AN ABSTRACT OF THE THESIS OF MEGAN K. CLEARY, for the Master of Arts degree in ANTHROPOLOGY, presented on MARCH 28th at 8am, at Southern Illinois University Carbondale TITLE: SEX ESTIMATION FROM THE CLAVICLE: A DISCRIMINANT FUNCTION ANALYSIS MAJOR PROFESSOR: Dr. Gretchen R. Dabbs The development of methods for sex estimation using postcranial remains other than the os coxa is imperative for physical anthropology to improve the reliability of biological profile estimates in cases of incomplete and/or fragmentary skeletal remains. As the last skeletal element to complete fusion, the clavicle has the longest period of time to develop sexually dimorphic features, making it an ideal skeletal element for use in sex estimation. Sexual dimorphism in the clavicle was assessed using 18 measurements of the left clavicle of 265 (129 females; 136 males) individuals from the Hamann-Todd Collection. Independent samples t-tests with Bonferroni correction show males and females differ at a statistically significant level for all 18 variables with a significance level of 0.0028. Discriminate function analyses using the stepwise method (0.05 to enter, 0.10 to exit) produced a four variable model with cross-validated accuracy of 89.8%. A holdout sample from the Hamann-Todd Collection (n=30) similar in demographic character to the calibration sample was tested using the four variable model. The accuracy of the four variable model on the holdout sample was 90.0%. Additionally, four single variable models developed to accommodate fragmentary remains also have high predictive power (75.1-82.3% cross-validated calibration sample; 60.0-86.7% hold-out sample).

This thesis presents a validation study of the research by Hassett (2011). It examined the permanent canines’ cervical diameters using established measurement techniques set forth by Hillson et al. (2005) to determine sex in a known population of male and female adults and juveniles. The present study combined the Maxwell Collection, housed at University of New Mexico, and the Hamann-Todd Collection, housed at the Cleveland Museum of Natural History, as the known-sex sample. The sample included 642 permanent canines resulting in 862 measurements from 218 individuals. There were 120 males and 98 females between the ages of 12 and 98 years old. Of the 218 individuals, 148 were White, 62 were Black, 2 were Hispanic, 1 was Native American, and 5 were an unknown ancestry. The measurements used were the cervical mesiodistal diameter and the cervical buccolingual diameter of each upper and lower, right and left canine. The author hypothesized that research conducted on this known age skeletal collection sample would support Hassett (2011), who concluded that the cervical diameter of the canine is sexually dimorphic and can be used to predict sex accurately. In addition, it was predicted that there would not be a significant statistical difference between adult and juvenile permanent canine measurements. An intra-observer error test found that original and repeated measures were not statistically different from one another. Statistical analysis found that adults and juveniles did not have significantly different measurements, so the two samples were combined into one larger known-sex sample. The accuracy of all the functions for both sexes using the cervical diameter method is between 80.2% and 87.5%. The fourth function’s formula, which uses both diameters from one maxillary canine and one mandibular canine, had the best overall accuracy of 87.1%. The accuracy of all the functions for males was between 81.1% and 91.7% and for females the accuracy was between 74.8% and 89.7%. Analysis also indicated that no tooth nor measurement proved to be a better predictor of sex; therefore, any tooth and measurement can be used to estimate sex. The author believes that this validation will allow further research into the applicability of the permanent canine using cone-beam computed tomography to determine sex in juveniles whose permanent canines have not yet erupted. This determination is highly significant, given the dearth of usable techniques to sex juvenile human remains.

