Comparison of population structure in Ohio's late archaic and late prehistoric periods

Previous studies of population structure among prehistoric groups in the Ohio valley region have shown that hunting-gathering populations exhibited a different structure than horticultural populations. Among both Late Archaic hunter-gatherers and Late Prehistoric horticulturists, covariance structures for cranial metrics were found to be homogenous within the populations, but the Late Archaic subpopulations showed little differentiation while the Late Prehistoric subpopulations exhibited a marked differentiation. Biodistance based on cranial discrete trait frequency showed similar patterns, but in the Late Archaic discrete trait distance was associated significantly with the geographical distance separating populations. The present investigation is an extension of the previous studies increasing the Late Prehistoric sample (n = 8 samples and n = 341 individuals) and using the Harpending-Ward model, modified for use with multivariate quantitative data, to estimate the effects of differential gene flow and the amount of differentiation within populations. Results of the present analyses indicate that differentiation among subpopulations, measured by minimum F(ST), was greater in the Late Prehistoric compared to the Late Archaic period. However, for both periods the minimum F(ST) is comparable to values found for historic native populations of the northeast woodlands. Analysis of differential gene flow in the Late Archaic period indicates that geographically peripheral populations were affected more by external gene flow than more central populations. Late Prehistoric populations exhibit a very complex pattern of differential gene flow. We discuss the latter pattern in terms of proposed culture change in the Late Prehistoric period of Ohio.     

Carnivore alteration of human bone from a late prehistoric site in Illinois

The nature and pattern of destruction of human bone by scavenging animals, probably canids, is described for 30 Oneota skeletons from a west-central Illinois cemetery dated at ca. A.D. 1300. The most frequently damaged parts of the skeleton include bones covered by relatively little soft tissue, such as the major joints of the limbs, and those in the facial, abdominal, and gluteal regions.     

Monostotic fibrous dysplasia in the temporal bone: A late prehistoric occurrence

Fibrous dysplasia, characterized by benign osteolytic and osteoblastic lesions may involve one or several bones. Recent investigators have suggested that it may be merely a phase of what have previously been thought to be several different bone disease. Isolated fibrous dysplasia in the temporal bone is infrequent. Several reports of this disease have appeared in the literature of paleopathology, but none involved only the temporal bone. Monostotic involvement of the right temporal bone was discovered in the skull of an adult male recovered from an archeological site dating from the Late Mississippian period (A. D. 1,350–A. D. 1,650). It will provide an opportunity for preliminary documentation of the antiquity of this disease in the southeastern portion of the United States.     

On the estimation of some demographic characteristics on a prehistoric population from the American Southwest

After a general discussion of some of the limitations and assumptions inherent in paleodemographic studies, a method for the estimation of average life expectancy when only deaths by age are known is described and applied to the remains from Point of Pines, a prehistoric Western Pueblo population from the American Southwest. It was found that the method was not applicable to these data in its entirety, since there were considerable differences in mortality shapes between this prehistoric group and those summarized in the U. N. Model Life Tables. It is suggested that a range of average life expectancy can be calculated when the intrinsic rates of natural increase vary, and these are given for the Point of Pines data.     

Dental indicators of stress and reduced age at death in prehistoric Native Americans

Considerable evidence supports the hypothesis that developmental enamel defects represent stress-induced growth disruptions. In this investigation, the relationship between different kinds of enamel defects and age at death is examined in the prehistoric Libben population from Ottawa County, Ohio. The sample consisted of the permanent dentitions of 143 individuals. Defects were classified based on the criteria of the Developmental Defects of Enamel (DDE) Index. The multifactorial age at death determinations of Lovejoy and coworkers (1977) were used in this analysis. Results reveal a significantly lower mean age at death for individuals with enamel defects vs. individuals with normal teeth. This pattern was clearly present for all defect types examined. No significant differences by sex were detected. The age-at-death distribution for individuals with normal teeth approximated the normal curve. The modal value was reached in the 35–40 year age class. The age-at-death distribution for individuals with enamel defects showed two peaks. The mode occurred in the 15–20 year age class, and the second, lower peak occurred in the 30–35 year age class. The early mortality of individuals with enamel defects may be related to biological damage to the immune system during prenatal or postnatal development. © 1996 Wiley-Liss, Inc.     

Diachronic patterns of change in structural properties of the femur in the prehistoric American Southwest

Diachronic patterns of change in the femoral diaphysis are examined in archaeological skeletal samples from the American Southwest. Three cultural periods differing in subsistence-settlement strategies are represented: Early Villages (A.D. 500-1150), Abandonments (A.D. 1150-1300), and Aggregated Villages (A.D. 1300-1540). Relevant properties of cross-sectional geometry and bone density were obtained using computerized tomography. Temporal trends in geometry suggest that activity levels increased between Early Villages and Abandonments, then declined during Aggregated Villages. In both sexes, femoral shape became more circular, and bending stresses were reduced in the a-p plane through time. Compared to the other periods, bone density was the lowest during Abandonments in both sexes. The reduction in bone density may reflect declining nutritional quality through time that was especially poor during the Abandonments period. Patternings in sexual dimorphism suggest that Abandonments males may have been more sensitive to nutritional stress than contemporary females.     

