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ABSTRACT Approaching the study of camelid bone size change in the meridional portion of the South Central Andes is a significant subject especially when the assemblages are associated to radiocarbon dates placed at a time of social transition from an extractive to a producer economy. In this sense, this paper presents the results of applying osteometric techniques on a set of 10 elements from the Peñas Chicas 1.5 site dated around 3800 BP. The analysis shows the presence of at least three individuals, one of which corresponds to an Andean guanaco ( Lama guanicoe) morphotype. The second and the third are similar in size to a modern llama ( Lama glama) in their 'intermediate' and 'cargo' morphotypes. This is consistent with patterns already seen for sites from the Argentinian and Chilean Puna where the identification of larger individuals than the Andean guanaco modern standard shows the early stages of an increasingly bone size variability of South American camelids. This paper contributes with new data to understand the complex processes that occurred in the South Central Andes that led to the domestication of one of the most conspicuous animals in the archaeological record of the Argentinian Northwest. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

History and environment shape crop biodiversity, particularly in areas with vulnerable human communities and ecosystems. Tracing crop biodiversity over time helps understand how rural societies cope with anthropogenic or climatic changes. Exceptionally well preserved ancient DNA of quinoa (Chenopodium quinoa Willd.) from the cold and arid Andes of Argentina has allowed us to track changes and continuities in quinoa diversity over 18 centuries, by coupling genotyping of 157 ancient and modern seeds by 24 SSR markers with cluster and coalescence analyses. Cluster analyses revealed clear population patterns separating modern and ancient quinoas. Coalescence-based analyses revealed that genetic drift within a single population cannot explain genetic differentiation among ancient and modern quinoas. The hypothesis of a genetic bottleneck related to the Spanish Conquest also does not seem to apply at a local scale. Instead, the most likely scenario is the replacement of preexisting quinoa gene pools with new ones of lower genetic diversity. This process occurred at least twice in the last 18 centuries: first, between the 6th and 12th centuries-a time of agricultural intensification well before the Inka and Spanish conquests-and then between the 13th century and today-a period marked by farming marginalization in the late 19th century likely due to a severe multidecadal drought. While these processes of local gene pool replacement do not imply losses of genetic diversity at the metapopulation scale, they support the view that gene pool replacement linked to social and environmental changes can result from opposite agricultural trajectories., Competing Interests: The authors have declared that no competing interests exist.

This article focuses on local paleohydrological changes experienced by the Las Pitas and Miriguaca Rivers in the south-central Andes of Argentina and their impacts on hunter-gatherers as they transitioned to food-producing communities 7000-3000 cal. yr B.P. Paleoenvironmental reconstruction based on geomorphology, alluvial sedimentology, and diatom evidence indicates a dry phase of reduced streamflow between ca . 6700 and 4800 cal. yr B.P. for the Las Pitas River, and 6600 and 3000 cal. yr B.P. for the Miriguaca River. A phase of more humid environmental conditions commenced after ca . 4900 cal. yr B.P. along the Las Pitas River, and after 3000 cal. yr B.P. along the Miriguaca River. Differences in the chronology and magnitude of hydrological changes along both rivers are related to topographic and hydrological characteristics of their respective watersheds. Higher catchment elevation and enhanced orographic precipitation favored greater sensitivity for the Las Pitas River to short humid events during the middle-to-late Holocene. The archaeological evidence suggests that the paleohydrological changes within these catchments played a significant role in human occupational dynamics such that the Las Pitas River offered better environmental conditions for human occupation relative to the Miriguaca River as foragers increasingly relied on plant and animal domestication., (Copyright © 2016 Wiley Periodicals, Inc.)