Sex estimation is one of the most important, and arguably the first, parts of the biological profile that is estimated for purposes of human identification. This study will examine the utility of the distal humerus in sex estimation. The goal of this research is to corroborate the usefulness of the distal humerus in sex estimation and the usefulness of geometric morphometrics in sex estimation, as well as validate metric and visual methods for sex estimation using the distal humerus. Multiple methods of sex estimation are necessary because complete skeletons are rarely found, and often only fragments are discovered. Three methods of sex estimation utilizing the distal humerus are used in this study: epicondylar breadth (n=448), nonmetric traits per Rogers (1999) and Vance et al. (2011 (n=444)), and geometric morphometrics via a Microscribe digitizer and MorphoJ software (n=227). The sample was taken from the William M. Bass Donated Skeletal Collection and was primarily composed of White Americans. The male to female ratio was approximately equal. The results of the metric aspect of the study showed a classification accuracy of 88.84% with low intra-observer and inter-observer error rates. The results of the nonmetric aspect of the study showed a classification accuracy of 77% when all traits were combined with low intra-observer and high inter-observer error rates. The results of the geometric morphometric aspect of the study showed a classification accuracy of 55% for all landmarks, 57% for anterior landmarks, and 63% for posterior landmarks. The results show that not only is the epicondylar breadth a reliable and effective method of sex estimation, it is easily repeatable by other observers. The nonmetric method is useful when epicondylar breadth cannot be measured or when an observer is familiar with the method. The geometric morphometric method is not as strong as the other two methods, but with further research and modifications may become a feasible option for sex estimation using the distal humerus. The author concludes that the distal humerus is sexually dimorphic and can be used to estimate sex accurately.

The use of the Daubert Standard in court proceedings has highlighted the need to substantiate scientific findings or claims beyond simply accepting the word of a respected expert. The concept of postmenopausal masculinization of the skull in female crania falls into this category. Dr. Walker references this concept in several articles but there is no research to support this hypothesis. This project examines the theory of postmenopausal masculinization of female crania from several perspectives, using the visual sex estimation method set forth in Standards for Data Collection from Human Skeletal Remains edited by Jane E. Buikstra and Douglas H Ubelaker, photographic seriation of these sex estimation traits, and metric measurements in conjunction with Fordisc 3.1. A sample of 395 crania from the Hamann-Todd Collection at the Cleveland Museum of Natural History was analyzed using all three of these methods to determine if there was a pattern of masculinization in the postmenopausal female sample. The average age for the onset of menopause in the United States is 50, thus there should be an increase in "masculinization" observable through more rugged sex estimation traits, a higher number of females 50 or over being found below the midpoint in photographic seriations of sex estimation traits, and an increase in Fordisc 3.1 sex identification misclassifications in females in this age category. The results of the analyses revealed that there were statistically significant differences between ancestry groups, the sexes, and in some cases, age-groups. The results of this research indicate that though there are some differences between comparison groups, there does not appear to be a cohesive pattern of masculinization in female crania at or after the average age of onset of menopause. Human variation is endless, and even in areas of the skeleton for which it has been established that there is a significant degree of sexual dimorphism, there will be individuals who do not fit neatly into a binary conception of sexual divergence. Though these individuals may be misidentified as the opposite sex using one or all of the methods utilized in this project, this falls short of being classified as a part of the menopausal process in females.

