Frontal sinus size in South African Later Stone Age Holocene Khoe-San

Frontal size variation is comparatively poorly sampled among sub-Saharan African populations. This study assessed frontal sinus size in a sample of Khoe-San skeletal remains from South African Later Stone Age contexts. Volumes were determined from CT scans of 102 adult crania; individual sex could be estimated in 82 cases. Sinus volume is not sexually dimorphic in this sample. The lack of frontal sinus aplasia is concordant with the low incidences recorded for other sub-Saharan African and most other global populations save those that inhabit high latitudes. There is considerable variation in frontal sinus size among global populations, and the Khoe-San possess among the smallest. The Khoe-San have rather diminutive sinuses compared to sub-Saharan Bantu-speaking populations but resemble a northern African (Sudanese) population. Genetic studies indicate the earliest population divergence within Homo sapiens to have been between the Khoe-San and all other living groups, and that this likely occurred in Africa during the span of Marine Isotope Stages 8-6. There is scant information on frontal sinus development among Late Quaternary African fossils that are likely either closely related or attributable to Homo sapiens. Among these, the MIS 3 cranium from Hofmeyr, South Africa, exhibits distinct Khoe-San cranial affinities and despite its large size has a very small frontal sinus. This raises the possibility that the small frontal sinuses of the Holocene South African Khoe-San might be a feature retained from an earlier MIS 3 population.

Evaluating predictions of the patterning cascade model of crown morphogenesis in the human lower mixed and permanent dentition

OBJECTIVE

The patterning cascade model of crown morphogenesis has been studied extensively in a variety of organisms to elucidate the evolutionary history surrounding postcanine tooth form. The current research is the first to use a large modern human sample to examine whether the crown configuration of lower deciduous and permanent molars aligns with expectations derived from the model. This study has two main goals: 1) to determine if metameric and antimeric pairs significantly differ in size, accessory trait expression, and relative intercusp spacing, and 2) assess whether the relative distance among early-forming cusps accounts for observed variation in accessory cusp expression.

METHODS

Tooth size, intercusp distance, and morphological trait expression data were collected from 3D scans of mandibular dental casts representing participants of the Harvard Solomon Islands Project. Paired tests were utilized to compare tooth size, accessory trait expression, and relative intercusp distance between diphyodont metameres and permanent antimeres. Proportional odds logistic regression was implemented to investigate how the odds of greater accessory cusp expression vary as a function of the distance between early-developing cusps.

RESULTS/SIGNIFICANCE

Comparing paired molars, significant differences were identified for tooth size and cusp 5 expression. Several relative intercusp distances emerged as important predictors of cusp 6 expression, however, results for cusp 5 and cusp 7 did not match expected patterns. These findings support previous quantitative genetic results and suggest the development of neighboring crown structures represents a zero-sum partitioning of cellular territory and resources. As such, this study contributes to a better understanding of the foundations of deciduous and permanent molar crown variation in humans.

Agenesis of the permanent teeth in sub-Saharan Africans: Prevalence, patterns, interpretations

OBJECTIVE

Dental agenesis data in modern and premodern sub-Saharan Africans are presented by region, West, Central, East, and South, and by sex. Beyond characterizing the anomaly, comparisons are made with other populations and future work is encouraged. The findings should be of use to dental clinicians and anthropologists.

METHODS

Agenesis of the UI2, LI1, UP2, LP2, UM3, and LM3 was recorded in 52 discrete samples of mainly skeletal dentitions (n = 2162) from across the subcontinent. After dividing into temporal categories, regional pooling was effected for adequate sample sizes across the vast geographic area. Only adults were included to record M3 status. Analyses included 95% confidence intervals and chi-square comparisons by region and sex.

RESULTS

Of 1668 modern individuals 2.3% have UI2-LP2 agenesis (CI 1.6-3.1%). Regional and sex differences are non-significant, though females are most affected. For M3s it is 7.0% (5.7-8.4%), with the Central region sample differing significantly from the East and South. Females again have greater prevalence, with the difference in the West significant. UI2-LP2 agenesis affects 0.6% of 494 premodern individuals (0.1-1.8%), while M3 agenesis is 8.5% (6.1-11.5%). None of these differences are significant.

