component in conceptual models of human evolution and early demography over the past 620 ky.In this study, we synthesize terrestrial and marine proxy records, spanning the past 620 ky, to decipher pan-African climate variability and its drivers and potential linkages to hominin evolution. We find a tight correlation between moisture availability across Africa to El Niño Southern Ocean oscillation (ENSO) variability, a manifestation of the Walker Circulation, that was most likely driven by changes in Earth’s eccentricity. Our results demonstrate that low-latitude insolation was a prominent driver of pan-African climate change during the Middle to Late Pleistocene. We argue that these low-latitude climate processes governed the dispersion and evolution of vegetation as well as mammals in eastern and western Africa by increasing resource-rich and stable ecotonal settings thought to have been important to early modern humans.All study data are included in the article and/or supporting information.Results Discussion Conclusion Materials and Methods - pwPCA. - Breakpoint Analysis. - Median Calculation

A new stone tool assemblage revisited: reconsidering the 'Aterian' in Arabia

The Aterian is perhaps the major manifestation of the Middle Stone Age (MSA) in North Africa and is frequently framed in terms of the first human dispersals into the north of Africa. The possibility of an Aterian presence in the Arabian Peninsula is widely cited and is of particular interest, given the significant ongoing debate on the character of the dispersal(s) of Homo sapiens out of Africa. This paper presents a reanalysis of this data. Strong covariance was found between the tanged tools of the Banī KhaΓmah assemblage of south-western Saudi Arabia and the Aterian of north-east Africa. Comparison with other technologically similar assemblages from the Saudi Arabian south-west, however, shows that this apparent similarity results from technological convergence rather than demographic connections with Aterian populations. This convergence is likely to date to the Holocene

Earliest evidence for the structure of <i>Homo sapiens</i> populations in Africa

Understanding the structure and variation of Homo sapiens populations in Africa is critical for interpreting multiproxy evidence of their subsequent dispersals into Eurasia. However, there is no consensus on early H. sapiens demographic structure, or its effects on intra-African dispersals. Here, we show how a patchwork of ecological corridors and bottlenecks triggered a successive budding of populations across the Sahara. Using a temporally and spatially explicit palaeoenvironmental model, we found that the Sahara was not uniformly ameliorated between similar to 130 and 75 thousand years ago (ka), as has been stated. Model integration with multivariate analyses of corresponding stone tools then revealed several spatially defined technological clusters which correlated with distinct palaeobiomes. Similarities between technological clusters were such that they decreased with distance except where connected by palaeohydrological networks. These results indicate that populations at the Eurasian gateway were strongly structured, which has implications for refining the demographic parameters of dispersals out of Africa

Neolithic pastoralism in marginal environments during the Holocene Humid Period, northern Saudi Arabia

The origins of agriculture in South-west Asia is a topic of continued archaeological debate. Of particular interest is how agricultural populations and practices spread inter-regionally. Was the Arabian Neolithic, for example, spread through the movement of pastoral groups, or did ideas perhaps develop independently? Here, the authors report on recent excavations at Alshabah, one of the first Neolithic sites discovered in Northern Arabia. The site’s material culture, environmental context and chronology provide evidence suggesting that well-adapted, seasonally mobile, pastoralist groups played a key role in the Neolithisation of the Arabian Peninsula

A taxonomic and taphonomic study of Pleistocene fossil deposits from the western Nefud Desert, Saudi Arabia

Over the past decade, a growing interest has developed on the archaeology, palaeontology, and palaeoenvironments of the Arabian Peninsula. It is now clear that hominins repeatedly dispersed into Arabia, notably during pluvial interglacial periods when much of the peninsula was characterised by a semiarid grassland environment. During the intervening glacial phases, however, grasslands were replaced with arid and hyperarid deserts. These millennial-scale climatic fluctuations have subjected bones and fossils to a dramatic suite of environmental conditions, affecting their fossilisation and preservation. Yet, as relatively few palaeontological assemblages have been reported from the Pleistocene of Arabia, our understanding of the preservational pathways that skeletal elements can take in these types of environments is lacking. Here, we report the first widespread taxonomic and taphonomic assessment of Arabian fossil deposits. Novel fossil fauna are described and overall the fauna are consistent with a well-watered semiarid grassland environment. Likewise, the taphonomic results suggest that bones were deposited under more humid conditions than present in the region today. However, fossils often exhibit significant attrition, obscuring and fragmenting most finds. These are likely tied to wind abrasion, insolation, and salt weathering following fossilisation and exhumation, processes particularly prevalent in desert environments

Multiple hominin dispersals into Southwest Asia over the past 400,000 years

Pleistocene hominin dispersals out of, and back into, Africa necessarily involved traversing the diverse and often challenging environments of Southwest Asia1,2,3,4. Archaeological and palaeontological records from the Levantine woodland zone document major biological and cultural shifts, such as alternating occupations by Homo sapiens and Neanderthals. However, Late Quaternary cultural, biological and environmental records from the vast arid zone that constitutes most of Southwest Asia remain scarce, limiting regional-scale insights into changes in hominin demography and behaviour1,2,5. Here we report a series of dated palaeolake sequences, associated with stone tool assemblages and vertebrate fossils, from the Khall Amayshan 4 and Jubbah basins in the Nefud Desert. These findings, including the oldest dated hominin occupations in Arabia, reveal at least five hominin expansions into the Arabian interior, coinciding with brief ‘green’ windows of reduced aridity approximately 400, 300, 200, 130–75 and 55 thousand years ago. Each occupation phase is characterized by a distinct form of material culture, indicating colonization by diverse hominin groups, and a lack of long-term Southwest Asian population continuity. Within a general pattern of African and Eurasian hominin groups being separated by Pleistocene Saharo-Arabian aridity, our findings reveal the tempo and character of climatically modulated windows for dispersal and admixture

The Aterian and its place in the North African Middle Stone Age

The Aterian is a frequently cited stone tool (‘lithic’) industry of the Middle Stone Age (MSA) (ca. 270-50,000-ka) of North Africa. Dating from at least 145 ka, the Aterian’s association with distinctive ‘tang’ hafted tools, the use of pigments, shell beads and other non-lithic artefacts is hypothesised to represent the earliest manifestations of identity and ethnicity, a reflection of ‘modern human cognition’. However, an alternative view contests the extent of the Aterian’s geographical, temporal and cultural integrity. This thesis is the first detailed study to quantitatively test both these hypotheses and establish the technological character of a region at the nexus of human dispersals. Nineteen spatially and temporally representative lithic assemblages from the North African MSA, together with one outgroup from the Arabian Middle Palaeolithic are compared. Building on the emerging evidence for North African population increases and climatic amelioration in Marine Isotope Stage (MIS) 5, this research develops nested analytical models premised on cultural ecology and niche construction. Subsequent analysis explores the North African MSA as a landscape of population differentiation and/or isolation by distance. A suite of multivariate statistics is used to isolate uncorrelated sources of variability in the data. Principal Components, Correspondence and Regression Analyses suggest that the patterns of similarity and difference observed between assemblages do not simplistically articulate with traditional divisions between named industries. In particular, the Aterian is not defined by the presence of tanged tools. Results instead indicate technological convergence and isolation-by distance structure much of the variability. The identification of aggregation sites also attests the presence of social networks. It is argued that the existence of population structure in the North African MSA has important implications for the evolutionary dynamics of modern human dispersals. The methods and models used here are particularly relevant to further exploring the origins of cultural diversification