Estimating sex and age at death are two crucial processes during the creation of a biological profile for a set of skeletal remains. Whether the remains are archaeological or forensic, estimating the sex and age of the individual is necessary for further analysis and interpretation. Specifically, in a medicolegal context, knowing the biological sex and approximate age of the remains assists law enforcement or government agencies in identifying unknown individuals. Since the inception of the field of forensic anthropology, practitioners have been developing methods to perform the aforementioned tasks. It is crucial that these methods be consistent, repeatedly tested, validated, and improved for multiple reasons. Firstly, to conform to Daubert (1993) standards, and additionally, to make sure that they are accurate and applicable to modern forensic cases. The present study was performed to validate the efficacy of the method for estimating sex from the os pubis originally proposed in Klales et al. (2012), as well as the efficacy of the “transition analysis” method for estimating age, originally outlined in Boldsen et al. (2002). Considering the recent popularity of using these methods to create a biological profile for forensic cases, it is necessary to develop error rates on a large, modern, American autopsy sample. These two methods are not only being readily utilized, but are additionally being taught to students in training. The utilization of these models involves a “logistic regression model” created by Klales et. al (2012) to process ordinal scores, and the Bayesian statistics software program “ADBOU” that was created for processing data collected using the method in Boldsen et. al (2002). These statistical systems which produced age estimates are relatively young compared to methods developed for the same purpose. The new generation of forensic anthropologists is fully responsible for objectively critiquing and validating these methods that are being disseminated by their professors and senior practitioners. The goal of the present study is to do just that. A skeletal reference sample of 630 pubic bones, all removed from modern autopsy cases and housed at the Maricopa County Forensic Science Center in Phoenix, Arizona, was utilized for data collection in the present study. Each pubic bone was assessed and scored according to the exact instructions outlined in the materials for each method, which was the Klales et al. (2012) paper for sex estimation, and the UTK Data Collection Procedures for Forensic Skeletal Material 2.0 for age estimation (Langley et al. 2016). Additionally, the observers recorded their “gestalt” estimates for sex using the Phenice (1969) system, as well as Brooks and Suchey (1990) and Hartnett (2010a) phases for each pubis. Demographic information labels were hidden, and the collection demographic information was not viewed until the completion of data collection. The null hypothesis in the present study is that both methods (the Klales et al. method (2012) and “transition analysis” method (Boldsen et al. 2002) will perform as well as they did in the original studies. The alternate hypothesis is that they do not result in the same accuracy rates reported in the original studies. Statistical analysis of the data indicates that there is sufficient evidence to reject the null hypothesis as it applies to the Klales et al. (2012) method. The classification accuracies achieved applying the logistic regression equation to the sample of pubic bones was found to be significantly lower than reported in the original study (86.2%), averaging around 70% between observers. The level of both intraobserver and interobserver agreement was only moderate for this method. It was also found that asymmetry occurred in some individuals, producing differing estimates of sex when the left and right pubes were scored separately. When utilizing the Boldsen et al. (2012) method and the ADBOU software package on only pubic symphyseal components to estimate age, the method was found to perform reasonably well. The majority (about 82%) of individuals had actual ages at death that fell within the predicted range produced by the statistical analysis. The majority of the symphyseal component scores showed moderate to good levels of interobserver agreement, and the estimated maximum likelihood (point estimate) of age at death predicted by the software package correlated moderately well with the actual age of death of the individual. These methods did not perform as well as reported in the original studies, and they should be further validated and recalibrated to improve their accuracy and reliability.

AN ABSTRACT OF THE DISSERTATION OFKaleigh C. Best, for the Doctor of Philosophy degree in Anthropology, presented on May 12, 2023, at Southern Illinois University Carbondale. TITLE: AN INVESTIGATION INTO INTRAINDIVIDUAL VARIATION IN HUMAN SKELETAL SEXUAL TRAIT MORPHOLOGYMAJOR PROFESSOR: Dr. Izumi ShimadaSex estimation is the most vital component of the biological profile assessment as several other subsequent analyses across biological anthropology rely on the correct identification of biological sex. This is especially important in times of commingling, fragmentary and partial remains, in inconsistent sex estimation, or in studies of sex estimation variation. While a multitude of studies have contributed to the documentation of similarities and differences in the morphological expression of a specific trait and how well this trait can be used to classify the sex of an unknown individual, how the expression of these morphological traits relate to each other within the individual has been poorly studied. Further, although several intrinsic and extrinsic factors are known to contribute to sexual trait expression, how they interact to produce morphology, and how that morphology may change in response to different biological conditions is not well understood. This dissertation utilizes 3D scans of 235 individuals collected from the University of Tennessee Donated Skeletal Collection (UTK) and the Robert J. Terry Osteological Collection (Terry) to examine sexual trait expression across the cranium, mandible, os coxae, sacrum and scapula. Specifically, it evaluates: 1) if sexual trait expression is correlated between skeletal regions including localized anatomical regions, through matrix correlation and Pearson correlation tests, 2) if age affects morphological sexual trait expression through M/ANOVA and if so, how and when these changes occur using ANOVA and Tukey post-hoc tests, 3) if the magnitude and pattern of sexual trait expression varies between populations through M/ANOVA and matrix correlations, 4) using discriminate function analyses, how well geometric morphometric analyses capture sexual trait expression compared to published rates, and 5) through M/ANOVA and discriminant function analyses, which intraindividual skeletal regions are the most accurate in sex classification analyses compared to others. For each skeletal element, landmarks were placed on each scan and sexual trait expression and an intra observer placement study was conducted. The landmark configurations were then subjected to a generalized Procrustes analysis, variance- covariance matrices were generated, and a principal component (PC) analyses in MorphoJ for combined sex data, derived male and females from combined sex data, and for independently input males and females. PCs were visually interpreted and subjected to M/ANOVA for three age groups: 18-29, 30-45, and 45 and older. PCs were then subjected to stepwise linear discriminant function analyses with leave- one-out cross validation. The first five PCs for each element were then utilized for a matrix correlation test and evaluated using a strength of correlation test (Chan et al 2003) and for significance using a Pearson’s correlation test. Results indicate that for intraobserver error is low, with scores being mostly considered excellent in reliability. For UTK data, shape changes associated with sexual trait classification were found for each of the five elements. Within these tests, many influential regions were known to sex estimation analyses, but other, such as the basicranium are currently underutilized. M/ANOVA revealed that sex was significant for all five skeletal elements, with some contributions from age and ancestry impacting sexual trait expression, however these interactions were not within a consistent pattern. Through the results of the discriminant function analyses, it appears some skeletal elements, such as the os coxae, scored higher correct classification rates than those reported in the literature, while others were on par or below reported rates. The os coxae and regions around it, were the best elements for correct sex classification accuracy, with the scapula rated as the worst. In the Terry data, sexual trait related shape changes are presented for each of the skeletal elements studied. Known morphological regions, as well as some more subtle ones, were found to be influential. M/ANOVA revealed that all elements, but the scapula had statistically significant shape changes present for sex estimation. Age and ancestry appear to contribute minimally to sexual trait morphology, but again, not in a way that is consistent, either within the collection or similarly to UTK. By examining the discriminant function analyses, some correct sex-estimation rates were on higher or on par with those reported in the literature, but others, such as the scapula were lower. This may be due the size being a larger contributor for sex estimation than shape, and the geometric morphometric analyses minimizing its effects in these analyses. Also using these tests, the os coxae was selected as the best element for high levels of sex classification accuracy, but which element was next best was different than the UTK results. This likely indicates biocultural influences are affecting sexual trait morphology and should be considered in future analyses. Significant inter-element correlations were detected in both skeletal collections, with UTK having more pairings than Terry. The most common and most statistically significant inter-element correlation across collections was between the cranium-mandible, which may be reflective of the integrated nature of these two elements. Different element correlations existed between each collection, with no clear pattern in pairings present in both collections, which may suggest that biocultural influences are impacting sexual trait expression. However, in both collections, females had more overall correlations, and more statistically significant correlations than males, although there was less of a difference between sexes in Terry than in UTK. This result may be due to circulating hormones present during puberty, which may be contributing to more correlation between elements in females and not males. It also suggests that once again, biocultural differences between the Terry and UTK collections may be impacting the magnitude and patterns of correlation. This research highlights the complex dynamic nature of sexual trait expression in bone in relation to several intrinsic and extrinsic factors. It supports the idea that sexual trait expression is not concordant between skeletal regions among the same individual and that these inter-element correlations appear to be different between skeletal collections. Likewise, it suggests that age and ancestry may minimally be affecting sexual trait expression, but not in a consistent way across skeletal elements or between collections. It also suggests that while geometric morphometrics may help in capturing shape variation, it does not always translate to higher correct classification rates. This research also supports previous literature that the os coxae is the best element for sex estimation, although is not clear on what element is next best. Future studies in sexual trait expression should account for biocultural influences, as this research suggests that sexual trait expression is influenced by poorly understood intrinsic and extrinsic factors.

