Test of the auricular surface sex estimation method in fetuses and non-adults under 5 years old from the Lisbon and Granada Reference Collections.

Non-adult sex estimation is an active field of forensic inquiry as morphological variations between males and females are subtle, but observable, even from intrauterine development. The objectives of this study are threefold: to test the validity of the auricular surface method for sex estimation (Int J Osteoarchaeol 27:898-911, 2017) in fetuses and children under the age of 5 years old; to evaluate if health conditions, reported as the cause of death, influence its accuracy; and to detect possible secular trends in sexual dimorphism. One-hundred and ninety-seven skeletal individuals from the Lisbon and Granada Identified Collections were studied. Individuals were divided according to the hormonal peaks (< 0, 0-2, < 2, and 2.1-5 years old), cause, and year of death (before and after 1960). As in previous studies, two ratios (FI/CF and DE/AD) and two qualitative variables (OM and MRS) showed the highest frequencies of correct estimation (0.81-0.86). The correct sex allocations increased when the discriminant function (0.85) and logistic regression (0.86) were applied. Males of the age groups < 0 and 2.1-5 years were all correctly sexed by both formulae, and the same was observed for the female probabilities of adequate allocation. The cause and year of death were identified as variables without statistical significance. It is proposed that this method can be incorporated with confidence into the multifactorial laboratory protocols for non-adult sex estimation from skeletal remains.

Evaluation of the auricular surface method for non-adult sex estimation on the Lisbon documented collection.

OBJECTIVES: Sex is usually not estimated in skeletonized non-adult individuals because sexual dimorphism is considered minimal before puberty. In 2017, a new approach based on the shape of the auricular surface was proposed, showing that this anatomic area of the ilium is dimorphic. This study tests the reproducibility and evaluates the accuracy of the method in a bigger sample. MATERIALS AND METHODS: Thirty males and 31 females from the Lisbon Collection (1 day-18 years old) were analyzed by two researchers, one experienced, and the other without previous knowledge of the method. The sample was divided into three groups according to prepubertal and pubertal hormonal peaks (<2, 0-12, and 13-18 years old). Two metric variables (DE/AD and FI/CF ratios), two morphological features (Overall Morphology, OM and Morphology of the Retroauricular End of the Superior Demiface, MRS), and two formulae were tested based on the adequate results obtained in the original article. RESULTS: Data shows a low interobserver error (ICC > 0.92; K > 0.74). Morphological features provide better results than the metrics (DE/AD = 77.05%; FI/CF = 73.77%; OM = 80.33%; MRS = 85.24%). The discriminant function correctly classified 86.66% of the males and the logistic regression, 83.33%. The method was equally reliable in 0-12 and 13-18 years-old age groups and more accurate in males. The accuracy of most of the variables reached 100% for males under 2 years-old, and the probabilities were higher than for older individuals. The percentages of correct estimations are not influenced by the age, year, and cause of death. DISCUSSION: Despite the relatively small sample size, this study confirms the usefulness of the auricular surface for non-adult sexual estimation, especially for those younger than 2 years old. Additional validation tests in documented individuals from other geographic regions are suggested.

Methods for sex estimation of prepubertal individuals (< 12 years old): bibliographic review and future directions.

Sex estimation is essential in both bioarchaeological and forensic research. Based on bibliographical research, this study aims to systematize and compare the existing methods and glance at the future on this research topic. The survey in Web of Science and Google Scholar revealed 37 papers describing the generation of original procedures, and 25 validation studies. The results show that the pelvis, namely the ilium, is the most analyzed anatomical region, followed by the deciduous teeth, the cranium, the mandible, and the long bones. The morphometric approaches are addressed in greater proportion, both as original methods (n = 19) or validations (n = 24). Only one of the 19 approaches that require expensive equipment (conventional radiology, computer tomography, geometric morphometrics and 3D modelling) was tested. Most of them were generated during the 21st century; however, 24 have not been tested yet. Comparing all the methods tested, the percentages of correctly estimated cases are always lower in validation studies. It is suggested that the most promising ones be tested in documented samples by a group of researchers. Thus, the interobserver error would be evaluated and may also lead to new methodological proposals and refinements.

Root dentin translucency and age at death estimation in adults using single rooted teeth: Update of the Forensic International Dental Database.

Since the publication of Lamendin's age estimation technique, the root dentin translucency has received increasing attention as an important indicator of age. Recently, Parra and colleagues presented the Forensic International Dental Database (FIDB), a proposal to estimate age at death in adults based on Bayes theorem by applying the criteria of Lamendin's technique. The present study aims to update the procedure and to evaluate a new version of the method (named FIDBv2) using two control samples from Colombia and Greece. The performance of this new version was acceptable and suggests that the method is suitable for age at death estimation in adult individuals from different forensic contexts. The best approximations to chronological age were obtained for individuals between 30 and 60 years old, with errors less than 10 years. The age estimations calculated on control samples suggest the adequate performance of FIDBv2 on individuals from varied populations. It can be stated that the FIDBv2 constitutes a solid alternative to be used in contexts where no additional data are available. Here we reinforce the initial idea that this model for estimating age at death in adults may be generalizable to any forensic context in the world.

Adult age-at-death estimation using the first rib: A simple probabilistic approach.

