Different Cranial Ontogeny in Europeans and Southern Africans

Modern human populations differ in developmental processes and in several phenotypic traits. However, the link between ontogenetic variation and human diversification has not been frequently addressed. Here, we analysed craniofacial ontogenies by means of geometric-morphometrics of Europeans and Southern Africans, according to dental and chronological ages. Results suggest that different adult cranial morphologies between Southern Africans and Europeans arise by a combination of processes that involve traits modified during the prenatal life and others that diverge during early postnatal ontogeny. Main craniofacial changes indicate that Europeans differ from Southern Africans by increasing facial developmental rates and extending the attainment of adult size and shape. Since other studies have suggested that native subsaharan populations attain adulthood earlier than Europeans, it is probable that facial ontogeny is linked with other developmental mechanisms that control the timing of maturation in other variables. Southern Africans appear as retaining young features in adulthood. Facial ontogeny in Europeans produces taller and narrower noses, which seems as an adaptation to colder environments. The lack of these morphological traits in Neanderthals, who lived in cold environments, seems a paradox, but it is probably the consequence of a warm-adapted faces together with precocious maturation. When modern Homo sapiens migrated into Asia and Europe, colder environments might establish pressures that constrained facial growth and development in order to depart from the warm-adapted morphology. Our results provide some answers about how cranial growth and development occur in two human populations and when developmental shifts take place providing a better adaptation to environmental constraints

Diversity among African Pygmies

Although dissimilarities in cranial and post-cranial morphology among African pygmies groups have been recognized, comparative studies on skull morphology usually pull all pygmies together assuming that morphological characters are similar among them and different with respect to other populations. The main aim of this study is to compare cranial morphology between African pygmies and non-pygmies populations from Equatorial Africa derived from both the Eastern and the Western regions in order to test if the greatest morphological difference is obtained in the comparison between pygmies and non-pygmies. Thirty three-dimensional (3D) landmarks registered with Microscribe in four cranial samples (Western and Eastern pygmies and non-pygmies) were obtained. Multivariate analysis (generalized Procrustes analysis, Mahalanobis distances, multivariate regression) and complementary dimensions of size were evaluated with ANOVA and post hoc LSD. Results suggest that important cranial shape differentiation does occur between pygmies and non-pygmies but also between Eastern and Western populations and that size changes and allometries do not affect similarly Eastern and Western pygmies. Therefore, our findings raise serious doubt about the fact to consider African pygmies as a homogenous group in studies on skull morphology. Differences in cranial morphology among pygmies would suggest differentiation after divergence. Although not directly related to skull differentiation, the diversity among pygmies would probably suggest that the process responsible for reduced stature occurred after the split of the ancestors of modern Eastern and Western pygmies

Carbon and Nitrogen Isotopic Signatures of Hair, Nail, and Breath from tropical African Human Populations

RATIONALE: Stable isotopic analyses are increasingly used to study the diets of past and present human populations. Yet, the carbon and nitrogen isotopic data of modern human diets collected so far are biased towards Europe and North America. Here, we address this gap by reporting on the dietary isotopic signatures of six tropical African communities: El Molo, Turkana (Kerio), Luhya (Webuye), Luhya (Port Victoria), and Luo (Port Victoria) from Kenya, and Baka from Cameroon; representing four subsistence strategies: fishing, pastoralism, agriculturalism, and hunter-gatherer. METHODS: We used EA-CF-IRMS to measure the carbon and nitrogen isotopic ratios of hair (n = 134) and nail (n = 80), and the carbon isotopic ratios of breath (n = 184) from these communities, as well as the carbon and nitrogen isotopic ratios of some food samples from the Kenyan communities. RESULTS: We expand on the known range of δ13 C values in human hair through the hunter-gatherer Baka, with a diet based on C3 plants, and through the agriculturalist Luhya (Webuye), with a diet based on C4 plants. In addition, we found that the consumption of fish from East African lakes is difficult to detect isotopically due to the combined effects of high nitrogen isotopic ratios of plants and the low nitrogen isotopic ratios of fish. Finally, we found that some of the communities studied are markedly changing their diets through increasing sedentism and urbanization. CONCLUSION: Our findings contribute substantially to the understanding of the environmental, demographic and economic dynamics that affect the dietary landscape of different tropical populations of Africa. These results highlight the importance of studying a broader sample of human populations and their diet, with a focus on their precise context - both from an isotopic and more general anthropological perspectives.This study was funded by a European Research Council Advanced Award to MML (In-Africa Project, ERC 295907), and carried out with permission from the National Commission for Science, Technology and Innovation, Kenya, No. NACOSTI/P/15/2669/4758

Ontogenia das órbitas em Pan troglodytes: implicações estruturais e funcionais.

