Publications by authors named "Julio Mercader"

15 Publications

  • Page 1 of 1

Earliest known human burial in Africa.

Nature 2021 May 5;593(7857):95-100. Epub 2021 May 5.

UMR 5199 CNRS De la Préhistoire à l'Actuel: Culture, Environnement, et Anthropologie (PACEA), Université Bordeaux, Talence, France.

The origin and evolution of hominin mortuary practices are topics of intense interest and debate. Human burials dated to the Middle Stone Age (MSA) are exceedingly rare in Africa and unknown in East Africa. Here we describe the partial skeleton of a roughly 2.5- to 3.0-year-old child dating to 78.3 ± 4.1 thousand years ago, which was recovered in the MSA layers of Panga ya Saidi (PYS), a cave site in the tropical upland coast of Kenya. Recent excavations have revealed a pit feature containing a child in a flexed position. Geochemical, granulometric and micromorphological analyses of the burial pit content and encasing archaeological layers indicate that the pit was deliberately excavated. Taphonomical evidence, such as the strict articulation or good anatomical association of the skeletal elements and histological evidence of putrefaction, support the in-place decomposition of the fresh body. The presence of little or no displacement of the unstable joints during decomposition points to an interment in a filled space (grave earth), making the PYS finding the oldest known human burial in Africa. The morphological assessment of the partial skeleton is consistent with its assignment to Homo sapiens, although the preservation of some primitive features in the dentition supports increasing evidence for non-gradual assembly of modern traits during the emergence of our species. The PYS burial sheds light on how MSA populations interacted with the dead.
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http://dx.doi.org/10.1038/s41586-021-03457-8DOI Listing
May 2021

Early human impacts and ecosystem reorganization in southern-central Africa.

Sci Adv 2021 May 5;7(19). Epub 2021 May 5.

Ministry of Civic Education and National Unity, Lilongwe, Malawi.

Modern engage in substantial ecosystem modification, but it is difficult to detect the origins or early consequences of these behaviors. Archaeological, geochronological, geomorphological, and paleoenvironmental data from northern Malawi document a changing relationship between forager presence, ecosystem organization, and alluvial fan formation in the Late Pleistocene. Dense concentrations of Middle Stone Age artifacts and alluvial fan systems formed after ca. 92 thousand years ago, within a paleoecological context with no analog in the preceding half-million-year record. Archaeological data and principal coordinates analysis indicate that early anthropogenic fire relaxed seasonal constraints on ignitions, influencing vegetation composition and erosion. This operated in tandem with climate-driven changes in precipitation to culminate in an ecological transition to an early, pre-agricultural anthropogenic landscape.
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http://dx.doi.org/10.1126/sciadv.abf9776DOI Listing
May 2021

Earliest Olduvai hominins exploited unstable environments ~ 2 million years ago.

Nat Commun 2021 01 7;12(1). Epub 2021 Jan 7.

Max Planck Institute for the Science of Human History, Jena, Germany.

Rapid environmental change is a catalyst for human evolution, driving dietary innovations, habitat diversification, and dispersal. However, there is a dearth of information to assess hominin adaptions to changing physiography during key evolutionary stages such as the early Pleistocene. Here we report a multiproxy dataset from Ewass Oldupa, in the Western Plio-Pleistocene rift basin of Olduvai Gorge (now Oldupai), Tanzania, to address this lacuna and offer an ecological perspective on human adaptability two million years ago. Oldupai's earliest hominins sequentially inhabited the floodplains of sinuous channels, then river-influenced contexts, which now comprises the oldest palaeolake setting documented regionally. Early Oldowan tools reveal a homogenous technology to utilise diverse, rapidly changing environments that ranged from fern meadows to woodland mosaics, naturally burned landscapes, to lakeside woodland/palm groves as well as hyper-xeric steppes. Hominins periodically used emerging landscapes and disturbance biomes multiple times over 235,000 years, thus predating by more than 180,000 years the earliest known hominins and Oldowan industries from the Eastern side of the basin.
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http://dx.doi.org/10.1038/s41467-020-20176-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7791053PMC
January 2021

Isotopic and microbotanical insights into Iron Age agricultural reliance in the Central African rainforest.

Commun Biol 2020 Oct 27;3(1):619. Epub 2020 Oct 27.

Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Straße 10, 07745, Jena, Germany.

The emergence of agriculture in Central Africa has previously been associated with the migration of Bantu-speaking populations during an anthropogenic or climate-driven 'opening' of the rainforest. However, such models are based on assumptions of environmental requirements of key crops (e.g. Pennisetum glaucum) and direct insights into human dietary reliance remain absent. Here, we utilise stable isotope analysis (δC, δN, δO) of human and animal remains and charred food remains, as well as plant microparticles from dental calculus, to assess the importance of incoming crops in the Congo Basin. Our data, spanning the early Iron Age to recent history, reveals variation in the adoption of cereals, with a persistent focus on forest and freshwater resources in some areas. These data provide new dietary evidence and document the longevity of mosaic subsistence strategies in the region.
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http://dx.doi.org/10.1038/s42003-020-01324-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7591565PMC
October 2020

Ancient genomes reveal complex patterns of population movement, interaction, and replacement in sub-Saharan Africa.

Sci Adv 2020 Jun 12;6(24):eaaz0183. Epub 2020 Jun 12.

Department of Archaeogenetics, Max Planck Institute for the Science of Human History, Jena, Germany.

Africa hosts the greatest human genetic diversity globally, but legacies of ancient population interactions and dispersals across the continent remain understudied. Here, we report genome-wide data from 20 ancient sub-Saharan African individuals, including the first reported ancient DNA from the DRC, Uganda, and Botswana. These data demonstrate the contraction of diverse, once contiguous hunter-gatherer populations, and suggest the resistance to interaction with incoming pastoralists of delayed-return foragers in aquatic environments. We refine models for the spread of food producers into eastern and southern Africa, demonstrating more complex trajectories of admixture than previously suggested. In Botswana, we show that Bantu ancestry post-dates admixture between pastoralists and foragers, suggesting an earlier spread of pastoralism than farming to southern Africa. Our findings demonstrate how processes of migration and admixture have markedly reshaped the genetic map of sub-Saharan Africa in the past few millennia and highlight the utility of combined archaeological and archaeogenetic approaches.
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http://dx.doi.org/10.1126/sciadv.aaz0183DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7292641PMC
June 2020

Soil and plant phytoliths from the mosaics at Oldupai Gorge (Tanzania).

PeerJ 2019 11;7:e8211. Epub 2019 Dec 11.

ASM Research Group, Cochrane, Canada.

This article studies soil and plant phytoliths from the Eastern Serengeti Plains, specifically the mosaics from Oldupai Gorge, Tanzania, as present-day analogue for the environment that was contemporaneous with the emergence of the genus . We investigate whether phytolith assemblages from recent soil surfaces reflect plant community structure and composition with fidelity. The materials included 35 topsoil samples and 29 plant species (20 genera, 15 families). Phytoliths were extracted from both soil and botanical samples. Quantification aimed at discovering relationships amongst the soil and plant phytoliths relative distributions through Chi-square independence tests, establishing the statistical significance of the relationship between categorical variables within the two populations. Soil assemblages form a spectrum, or cohort of co-ocurring phytolith classes, that will allow identifying environments similar to those in the - ecozone in the fossil record.
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http://dx.doi.org/10.7717/peerj.8211DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6911344PMC
December 2019

Publisher Correction: 78,000-year-old record of Middle and Later Stone Age innovation in an East African tropical forest.

Nat Commun 2018 06 5;9(1):2242. Epub 2018 Jun 5.

Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Strasse 10, Jena, D-07745, Germany.

The originally published version of this Article contained an error in Fig. 3, whereby an additional unrelated graph was overlaid on top of the magnetic susceptibility plot. Furthermore, the Article title contained an error in the capitalisation of 'Stone Age'. Both of these errors have now been corrected in both the PDF and HTML versions of the Article.
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http://dx.doi.org/10.1038/s41467-018-04753-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5988799PMC
June 2018

78,000-year-old record of Middle and Later stone age innovation in an East African tropical forest.

Nat Commun 2018 05 9;9(1):1832. Epub 2018 May 9.

Department of Archaeology, Max Planck Institute for the Science of Human History, Kahlaische Strasse 10, Jena, D-07745, Germany.

