A multifaceted exploration of ontogenetic variation in vertebral neural canal size across contemporary populations

DATA AVAILABILITY STATEMENT : The data that support the findings of this study are openly available in the SVAD Zenodo Community repository at https://zenodo.org/communities/svad/ (DOI: 10.5281/zenodo.6342097).OBJECTIVES : Vertebral neural canal (VNC) dimensions are considered a reliable indicator of childhood stress. However, no study has characterized variation in VNC size or shape or the impact of extrinsic or intrinsic factors on their range of variation. The present study explores VNC dimensions of subadult samples varying in chronology, population of origin, geography, and socioeconomic backgrounds. MATERIALS AND METHODS : Antero-posterior (AP) and transverse (TR) diameters were measured on the tenth thoracic to the fifth lumbar vertebrae of 1404 contemporary individuals aged between birth and 22 years from Colombia (N = 28), France (N = 484), the Netherlands (N = 23), Taiwan (N = 31), and the United States (N = 838), and compared to lumbar diameters of subadults from the Spitalfields collection (N = 84) and the East Smithfield cemetery (N = 65). VNC variation was evaluated with skeletal growth profiles, principal component analyses (PCA), MANOVAs and ANOVAs. RESULTS : AP diameter growth ends during childhood, while TR diameter growth progressively slows before ending in adolescence. The Colombian sample presented the smallest VNC diameters compared to the other contemporary and historic samples. VNC shape (AP/TR ratio) was similar in contemporary samples. MANOVAs and ANOVAs revealed significant differences in VNC size according to country of origin and socio-economic status, primarily differentiating the Colombian sample. DISCUSSION : The overall consistency in size and shape among groups is remarkable. While physiological stress may contribute to variability in VNC size, intrinsic ontogenetic processes and other individual and environmental factors also influence variability in VNC size.National Institute of Justice and National Science Foundation.http://wileyonlinelibrary.com/journal/ajpa2023-12-09hj2023AnatomySDG-03:Good heatlh and well-bein

New insights on hip bone sexual dimorphism in adolescents and adults using deformation-based geometric morphometrics

Morphological variation of the human pelvis, and particularly the hip bone, mainly results from both female-specific selective pressure related to the give birth of large-headed newborns, and constraints in both sexes for efficient bipedal locomotion, abdominal stability, and adaptation to climate. Hip bone morphology has thus been extensively investigated using several approaches, although the nuances of inter-individual and sex-related variation are still underappreciated, and the effect of sex on ontogenetic patterns is debated. Here, we employ a landmark-free, deformation-based morphometric approach to explore variation in modern human hip bone shape and size from middle adolescence to adulthood. Virtual surface models of the hip bone were obtained from 147 modern human individuals (70 females and 77 males) including adolescents, and young and mature adults. The 3D meshes were registered by rotation, translation, and uniform scaling prior to analysis in Deformetrica. The orientation and amplitude of deviations of individual specimens relative to a global mean were assessed using Principal Component Analysis, while colour maps and vectors were employed for visualisation purposes. Deformation-based morphometrics is a time-efficient and objective method free of observer-dependent biases that allows accurate shape characterisation of general and more subtle morphological variation. Here, we captured nuanced hip bone morphology revealing ontogenetic trends and sex-based variation in arcuate line curvature, greater sciatic notch shape, pubic body and rami length, acetabular expansion, and height-to-width proportions of the ilium. The observed ontogenetic trends showed a higher degree of bone modelling of the lesser pelvis of adolescent females, while male variation was mainly confined to the greater pelvis

Mixed cumulative probit : a multivariate generalization of transition analysis that accommodates variation in the shape, spread and structure of data

DATA AVAILABITY STATEMENT: The data and analyses are all freely available. The data used in the current study are available in the Zenodo Subadult Virtual Anthropology Database Community: https://doi.org/10.5281/zenodo.5193208 [71]. The vignette is freely available here: https://rpubs.com/elainechu/mcp_vignette. The relevant code for this work is stored in GitHub: https://github.com/michaelholtonprice/rsos_mcp_intro and has been archived within the Zenodo repository: https://doi.org/10.5281/zenodo.7603754 [72].SUPPORTING INFORMATION: FILE S1: Supplemental material is hosted by figshare.Biological data are frequently nonlinear, heteroscedastic and conditionally dependent, and often researchers deal with missing data. To account for characteristics common in biological data in one algorithm, we developed the mixed cumulative probit (MCP), a novel latent trait model that is a formal generalization of the cumulative probit model usually used in transition analysis. Specifically, the MCP accommodates heteroscedasticity, mixtures of ordinal and continuous variables, missing values, conditional dependence and alternative specifications of the mean response and noise response. Cross-validation selects the best model parameters (mean response and the noise response for simple models, as well as conditional dependence for multivariate models), and the Kullback–Leibler divergence evaluates information gain during posterior inference to quantify mis-specified models (conditionally dependent versus conditionally independent). Two continuous and four ordinal skeletal and dental variables collected from 1296 individuals (aged birth to 22 years) from the Subadult Virtual Anthropology Database are used to introduce and demonstrate the algorithm. In addition to describing the features of the MCP, we provide material to help fit novel datasets using the MCP. The flexible, general formulation with model selection provides a process to robustly identify the modelling assumptions that are best suited for the data at hand.The National Institute of Justice and the National Science Foundation.https://royalsocietypublishing.org/journal/rsosAnatomySDG-03:Good heatlh and well-bein

