25th Center for Archaeological Investigations Visiting Scholar Conference
Biological and Archaeological Variation in the New World
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Giants among us? Detecting North American patterns of migration from variation in postcranial morphology
Benjamin M. Auerbach (Southern Illinois University Carbondale)
Both archaeologists and skeletal biologists recognize a discontinuity between two groups in the Northern Plains: the Pawnee (Central Plains) and Arikara (Northern Plains) are craniometrically distinct from the Mandan and Hidatsa (both Northern Plains). The latter have a longer archaeological record in the region, and it has generally been agreed that the Arikara represent a recent (ca. 500 yBP) incursion of Pawnee-derived peoples into the Northern Plains. Yet, there is some contention concerning the origins of the Pawnee, and, ultimately, the Arikara. Both of these groups are members of the Caddoan linguistic grouping, representing a distinct branch of the language family, but there is a geographic distinction between the Pawnee and the (Arkansas and Louisiana) Caddo. Furthermore, an archaeological link between them is lacking. The evidence is therefore ambiguous for a Pawnee replacement of previous cultures from the Central Plains, such as the Itskari, originating from the southeast.
Previous studies have indicated that postcranial morphologies are unequally affected by environmental variables (e.g., climate or subsistence), and that some are more mutable across generations than others. For example, bi-iliac breadth may change less rapidly in relation to climatic factors than intralimb indices. This study compares postcranial morphologies that covary with environmental factors—body mass, body breadth, stature, and intralimb indices—between pre-contact Caddoan samples and various Great Plains samples to ascertain if these morphologies may elucidate relationships among these groups.
A sample of 41 Caddo, 88 Arikara, and 95 Central Plains individuals, were compared with each other and against climatic variables. Results show that the Arikara have unexpectedly tall statures, high body masses and wide body breadths, which are significantly more like the Caddo samples than earlier (ostensibly pre-Pawnee) Central Plains groups. These results tentatively support a Caddoan demic expansion into the Great Plains within the last millennium, or an alternate, unknown exotic origin.
This research was supported, in part, by a National Science Foundation Doctoral Dissertation Improvement Grant (#0550673).
Technological change as a contributor to craniofacial differences between Paleoindians and later peoples: a Pacific Northwest example
James C. Chatters (AMEC Earth and Environmental, Inc.)
Comparisons of craniofacial morphometrics between Paleoindians and recent Native-Americans reveal marked differences. Recent populations resemble their Northeast Asian contemporaries, whereas Paleoindians appear more generalized. Some researchers see this as evidence for multiple episodes of Asian immigration to the Americas, with the Northeast Asian ancestors of Native-Americans arriving most recently. Others envision a single founder population, explaining morphometric patterns by invoking population genetics and the convergent evolutionary response of related peoples to post Pleistocene conditions. A third possibility-biomechanical response to changing subsistence technologies-has received little attention.
The principal morphometric differences between Paleoindian and later crania lie in neurocranial length-width-height relationships and the degree of facial forwardness. These might be mechanically linked through the masticulatory musculature to diet and patterns of tooth use. We would expect, and recent comparisons of foraging and food producing populations have shown, that Paleoindian, Archaic, and Agricultural adaptations placed differential stresses on the human skull.
The biomechanical explanation is explored in this paper using archaeological and physical anthropological data from the Pacific Northwest, with emphasis on craniometrics, dental wear, and masticulatory musculature in the transition from Paleoindian to Archaic cultures. The archaeological record exhibits an abrupt change in land use, lithic, bone, fiber, and food processing technologies around 9000 cal BP, with an upland, hunting focus replaced by an emphasis on riparian resources. Morphometric differences between Paleoindian and Archaic crania follow the continent-wide pattern. Dental wear in Paleoindians shows heavy incisor use, matched by hypertrophy of temporalis to the extent that it constrained cranial breadth. No such wear or muscle over-development is evident during the Archaic. Thus it appears that technological changes alleviated pressure on the incisors, relaxing stresses on the neurocranium, and may account for some of the difference between Paleoindians and later peoples. Other Paleoindian skulls show similar dental wear and muscle development, marking biomechanics as a direction for future research.