The orbits of Haplorrhini primates are distinct among mammals because they are completely separated from the temporal fenestra and surrounded by bone; they are also convergent and frontalized, and provide the basis for the development of a notorious supraorbital torus. These characteristics have been described both as adaptations to their life habits and as resulting from structural rearrangements of the skull functional matrices. The goal of this work is to analyze morphological changes of the orbits in a transversal ontogenetic sample of Pan troglodytes and their association with adjacent structures in order to discuss structural and functional implications of these changes. We used 52 computerized tomography images of Pan troglodytes skulls ranging in age from 8 months to adults. Landmarks were recorded; in addition, volumetric and linear measurements were taken to extract angular variables and proportions. ANOVA, linear and partial regressions and Principal Component Analysis were performed. Our results indicate that the adaptive (functional) traits of the orbits in Pan troglodytes are set early in ontogeny and do not vary during the postnatal period, whereas their relationship with adjacent structures undergoes major changes.Las órbitas de los primates Haplorrhini son particulares dentro de los mamíferos por estar completamente separadas de la fenestra temporal y rodeadas por hueso, ser convergentes, estar frontalizadas y proveer la base para el desarrollo de un notorio torus supraorbitario. Estas características han sido descriptas, algunas como adaptaciones al hábito de vida y otras como resultado de reacomodaciones estructurales de las matrices funcionales del cráneo. El objetivo de este trabajo es analizar los cambios morfológicos de las órbitas en una muestra ontogenética transversal de Pan troglodytes y su asociación con estructuras adyacentes a fin de discutir implicancias estructurales y funcionales. Se utilizaron 52 imágenes de tomografías computadas de cráneos de Pan troglodytes desde 8 meses de vida postnatal hasta adultos. Se registraron landmarks y se tomaron medidas volumétricas y lineales que permitieron extraer variables angulares y proporciones. Se realizó ANOVA, regresiones lineales y parciales y Análisis de Componentes Principales. Los resultados indican que los rasgos de valor adaptativo (funcionales) de la órbita de Pan troglodytes se establecen tempranamente en la ontogenia y no varían durante el período postnatal, mientras que su relación con estructuras adyacentes muestra importantes cambios.As órbitas dos primatas Haplorrhini são peculiares entre os mamíferos por serem completamente separadas da fenestra temporal e rodeadas por osso, serem convergentes, estarem frontalizadas e proporcionarem a base para o desenvolvimento de um notório toro supraorbital. Algumas destas características foram descritas como adaptações ao hábito da vida, enquanto outras como resultado de rearranjos estruturais das matrizes funcionais do crânio. O objetivo deste trabalho consiste em analisar as alterações morfológicas das órbitas em uma amostra ontogenética transversal de Pan troglodytes e sua associação com estruturas adjacentes, a fim de discutir implicações estruturais e funcionais. Foram utilizadas 52 imagens de tomografias computadorizadas de crânios de Pan troglodytes de 8 meses de vida pós-natal a adultos. Foram registrados landmarks e tomadas medidas volumétricas e lineares que permitiram extrair variáveis ​​angulares e proporções. ANOVA, regressões lineares e parciais e Análise de Componentes Principais foram realizadas. Os resultados indicam que as características de valor adaptativo (funcionais) da órbita de Pan troglodytes se estabelecem no início da ontogenia e não variam durante o período pós-natal, enquanto sua relação com as estruturas adjacentes mostram alterações significativas

Tooth dimensions and body size in a Pygmy population

Background: The relationship between tooth size and stature has been analysed extensively at the interspecies level but has received less attention at the intraspecies level. The relationship between these two parameters does not seem to be the same among modern human populations. Aim: The aim of this study is to analyse the relationship between tooth dimensions and body measurements in the Baka Pygmies. Subjects and methods: Height, weight, and tooth dimensions were obtained for 45 adult Baka females and 17 males from Le Bosquet (Cameroon). Correlations were obtained between the variables and compared to results for other human populations. Results: The Baka population is distinctive in the small number of significant correlations. Only two buccolingual diameters among Baka females show any significant correlation with height. The lack of significant correlations between tooth dimensions and body dimensions among the Baka means that changes in body size are accompanied by random variations in tooth dimensions. Conclusion: The absence of correlations may be accounted for by the impact of environmental effects on the somatic growth of the Baka producing a Pygmy phenotype adapted to live in the forest. It is worth noting that many correlations become significant when sexes are pooled.This research was funded by PICS 07492 MAMIBAKA, Wenner-Gren Foundation [grant No. 7819], National Geographic Society [grant No. 8863-10], and Agence National de la Recherche [ANR-11-BSV7-0011] to F.V.R.R. and Spanish Ministerio de Economía y Competitividad [grant Nos. CGL2011-22999 and CGL2014-52611-C2-1-P] to A.R