The Middle to Later Stone Age transition in Africa has been debated as a significant shift in human technological, cultural, and cognitive evolution. However, the majority of research on this transition is currently focused on southern Africa due to a lack of long-term, stratified sites across much of the African continent. Here, we report a 78,000-year-long archeological record from Panga ya Saidi, a cave in the humid coastal forest of Kenya. Following a shift in toolkits ~67,000 years ago, novel symbolic and technological behaviors assemble in a non-unilinear manner. Against a backdrop of a persistent tropical forest-grassland ecotone, localized innovations better characterize the Late Pleistocene of this part of East Africa than alternative emphases on dramatic revolutions or migrations.
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http://dx.doi.org/10.1038/s41467-018-04057-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5943315PMC
May 2018

Phytoliths from Middle Stone Age habitats in the Mozambican Rift (105-29 ka).

J Hum Evol 2013 May 16;64(5):328-36. Epub 2013 Mar 16.

Department of Archaeology, University of Calgary, Alberta T2N 1N4, Canada.

The detection of areas suitable for hominins during late Pleistocene drought intervals is currently a priority for Middle Stone Age research. Predicting the location of populations and dispersal pathways through the East African Rift System during the last glacial phase is a challenging task due to scarce direct archaeo-vegetation data. We present a Mozambican phytolith record spanning 105-29 ka and argue for the necessity and utility of using local plant microbotanical data from archaeological sites to understand the past environments in which early modern humans lived. We assess biome structure, spatial variability, and compare phytolith-based to lacustrine environmental reconstructions to conclude that dense wooded landscapes dominated the area over much of the last glacial phase. Archaeological and botanical data suggest the hypothesis of a palaeodispersal along a montane woodland archipelago that could have attracted hominin settlement and facilitated dispersals through an inland bridge that connected southern, central and East Africa, and the two branches of the East African Rift System.
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http://dx.doi.org/10.1016/j.jhevol.2012.10.013DOI Listing
May 2013

Mozambican grass seed consumption during the Middle Stone Age.

Authors:
Julio Mercader

Science 2009 Dec;326(5960):1680-3

Department of Archaeology, University of Calgary, Alberta, T2N 1N4, Canada.

The role of starchy plants in early hominin diets and when the culinary processing of starches began have been difficult to track archaeologically. Seed collecting is conventionally perceived to have been an irrelevant activity among the Pleistocene foragers of southern Africa, on the grounds of both technological difficulty in the processing of grains and the belief that roots, fruits, and nuts, not cereals, were the basis for subsistence for the past 100,000 years and further back in time. A large assemblage of starch granules has been retrieved from the surfaces of Middle Stone Age stone tools from Mozambique, showing that early Homo sapiens relied on grass seeds starting at least 105,000 years ago, including those of sorghum grasses.
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http://dx.doi.org/10.1126/science.1173966DOI Listing
December 2009

Primate archaeology.

Nature 2009 Jul;460(7253):339-44

Leverhulme Centre for Human Evolutionary Studies, University of Cambridge, Cambridge CB2 1QH, UK.

All modern humans use tools to overcome limitations of our anatomy and to make difficult tasks easier. However, if tool use is such an advantage, we may ask why it is not evolved to the same degree in other species. To answer this question, we need to bring a long-term perspective to the material record of other members of our own order, the Primates.
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http://dx.doi.org/10.1038/nature08188DOI Listing
July 2009

Initial excavation and dating of Ngalue Cave: a Middle Stone Age site along the Niassa Rift, Mozambique.

J Hum Evol 2009 Jul 31;57(1):63-74. Epub 2009 May 31.

Department of Archaeology, University of Calgary, Alberta, Canada.

Direct evidence for a systematic occupation of the African tropics during the early late Pleistocene is lacking. Here, we report a record of human occupation between 105-42ka, based on results from a radiometrically-dated cave section from the Mozambican segment of the Niassa (Malawi/Nyasa) Rift called Ngalue. The sedimentary sequence from bottom to top has five units. We concentrate on the so-called "Middle Beds," which contain a Middle Stone Age industry characterized by the use of the discoidal reduction technique. A significant typological feature is the presence of formal types such as points, scrapers, awls, and microliths. Special objects consist of grinders/core-axes covered by ochre. Ngalue is one of the few directly-dated Pleistocene sites located along the biogeographical corridor for modern human dispersals that links east, central, and southern Africa, and, with further study, may shed new light on hominin cave habitats during the late Pleistocene.
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http://dx.doi.org/10.1016/j.jhevol.2009.03.005DOI Listing
July 2009

Phytoliths in woody plants from the Miombo woodlands of Mozambique.