Skeletal variation and environmental diversity in northwestern North America
Jerome S. Cybulski (Canadian Museum of Civilization)
The Northwest Coast and adjacent Plateau provide a regional microcosm of evolutionary variation in native North America. Human skeletal remains from these culture areas differ in stature, limb proportions, and femoral shaft shape in apparent congruence with environmental differences. Men and women of the Plateau were variably taller than those of the coast, lower limbs were significantly longer relative to upper limbs, and femur mid-shafts were elliptical in cross section rather than round, a plausible indicator of femur strength. People of the Plateau appear to have been well adapted for hunting land game. People of the coast, in addition to their short stature, had sinuous humeri and flatter upper femoral shafts, all more suitable, perhaps, for paddling canoes, hunting sea mammals and fishing.
The Northwest Coast and Plateau present contrasting environments. Despite insignificant shorelines, especially in the northern and central portions, the Northwest Coast was one of the most heavily populated and culturally complex areas in North America, derived from a successful human maritime adaptation and primary dependence on marine dietary resources. By contrast, the Plateau was sparsely settled despite having a greater habitable land area. Plateau people were dependent on large and small game animals, plant roots, and anadromous fish though the degree of dependence on land game and fish varied by habitat and proximity to major river drainages. Corresponding patterns of dietary difference are reflected in stable isotope signatures (15N/14N and 13C/12C), while disproportionate incidences of dental caries and abscesses reflect in large part dependencies on available plant foods. Overall, the results of the study provide regional insight into evolutionary forces that could have shaped patterns of biological diversity in the Americas.
This research was funded by the Physical Anthropology Program of the Canadian Museum of Civilization.
Discrete dental trait evidence of migration patterns in the Northern Southwest
Kathy R. Durand (Eastern New Mexico University)
Migration patterns are the focus of much current research in the Southwest, but are usually identified using indirect methods, such as documenting changes in ceramic styles or architecture. This study tests models of migration patterns in the prehistoric northern Southwest more directly using discrete dental traits. These traits are under tight genetic control and provide a nondestructive means of documenting genetic relatedness among regional populations.
I have documented a change in the dentition between the populations at two small, adjacent sites in the Middle San Juan Region of northwest New Mexico, one dating to the Pueblo II period (the Tommy Site) and the other to the Pueblo III period (the Mine Canyon Site). The initial interpretation of these sites, based on the material culture record, suggested that they represent the same population through time. Nevertheless, there are fairly dramatic differences in the dentition of the human remains from the sites that mirror patterns found in an analysis of their DNA, indicating a likely influx of migrants to the area by A.D. 1150. By including data from additional sites in the region, I am able to suggest an origin for the Pueblo III immigrants. Some of the models that are tested through this research include the timing of the southward migration from the Mesa Verde region and the proposal that groups moved from Chaco Canyon into the Middle San Juan Region after A.D. 1150.
Despite the usefulness of discrete dental traits for tackling the issue of migration, they have been underutilized. I believe that this is due to a lack of integration between the disciplines of archaeology and biological anthropology–studies in biological anthropology often do not address regional archaeological questions. This study helps to bridge that gap by using biological data from prehistoric samples to address archaeological questions.
Funding supplied by Tommy Bolack of the B-Square Ranch and Eastern New Mexico University.
Paleoamerican and Amerindian morphological variation: implications for the settlement of the New World
Mark Hubbe (Universidad Católica del Norte, Chile)
Walter A. Neves (Universidad de São Paulo, Brazil)
Katerina Harvati (Max Planck Insititute for Evolutionary Anthropology)
The morphology of the earliest human remains of America has been shown to differ from the morphological pattern that characterizes recent Amerindians. While the later groups share a clear morphological association with East Asians, the former (Paleoamericans) share the morphological pattern that typifies Autralo-Melanesians. Based on these differences a model of occupation of the New World based on two distinct biological stocks arriving into America has been proposed by Neves and collaborators since the late 1980s. This model predicts that Paleoamericans share a common ancestor with Australo-Melanesians in Southeast Asia prior to the appearance of groups showing the typical East Asian morphology, while Amerindians would have their ancestor within East Asian groups already showing the nowadays typical Asian morphology.