CONCLUSIONS

Rates are toward the low end of global ranges, including 0.0-12.6% for UI2-LP2 from case reports, and 5.3-56.0% for M3 agenesis. With exceptions, generally insignificant inter-region differences imply that rates reasonably represent sub-Saharan peoples overall. Results will be of interest to anthropologists, but those related to risk factors, patterning, and prevalence may assist clinicians in tailoring treatment, while informing patients how this anomaly differs by population ancestry.

New insights on Celtic migration in Hungary and Italy through the analysis of non-metric dental traits

The Iron Age is characterized by an extended interweaving of movements by Celts in Europe. Several waves of Celts from Western and Central Europe migrated southeast and west from the core area of the La Téne culture (between Bourgogne and Bohemia). Through the analysis of non-metric dental traits, this work aims to understand the biological relationship among Celtic groups arrived in Italy and the Carpathian Basin, as well as between local populations and Celtic newcomers. A total of 10 non-metric dental traits were analyzed to evaluate biological affinities among Celts (Sopron-Krautacker and Pilismarót-Basaharc) and Scythians-related populations from Hungary (Tápiószele), Celts from continental Europe (Switzerland and Austria), two Iron Age Etruscan-Celtic sites from northern Italy (Monterenzio Vecchio and Monte Bibele), 13 Iron Age central-southern Italic necropolises, and the northern Italian Bronze Age necropolis of Scalvinetto. Strontium isotopes were measured on individuals from the necropolis of Monte Bibele to infer their local or non-local origin. Results highlight the existence of statistically significant differences between Celts and autochthonous Italian groups. Celtic groups from Hungary and Italy (i.e., non-local individuals of Monterenzio Vecchio and Monte Bibele) share a similar biological background, supporting the historical records mentioning a common origin for Celts migrated to the eastern and southern borders of today's Europe. The presence of a supposed Steppean ancestry both in Celts from Hungary and Celts from northern Italy corroborates the hypothesis of the existence of a westward migration of individuals and genes from the Steppe towards northern Italy during the Bronze and Iron Age, which contributed to the biological variability of pre-Celtic and later Celtic populations, respectively. Conversely, individuals from central-southern Italy show an autochthonous pre-Iron Age background. Lastly, this work supports the existence of Celtic migratory routes in northern Italy, as shown by biological and cultural admixture between Celts and Italics living together.

Variation in Middle Stone Age mandibular molar enamel-dentine junction topography at Klasies River Main Site assessed by diffeomorphic surface matching

The morphology and variability of the Middle Stone Age (MSA) hominin fossils from Klasies River Main Site have been the focus of investigation for more than four decades. The mandibular remains have figured prominently in discussions relating to robusticity, size dimorphism, and symphyseal morphology. Variation in corpus size between the robust SAM-AP 6223 and the diminutive SAM-AP 6225 mandibles is particularly impressive, and the difference between the buccolingual diameters of their M₂s significantly exceeds recent human sample variation. SAM-AP 6223 and SAM-AP 6225 are the only Klasies specimens with homologous teeth (M₂ and M₃) that permit comparisons of crown morphology. While the differences in dental trait expression at the outer enamel surfaces of these molars are slight, diffeomorphic surface analyses of their underlying enamel-dentine junction (EDJ) topographies reveal differences that are well beyond the means of pairwise differences among comparative samples of Later Stone Age (LSA) Khoesan and recent African homologues. The EDJs of both SAM-AP 6225 molars and the SAM-AP 6223 M₃ fall outside the envelopes that define the morphospace of these two samples. Although the radiocarbon dated LSA individuals examined here differ by a maximum of some 7000 years, and the two Klasies jaws may differ by perhaps as much as 18,000 years, it is difficult to ascribe their differences to time alone. With reference to the morphoscopic traits by which the SAM-AP 6223 and SAM-AP 6225 EDJs differ, the most striking is the expression of the protoconid cingulum. This is very weakly developed on the SAM-AP 6223 molars and distinct in SAM-AP 6225. As such, this diminutive fossil exhibits a more pronounced manifestation of what is likely a plesiomorphic feature, thus adding to the morphological mosaicism that is evident in the Klasies hominin assemblage. Several possible explanations for the variation and mosaicism in this MSA sample are discussed.

