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The archaeology of East Africa during the last ~65,000 years plays a central role in debates about the origins and dispersal of modern humans, Homo sapiens. Despite the historical importance of the region to these discussions, reliable chronologies for the nature, tempo, and timing of human behavioral changes seen among Middle Stone Age (MSA) and Later Stone Age (LSA) archaeological assemblages are sparse. The Kisese II rockshelter in the Kondoa region of Tanzania, originally excavated in 1956, preserves a ≥ 6-m-thick archaeological succession that spans the MSA/LSA transition, with lithic artifacts such as Levallois and bladelet cores and backed microliths, the recurrent use of red ochre, and >5,000 ostrich eggshell beads and bead fragments. Twenty-nine radiocarbon dates on ostrich eggshell carbonate make Kisese II one of the most robust chronological sequences for understanding archaeological change over the last ~47,000 years in East Africa. In particular, ostrich eggshell beads and backed microliths appear by 46-42 ka cal BP and occur throughout overlying Late Pleistocene and Holocene strata. Changes in lithic technology suggest an MSA/LSA transition that began 39-34.3 ka, with typical LSA technologies in place by the Last Glacial Maximum. The timing of these changes demonstrates the time-transgressive nature of behavioral innovations often linked to the origins of modern humans, even within a single region of Africa.

Eastern Africa is an important area to study early populations ofHomo sapiensbecause subsets of those populations likely dispersed to Eurasia and subsequently throughout the globe during the Upper Pleistocene. The Middle Stone Age (MSA) archaeology of this region, particularly aspects of stone-tool technology and typology, is highly variable with only rare cases of geographic and temporal patterning. Although there are differences in timing and perhaps frequency of occurrence, those elements that make up the MSA lithic tool kit are also found at contemporaneous sites elsewhere in Africa and Eurasia, making it difficult to identify a unique archaeological signal for hominin dispersals out of eastern Africa. Rather, regional variation appears to be the outcome of possibly long-term interactions between particular physical and social environments experienced by hominin populations.

The Olorgesailie basin in the southern Kenya rift valley contains sediments dating back to 1.2 million years ago, preserving a long archaeological record of human activity and environmental conditions. Three papers present the oldest East African evidence of the Middle Stone Age (MSA) and elucidate the system of technology and behavior associated with the origin of Homo sapiens . Potts et al. present evidence for the demise of Acheulean technology that preceded the MSA and describe variations in late Acheulean hominin behavior that anticipate MSA characteristics. The transition to the MSA was accompanied by turnover of large mammals and large-scale landscape change. Brooks et al. establish that ∼320,000 to 305,000 years ago, the populations in eastern Africa underwent a technological shift upon procurement of distantly sourced obsidian for toolmaking, indicating the early development of social exchange. Deino et al. provide the chronological underpinning for these discoveries. Science , this issue p. 86 , p. 90 , p. 95 Changes in fauna, landscapes, and climate were associated with novel adaptive behaviors in the earliest Homo sapiens . Development of the African Middle Stone Age (MSA) before 300,000 years ago raises the question of how environmental change influenced the evolution of behaviors characteristic of early Homo sapiens . We used temporally well-constrained sedimentological and paleoenvironmental data to investigate environmental dynamics before and after the appearance of the early MSA in the Olorgesailie basin, Kenya. In contrast to the Acheulean archeological record in the same basin, MSA sites are associated with a markedly different faunal community, more pronounced erosion-deposition cycles, tectonic activity, and enhanced wet-dry variability. Aspects of Acheulean technology in this region imply that, as early as 615,000 years ago, greater stone material selectivity and wider resource procurement coincided with an increased pace of land-lake fluctuation, potentially anticipating the adaptability of MSA hominins.

Significance Modern human ( Homo sapiens ) fossils from eastern African archaeological contexts from ∼70,000–20,000 years ago are rare, limiting our ability to understand the relationship between biological and behavioral change during a time and place characterized by major human demographic shifts, including dispersals. Our chronological, archaeological, and human paleontological analyses of the GvJm-22 rock shelter and Kenya National Museums Lukenya Hill Hominid 1 partial calvaria constrain the age of major behavioral changes among African foragers (the shift to Later Stone Age technologies) and demonstrate the morphological distinctness of Late Pleistocene African hominins from African Holocene or Late Pleistocene Eurasian hominins, complicating the history of modern human diversity. Kenya National Museums Lukenya Hill Hominid 1 (KNM-LH 1) is a Homo sapiens partial calvaria from site GvJm-22 at Lukenya Hill, Kenya, associated with Later Stone Age (LSA) archaeological deposits. KNM-LH 1 is securely dated to the Late Pleistocene, and samples a time and region important for understanding the origins of modern human diversity. A revised chronology based on 26 accelerator mass spectrometry radiocarbon dates on ostrich eggshells indicates an age range of 23,576–22,887 y B.P. for KNM-LH 1, confirming prior attribution to the Last Glacial Maximum. Additional dates extend the maximum age for archaeological deposits at GvJm-22 to >46,000 y B.P. (>46 kya). These dates are consistent with new analyses identifying both Middle Stone Age and LSA lithic technologies at the site, making GvJm-22 a rare eastern African record of major human behavioral shifts during the Late Pleistocene. Comparative morphometric analyses of the KNM-LH 1 cranium document the temporal and spatial complexity of early modern human morphological variability. Features of cranial shape distinguish KNM-LH 1 and other Middle and Late Pleistocene African fossils from crania of recent Africans and samples from Holocene LSA and European Upper Paleolithic sites.