To test for this model we analyzed the morphological affinities of six cranial series showing Paleoamerican morphology from South and Meso America in relation to reference samples from America, East Asia and Australo-Melanesia. Two late Pleistocene skulls from Upper Cave (UC-101 and UC103) were also included in the analyses and were considered the common ancestors of Paleoamericans and Australo-Melanesians. Mahalanobis distances among the samples were used to compute a Neighbor Joining Tree using Upper Cave as the outgroup.
The results show that Paleoamericans appear as a sister clade to all Asians and Amerindians, suggesting that they represent a retention of the morphology existent in Asia prior to the appearance of the mongoloid morphology. The Mahalanobis distances were then compared to distinct models of geographic dispersion of the series using Mantel correlation tests. The results show that a two migration model to explain the morphological variation of Paleoamerican and Amerindian populations presents the higher correlation to the biological distances (r=0.38), considerably higher than the ones obtained for a transpacific migration (r=0.27) or a one migration model via Bering Strait (r=0.25).
Body proportions in recent Native Americans: colonization history versus ecogeographical rules
Richard L. Jantz (University of Tennessee)
Paul Marr (Shippensburg University)
Claire Jantz (Shippensburg University)
The ecogeographical rules set forth over 100 years ago by Bergmann and Allen have been widely applied to human populations. Correlations of body size and shape variables with climate have resulted in widespread agreement that humans generally conform to Bergmann-Allen predictions. The limited data available from Native Americans has also been argued to support their conformation to Bergmann-Allen expectations. The paucity of data has been partially remedied by the rediscovery of Boas’s anthropometric data, obtained in the late 19th and early 20th centuries, including approximately 7000 adults from all parts of North America North of Mexico. Boas’s data are limited to linear dimensions, consisting of height and limb lengths and biacromial breadth. Correlations of relative and absolute dimensions with temperature were carried out, along with analysis of spatial patterning. The absolute dimensions of height, leg length, arm length and shoulder breadth have moderate positive correlations (0.4-0.6) with temperature, meaning larger individuals are found in warmer climates. The cormic index (relative sitting height) shows a moderate negative correlation with temperature (-0.5- -0.68), conforming to ecogeographical predictions. Relative arm length and relative shoulder breadth are not correlated with temperature. Native Americans also exhibit extreme interpopulation variation with respect to Cormic index, variation which ranges from what would be considered polar (Arctic and N.W. Coast) on the one hand to tropical on the other (Southeast, Northeast, Plains). We conclude that there is some support for ecogeographical patterning, especially in cormic index. On the other hand the high level of interpopulation variability and the spatial patterning are more consistent with multiple colonization events modified by population movements. Funds required to locate and develop a data base of Boas’s data were provided by the American Philosophical Society, the Wenner-Gren Foundation and the National ScienceFoundation.
Ancient human genetic variation in the Americas
Brian M. Kemp (Washington State University)
Ripan S. Malhi (University of Illinois)
Deciphering patterns of genetic variation exhibited by contemporary Native American populations has been instrumental to our understanding about the entrance of their ancestors into the Americas and the subsequent ~15,000 years of population history. However, studies of contemporary populations are unable to provide us any information about prehistoric migrants who have no living descendants. Ancient DNA (aDNA) methods permit direct assessment of genetic variation exhibited by ancient humans [either directly from their remains, their feces (coprolites), and/or genetic material preserved in artifacts (e.g. quids)] and can provide important information about failed migrations, lineage extinctions, and the effects of European colonization.
Recent studies of mitochondrial DNA extracted from Native American remains in excess of 5000 years old have revealed additional genetic variants in the Americas that have not been account for by >20 years of research on contemporary populations. These important data add increasing details about the Peopling of the Americas and suggest that ancient DNA will provide a wealth of information about the earliest Americans, especially those in regions where populations have been unstable and have experienced bottlenecks and expansions.
