[Show abstract][Hide abstract] ABSTRACT: The results of archaeological and bioarchaeological research are presented from an area located in the lower Gualcamayo River Basin (in the northwestern part of the Province of San Juan), which includes sites
with surface and sub-surface material, as well as burials from a period between 2300 and 1100 bp. Using these results, ideas for the development or expansion of agropastoral practices in northwest San Juan are discussed. Based on this, arguments are presented in favor of the possibility that there was an expansion of agropastoral groups from the northeastern valleys after 2100 bp. It is also argued that these societies did not incorporate maize as an important resource in their diets during at least 1000 years.
Arqueología de Ambientes de Altura de Mendoza y San Juan (Argentina)., first edited by Valeria Cortegoso, Victor Durán, 08/2014: pages 163-201; EDIUNC., ISBN: 978-950-39-0308-7
Arqueología de Ambientes de Altura de Mendoza y San Juan (Argentina)., Edited by first edited by Valeria Cortegoso, Victor Durán, Alejandra Gasco, 01/2014: pages 43-55; EDIUNC., ISBN: 978-950-39-0308-7
[Show abstract][Hide abstract] ABSTRACT: "The developmental processes that contribute to variation of morphological traits are the subject of considerable interest when attempting to understand phenotypic evolution. It is well demonstrated that most characteristics
of tooth pattern can be modified by tinkering conserved
signal pathways involved in dental development. This effect can be evaluated by comparing developmental models with naturally occurring variation within explicit phylogenetic contexts. Here, we assess whether evolutionary changes in lower molar (M) ratios among platyrrhines were channelled by alterations in the balance of activators and inhibitors as predicted by the inhibitory cascade (IC) model (Kavanagh et al. in Nature 449:427–432, 2007). Ordinary linear regression adjusted to M2/M1 versus M3/M1 ratios of 38 species of platyrrhines indicated that the slope and intercept were significantly different from the IC model. Conversely, when the phylogeny was incorporated into the regression
analyses (PGLS), variation in molar ratios did not differ from the developmental model. PGLS also showed that changes in molar proportions are not an allometric effect associated with body size. Discrepancies between phylogenetically corrected and non-corrected analyses are mainly due to the departure of Callitrichines from the predicted values. This subfamily displays agenesis of M3 with higher than expected M2/M1 ratios, indicating that M3 fails to develop even when the inhibition by M1 on the subsequent molars is not increased. Our results show that evolution in molar ratios is concordant with slight changes in the proportion of activators and inhibitors that regulate molar development; however, other processes are required to account for variation in the number of teeth."
Journal of Evolutionary Biology 04/2013; · 3.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previous studies have shown that ecological factors had a significant role in shaping the patterns of craniofacial variation among South American populations. Here, we evaluate whether temperature and diet contributed to facial diversification in small geographic areas. Facial size and shape of 9 osteological samples from central Patagonia (Argentina) were described using 2D landmarks and semilandmarks. Data on mean annual temperature, diet composition (δ13C and δ15N values) and femoral head maximum breadth, used as a proxy of body mass, were obtained for each sample. We then tested the association of body mass and the ecological variables with facial morphology using spatial regression techniques and a model selection approach. Akaike Information Criterion, produced disparate results for both components of facial morphology. The best model for facial size included temperature and body mass proxy, and accounted for more than 80% of variation in size. Lower temperatures were related to larger facial sizes. Body mass was negatively associated with facial size and showed no relationship with the temperature. This suggests a relatively independent variation of cranial traits and body mass at the spatial scale studied here. Facial shape was not associated with the temperature or diet composition, contrasting with the patterns observed at larger spatial scales. Our results point out that the effect of climatic variables on cranial traits might be a source of morphological differentiation not only at large scales but also in small geographic areas, and that size and shape display a differential preservation of environmental signals.
HOMO - Journal of Comparative Human Biology 01/2013; · 0.73 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper presents the results obtained from the analysis of grinding artefacts recovered in Aqui-huecó (3.700 AP) and Michacheo (1.860 años AP) archaeological sites from the Neuquen province. Such analysis involved the identification of plant microremains adhered to their surfaces. Results show processing of Prosopis sp pods in both sites and of Zea mays grains in Michacheo. This last site also has ceramic sherds, therefore at ca. 2.000 AP there was a broadening of the technological base together with food resources. Analysis of archaeological contexts point to the association of these artefacts and the burial of adult female individuals along Late Holocene. Bioanthropological evidence show an increase in the presence of caries and a reduction of dental wear around 2.000 A P, which might have been associated to the incorporation of new resources and technology, although the stable isotope analysis suggest the absence of diets rich in C4 plants -such as corn- among these populations.