Enameloma in a prehistoric Indian skull

Two enamel pearls or enamelomata are described and pictured on the molar tooth of a prehistoric Illinois Indian. One is at the cervical margin and the other is in the very rare location of the apical third of the root.     

Cell death in late embryogenesis of the leech Helobdella

Cell death was characterized during stages 8 and 9 in the leech Helobdella with a modified terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling method. Using confocal analysis, the positions of dying cells were compared to rows of cells expressing the leech engrailed protein ht-en and to fluorescently marked cell lineages. Dying cells were present in diverse tissues. Some dying cells were in no obvious pattern, and others were in segmentally iterated patterns. Particular attention was paid to the ectoderm and mesoderm, where most of the cells examined died over a period equivalent to 1–4 h at 25°C. Segmentally iterated rows of dying cells were observed in the mesoderm just beneath the nf-derived ht-en expressing cell rows at a time when ht-en expressing cells were beginning to disappear. The position of these dying cell rows was consistent with a role in the partial deterioration of the septum. Received: 12 October 1998 / Accepted: 8 February 1999     

Predicting future coexistence in a North American ant community

Global climate change will remodel ecological communities worldwide. However, as a consequence of biotic interactions, communities may respond to climate change in idiosyncratic ways. This makes predictive models that incorporate biotic interactions necessary. We show how such models can be constructed based on empirical studies in combination with predictions or assumptions regarding the abiotic consequences of climate change. Specifically, we consider a well‐studied ant community in North America. First, we use historical data to parameterize a basic model for species coexistence. Using this model, we determine the importance of various factors, including thermal niches, food discovery rates, and food removal rates, to historical species coexistence. We then extend the model to predict how the community will restructure in response to several climate‐related changes, such as increased temperature, shifts in species phenology, and altered resource availability. Interestingly, our mechanistic model suggests that increased temperature and shifts in species phenology can have contrasting effects. Nevertheless, for almost all scenarios considered, we find that the most subordinate ant species suffers most as a result of climate change. More generally, our analysis shows that community composition can respond to climate warming in nonintuitive ways. For example, in the context of a community, it is not necessarily the most heat‐sensitive species that are most at risk. Our results demonstrate how models that account for niche partitioning and interspecific trade‐offs among species can be used to predict the likely idiosyncratic responses of local communities to climate change.     

Patterns of stress,disease and mortality in two prehistoric populations from North American

Archaeological data from the Dickson Mounds site was employed to reconstruct the cultural-ecological context of two prehistoric American Indian populations. These populations were identified as the Mississippian Acculturated Late Woodland (A.D. 1050–1200) and the Spoon River Focus of the Middle Mississippian (A.D. 1200–1300). The cultural-ecological data was then employed to interpret some of the biological parameters of the two skeletal populations.The cultural-ecological variables included: (a) subsistence technology; (b) population density and degree of sedentarism; and (c) the extent and intensity of contacts with surrounding social groups. The biological parameters included: (a) infectious disease; (b) micro-structural dental defects; and (c) mortality.The results of the analysis suggested that as alterations occurred in the cultural-ecological adaptations of the populations in the form of an increased reliance upon maize agriculture, an increase in population density and sedentarism, and an increase in social contacts; there occurred an increase in the frequency of infectious disease, micro-structural dental defects and mortality.     

More lingual surface attrition of the maxillary anterior teeth in American Indians: prehistoric Panamanians

Lingual surface attrition of the maxillary anterior teeth (LSA-MAT) has been found in additional prehistoric Latin American Indian skeletons. LSAMAT was first observed in crania from an Archaic Brazilian site. This second finding occurs in teeth from Venado Beach, a late prehistoric site in Panama. LSAMAT is also present in some fragmentary specimens from the Archaic Cerro Mangote site in Panama. LSAMAT at Venado Beach is present in 57% of 28 adult crania. As in the Brazilian study, LSAMAT is associated with a high caries rate (82% of 50 adults; 11.7% of 852 permanent teeth). As first suggested, eating and processing of some type of abrasive carbohydrate food, such as manioc, is the possible cause of LSAMAT. However, other possible causes relating to habitation on or near marine coasts cannot be totally ruled out.     

Amino acid analysis of bone from a possible case of prehistoric iron deficiency anemia from the American southwest

It is possible that dietary conditions can result in the production of abnormal bone protein. For example, a heavily maize-dependent diet could be deficient in one or more essential amino acids necessary to normal human biochemistry and consequently necessary for normal bone protein synthesis. Amino acid analysis of bone tissues, thus, could provide a useful diagnostic tool in paleopathology. To test this potential we have compared the amino acid analyses of bone samples from a prehistoric Southwest Indian child exhibiting porotic hyperostosis with samples taken from (1) two children's skeletons lacking bone lesions but from the same area and time, (2) a modern child who died from accidental causes, and (3) adult human compact bone. Analytical results of the nonpathological prehistoric specimens were virtually identical to that of the modern infant, indicating remarkable preservation of bone protein. The pathological bone sample differed from the three control specimens by having as much as 25% less of those amino acids containing hydroxyl group and acidic side chains. We interpret the amino acid profile for the diseased child as indicating the presence of a greater proportion of helical protein (or less noncollagenous protein) as well as a lowered degree of hydroxylation of proline and lysine. One explanation for our data is that protein biosynthesis is altered in the child exhibiting porotic hyperostosis, and either some proteins important in the early phases of mineralization are not produced in sufficient quantity, or some necessary enzyme cofactors (e.g., dietary ferrous ions) are missing. We conclude that our data are compatible with, but do not prove, the hypothesis that the porotic hyperostosis exhibited by the Southwest Indian child is the result of iron deficiency anemia.     

