Search

Homo sapiens have adapted to an incredible diversity of habitats around the globe. This capacity to adapt to different landscapes is clearly expressed within Africa, with Late Pleistocene Homo sapiens populations occupying savannahs, woodlands, coastlines and mountainous terrain. As the only area of the world where Homo sapiens have clearly persisted through multiple glacial-interglacial cycles, Africa is the only continent where classic refugia models can be formulated and tested to examine and describe changing patterns of past distributions and human phylogeographies. The potential role of refugia has frequently been acknowledged in the Late Pleistocene palaeoanthropological literature, yet explicit identification of potential refugia has been limited by the patchy nature of palaeoenvironmental and archaeological records, and the low temporal resolution of climate or ecological models. Here, we apply potential climatic thresholds on human habitation, rooted in ethnographic studies, in combination with high-resolution model datasets for precipitation and biome distributions to identify persistent refugia spanning the Late Pleistocene (130–10 ka). We present two alternate models suggesting that between 27% and 66% of Africa may have provided refugia to Late Pleistocene human populations, and examine variability in precipitation, biome and ecotone distributions within these refugial zones. This article is part of the theme issue 'Tropical forests in the deep human past'. [ABSTRACT FROM AUTHOR]

Eastern Africa has played a prominent role in debates about human evolution and dispersal due to the presence of rich archaeological, palaeoanthropological and palaeoenvironmental records. However, substantial disconnects occur between the spatial and temporal resolutions of these data that complicate their integration. Here, we apply high-resolution climatic simulations of two key parameters, mean annual temperature and precipitation, and a biome model, to produce a highly refined characterisation of the environments inhabited during the eastern African Middle Stone Age. Occupations are typically found in sub-humid climates and landscapes dominated by or including tropical xerophytic shrubland. Marked expansions from these core landscapes include movement into hotter, low-altitude landscapes in Marine Isotope Stage 5 and cooler, high-altitude landscapes in Marine Isotope Stage 3, with the recurrent inhabitation of ecotones between open and forested habitats. Through our use of high-resolution climate models, we demonstrate a significant independent relationship between past precipitation and patterns of Middle Stone Age stone tool production modes overlooked by previous studies. Engagement with these models not only enables spatiotemporally explicit examination of climatic variability across Middle Stone Age occupations in eastern Africa but enables clearer characterisation of the habitats early human populations were adapted to, and how they changed through time. [ABSTRACT FROM AUTHOR]

The Middle to Later Stone Age transition marks a major change in how Late Pleistocene African populations produced and used stone tool kits, but is manifest in various ways, places and times across the continent. Alongside changing patterns of raw material use and decreasing artefact sizes, changes in artefact types are commonly employed to differentiate Middle Stone Age (MSA) and Later Stone Age (LSA) assemblages. The current paper employs a quantitative analytical framework based upon the use of neural networks to examine changing constellations of technologies between MSA and LSA assemblages from eastern Africa. Network ensembles were trained to differentiate LSA assemblages from Marine Isotope Stage 3&4 MSA and Marine Isotope Stage 5 MSA assemblages based upon the presence or absence of 16 technologies. Simulations were used to extract significant indicator and contra-indicator technologies for each assemblage class. The trained network ensembles classified over 94% of assemblages correctly, and identified 7 key technologies that significantly distinguish between assemblage classes. These results clarify both temporal changes within the MSA and differences between MSA and LSA assemblages in eastern Africa. [ABSTRACT FROM AUTHOR]

Central Africa is a key region for examining patterns of hunter-gatherer inhabitation and engagement with ecological diversity and environmental change. In contrast to adjacent regions, however, the archaeological record of prehistoric hunter-gatherer populations in Central Africa is underrepresented in studies of recent human evolution. This limited engagement with Central African archaeological records in part stems from the complexities of identifying, excavating, and dating hunter-gatherer sites in what are today often heavily forested environments, a focus on named stone tool industries from undated sites to structure the record, and highly limited means to associate dated hunter-gatherer occupations with proxy records of environmental conditions. Here, we present a novel synthesis of prehistoric hunter-gatherer stone tool assemblages from dated Central African sites and use climate model datasets to illuminate the environmental and ecological landscapes in which they were deployed. Our results suggest a significant ecological shift occurred from 14,000 years ago onwards, associated with a greater engagement with broadleaf forests. We examine the extent to which a range of geographic and paleoclimatic drivers can explain patterns of gross assemblage composition and the appearance of individual lithic technologies highlighting the significant role of changes in altitude, precipitation, seasonality, and ecology. Notably, considerable continuity can be observed between the habitat ranges of contemporary hunter-gatherer populations in Central Africa and prehistoric occupations that significantly precede the appearance of farming lifeways in the region. • Synthetic review of Late Pleistocene and Holocene lithic assemblages in Central Africa. • Environmental contextualization of lithic assemblages over time. • Shift of environmental context occupied by Central African hunter-gatherers identified in the Pleistocene-Holocene transition. • Quantitative assessment of drivers of similarity in assemblage composition over time. • Altitude, site type, ecology and precipitation seasonality identified as significant drivers of similarity in assemblage composition. [ABSTRACT FROM AUTHOR]

We challenge the view that our species, Homo sapiens , evolved within a single population and/or region of Africa. The chronology and physical diversity of Pleistocene human fossils suggest that morphologically varied populations pertaining to the H. sapiens clade lived throughout Africa. Similarly, the African archaeological record demonstrates the polycentric origin and persistence of regionally distinct Pleistocene material culture in a variety of paleoecological settings. Genetic studies also indicate that present-day population structure within Africa extends to deep times, paralleling a paleoenvironmental record of shifting and fractured habitable zones. We argue that these fields support an emerging view of a highly structured African prehistory that should be considered in human evolutionary inferences, prompting new interpretations, questions, and interdisciplinary research directions. [ABSTRACT FROM AUTHOR]

The hypothesis of a connection between the onset (or intensification) of Northern Hemisphere Glaciation, the stepwise increase in African aridity (and climate variability), and an important mammalian (including hominin) species turnover is a textbook example of the initiation of a scientific idea and its propagation in science. It is, however, also an example of the persistent popularity of a hypothesis despite mounting evidence against it. A critical review of key publications on the topic and statistical re-analysis of key records of global ice volume and African climate leads to three conclusions: (1) The Northern Hemisphere Glaciation was a gradual process occurring between ∼3.5 and 2.5 Ma, not a single event at ∼2.8 Ma or at any other time. (2) A consistent stepwise (+/−0.2 Ma) transition toward greater aridity in Africa at ∼2.8 Ma does not exist; instead, there are regionally different, gradual transitions partly in connection with the intensification of the Northern Hemisphere Glaciation, but above all with the establishment of the tropical Walker Circulation after ∼2 Ma. (3) Mammalian (including hominin) species turnovers at this time also appear to have been gradual, rather than stepwise. • We falsified the hypothesis of a connection between Northern Hemisphere Glaciation, African climate and human evolution. [ABSTRACT FROM AUTHOR]