[Show abstract][Hide abstract] ABSTRACT: Modifications of ontogenetic allometries play an important role in patterning the shape differentiation among populations. This study evaluates the influence of size variation on craniofacial shape disparity among human populations from South America and assesses whether the morphological disparity observed at the interpopulation level resulted from a variable extension of the same ontogenetic allometry, or whether it arose as a result of divergences in the pattern of size-related shape changes. The size and shape of 282 adult and subadult crania were described by geometric morphometric-based techniques. Multivariate regressions were used to evaluate the influence of size on shape differentiation between and within populations, and phylogenetic comparative methods were used to take into account the shared evolutionary history among populations. The phylogenetic generalized least-squares models showed that size accounts for a significant amount of shape variation among populations for the vault and face but not for the base, suggesting that the three modules did not exhibit a uniform response to changes in overall growth. The common slope test indicated that patterns of evolutionary and ontogenetic allometry for the vault and face were similar and characterized by a heightening of the face and a lengthening of the vault with increasing size. The conservation of the same pattern of shape changes with size suggests that differences in the extent of growth contributed to the interpopulation cranial shape variation and that certain directions of morphological change were favored by the trait covariation along ontogeny.
The Anatomical Record Advances in Integrative Anatomy and Evolutionary Biology 09/2011; 294(11):1864-74. · 1.34 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The aim of this paper is to conduct a historical analysis of the research-oriented studies related to dental anthropology in Argentina, evaluate its current state and discuss future expectations and perspectives. In this country, anthropological studies based on analysis of dentition have been scarce and even temporarily discontinued, since they began in the late nineteenth century, simply following the course of the predominant theoretical and methodological approaches over time. Early papers, guided mainly by evolutionary ideas, were oriented towards establishing the taxonomic position of humans through the description and comparison of morphological and morphometric aspects of the dental crown and root. Later studies mainly described types of intentional modifications (i.e. dental mutilations) and tooth wear in the context of Historic-Cultural School. However, they failed to constitute valid lines of research over time. In recent years, there has been a significant change in dental studies, mainly as a result of the interest in evaluating the adaptive aspects of human populations within biocultural settings. One of the most relevant lines of studies has been the bioarchaeological analysis of health and stress indicators, such as enamel hypoplasia, caries and tooth wear in hunter-gatherer and farmer societies. More recently, the study of discrete and metric dental traits began, with a goal to contribute to the study of evolution and inter-populational biological relations among South American groups. Since teeth contain valuable information not only about the environment in which the individual lived, but also about the action of neutral and non-neutral factors on human groups, the consolidation of ongoing studies will contribute to knowledge of various aspects of the adaptation and evolution of native American populations.
Homo: internationale Zeitschrift fur die vergleichende Forschung am Menschen 09/2011; 62(5):315-27. · 0.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper describes and discusses the research in the field of dental anthropology in Argentina. It has been presented at the symposium entitled "The development of dental research in Argentine Biological Anthropology: current status and perspectives", coordinated by the authors at the IX National Meeting of Biological Anthropology of Argentina, Puerto Madryn, 20th-23rd October 2009. The aim of the symposium was to present new results and future prospects of this discipline in the country and to create a forum for discussion of current research within this field. Six contributions that focused on the study of teeth from different perspectives and analysed bioarchaeological samples from different areas of Argentina (Central Highlands, Pampa and Patagonia) were presented. After the presentations, a discussion about the state of the art of dental research in the country was generated, in which the need for the generation of methodological consensus on the criteria for the evaluation of the variables considered was stated, so that research conducted in different areas can be compared. In short, the contributions of this symposium provide insights into the diversity of dental anthropology in contemporary Argentina and the potential of these types of studies to gain important information about biological and cultural aspects of the native populations in the country.
Homo: internationale Zeitschrift fur die vergleichende Forschung am Menschen 09/2011; 62(5):328-34. · 0.96 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aim Understanding the importance of ecological factors in the origin and maintenance of patterns of phenotypic variation among populations, in an explicit geographical context, is one of the main goals of human biology, ecology and evolutionary biology. Here we study the ecological factors responsible for craniofacial variation among human populations from South America.Location South America.Methods We studied a dataset of 718 males from 40 South American populations, coming from groups that inhabited different geographical and ecological regions. Cranial size and shape variation were studied using 30 cranial measurements. We first used spatial correlograms and interpolated maps to address spatial patterns. We then regressed the shape (principal component scores) and size variables against ecology (mean annual temperature and diet) using multiple and multivariate spatial regression. Finally, the expected magnitudes of shape and size divergence under the influence of genetic drift and mutations alone were evaluated using neutral expectation for the divergence rate.Results The spatial correlograms showed a cline affecting the entire South American distribution. Interpolated maps showed that size and allometric shape vary from south-east to north-west. Multiple and multivariate regression analyses suggested that diet has the largest and most significant effect on this pattern of size and allometric shape variation. Finally, the results of the divergence rate test suggested that random processes alone cannot account for the morphological divergence exhibited by cranial size and allometric shape scores among southernmost populations.Main conclusions Correlograms, spatial regression and divergence rate analyses showed that although local factors (neutral processes or local environmental conditions) are important to explain spatial interpopulation differentiation in cranial characteristics among these populations, there is significant correlation of cranial size and allometric shape variation with diet. Gene flow among human populations, or local environmental conditions, could explain spatial variation mainly at smaller spatial scales, whereas the large-scale pattern of the South American dataset is mainly related to the high proportion of carbohydrates and low proportion of proteins consumed.