Rather than resorting to a “stock-migrationist” view to explain ancient variation in the Americas, ancient DNA research underscores that this variation is best explained by employing microevolutionary models.
Climate variation, biological adaptation, and postcranial metric variation in precontact North America
Kathyrn A. King (State University of New York - Oswego)
The purpose of this project is to investigate patterns of variation in the postcranial skeleton of prehistoric American populations as they are related to variation in climate. Two ecogeographical rules proposed by Karl Bergmann and Joel Allen describe expected patterns of variation with widespread, warm-blooded species. Modern humans in the Old World largely conform to this pattern. This study seeks to explore if the same patterns are present in the New World.
Skeletal material from 25 North American bioarchaeological collections was used in this analysis. A series of 29 measurements of the postcranial skeleton were collected from 854 individuals. These measurements were analyzed with respect to site-specific temperature and precipitation data using univariate and multiple regression analysis, analysis of size and shape using "Mosimann" type shape variables (Darroch and Mosimann 1985, "Canonical and principal components of shape", Biometrika), and canonical correlation analysis.
The results of this study show that there is a significant relationship between climate and postcranial variation in this sample, particularly in measurements of long bone length and epiphyseal size. Radius and tibia length appear to be the most highly correlated with climate variables, as would be expected if thermoregulation is a significant biological stress.
Comparison between this sample and data collected from Old World samples suggest that adaptation to climate has occurred in North America, but not to the same degree as is seen in the Old World. This suggests that the relatively recent peopling of the Americas, as well as other factors such possible long-distance migrations, have influenced the potential effects of adaptation to climate.
Portions of this research were funded by the Charles Faulkner dissertation improvement grant.
A model to understand early human demographic variation and Mt haplogroup distribution in the Americas
José L. Lanata (Universidad de Buenos Ares; LCHES, Cambridge)
Luis Martino (Universidad de Buenos Ares)
Cristina Dejean (Universidad de Buenos Ares)
Ana Osella (Universidad de Buenos Ares)
Francisco R. Carnese (Universidad de Buenos Ares)
Understanding the tempo and mode of the initial human dispersal in the Americas is a key issue for the study of its ulterior variation and diversity through time. We present a demographic model to explore the population dynamic on the base of paleo-environmental reconstructions between the ca. 18 and 10 kybp and different dispersal simulations are presented by considering a fast invasive process and a slow one. The model used Fisher equation plus a term related to carrying capacity; when population density achieved certain threshold, it has to move to the best neighbor environment. Fisher equation is solved using a Monte Carlo approach. The new equation includes also a diffusion coefficient based on random rates from Gaussian distributions, with defined average values and variance for each environment. For these coefficients, we used ethnographic and ethno-archaeological demographic data from contemporary hunter-gatherer populations. In this way, our population dispersal model depends on population growth, diffusion and a minimum population to produce a migration. The equation considers gender differences in the populations and also estimates the reproduction probability for men and women.
The results show a relatively similar demographic distribution in both cases, where Mesoamerica and the Amazon were areas with higher population densities since early moments. We also consider Mt haplogroups inheritance in the models and its shows a very similar distribution with the actual ancient DNA available data. It seems that Mt haplogroups distribution is probably related to major bottleneck effects during the initial population dispersal in North and South America. The simulations also reveal that a high average annual population growth could be necessary to explain the Americas colonization by a single population spreading from Beringia to Tierra del Fuego. The models show diverse scenarios useful for highlight different aspects of the Pre Clovis-Clovis debate. The evolutionary consequences are discussed.
Native American genomic variation
Ripan S. Malhi (University of Illinois)
Brian M. Kemp (Washington State University)
Analyzing patterns of genetic diversity from living groups to study the population history of the Americas has been a burgeoning field over the past two decades. Most of the research has focused on analyzing the control region (CR) of the mitochondrial genome and the non-recombining portion of the Y chromosome (NRY) in indigenous populations throughout the Americas. Although these studies have been very insightful, noticeable discontinuities between the conclusions made from these genetic studies and other anthropological research analyzing archaeological and linguistic evidence remain.