A antropometria é o estudo das medidas do corpo. A medição pode ser realizada no próprio corpo, na chamada técnica direta, ou na representação do indivíduo, na técnica indireta. Os resultados podem ser aplicados nas áreas da medicina, odontologia, fisioterapia, fonoaudiologia, entre outros. A antropometria aplicada à face traz dados referentes ao crescimento, ao envelhecimento e é capaz de traçar características de tecidos moles. É consenso na literatura que não há um padrão facial único que possa servir para todas as populações, sendo que cada uma possui características que as tornam únicas e que devem ser levadas em consideração no planejamento de cirurgias estéticas, ortognáticas e reconstrutivas. Até o momento, não há estudos que tragam o detalhamento antropométrico da face da população brasileira. Assim, o objetivo geral desse trabalho é trazer o levantamento antropométrico facial da população de adultos jovens brancos brasileiros por meio da análise de fotografias em norma frontal, método conhecido como fotoantropometria. As fotografias têm origem de um banco civil de imagens da Polícia Federal brasileira, sendo 689 de indivíduos do sexo feminino (F) e 660 do sexo masculino (M). Foram selecionadas as imagens que possibilitavam a visualização dos pontos fotoantropométricos de interesse e que apresentavam a centralização da cabeça em relação ao plano sagital, ao plano horizontal e ao eixo sagital. Os indivíduos representados nas fotografias foram classificados quanto à ancestralidade levando-se em consideração aspectos como cor da pele, textura do cabelo e morfologia nasal e labial. Os pontos fotoantropométricos foram marcados manualmente nas imagens fotográficas por meio do software SAFF 2D®. As coordenadas em pixels foram transformadas em distâncias lineares e deram origem aos índices, os quais foram analisados sob diversos aspectos. Além das análises realizadas para a população total, os indivíduos foram separados em grupos, considerando-se o sexo e o local de nascimento correspondente às regiões do país, sendo: Sul, Sudeste, Centro-oeste, Nordeste e Norte. A morfologia da face da população de adultos jovens brancos do Brasil foi exaustivamente analisada sob vários aspectos e foi possível concluir que há diferença na morfologia facial entre os sexos e regiões de nascimento. O estudo ainda mostra qual a acurácia dos índices para a estimativa de sexo e predição da região de nascimento. Estudos futuros devem ser realizados para as demais ancestralidades que compõem a população do Brasil. / Anthropometry is the scientific study of the measurements of the human body. These measurements can be performed directly on the body or indirectly on the images of individuals. Their findings can be used in areas such as medicine, dentistry, physical therapy, and speech therapy, among others. Facial anthropometry provides information on growth and aging and can be used to outline characteristics of soft tissues. A consensus agreement has been reached in the literature that there is not a single facial pattern that fits all populations, as each population has unique features that should be taken into account in the planning of esthetic, orthognathic, and reconstructive surgeries. To date, no studies in Brazil have conducted an extensive investigation into the facial pattern of the Brazilian population. Therefore, the overall aim of this study is to carry out a photoanthropometric analysis of the population of young adult white Brazilians by analyzing frontal photographic images. The photographs were obtained from the Brazilian Federal Police image database and include 689 female (F) and 660 male (M) individuals. The images that allowed observing the anthropometric parameters of interest and on which the head had been placed centrally to the sagittal plane, to the horizontal plane, and to the sagittal axis were selected. The individuals depicted on the photographs were classified as to ancestry based on aspects such as skin color, hair texture, and nose and lip morphology. Anthropometric landmarks were made manually on the photographic images using the SAFF 2D® software program. The pixel coordinates were converted to linear distances, giving rise to indices, which were assessed with respect to various aspects. In addition to the analyses of the total population, individuals were categorized into groups according to sex and region of birth (south, southeast, midwest, northeast, or north). The facial morphology of the population of young adult white Brazilians was analyzed comprehensively as to different aspects, leading to the conclusion that facial morphology varies between the sexes and across regions of birth. The study also shows the accuracy of the indices for sex assessment and for prediction of the region of birth. Further studies are needed to evaluate other ancestries that make up the Brazilian population.