Increased population density is among the proposed drivers of the behavioural changes culminating in the Middle to Later Stone Age (MSA–LSA) transition and human dispersals from East Africa, but reliable archaeological measures of demographic change are lacking. We use Late Pleistocene–Holocene lithic and faunal data from Nasera rockshelter (Tanzania) to show progressive declines in residential mobility—a variable linked to population density—and technological shifts, the latter associated with environmental changes. These data suggest that the MSA–LSA transition is part of a long-term pattern of changes in residential mobility and technology that reflect human responses to increased population density, with dispersals potentially marking a complementary response to larger populations. This article is part of the themed issue ‘Major transitions in human evolution’.

The production of Levallois flakes is considered a hallmark of many Middle Stone Age (MSA) sites, but this aspect of African Pleistocene hominin technology remains poorly documented relative to that from adjacent regions. The site of Koimilot, from the Kapthurin Formation of Kenya, preserves stratified artifact assemblages that show use of multiple Levallois methods to produce flakes of varied shapes and sizes, comparable to that described from Levantine and European Middle Paleolithic sites. Koimilot has an age of 200,000 years on the basis of geochemical correlation with dated volcanic tephra and therefore joins a small but growing number of early MSA sites which antedate the last interglacial (130,000) years ago and provide the most relevant comparisons for understanding the end of the Acheulian. The Kapthurin Formation archaeological sequence suggests that it is the diversification of Levallois technology rather than its origin that characterizes early MSA assemblages. MSA Levallois technology may have developed from local Acheulian antecedents.

Introduction Fossil, genetic, archaeological, and biogeographical lines of evidence are consistent for the African origin of modern Homo sapiens and associated Middle Stone Age (MSA) technologies around 300,000 years ago. Given its size and geographic and ecological diversity, we are excited by scenarios that assume equally complex situations and explore population dynamics within Africa, rather than treating the continent as a source of dispersals out of Africa. There remain substantial numbers of understudied artifact collections and related personal archives in museums, and even well-documented archaeological or fossil collections merit continued investigations using novel methodologies and dating tools. Sutton (2017) once distinguished between “universalists” who are more interested in addressing broad questions about human evolution (e.g., “modern human origins”) that happen to use datasets drawn from Africa and “Africanists” who focus on how the archaeological record might tell us something about the deep history of people in Africa. For some projects, local community members remain an underappreciated resource, yet they have intimate knowledge of their landscapes and the fossil and archaeological remains they contain.

Multiple lines of genetic and archaeological evidence suggest that there were major demographic changes in the terminal Late Pleistocene epoch and early Holocene epoch of sub-Saharan Africa 1 – 4 . Inferences about this period are challenging to make because demographic shifts in the past 5,000 years have obscured the structures of more ancient populations 3 , 5 . Here we present genome-wide ancient DNA data for six individuals from eastern and south-central Africa spanning the past approximately 18,000 years (doubling the time depth of sub-Saharan African ancient DNA), increase the data quality for 15 previously published ancient individuals and analyse these alongside data from 13 other published ancient individuals. The ancestry of the individuals in our study area can be modelled as a geographically structured mixture of three highly divergent source populations, probably reflecting Pleistocene interactions around 80–20 thousand years ago, including deeply diverged eastern and southern African lineages, plus a previously unappreciated ubiquitous distribution of ancestry that occurs in highest proportion today in central African rainforest hunter-gatherers. Once established, this structure remained highly stable, with limited long-range gene flow. These results provide a new line of genetic evidence in support of hypotheses that have emerged from archaeological analyses but remain contested, suggesting increasing regionalization at the end of the Pleistocene epoch. DNA analysis of 6 individuals from eastern and south-central Africa spanning the past approximately 18,000 years, and of 28 previously published ancient individuals, provides genetic evidence supporting hypotheses of increasing regionalization at the end of the Pleistocene.

Abstract Late Pleistocene and Holocene evidence from multiple rockshelters in north-central Tanzania suggests a regional pattern of changing technological behaviors through time. We use independent chronological evidence to test if the proposed technological patterns across space were also temporally equivalent. We applied AMS radiocarbon dating methods to the carbonate fraction of five ostrich eggshell fragments from Mehlman's 1975-1976 excavations at Nasera rockshelter and compared our results to recent re-dating efforts of Mumba rockshelter. We document radiocarbon results >46 ka at Nasera in Level 5, indicating that associated and underlying technologies (including what Mehlman termed the 'Nasera Industry') are older than previously documented. Backed pieces first appear >46 ka at Nasera, which is in accordance with recent evidence from nearby rockshelters like Enkapune ya Muto, Panga ya Saidi, and potentially Kisese II. We also provide an age of 11,260-11,710 calBP for the 'Silale Industry' of Level 3B. Overall, the shifts in lithic technology previously considered to be shared between Mumba and Nasera rockshelters are not temporally aligned, emphasizing the possibility that intra-site variability was the norm throughout the Late Pleistocene in eastern Africa.