Recently, with the analysis of complete mitochondrial genomes, NRY, and panels of autosomal-wide genomic markers for a large number of indigenous populations from the Americas, a more detailed understanding of the population history of the Americas has been obtained. These new insights may possibly resolve the perceived discrepancies among the different anthropological sources of evidence used to study the peopling of the Americas.
Here we review and critique the anthropological genomic studies that have revealed additional genetic variation and structure in the Americas and we assess how these studies will impact the study of the peopling of the Americas.
Random genetic drift and the peopling of the Americas: evidence from ancient skeletal remains
Joseph F. Powell (University of New Mexico)
Most models of the peopling of the Americas envision one or more massive migration / colonization events with hundreds if not thousands of people. Given the paucity of archaeological evidence of such demographic events, especially in or near the "Ice-free Corridor" (Dixon, 1999; Powell, 2005), there must be other explanations for the unusual levels of craniometric and odontometric variation seen among the remains of the First Americans, as well as their lack of strong biological affinity to contemporary Amerindindians (Powell and Neves, 1999). Here I examine the possibility that evolutionary forces produced the observed patterns of dental variation in late Pleistocene / early Holocene human remains from North and South America. Some recent assessments of mtDNA variation in Amerindians point toward small numbers of founding migrants with low effective sizes on the order of 80 or fewer individuals (Hey 2005).
In this paper, I assume a neutral model for dental variation following Stojanowski (2003, 2006) and Relethford (1996). Dental morpolological and metric data were obtained from 13 North American and 12 South American Paleoindians dating from 9,700 to 11,568 yr B.P. Comparative odontometric values for Amerindians were obtained from published literature (Turner and colleagues).
Since there are so few Paleoindian remains, and most are separated in time and space, sample pooling is inappropriate. Instead, inter-individual analyses were conducted assuming that individuals are random samples from their respective subpopulations. Analyses included inter-individual Mahalanobis D2, computed from a pooled within-groups covariance of world-wide samples in the Howells dataset. Relethford-Blangero analysis, principal components and tests of matrix correlation were also performed. Inter-individual spatial distances were computed using great-circle distances. Fst values were generated from Relethford-Blangero analysis using narrow sense heritability (h2) values in a range from ~0.50 to 0.70 with an average of h2=0.62 (Stojanowski, 2003).
North American samples displayed considerable inter-individual dental variation. Relethford-Blangero results indicate that that effective population size and therefore genetic drift, played a large role in shaping early dental variation in the New World. The dental morphology of Paleoindians demonstrated the presence of rare dental traits in high frequency, suggesting the presence of founder effect in the peopling of the Americas. The observed results are discussed in light of modes and directions of migration and regional effects.
References:
Dixon, EJ. 1999. Bones, Boats and Bison. Albuquerque, NM: University of New Mexico Press.
Hey, J. 2005. On the number of New World founders: a population genetic portrait of the peopling of the Americas. PLoS Biol 3:965-975.
Powell, JF. 2005. The First Americans. Cambridge: Cambridge University Press.
Powell, JF & WA Neves. 1999. Craniofacial morphology of the first Americans: pattern and process in the peopling of the Amerias. Yrbk Phys Anthropol 42:153-188.
Relethford, JH. 1996. Genetic drift can obscure population history: problem and solution. Hum Biol 68:29-144.
Stojanowski, CM. 2003. Differential phenotypic variability among the apalachee mission populations of La Florida: A diachronic perspective. Amer J Phys Anthropol 120:352-363.
Stojanowski, CM. 2006. Phenotypic approaches for understanding patterns of intracemetery biological variation. Yrbk Phys Anthropol 49:49-88.