Rocker jaw: Global context for a Polynesian characteristic

Our goal is to describe the global distribution of the "rocker jaw" variant in human populations. Rocker jaw refers to mandibles that lack the antegonial notch, making them unstable on a flat surface. Data were collected by C.G. Turner II on 9,207 individuals from Asia, Europe, the Pacific, and the Americas, and by J.D. Irish on 3,526 individuals from North and South Africa. With a focus on Polynesia, where the trait is most common, frequencies are presented for subdivisions of Oceania, Australasia, Eurasia, the Americas, and Africa. While the rocker jaw is a Polynesian characteristic, the trait is found throughout the world. Within major geographic regions, there are interesting contrasts, for example, (a) the similarity of Jomon and Ainu and their difference from modern Japanese; (b) Aleuts and Northwest Coast Indians are similar and both are distinct from the Inuit and other Native Americans; and (c) North and Sub-Saharan Africans show a regional difference that parallels genetic and dental distinctions. Skeletons in South America that exhibit the rocker jaw have been interpreted as Polynesian voyagers who ventured to the west coast of South America. The rarity of rocker jaw in South American natives supports this view. The rocker jaw can be attributed to the unique basicranium morphology and large upper facial height of Polynesians, which highlights the integrated growth of a functional module (i.e., mastication) of the craniofacial complex. The unusually high frequency of the trait in Polynesians is a product of both function and founder effect/genetic drift.

Biocultural diversity in Late Pleistocene/Early Holocene Africa: Olduvai Hominid 1 (Tanzania) biological affinity and intentional body modification

OBJECTIVES

The dentition of Olduvai Hominid 1 (OH1) exhibits an anomalous pattern of dental wear that was originally attributed to either intentional cultural modification (filing) or plant processing behaviors. A differential diagnosis of the wear and assessment of the biological affinity of OH1 is presented.

MATERIALS AND METHODS

Macroscopic and microscopic observations of all labial and buccal tooth surfaces were undertaken to assess wear patterns. A multivariate analysis of mandibular morphology of OH1 compared to other Late Pleistocene, Holocene, and recent modern humans was used to ascertain biological affinity.

RESULTS

The morphological variation of the OH1 mandible is closely aligned with variation in penecontemporaneous fossils from Africa and outside that of recent humans. The concave wear facets exposing dentin on the labial surfaces of all three preserved mandibular incisors is confirmed. Substantial loss of labial/buccal surfaces was documented on the surfaces of all in situ maxillary and mandibular canines, premolars, and molars ranging from distinct facets with well-defined edges, to blunting or "polishing" around areas of maximum buccal curvature. The wear on both the anterior and postcanine teeth closely resemble that caused by adornments ("labrets") worn in lower-lip and buccal facial piercings known from bioarchaeological and ethnographic contexts. The wear pattern suggests that the OH1 wore three facial piercings-two buccal/lateral and a medial one in the lower lip.

DISCUSSION

Our findings suggest that the expression of social identities through intentional body modification is more diverse than previously documented elsewhere in Africa during the Late Pleistocene (i.e., ablation) and Early Holocene (i.e., ablation, chipping, and filing).

Tooth transposition prevalence and type among sub-Saharan Africans

OBJECTIVES

Although rare, tooth transposition-an exchange in location of two teeth-is a frequent topic of study. Clinical and, to a much lesser extent, dental anthropological research have focused predominantly on prevalence (0.03%-0.74% in several world populations) and case studies, albeit on a restricted spatiotemporal scale. Many regions have received little attention, including sub-Saharan Africa, while premodern data are few. Here, the aim is to supplement both fields of dental research by reviewing previous publications, and newly reporting transposition rates, types, and co-occurring abnormalities in time-successive samples across the subcontinent.

METHODS

Dental data in 51 sub-Saharan samples (>2500 individuals) dating >10 000 BC to 20th century were recorded. Of these, 36 are of modern and 15 premodern age, comprising males and females ≥12-years of age. Transposition presence, quadrant, and type were tabulated, cases described, and prevalence presented. In the latter case, Poisson 95% confidence intervals were calculated to better discern true population rates at various geographic levels.