Indigenous peoples' health : Culturally grounded evidence from the Baka, Southeastern Cameroon

Altres ajuts: acords transformatius de la UABUnidad de excelencia María de Maeztu CEX2019-000940-MIndigenous Peoples are exposed to the impacts of the climatic, ecological and socioeconomic changes, yet there is a need for a better understanding of their health and higher involvement of Indigenous Peoples in health promotion design and implementation. Our study brings empirical data on the healthcare system of the Baka, forager-horticulturalists from Cameroon. Using a mixed methods approach, we explored the health issues they encounter, the emic determinants of health and healthcare system, and the different threats towards their healthcare system. We conducted focus group discussions, interviews with experts, and self-reported health recalls with 302 individuals living in two settlements from southeastern Cameroon during two fieldwork periods between June and November 2022. Our insights highlight the prevalence of respiratory and children's digestive issues, and the occurrence of illnesses implying a combination of symptoms that would deserve further Western biomedical attention. The Baka's healthcare relies on medicinal plants, knowledge experts, and on the social cohesion of the community, all largely affected by the local social-ecological impacts of global change. Exposure to the market and health facilities does not seem to relate to Baka's health state and practices but might affect their perception of health. Deforestation, poor water quality, and alcohol (ab)use were reported and observed threats to the Baka's health and healthcare system. Our work supplies empirical evidence for a better understanding of Baka's health and healthcare system, helpful in designing health prevention and policies adapted to their reality and culture. Further research and interventions on health should consider the current threats to Baka's local ecosystems and cultural knowledge. These insights contribute to a higher recognition of the Baka's, and most broadly, the Indigenous Peoples' emic perspective on health, and on culturally grounded indicators of the resilience of their healthcare system to current and future challenges

Morphologie crânio-faciale des populations de l'Europe et du Maghreb depuis le Paléolithique Supérieur jusqu'à présent

Il n¿y a pas de consensus sur les processus responsables de la Néolithisation en Europe et en Afrique du Nord. Le passage Paléolithique Supérieur-Néolithique a pu s¿opérer par une migration des peuples du Proche-Orient ou par des changements économiques des populations locales. Nous avons effectué l¿analyse de la taille et de la conformation crâniennes des populations qui ont habité ces deux régions depuis le Paléolithique Supérieur jusqu¿à présent. Notre travail se fonde sur l ¿étude des composantes crâniennes fonctionnelles (CCF) suivantes: neurale antérieure, moyenne et postérieure, otique, optique, respiratoire, masticatoire et alvéolaire. Les différences observées ne mettent en évidence ni des tendances temporelles ni régionales. On observe, par contre, une nette différence entre les groupes du Paléolithique Supérieur et les autres. Les premiers se caractérisent par une taille plus grande et leur conformation est influencée par des CCF masticatoire et neurale moyenne importantes et une CCF optique réduite. Le développement de la CCF masticatoire est associé à une large face chez les groupes du Paléolithique Supérieur. Notre étude ne permet pas de résoudre la discussion sur la Néolithisation. Néanmoins, elle permet de suggérer que les différences dans la morphologie résultent d¿un nouveau type de vie (nutrition, mobilité, contraintes masticatoires) à partir du Néolithique

GPA/PCA results for neurocranial PC2.

<p>(a) PC2 scores vs chronological age. Smoothing splines accounted for 10.5 and 13% of variation in Europeans and Southern Africans, respectively. (b) PC2 scores vs dental age. (c) PC2 scores vs CS. (d) Lateral view of neurocranial shape, considering extreme negative values as the reference and extreme positive values as the target (other views do not show deformation). (e) Mean and 95% standard error for PC2 scores vs post-pubertal stages. Green: Europeans. Red: Southern Africans. Horizontal lines in a represent adult means: Europeans, solid line; Southern Africans, dotted line.</p

Ranking of dental maturation and sample distribution.

<p>Ranking of dental maturation and sample distribution.</p

Landmarks registered with Microscribe on the left side of the skull.

<p>Landmarks registered with Microscribe on the left side of the skull.</p