Skeletal evidence of cultural variation: mutilation related to warfare and mortuary treatment
Christopher W. Schmidt (University of Indianapolis)
Rachel Lockhart (University of Indianapolis)
Christopher Newman (University of Indianapolis)
Anna Serrano (University of Indianapolis)
Melissa Zolnierz (University of Indianapolis)
Ongoing research in Indiana indicates that certain perimortem skeletal traumata considered indicative of warfare may in fact represent complex mortuary behavior. It is becoming increasingly clear that some Middle and Late Archaic mutilations including decapitation, glossectomy, dismemberment, and scalping are associated with complex mortuary ritual. This interpretation is based upon the consistent manners in which body parts are removed and mutilated bodies are buried. However, by the Late Woodland similar mutilations, in particular scalping, appear to reflect at least some level of interpersonal conflict as evidenced by mass graves and the inconsistent ways in which scalps are taken. Thus, the developing picture is that rather than representing a monolithic pattern of warfare-related damage, the osteological record points to a transition in the circumstances of mutilation; earlier groups have more mortuary-related traumata while later groups bear more evidence of warfare.
Searching for the Eurasian roots of Native American populations: evidence from mtDNA, Y chromosome and autosomal DNA studies
Theodore G. Schurr (University of Pennsylvania)
Although current genetic evidence points to south-central Siberia as the homeland of ancestral Native American populations, the place of origin of certain genetic lineages present in the Americas is not clear (e.g., mtDNA haplogroup X). There is still also some debate over the role that the Russian Far East may have played in the initial peopling of the New World. In addition, the possibility that Beringia served as a refugium and dispersal area for founding Native American populations during the last glacial maximum has implications for the time at which ancient Asian populations first entered this region (~25,000-18,000 ybp), and the area of northern Asia from which they could have come. We investigated these issues by analyzing genetic data from populations inhabiting northern Eurasia and the Americas, including those from mtDNA, Y-chromosome and autosomal loci. Our results provide new information about the patterns of genetic diversity in south-central Siberia, and its role in the formation of the ancestral Native American gene pool.
Population history of the South Andean coastal region
Ken-ichi Shinoda (National Museum of Nature and Science, Tokyo)
Sonia Guillén (Centro Mallqui)
Izumi Shimada (Southern Illinois University Carbondale)
Ancient DNA analysis has become an increasingly important tool in elucidating the geographical origins of ancient populations and their relationships. To define the population history of the Andean southern coast, an aDNA investigation was conducted on the human skeletal remains excavated from 8 archaeological contexts in the Moquegua Valley in the extreme south of Peru. DNA was extracted from 0.5 grams of the powder for each teeth sample using a commercial DNA extraction kit. Among the 37 individuals considered in this study, we obtained the hypervariable segment I (HVSI) portion of the mtDNA control region sequence from the 10 individuals of the Formative period (1500 B.C. – A.D. 100) and 17 of the Chiribaya culture (A.D. 900 – 1350). Almost all sequences obtained were ascribed to the Native American haplogroups on the basis of a haplogroup specific D- loop sequence (HVS-I motif) search and 9bp deletion between genes COII/tRNAlys, but few samples do not belong to the classical Native American haplogroups.
Looking at the coastal area from southern Peru to northern Chile, the genetic stock of the regional population (mitochondrial haplogroup A) was consistent with the stock of people of the equatorial coastal region during the Formative periods but, as time went on, people of the different stock (haplogroup B) increasingly arrived from the highland area. This influx accelerated during the Inca and colonial periods, nearly replacing the indigenous population of this area. It appears the genetic study of ancient population of Andean coast region brings important element to the understanding of human population movement in South America.
The spread of agriculture into the North American Desert West: language, genes and teeth
James T. Watson (Indiana University-Purdue University Indianapolis)
Archaeologists have long debated the nature of the introduction and adoption of domesticated cultigens and agriculture into the North American Desert West. Linguistic models tend to support a migration of proto-Uto-Aztecan peoples from central Mexico. Recent analyses of mtDNA suggest diffusion of language, plants and technology and possibly limited migration. The validity of these explanatory models was tested by examining the dentition of 295 early agriculturalists (circa 1600 B.C-A.D. 200) from the archaeological site of La Playa in northwest Mexico. The presence and severity of dental decay and tooth loss was measured to assess dietary composition and wear plane of the molar occlusal surface was measured to assess dietary consistency. Dental disease was found to represent a continuum of decay reflective of a diet steeped in local ecology and the consumption of cactus and mesquite. Changes in molar occlusal wear angles over this 1800 year period document the transition from local foodstuffs to domesticated cultigens.