Estimation de l’âge des individus immatures en anthropologie biologique : Analyse critique de méthodes existantes et application de deux approches méthodologiques standardisées

Age is one of the parameters of the biological profile of a juvenile individual that can be estimated from bones or teeth with sufficient reliability and precision. Many juvenile age estimation methods currently available to anthropologists do not follow scientifically nor biologically valid methodological criteria. This work starts with the critical analysis of a corpus of 256 juvenile age estimation methods used in physical anthropology. This analysis qualified and quantified the biases and limitations of method construction and application. It also presents an objective and practical classification of methods that highlights methods respecting valid sampling and methodological protocols and statistical criteria. The conclusions of this first study enabled the elaboration of a valid and standardised methodological protocol to construct a new standardised juvenile age estimation method. The surfaces of the iliac bone, fifth lumbar vertebra and the clavicle were virtually reconstructed from CT scans of individuals from Marseilles using the AVIZO® software. Biometric growth variables and non-biometric maturation indicators were taken on the three bone types. Several non-parametric Multivariate Adaptive Regression Splines (MARS) models were calculated to model the relationship between age and the variables using the R® software. The best age prediction models were obtained with the variables taken on the ilium, left and right vertebral heights and maximal clavicular length. These models were validated on three test samples from Marseilles, Toulouse and the Luis Lopes referenced osteological collection and gave comparable or better results than other referenced juvenile age estimation methods. Posterior probabilities of age were calculated using the maturation stages of four iliac bone epiphyses. Results were reliable, but precision was too low for validation. Our new juvenile age estimation method can be used as an abacus or as regression equations to predict individual age with 95% reliability and at least 90% accuracy. It is standardised, statistically valid, integrates changes in normal growth variability and is applicable in both a forensic or bioarchaeological context.L’âge est l’un des paramètres du profil biologique que l’on puisse estimer de manière suffisamment fiable et précise pour caractériser un individu immature à partir de ses restes osseux. Les nombreuses méthodes utilisées respectent de manière inégale des critères méthodologiques scientifiquement et biologiquement valides. Elles demeurent donc relativement critiquables. Ce travail présente une analyse critique d’un corpus de 256 méthodes d’estimation de l’âge des immatures utilisées en anthropologie biologique. Cette première analyse a permis de qualifier et quantifier les biais et les limites de construction et d’application des méthodes et propose une classification objective des méthodes utilisable en pratique, mettant en évidence celles qui respectent des critères statistiques et méthodologiques valides. Les conclusions tirées de cette analyse critique ont servi à élaborer le protocole méthodologique d’une nouvelle méthode standardisée d’estimation de l’âge osseux d’individus immatures. Les surfaces osseuses de l’os iliaque, de la cinquième vertèbre lombaire et de la clavicule ont été virtuellement reconstruites à partir de coupes tomodensitométriques grâce au logiciel AVIZO®. Des variables de croissance biométriques et des variables maturationelles non-biométriques ont été obtenues sur ces trois os. Un ensemble d’équations de régression non-paramétriques de type Multi Adaptive Regression Splines (MARS) modélisant la relation des variables biométriques avec l’âge a été calculé à partir d’échantillons d’apprentissage grâce au logiciel statistique R®. Les meilleures prédictions de l’âge ont été obtenues avec les variables biométriques iliaques, la longueur maximale de la clavicule et les hauteurs latérales de la cinquième vertèbre lombaire. Trois échantillons de validation provenant de Marseille, Toulouse et de la collection ostéologique de référence d’immatures de Lisbonne ont montré qu’il n’existait pas de différence significative entre les âges réels et estimés par les modèles de régression. Ces modèles donnaient des résultats meilleurs ou comparables à d’autres méthodes « classiques » d’estimation de l’âge. Des probabilités d’âge en fonction des indicateurs non-biométriques de maturation ont été calculées. Les résultats étaient suffisamment fiables, mais la précision était trop faible pour être valide. Notre nouvelle méthode d’estimation de l’âge des immatures respecte les standards méthodologiques identifiés lors de l’analyse critique et se présente sous la forme d’un abaque et d’équations de régressions relativement simples d’application. Elle est statistiquement valide et utilisable en contexte médico-légal et archéoanthropologique

The effects of epiphyseal fusion asymmetry on juvenile age estimation

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The effects of epiphyseal fusion asymmetry on juvenile age estimation

International audienc

The effects of epiphyseal fusion asymmetry on juvenile age estimation

International audienc

Une analyse critique des méthodes d'estimation de l'âge des individus immatures en anthropologie médico-légale

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