Historically, metric and morphological standards used in forensic anthropology and bioarcheology were derived from individuals of European and African descent and ancient Native Americans. However, it is unlikely that these standards can be accurately applied to modern Asian populations. Due to different population histories, it is hypothesized that ancient Native American and modern Thai individuals are metrically distinct. This study investigates the metric differences in sexual dimorphism between 102 Native American (American Museum of Natural History) and 100 modern Thai (Khon Kaen University) individuals 17 to 96 years of age. A total of 28 cranial, 9 mandibular and 58 postcranial measurements were compared between Native American and Thai individuals. Subsequently, select measurements were tested in Spradley and Jantz's (2011) American Black and White sex estimation equations to see how equations derived from non-Asian populations perform on Native American and Thai individuals and to ascertain if population differences exist in the expression of sexual dimorphism. Lastly, population-specific logistic regression equations were developed for both sample populations. Using logistic regression equations and discriminant function analyses - quasi-ordinary least squares, the Native American and Thai groups are significantly different in the expression of sexual dimorphism. Further, Spradley and Jantz's (2011) equations often fail to correctly classify Native American and Thai individuals. In particular, the equations derived from American Black and White individuals frequently classified modern Thai and Native American males as females. Conversely, three American White equations and eight American Black equations classified more females as males for both populations. Therefore, the metric sex estimation methods developed on non-Asian populations do not adequately classify Native American and Thai individuals. The application of sex estimation methods developed on non-Asian populations results in reduced discriminatory power because Native Americans and Thais are less sexually dimorphic than African and European American individuals. The equations developed on the modern Thai sample correctly classified 71.1 - 96.0% of the individuals, while those developed on the Native American samples correctly 78.1 - 97.8%.

A antropometria é o estudo das medidas do corpo. A medição pode ser realizada no próprio corpo, na chamada técnica direta, ou na representação do indivíduo, na técnica indireta. Os resultados podem ser aplicados nas áreas da medicina, odontologia, fisioterapia, fonoaudiologia, entre outros. A antropometria aplicada à face traz dados referentes ao crescimento, ao envelhecimento e é capaz de traçar características de tecidos moles. É consenso na literatura que não há um padrão facial único que possa servir para todas as populações, sendo que cada uma possui características que as tornam únicas e que devem ser levadas em consideração no planejamento de cirurgias estéticas, ortognáticas e reconstrutivas. Até o momento, não há estudos que tragam o detalhamento antropométrico da face da população brasileira. Assim, o objetivo geral desse trabalho é trazer o levantamento antropométrico facial da população de adultos jovens brancos brasileiros por meio da análise de fotografias em norma frontal, método conhecido como fotoantropometria. As fotografias têm origem de um banco civil de imagens da Polícia Federal brasileira, sendo 689 de indivíduos do sexo feminino (F) e 660 do sexo masculino (M). Foram selecionadas as imagens que possibilitavam a visualização dos pontos fotoantropométricos de interesse e que apresentavam a centralização da cabeça em relação ao plano sagital, ao plano horizontal e ao eixo sagital. Os indivíduos representados nas fotografias foram classificados quanto à ancestralidade levando-se em consideração aspectos como cor da pele, textura do cabelo e morfologia nasal e labial. Os pontos fotoantropométricos foram marcados manualmente nas imagens fotográficas por meio do software SAFF 2D®. As coordenadas em pixels foram transformadas em distâncias lineares e deram origem aos índices, os quais foram analisados sob diversos aspectos. Além das análises realizadas para a população total, os indivíduos foram separados em grupos, considerando-se o sexo e o local de nascimento correspondente às regiões do país, sendo: Sul, Sudeste, Centro-oeste, Nordeste e Norte. A morfologia da face da população de adultos jovens brancos do Brasil foi exaustivamente analisada sob vários aspectos e foi possível