Metricizing\u27 non-metric craniofacial traits: Application of three dimensional geometric morphometric analysis to ancestral identification

Non-metric traits are commonly used by anthropologists to distinguish between groups for such things as age, sex, and even ancestry. However, many non-metric traits cannot be measured with traditional osteological tools. While these traditional methods are useful, they do not take individual variation into account. This thesis uses geometric morphometric coordinate data to \u27metricize\u27 such traits and to evaluate their accuracy of correctly assigning unknown individuals to statistically defined groups; A 3-D digitizer was used to collect data from 39 craniofacial landmarks to capture the form of several phenotypic facial characteristics. The sample consisted of individuals from four different geographic locations (Precontact Peru, Historical China, Ancient Nubia, and Modern India). Principal Components Analysis confirmed that geographic groupings could be identified, while Procrustes Analysis and Thin-Plate Splines were used to assess the nature of form variation within and between groups. Discriminant functions calculated the probability of accurately assigning new individuals to their correct geographic group. The results indicate that phenotypic patterns, while variable, can be distinguished in certain populations and used successfully to predict group membership

Assessment of sexual dimorphism in brazilians using viscerocranium anthropometric parameters

Orientador: Eduardo Daruge JuniorDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de PiracicabaResumo: O processo de identificação é uma das principais e mais importantes tarefas dentro dos contextos médico e odontolegais. Nesses contextos, é sabido que o crânio pode fornecer diversas informações relevantes para a análise antropológica do sexo. O objetivo deste estudo foi avaliar a relação de medidas faciais para determinar o sexo em crânios humanos de brasileiros. Para isso, foram avaliados 113 crânios humanos íntegros (55 masculinos e 58 femininos). Foram realizadas 7 medidas faciais lineares em cada crânio, com paquímetro digital entre pontos craniométricos das regiões nasal e zigomática. Todas as medidas foram realizadas pelo mesmo pesquisador para evitar o erro interclasse e a análise estatística foi realizada no software R CRAN (open source). A curva de normalidade foi verificada pelo teste de Shapiro-Wilk, exceto para a medida da Largura Máxima Nasal, onde foi realizado o teste de Wilcoxon. Foi aplicado o teste comparativo T de Student para analisar o dimorfismo sexual, aplicando o nível de significância de p<0.05. Além disso, foram realizadas as médias, desvios padrões e gráficos box plots das mensurações realizadas. A partir do teste de correlação intraclasse foi obtido o valor de 0.986, o que demonstra uma reprodutibilidade excelente. As médias e desvios padrões de todas as medidas foram maiores no sexo masculino, exceto o índice nasal que possui relação inversamente proporcional. Verificou-se também que há interações estatisticamente significantes (p<0.05) entre o sexo para as medidas do índice nasal, altura nasal e largura facial máxima, com poder de teste T de Student igual a 0.0041, 1.835 e 1.377, respectivamente. Com isso, pode-se concluir que é possível criar padrões antropométricos regionalizados para a determinação do sexo em crânios não identificados, adequados à realidade brasileiraAbstract: The identification process is one of the major and most important tasks within Forensic Medicine and Forensic Dentistry. In these contexts, it is known that the skull can provide a relevant information to the anthropological analysis of sex. The objective of this study was to evaluate the relationship of facial measures to sex determination in human skulls of Brazilians. For this, 113 human skulls (55 males and 58 females) were evaluated. Seven linear facial measurements were performed on each skull, with a digital caliper between craniometric points of the nasal and zygomatic regions. All measurements were performed by the same researcher to avoid interclass error and statistical analysis was performed in CRAN (open source) software. The normality curve was verified by the Shapiro-Wilk test, except for the Maximum Nasal Width measurement, where the Wilcoxon test was performed. The Student's t-test was used to analyze the sexual dimorphism, applying the level of significance of p <0.05. In addition, the means, standard deviations and box plots of the measurements were performed. From the intraclass correlation test, a value of 0.986 was obtained, which shows excellent reproducibility. The means and standard deviations of all measurements were higher in males, except for the nasal index that has an inversely proportional relation. It was also verified that there were statistically significant (p <0.05) sex interactions for nasal index, nasal height and maximum facial width, with Student's t test power equal to 0.0041, 1,835 and 1,377, respectively. With this, it can be concluded that it is possible to create regionalized anthropometric standards for the determination of sex in unidentified skulls, appropriate to the Brazilian forensic contextMestradoOdontologia Legal e DeontologiaMestre em Biologia Buco-Dental33003033001P3CAPE

Estimation of sex from metatarsals using discriminant function and logistic regression analyses

South Africa has one of the highest crime rates in the world and the discovery of dismembered bodies for human identification process poses a greater challenge. The South African Africans (also known as South African blacks) population group is often the victims of crimes as they are the largest group. While measurements of several bones of the human skeleton have been used for sex estimation, the potential of metatarsals have not been explored in this population group. Metatarsal bones are usually well-preserved since they are recovered in shoes protected from scavengers and they are able to withstand environmental degradation and taphonomy. This study investigated the potential of measurements of metatarsals in sex estimate amongst South African Africans using logistic and discriminant function analysis. Six measurements of metatarsals from 100 individuals of known sex and population affinity from the Raymond Dart Collection of Human skeletons were analysed. Various combinations of measurements of metatarsal bones yielded suitably high average accuracies (79% to 84%) for sex estimation and are comparable to functions derived from other skeletal elements of South African Africans. Metatarsals of South African Africans are therefore useful as alternatives to highly sexual dimorphic bones in the forensic estimation of sex