Multiple causes of death and the epidemiological transition in American Samoa

Abstract

Multiple‐cause mortality data were used to examine changing patterns of mortality between 1950 and 1979 in American Samoa. This period coincided with a transition from infectious to chronic diseases as the primary causes of death. The available data indicate that as mortality rates from infections declined, the first chronic disease to increase in frequency was cancer. The absence of a lag period suggests that increased cancer mortality may be a consequence of life extension in the presence of modernization. In contrast, mortality rates from cardiovascular diseases tended to increase only after a lag period. As mortality from infections declined, ischemic heart disease replaced infections as the leading cause of death, in either a total‐mentions or an underlying‐cause model of mortality. The transition to degenerative disease mortality in American Samoa was neither as rapid nor as simple as a tabulation by underlying cause of death indicates. Patterns of change were interrelated.     

Maternal mortality or prolonged growth: Age at death and pelvic size in three prehistoric Amerindian populations

This study evaluates the relationship between age at death and pelvic size among adults in three prehistoric Amerindian populations. The issue is to identify if the pelvis continues to grow and remodel in adulthood, or if there is differential survivorship among adults, particularly among females, based on pelvic size. The samples used in this study are Indian Knoll, Pecos Pueblo, and Libben. Twenty-one measures of the pelvis are analyzed. A correlational analysis among individuals 18 years of age and older shows that the subpubic angle narrows with advancing age in both sexes. The suggested etiology is osteophytic growth on the ischiopubic ramus among older adults. A two-sample test comparing younger (ages 18–24) and older (25 years of age and older) adults shows that the linea terminalis (which represents the pubic and iliac components of the pelvic inlet) is significantly shorter in the younger age group, but this pattern is seen only in females. Two interpretations are consistent with this result. First, a female with a short linea terminalis (i. e., small pelvic inlet) may have died at a young age due to childbirth-related complications. In prehistory, maternal mortality may have been a leading cause of death, with pelvic inlet capacity being a determinant of survivorship among parturients. Second, the linea terminalis may be unique by continuing to grow in early adulthood in females but not in males; the growth occurs at the medial border of the pubis. Longitudinal growth studies of modern humans provide support for the second interpretation. The selective advantage of a later age at maturation of the pubis in females than males is that the period of growth is prolonged, thereby contributing to sexual dimorphism in pubic length and, correspondingly, linea terminalis length and pelvic inlet circumference. © 1994 Wiley-Liss, Inc.     

Factors influencing community structure in a South American tank bromeliad fauna

We examined factors influencing the structure of naturally replicated, taxonomically unrestricted communities inhabiting South American tank bromeliads. We measured aspects of plant physical structure and collected the entire macroscopic fauna of 209 bromeliads from the Yasuní Scientific Reserve in lowland eastern Ecuador. We collected a total of 11 219 individuals of 354 morphospecies. The morphospecies abundance distribution of our sample was approximated by a log-series distribution dominated by rare morphospecies (57% of the morphospecies were represented by a single individual). Six methods for estimating the total number of bromeliad associated morphospecies in our study area gave results which varied by a factor of three, illustrating that caution should be exercised in interpreting the results of any single estimator. Variation in plant volume, number of leaves, detritus content, and water volume explained 62% of the variation in morphospecies richness among plants. Finally, there was a quadratic relationship between body mass and both individual abundance and morphospecies richness in our sample. These results illustrate an important role of both biotic and abiotic factors influencing the structure of taxonomically unrestricted, ecologically defined natural communities.     

Seasonal cycles of diversity and similarity in a Central American rainforest butterfly community

Despite the importance of understanding the effects of tropical seasonality on ecological diversity, few studies have investigated the influence of environmental factors on seasonal community composition, and even fewer use standardized sampling and robust analytical methods that are directly comparable. Our 104 months of sampling in Costa Rican lowland rainforest yielded 12 757 individuals of 106 fruit‐feeding butterfly species demonstrated biannual cycles in species diversity, but community similarity showed an annual cycle that peaked in the driest months. We found that community diversity and similarity did not decline with increasing time lag, which we attribute to lack of long‐term changes in species abundances. Our findings differ from a similar study in Ecuador, where cycles in weather and community diversity were annual. Long‐term intensive monitoring and robust statistical analysis of changes in community composition in relation to environmental factors can help to elucidate the dynamics of communities, and their response to climate change.