concluir que há diferença na morfologia facial entre os sexos e regiões de nascimento. O estudo ainda mostra qual a acurácia dos índices para a estimativa de sexo e predição da região de nascimento. Estudos futuros devem ser realizados para as demais ancestralidades que compõem a população do Brasil. / Anthropometry is the scientific study of the measurements of the human body. These measurements can be performed directly on the body or indirectly on the images of individuals. Their findings can be used in areas such as medicine, dentistry, physical therapy, and speech therapy, among others. Facial anthropometry provides information on growth and aging and can be used to outline characteristics of soft tissues. A consensus agreement has been reached in the literature that there is not a single facial pattern that fits all populations, as each population has unique features that should be taken into account in the planning of esthetic, orthognathic, and reconstructive surgeries. To date, no studies in Brazil have conducted an extensive investigation into the facial pattern of the Brazilian population. Therefore, the overall aim of this study is to carry out a photoanthropometric analysis of the population of young adult white Brazilians by analyzing frontal photographic images. The photographs were obtained from the Brazilian Federal Police image database and include 689 female (F) and 660 male (M) individuals. The images that allowed observing the anthropometric parameters of interest and on which the head had been placed centrally to the sagittal plane, to the horizontal plane, and to the sagittal axis were selected. The individuals depicted on the photographs were classified as to ancestry based on aspects such as skin color, hair texture, and nose and lip morphology. Anthropometric landmarks were made manually on the photographic images using the SAFF 2D® software program. The pixel coordinates were converted to linear distances, giving rise to indices, which were assessed with respect to various aspects. In addition to the analyses of the total population, individuals were categorized into groups according to sex and region of birth (south, southeast, midwest, northeast, or north). The facial morphology of the population of young adult white Brazilians was analyzed comprehensively as to different aspects, leading to the conclusion that facial morphology varies between the sexes and across regions of birth. The study also shows the accuracy of the indices for sex assessment and for prediction of the region of birth. Further studies are needed to evaluate other ancestries that make up the Brazilian population.

Sex estimation in bioarchaeological research is paramount for comparative analyses of skeletal remains and developing estimates of other demographic variables. Frequently, sex is estimated utilizing the morphology of pelvic and cranial bones in archaeological skeletal samples. Regrettably, these bones are often damaged, destroyed, or lost and cannot be employed for the estimation of sex. Fortunately, a variety of metric and visual sex estimation methods have been developed on modern skeletal samples with known demography. Disappointingly, due to the population specific nature of many of these metric methods, they cannot be accurately applied directly to alternate skeletal samples. However, these methods can be redeveloped and retested for archaeological skeletal samples if the proper protocol is utilized. This research utilizes the protocol for developing methods of sex estimation on samples with unknown sex developed by Murail et al. (1999). Utilizing select hand and foot bones from four prehistoric Native American skeletal samples from Alabama and Illinois, multiple discriminant functions were developed and tested on both Archaic and Mississippian Period skeletal samples. Furthermore, the four individual site samples were combined into two geographical and two temporal samples, as well as an all pooled sample in order to test the broader applicability of these methods. The results indicate that sex estimation methods can be developed on samples where sex is not known. Additionally, the discriminant functions developed produce high levels of classification for the sites, individually, as well as for the geographic, temporal, and all pooled samples. The latter suggests these functions have broader applicability for these regions and temporal periods. Moreover, the concordance rates for these functions are similar to the accuracy rates when these bones were applied to samples with known sex.