Age-at-death estimation is a difficult task in fragmented or incomplete contexts. The generation and testing of methods are needed to identify their potential application in different types of osteological samples. This paper proposes a new method for age estimation using the first rib. Four hundred and fifteen individuals from the Coimbra Identified Skeletal Collections (Portugal) were studied; the sample was divided in two groups (reference and test samples), used to develop the procedure and to evaluate its reliability. The three rib joints and two variables (surface texture and topography, and periarticular margins and subsidence of the surface) were recorded. Statistical analyses were performed to test the procedure reproducibility, and side and sex variations. Posterior probabilities were calculated following Bayesian statistics and used to estimate the most likely age-at-death in the test sample. The results show the reproducibility of the method is adequate, left and right ribs can be indistinctly recorded, and both sexes show similar change patterns. The costal face and the head epiphyseal region offered satisfactory results and the percentages of correct estimations are greater for younger individuals, decreasing as ages-at-death are higher. This method is more effective among individuals in the 20-50 years cohort; nevertheless, it also offered satisfactory estimates in older ones. Overestimations in individuals younger than 40 years and underestimations in individuals older than 75 years were identified. In conclusion, the first rib offer adequate estimates when a basic probabilistic approach is chosen. Whenever possible, this proposal must be included in a multifactorial perspective with other age markers.

Inferences on mobility and subsistence patterns from degenerative joint disease and entheseal changes. Trends in the farmer/forager border (Central-Western Argentina).

This study tests the hypothesis that the incorporation of cultigens about ca. 2000 years BP substantially changed hunter-gatherer subsistence and mobility in the Atuel River valley (Central-Western Argentina), where the frontier of pre-Hispanic domesticated resource dispersion was defined. Degenerative joint disease and entheseal change markers were analyzed on skeletal remains from Cañada Seca-1, a burial archaeological site with commingled skeletal remains dated about ca. 1500 years BP (MNI = 24). The results show lower mobility in comparison with hunter-gatherer remains from the neighboring Pampa region and quite different manual activities compared to low-level producers. These trends are explained as a result of a mixed subsistence strategy and mobility in an area where the incorporation of domesticated plants was neither a linear nor a fast process, and a stereotypical view proves to be insufficient to understand it. Although further information is required for future discussions, the present research highlights the potential of commingled skeletal remains for this kind of study.

Adult sex estimation from the minimum supero-inferior femoral neck diameter in a contemporary osteological sample from Buenos Aires, Argentina.

Sex estimation of adult skeletons is an important step in forensic analysis. Although the femur has been metrically studied for sex assessment around the world, very limited information is actually available on modern populations of Argentina. In this paper, the estimation of sex based on the metric evaluation of the supero-inferior femoral neck diameter (SID) in a reference osteological collection from the contemporary Chacarita Cemetery of Buenos Aires City (Argentina), is evaluated. Protocols generated using SID in other three reference skeletal samples are also tested on this collection. One hundred and sixty-four individuals of both sexes and between 24 and 96 years old are analyzed. Inter and intra observer errors suggest that the replicability of the procedure is adequate. The sectioning point calculated from the direct measurements is 30.86 mm and results show a high degree of dimorphism. The proportions of correct sex discrimination and the likelihoods of correct allocation obtained with the direct measurements, along with the results of a discriminant function, a binary logistic regression and a Bayesian approach, are all higher than 0.85 (0.85-0.93 for females, 0.88-0.91 for males). When the formulae from other samples are used in the Chacarita Collection, the percentages of correct estimations range between 72.41% and 81.03% for females and between 80.46% and 88.50% for males, while the likelihoods are between 0.73 and 0.81 for females and between 0.79 and 0.82 for males. As the values for the estimations obtained using the statistical procedures generated in the present research are higher than those available for other collections, the method is more adequate to use in the analysis of contemporary skeletal remains from Buenos Aires and surrounding areas. The trends identified highlight the importance of population-specific metric methodologies in forensic contexts and deserve future testing in contemporary samples from neighbouring regions.

Age-at-death estimation in adults using three forensic methodologies: A Lamendin's technique approach for Latin American context and the extension of a forensic international dental database.

In forensic science, the information that teeth provide to the age estimation process is very important. In adults, one of the most widely used indicators of skeletal age is the Root Dentin Translucency (RDT), mainly through the Lamendin technique, which is used in various Latin American contexts. Recently, Parra et al. (2020) have developed a Bayesian regression model using the Lamendin technique to establish standardized criteria for estimating age-at-death in adults in various forensic contexts. In this study, we evaluate the applicability of this proposal together with the proposal by Lamendin et al. (1992) and Prince and Ubelaker (2002) in Latin American contexts. A sample of single-rooted teeth belonging to 805 individuals from six Latin American countries was used. The results of the three proposals considered were analyzed taking into account factors such as age, sex, origin, and the tooth surface on which the variables were surveyed. Of the factors that would affect the estimates, it was found that the age of the individuals had the greatest influence. However, it was confirmed that the sex and surface of the teeth on which the measurements were taken did not influence the final result. On the other hand, as we expected, the application of the analyzed proposals would also be possible in other forensic contexts, as shown by the results obtained according to the origin. This research expands the FIDB with more information on Latino contexts.

Current status and perspectives of the development of dental research in biological anthropology of Argentina: introduction and conclusions of the symposium.

This paper describes and discusses the research in the field of dental anthropology in Argentina. It has been presented at the symposium entitled "The development of dental research in Argentine Biological Anthropology: current status and perspectives", coordinated by the authors at the IX National Meeting of Biological Anthropology of Argentina, Puerto Madryn, 20th-23rd October 2009. The aim of the symposium was to present new results and future prospects of this discipline in the country and to create a forum for discussion of current research within this field. Six contributions that focused on the study of teeth from different perspectives and analysed bioarchaeological samples from different areas of Argentina (Central Highlands, Pampa and Patagonia) were presented. After the presentations, a discussion about the state of the art of dental research in the country was generated, in which the need for the generation of methodological consensus on the criteria for the evaluation of the variables considered was stated, so that research conducted in different areas can be compared. In short, the contributions of this symposium provide insights into the diversity of dental anthropology in contemporary Argentina and the potential of these types of studies to gain important information about biological and cultural aspects of the native populations in the country.