Ann Bot 2009 Jul 9;104(1):91-113. Epub 2009 May 9.

Department of Archaeology, University of Calgary, Calgary, Alberta, Canada.

Background And Aims: There are no descriptions of phytoliths produced by plants from the 'Zambezian' zone, where Miombo woodlands are the dominant element of the largest single phytochorion in sub-Saharan Africa. The preservation of phytoliths in fossil records of Africa makes phytoliths a tool to study early plant communities. Paleo-ethnobotanical interpretation of phytoliths relies on the comparison of ancient types with morphotypes extracted from living reference collections.

Methods: Phytoliths were extracted from plant samples representing 41 families, 77 genera and 90 species through sonic cleaning, dry ashing and acid treatment; and phytoliths thus extracted were quantified. For each species, an average of 216 phytoliths were counted. The percentage of each morphotype identified per species was calculated, and types were described according to the descriptors from the International Code for Phytolith Nomenclature. Phytolith assemblages were subject to discriminant analysis, cluster analysis and principal component analysis.

Key Results: Phytoliths were grouped into 57 morphotypes (two were articulated forms and 55 were discrete shapes), and provide a reference collection of phytolith assemblages produced by Miombo woody species. Common and unique morphotypes are described and taxonomic and grouping variables are looked into from a statistical perspective.

Conclusions: The first quantitative taxonomy of phytoliths from Miombos is presented here, including new types and constituting the most extensive phytolith key for any African ecoregion. Evidence is presented that local woody species are hypervariable silica producers and their phytolith morphotypes are highly polymorphic. The taxonomic significance of these phytoliths is largely poor, but there are important exceptions that include the morphotypes produced by members from >10 families and orders. The typical phytolithic signal that would allow scientists to identify ancient woodlands of 'Zambezian' affiliation comprises only half of the original number of phytoliths originally produced and might favour the more resilient blocky, cylindroid, globular and tabular forms.
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http://dx.doi.org/10.1093/aob/mcp097DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2706725PMC
July 2009

4,300-year-old chimpanzee sites and the origins of percussive stone technology.

Proc Natl Acad Sci U S A 2007 Feb 20;104(9):3043-8. Epub 2007 Feb 20.

Department of Archaeology, University of Calgary, Calgary, AB, Canada T2N 1N4.

Archaeological research in the African rainforest reveals unexpected results in the search for the origins of hominoid technology. The ancient Panin sites from Côte d'Ivoire constitute the only evidence of prehistoric ape behavior known to date anywhere in the world. Recent archaeological work has yielded behaviorally modified stones, dated by chronometric means to 4,300 years of age, lodging starch residue suggestive of prehistoric dietary practices by ancient chimpanzees. The "Chimpanzee Stone Age" pre-dates the advent of settled farming villages in this part of the African rainforest and suggests that percussive material culture could have been inherited from an common human-chimpanzee clade, rather than invented by hominins, or have arisen by imitation, or resulted from independent technological convergence.
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http://dx.doi.org/10.1073/pnas.0607909104DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1805589PMC
February 2007

Excavation of a chimpanzee stone tool site in the African rainforest.

Science 2002 May;296(5572):1452-5

Department of Anthropology, George Washington University, 2110 G Street NW, Washington, DC 20052, USA.

Chimpanzees from the Tai forest of Côte d'Ivoire produce unintentional flaked stone assemblages at nut-cracking sites, leaving behind a record of tool use and plant consumption that is recoverable with archaeological methods. About 40 kilograms of nutshell and 4 kilograms of stone were excavated at the Panda 100 site. The data unearthed show that chimpanzees transported stones from outcrops and soils to focal points, where they used them as hammers to process foodstuff. The repeated use of activity areas led to refuse accumulation and site formation. The implications of these data for the interpretation of the earliest hominin archaeological record are explored.
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http://dx.doi.org/10.1126/science.1070268DOI Listing
May 2002