RESULTS

Overall, six of 1886 modern individuals (0.32%) and one of premodern age evidence Mx.C.P1, an exchange of the maxillary canine and first premolar. Various associated dental abnormalities are also evident, including retained deciduous teeth, reduced permanent crowns, and agenesis.

CONCLUSIONS

This study provides additional insight into the geographic distribution, features, and time depth of transposition, along with hints supporting a genetic etiology and, potentially, some indications of diachronic change from an initial Mx.C.P1 to several types more recently based on premodern evidence. It is of clinical concern today, but is not just a modern anomaly.

Ethnogenetic analysis reveals that Kohistanis of Pakistan were genetically linked to west Eurasians by a probable ancestral genepool from Eurasian steppe in the bronze age

Despite the unique geographic, ethnic, social and cultural features of Kohistan in Pakistan, the origin and descent of Kohistanis remain still obscure. In an effort to address questions concerning the genetic structure, origin and genetic affinities of Kohistanis, we herein applied an ethnogenetic approach consisting on mitochondrial DNA (mtDNA) analysis and dental morphology analysis. We sequenced HVS1 of mtDNA, observed 14 haplotypes and assigned a total of 9 haplogroups belonging to macrolineages M (17%) and N (83%). Genetic diversity estimates in Kohistanis (Hd = 0.910 ± 0.014; Pi = 0.019 ± 0.001; θw = 0.019 ± 0.006) were similar to that of previous studies in other Pakistani populations. Overall, the analyses of dental morphology and mtDNA profile of Kohistanis resulted in similar findings. All the analyses indicate that Kohistanis share affinities to populations from Europe, Near East, Central Asia and South Asia. The Kohistani HVS1 haplotype 2 shares 100% identity to HVS1 haplotypes across the Europe. These results in light of recent insights into ancient genomics lead us to conclude that ancestry from Eurasian Steppe genetically linked Kohistanis to all these populations in the Bronze Age. This is consistent with linguistic evidence and also with the Indo-Aryan migration model for the peopling of South Asia.

Illuminating the processes of microevolution: A bioarchaeological analysis of dental non-metric traits from Armenian Highland

Non-metric dental traits provide useful information for assessing temporal changes as well as for assessing biological relationships among living and ancient populations. Dental morphological traits were employed in this study as direct indicators of biological affinities among the populations that inhabited the Armenian Highland from the Late Chalcolithic-Early Bronze Age to Modern times. Sixteen morphological features in 2643 permanent adult teeth from 41 samples coming from 5 areas within the Armenian Highland were scored. Both Zubov's standard protocol and Turner's ASUDAS were employed. Given the paucity of odontological data for this area, this study contributes to the dental non-metric traits' history of Armenian Highland and is a summary compilation and comparison of previously conducted work where non-metric traits were used in relation to dental reductions within the ancient Caucasus and Near East. The chronological sequence is considerable and spans from the Late Chalcolithic-Bronze Age to the Modern Age. It is suggested that offspring of ancient inhabitants of Armenian Highland continued to inhabit this area during the Late Iron Age, Classical/Late Antiquity, Middle Age and Modern period. This scenario indicates genetic continuity and gene flow between populations. Such a perspective is supported by the archaeological and molecular findings.

Unravelling biocultural population structure in 4th/3rd century BC Monterenzio Vecchio (Bologna, Italy) through a comparative analysis of strontium isotopes, non-metric dental evidence, and funerary practices