These results suggest that language and agriculture spread into an existing indigenous adaptation and increased in importance over time. It also suggests that cultural and biological interaction was far more complex prior to and during the Formative transition than previously proposed and that language, plants and technology spread over a vast cultural continuum during the Archaic period. After the initial introduction of cultigens and the adoption of agriculture in the North American Desert West, local environmental conditions and distinct adaptations created greater regional diversity and led to the development of the complex Formative cultures of the Hohokam and Anasazi.
Grant sponsors: Instituto Nacional de Antropología e Historia and CONACYT, México; National Science Foundation, Grant No. BCS-0433986.
Biological variation in the ancient Andes: climatic, hypoxic, and dietary factors
Karen J. Weinstein (Dickinson College)
Human biologists have long studied the adaptive responses to high altitudes in living Andeans. Small adult stature and increased lung volume and aerobic capacity are developmental acclimatization responses to under-nutrition and chronic exposure to high-altitude hypoxia during critical growth periods. Enlarged chests and reduced intralimb proportions are long-term adaptations to high-altitude hypoxia and cold climates that developed over many generations. Despite the longevity of human settlement across the Andes, biological adaptations to high altitudes have rarely been examined in ancient Andean groups.
This study compares limb proportions and thoracic skeletal morphology in four archaeological groups from the Andes (N=347: two groups from the central and south-central coasts and two highland groups from the Atacama Desert and the southern Peruvian highlands) to test for the presence of high-altitude adaptations in the Andean archaeological record. Individuals from coastal sites and the Atacama Desert share long intralimb proportions while southern Peruvian highlanders have short proportions suggesting that cold stress was not uniformly experienced throughout the highlands. Both highland groups have smaller body sizes than coastal individuals, a difference attributed to poorer quality diets in the highlands. Atacama males and females and southern Peruvian highland males have longer ribs with less curvature that encompass greater area than coastal individuals, features that may have developed in response to high-altitude hypoxia.
These results suggest that dietary practices, climatic conditions, hypoxic stress, and gene flow differentially affected the biology of ancient highland Andeans. Biological responses to high altitudes are not uniform across populations and indicate that ancient Andean groups expressed highly diverse traits in response to specific environmental pressures. Further examination of biological responses to local environmental conditions across wider regions of the Andes and elsewhere in South America will shed light on the degree of biological diversity present on this continent during the pre-Contact period.
Humeral and femoral variation in the American Great Plains
Daniel J. Wescott (University of Missouri - Columbia)
The American Great Plains is unique in its geology, climate, and biodiversity, and the peoples of the Plains developed remarkable and unparalleled ways of adapting to this biophysical environment. As a result, the long bone morphology of Plains Native Americans is also likely unique. In this presentation, I examine variation in humeral and femoral structural morphology among Great Plains populations as it relates to differences in subsistence practice and geographical location.
This study expands on previous research of Great Plains populations by employing a significantly larger and more geographically and temporally diverse sample, examining both upper and lower limb bone morphology, and interpreting the data within an archaeological and historical framework using a biomechanical approach. I used the humeri and femora of 1198 adults from Great Plains archaeological sites. Culturally, the sample consists of Archaic huntergatherers, early and middle Woodland hunter-gatherers, late Woodland incipient horticulturalists, Plains village horticulturalists, and equestrian nomads. Geographically, the sample was divided into northern, central, and southern Great Plains groups. Since a comparison of multiple subsistence groups from three geographical regions of the Plains requires an extremely large sample size, external dimensions are used to estimate crosssectional properties.
The results show that in general skeletal morphology on the Great Plains was relatively homogeneous throughout time and space. There are few significant univariate differences in same sex comparisons or in sexual dimorphism due to either subsistence practice or geographical region. However, males tend to cluster partially by subsistence practice, while females cluster by geographical region. Subsistence differences are generally associated with long bone size and activity related robusticity. Geographical variation between groups is most likely associated with climaticallyinduced differences in body build and not terrain relief.