Once upon a time
A 130,000-year-old archaeological site in southern California, USA
Steven Holen et al.
Nature, 27 April 2017, Pages 479–483
Abstract:
The earliest dispersal of humans into North America is a contentious subject, and proposed early sites are required to meet the following criteria for acceptance: (1) archaeological evidence is found in a clearly defined and undisturbed geologic context; (2) age is determined by reliable radiometric dating; (3) multiple lines of evidence from interdisciplinary studies provide consistent results; and (4) unquestionable artefacts are found in primary context. Here we describe the Cerutti Mastodon (CM) site, an archaeological site from the early late Pleistocene epoch, where in situ hammerstones and stone anvils occur in spatio-temporal association with fragmentary remains of a single mastodon (Mammut americanum). The CM site contains spiral-fractured bone and molar fragments, indicating that breakage occured while fresh. Several of these fragments also preserve evidence of percussion. The occurrence and distribution of bone, molar and stone refits suggest that breakage occurred at the site of burial. Five large cobbles (hammerstones and anvils) in the CM bone bed display use-wear and impact marks, and are hydraulically anomalous relative to the low-energy context of the enclosing sandy silt stratum. 230Th/U radiometric analysis of multiple bone specimens using diffusion–adsorption–decay dating models indicates a burial date of 130.7 ± 9.4 thousand years ago. These findings confirm the presence of an unidentified species of Homo at the CM site during the last interglacial period (MIS 5e; early late Pleistocene), indicating that humans with manual dexterity and the experiential knowledge to use hammerstones and anvils processed mastodon limb bones for marrow extraction and/or raw material for tool production. Systematic proboscidean bone reduction, evident at the CM site, fits within a broader pattern of Palaeolithic bone percussion technology in Africa, Eurasia and North America. The CM site is, to our knowledge, the oldest in situ, well-documented archaeological site in North America and, as such, substantially revises the timing of arrival of Homo into the Americas.
The Economics of Early Warfare Over Land
Gregory Dow, Leanna Mitchell & Clyde Reed
Journal of Development Economics, July 2017, Pages 297–305
Abstract:
We investigate the incidence of early warfare among foragers and farmers in prehistory. Our focus is specifically on conflict over land. Food is produced using inputs of labor and land, and the probability of victory in a conflict depends on relative group sizes. The group sizes are determined by individual migration and Malthusian population dynamics. Both factors result in larger populations at better sites, which deters attack. There are two necessary conditions for warfare: high enough individual mobility costs and large enough shocks to the relative productivities of the sites. Together, these conditions are sufficient. In particular, technological or environmental shocks that alter the productivities of sites can trigger warfare, but only if individual agents do not change sites in response. These results are consistent with evidence from archaeology and anthropology.
Aboriginal mitogenomes reveal 50,000 years of regionalism in Australia
Ray Tobler et al.
Nature, 13 April 2017, Pages 180–184
Abstract:
Aboriginal Australians represent one of the longest continuous cultural complexes known. Archaeological evidence indicates that Australia and New Guinea were initially settled approximately 50 thousand years ago (ka); however, little is known about the processes underlying the enormous linguistic and phenotypic diversity within Australia. Here we report 111 mitochondrial genomes (mitogenomes) from historical Aboriginal Australian hair samples, whose origins enable us to reconstruct Australian phylogeographic history before European settlement. Marked geographic patterns and deep splits across the major mitochondrial haplogroups imply that the settlement of Australia comprised a single, rapid migration along the east and west coasts that reached southern Australia by 49–45 ka. After continent-wide colonization, strong regional patterns developed and these have survived despite substantial climatic and cultural change during the late Pleistocene and Holocene epochs. Remarkably, we find evidence for the continuous presence of populations in discrete geographic areas dating back to around 50 ka, in agreement with the notable Aboriginal Australian cultural attachment to their country.
Reconciling evidence from ancient and contemporary genomes: A major source for the European Neolithic within Mediterranean Europe
Joana Pereira et al.
Proceedings of the Royal Society: Biological Sciences, 29 March 2017
Abstract:
Important gaps remain in our understanding of the spread of farming into Europe, due partly to apparent contradictions between studies of contemporary genetic variation and ancient DNA. It seems clear that farming was introduced into central, northern, and eastern Europe from the south by pioneer colonization. It is often argued that these dispersals originated in the Near East, where the potential source genetic pool resembles that of the early European farmers, but clear ancient DNA evidence from Mediterranean Europe is lacking, and there are suggestions that Mediterranean Europe may have resembled the Near East more than the rest of Europe in the Mesolithic. Here, we test this proposal by dating mitogenome founder lineages from the Near East in different regions of Europe. We find that whereas the lineages date mainly to the Neolithic in central Europe and Iberia, they largely date to the Late Glacial period in central/eastern Mediterranean Europe. This supports a scenario in which the genetic pool of Mediterranean Europe was partly a result of Late Glacial expansions from a Near Eastern refuge, and that this formed an important source pool for subsequent Neolithic expansions into the rest of Europe.