The 4^th century BC marks the main entrance of Celtic populations in northern Italy. Their arrival has been suggested based on the presence of Celtic customs in Etruscan mortuary contexts, yet up to now few bioarchaeological data have been examined to support or reject the arrival of these newcomers. Here we use strontium isotopes, non-metric dental traits and funerary patterns to unravel the biocultural structure of the necropolis of Monterenzio Vecchio (Bologna, Italy). Subsamples of our total sample of 38 individuals were analyzed based on different criteria characterizing the following analyses: 1) strontium isotope analysis to investigate migratory patterns and provenance; 2) non-metric dental traits to establish biological relationships between Monterenzio Vecchio, 13 Italian Iron age necropolises and three continental and non-continental Celtic necropolises; 3) grave goods which were statistically explored to detect possible patterns of cultural variability. The strontium isotopes results indicate the presence of local and non-local individuals, with some revealing patterns of mobility. The dental morphology reveals an affinity between Monterenzio Vecchio and Iron Age Italian samples. However, when the Monterenzio Vecchio sample is separated by isotopic results into locals and non-locals, the latter share affinity with the sample of non-continental Celts from Yorkshire (UK). Moreover, systematic analyses demonstrate that ethnic background does not retain measurable impact on the distribution of funerary elements. Our results confirm the migration of Celtic populations in Monterenzio as archaeologically hypothesized on the basis of the grave goods, followed by a high degree of cultural admixture between exogenous and endogenous traits. This contribution shows that combining different methods offers a more comprehensive perspective for the exploration of biocultural processes in past and present populations.

Revisiting historical Khoe-San skeletal remains in European collections: A search for identity through craniometric analysis

As the identity of a large number of Khoe-San skeletal material in European collections recently came into question during its documentation, a re-evaluation of the remains by employing a non-invasive method such as craniometrics was done to investigate the biological affinity. For this purpose, gene flow and population diversity present within the group, as well as between the study sample (N=63) and other modern and historic population groups from southern, central and east Africa were explored. Available comparative groups included the historic Khoe-San from Riet River (N=31), the Sotho-Tswana from southern Africa (N=61), the Basuku from central Africa (N=66) and the Bahutu (N=53) and Teita (N=24) from east Africa. Ten craniometric variables were selected and used to perform population structure analysis based on model bound quantitative genetics and multiple discriminant function analysis (MDA). Quantitative genetic distances revealed that the Khoe-San sample was closest to the Riet River group. Residual variance analysis performed on two-sample subsets of the Khoe-San group (Cape KS and Various KS) showed a higher level of heterogeneity in the Cape KS than seen in the Khoe-San from various other areas in southern Africa. MDA revealed that Khoe-San intra-sample variance is relatively high, with 44% of the sample (sexes pooled) classified into the Riet River group. The remaining individuals were classified (in decreasing order) into Bahutu (24%), Basuku (24%) and Sotho-Tswana (8%). Although the Khoe-San specimens are closest to the Riet River group, they are clearly not homogenous. Their high level of phenotypic diversity most likely originated from a complex population history involving many group interactions driven by social and political marginalization.

Internal Tooth Structure and Burial Practices: Insights into the Neolithic Necropolis of Gurgy (France, 5100-4000 cal. BC)

Variations in the dental crown form are widely studied to interpret evolutionary changes in primates as well as to assess affinities among human archeological populations. Compared to external metrics of dental crown size and shape, variables including the internal structures such as enamel thickness, tissue proportions, and the three-dimensional shape of enamel-dentin junction (EDJ), have been described as powerful measurements to study taxonomy, phylogenetic relationships, dietary, and/or developmental patterns. In addition to providing good estimate of phenotypic distances within/across archeological samples, these internal tooth variables may help to understand phylogenetic, functional, and developmental underlying causes of variation. In this study, a high resolution microtomographic-based record of upper permanent second molars from 20 Neolithic individuals of the necropolis of Gurgy (France) was applied to evaluate the intrasite phenotypic variation in crown tissue proportions, thickness and distribution of enamel, and EDJ shape. The study aims to compare interindividual dental variations with burial practices and chronocultural parameters, and suggest underlying causes of these dental variations. From the non-invasive characterization of internal tooth structure, differences have been found between individuals buried in pits with alcove and those buried in pits with container and pits with wattling. Additionally, individuals from early and recent phases of the necropolis have been distinguished from those of the principal phase from their crown tissue proportions and EDJ shape. The results suggest that the internal tooth structure may be a reliable proxy to track groups sharing similar chronocultural and burial practices. In particular, from the EDJ shape analysis, individuals buried in an alcove shared a reduction of the distolingual dentin horn tip (corresponding to the hypocone). Environmental, developmental and/or functional underlying causes might be suggested for the origin of phenotypic differences shared by these individuals buried in alcoves.