[Show abstract][Hide abstract] ABSTRACT: To date, differences in craniofacial robusticity among modern and fossil humans have been primarily addressed by analyzing adult individuals; thus, the developmental basis of such differentiation remains poorly understood. This article aims to analyze the ontogenetic development of craniofacial robusticity in human populations from South America. Geometric morphometric methods were used to describe cranial traits in lateral view by using landmarks and semilandmarks. We compare the patterns of variation among populations obtained with subadults and adults to determine whether population-specific differences are evident at early postnatal ontogeny, compare ontogenetic allometric trajectories to ascertain whether changes in the ontogeny of shape contribute to the differentiation of adult morphologies, and estimate the amount of size change that occurs during growth along each population-specific trajectory. The results obtained indicate that the pattern of interpopulation variation in shape and size is already established at the age of 5 years, meaning that processes acting early during ontogeny contribute to the adult variation. The ontogenetic allometric trajectories are not parallel among all samples, suggesting the divergence in the size-related shape changes. Finally, the extension of ontogenetic trajectories also seems to contribute to shape variation observed among adults.
American Journal of Physical Anthropology 12/2009; 142(3):367-79. · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The knowledge of processes involved in morphological variation requires the integrated analysis of evolutionary and ecological factors. Here, we investigate the factors responsible for dental variation among human populations from southern South America. The aim of this work is to test the correspondence of dental size and shape variation with geographical, molecular (i.e. mtDNA) and ecological (i.e. climate, diet and food preparation) variables employing comparative phylogenetic methods, which have not previously been extensively applied at a within-species level. The results of the Procrustes analysis show a significant association of shape variables with molecular distance and geography, whereas dental size is not associated with molecular or geographical distances among groups. Phylogenetic generalized least-squares analysis, which takes into account the evolutionary autocorrelation among populations, shows a significant relationship between dental size variation and diet, while temperature and pottery do not correspond with dental size or shape. Specifically, groups with diets rich in carbohydrates, as well as the maritime hunter-gatherers, have the smallest teeth. In summary, our results support ecological factors as the dominant factor on dental size diversification in this region, while evolutionary relationships account for variation in dental shape.
Proceedings of the Royal Society B: Biological Sciences 12/2009; 277(1684):1107-12. · 5.68 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The purpose of this article is to examine the patterns of evolutionary relationships between human populations from the later Late Holocene (1,500-100 years BP) of southern South America on the basis of dental morphometric data. We tested the hypotheses that the variation observed in this region would be explained by the existence of populations with different phylogenetic origin or differential action of gene flow and genetic drift. In this study, we analyzed permanent teeth from 17 samples of male and female adult individuals from throughout southern South America. We measured mesiodistal and buccolingual diameters at the base of the crown, along the cement-enamel junction. The results of multiple regression analysis and a mantel correlogram indicate the existence of spatial structure in dental shape variation, as the D(2) Mahalanobis distance between samples increases with increasing geographical distance between them. In addition, the correlation test results show a trend toward reduction of the internal variation of samples with increasing latitude. The detected pattern of dental variation agrees with the one expected as an outcome of founder serial effects related to an expansion of range during the initial occupation of southern South America.
American Journal of Physical Anthropology 11/2009; 142(1):95-104. · 2.48 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Understanding the importance of environmental dimensions behind the morphological variation among populations has long been a central goal of evolutionary biology. The main objective of this study was to review the spatial regression techniques employed to test the association between morphological and environmental variables. In addition, we show empirically how spatial regression techniques can be used to test the association of cranial form variation among worldwide human populations with a set of ecological variables, taking into account the spatial autocorrelation in data. We suggest that spatial autocorrelation must be studied to explore the spatial structure underlying morphological variation and incorporated in regression models to provide more accurate statistical estimates of the relationships between morphological and ecological variables. Finally, we discuss the statistical properties of these techniques and the underlying reasons for using the spatial approach in population studies.
Journal of Evolutionary Biology 11/2009; 23(2):237-48. · 3.48 Impact Factor