Sexual Dimorphism in the Crania in a Norwegian Sample

Physical anthropologists strive to improve the accuracy of sex identification and to establish criteria of measurements within various populations. Different groups of native inhabitants show dissimilar results within cranial measurements and inaccuracies have been confirmed when comparing all populations to the common standard lineal measurements. This research examined 24 measurements on 120 crania from Norway and used statistical analyses to determine the sexual dimorphism between male and female crania. The study established the measurements with the most sexual dimorphism. These are the measurements of bizygomatic breadth, basion-bregma, biauricular breadth, glabella-opisthocranion, and upper facial breadth. The similarity of the values of nasal breadth, maxillo-alveolar length, orbital breadth, orbital height, interorbital breadth, parietal chord, and foramen magnum length between the sexes within the sample can rule out these measurements as a way to establish the sex of an unidentified individual. When running the measurements through the Fordisc software, it becomes clear that the values already found in the software directory are insufficient to determine the correct sex and ancestry when compared to the measurements of crania of Norwegian decent. Males often are misclassified as females and both sexes often are determined to be of incorrect ancestral group

A Comprehensive Case Report of University of Montana Forensic Collection Case #141

UMFC case #141 was acqired in spring 2006, as a commercially prepared anatomical specimen, reportedly from the Peoples Republic of China. It is a nealy complete skeleton that exhibits severe trauma of hte lower limbs. I reviewed the literature on methods of estimating age from the skeleton, because age is difficult to estimate for this case nad presents an interesting challenge. I then proceeded to estimate sex, ancestry, age, stature, and weight. I conclude that UMFC #141 is a White male, 39 to 45 years old, 5\u270 to 5\u274 in height, 110 to 161 pounds in weight. Healed fractures of both tibiae and fibulae, and of ribs 8,9, and 10 are present. Degenerative joint disease is widespread throughout the skeleton, and cribra orbitalia is present. Time since death is difficult to estimate due to the manner of preparation of the skeleton

Estimating sex by analyzing linear measurements of Brazilians’s dry skulls

Brazilian forensic physical anthropology has developed substantially in recent years, thus, new regression models are being obtained and models proposed by international researchers are being validated, both in a national sample. This search is greatly significant for national forensic anthropology, due to our unique ancestral constitution, allowing for a gain in efficiency and reliability in the process of human identification. We sought to evaluate 12 linear measures, aiming to verify the existence of sexual dimorphism, as well as the possibility of developing a regression model to estimate sex. The researcher was properly trained and calibrated (ICC=0.95). After this stage, the data measured in 186 skulls (105 males and 81 females, with ages ranging from 18 to 80 years old, were analyzed. To perform the linear measurements, straight and curved digital calipers, duly calibrated, were used. According to the statistical analysis, all measurements performed are dimorphic. It was possible to build a logistic regression model for sex estimation. Notably, a sensitivity of 81.7% and specificity of 79.2% were found, with an accuracy of 80.65%. It was found that the logistic regression model obtained can be used as an auxiliary method in estimating sex in Brazilians

Sexual dimorphism in white South African crania

Original published work submitted to the Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, in fulfilment of the requirements for the degree of Doctor of Philosophy. Johannesburg, 2016Sexual dimorphism is one of four critical factors assessed by forensic anthropologists when compiling biological profiles. The current study used geometric morphometric methods to analyse various aspects of sexual dimorphism in white South African crania to significantly contribute to current forensic standards for this underrepresented population. As edentulous crania are a major contributing factor to the low number of publications on white South African populations, the question arose as to how tooth loss affects cranial structures and the accuracy of sex and ancestry estimation. Two hundred and twenty nine crania were digitised using landmarks and sliding semilandmarks, both globally and for a number of cranial subsets. Although a number of effects were identified when the skull was analysed globally, only the maxillary alveolar ridges were significantly affected when subsets were analysed individually. As both upper facial height and palate shape were significantly altered by tooth loss, the effects of tooth loss on cranial structures and sex and ancestry estimations were investigated. Next, to parse out the mechanisms by which sexual dimorphism causes morphological variation, overall sexual dimorphism, common allometry and nonallometric sexual dimorphism were individually assessed. Global and subset data were studied and the effects of sexual dimorphism and allometry were found to be universal, with significant differences being observed between the sexes both globally and regionally. A significant non-allometric component was, however, only found to contribute to the shape of the zygomatic bone. Finally, the accuracy of 17 widely used traditional cranial measurements was compared to all possible interlandmark distances (ILDs) attainable from 45 fixed landmarks. Discriminant functions derived using the ILDs compared well to those of previous work on white South Africans, thus demonstrating the similarity between traditional and 3-D methods. Finally, custom discriminant functions were created for a number of cranial subsets and for the cranium in its entirety. The subsets achieved sexing accuracies ranging between 71.8% and 83.7%, with the nasomaxilla proving most accurate. The overall cranial function attained a cross-validated sexing accuracy of 88.2%. These functions are critical for sex estimation not only for intact crania, but also for the innumerable fragmentary cranial remains recovered regularly in South Africa.MT201