Craniometric Variation Research Articles

Indian craniometric variability and affinities.

Recently published craniometric and genetic studies indicate a predominantly indigenous ancestry of Indian populations. We address this issue with a fuller coverage of Indian craniometrics than any done before. We analyse metrical variability within Indian series, Indians' sexual dimorphism, differences between northern and southern Indians, index-based differences of Indian males from other series, and Indians' multivariate affinities. The relationship between a variable's magnitude and its variability is log-linear. This relationship is strengthened by excluding cranial fractions and series with a sample size less than 30. Male crania are typically larger than female crania, but there are also shape differences. Northern Indians differ from southern Indians in various features including narrower orbits and less pronounced medial protrusion of the orbits. Indians resemble Veddas in having small crania and similar cranial shape. Indians' wider geographic affinities lie with “Caucasoid” populations to the northwest, particularly affecting northern Indians. The latter finding is confirmed from shape-based Mahalanobis-D distances calculated for the best sampled male and female series. Demonstration of a distinctive South Asian craniometric profile and the intermediate status of northern Indians between southern Indians and populations northwest of India confirm the predominantly indigenous ancestry of northern and especially southern Indians.

Exploring the Relative Importance of Spatial and Environmental Variation on the Craniometrics of the Modern Portuguese

Previous research on the causes of craniometric variation within and among human populations has invoked both genetic and environmental explanations. Recent studies of modern populations in the United States and Portugal, among other populations, suggest that changes in environmental conditions have resulted in significant changes in cranial morphology. While similar changes in cranial morphology have been observed in genetically diverse populations, these populations do not appear to be converging on a common form. This study seeks to understand the role that population history and environmental variation play in explaining craniometric variation in the modern Portuguese. Using three-dimensional craniometric data collected from an identified skeletal collection from Lisbon, Portugal, this research examines the relationship between cranial morphology and place of birth. Two hypotheses are tested with regard to craniometric variation. The first asks whether phenotypic variation is related to geographic distance in the sample and therefore accurately represents genetic relationships. The second explores whether the significant secular changes observed in the sample obscure the population history reconstructed using craniometric data. The results demonstrate a significant relationship between geography and cranial morphology in the modern Portuguese sample. The clinal distribution to the craniometric variation is similar to what has been reported in some studies of molecular DNA from the Portuguese. The results show that cranial morphology reflects both the geography and genetic history of the sample and, furthermore, that secular changes in the population neither obscure nor erase this pattern. This study illustrates that even when secular changes have a significant impact on cranial morphology, they do not impede researchers’ ability to reconstruct genetic relationships using craniometric data.

Exploring the Relative Importance of Spatial and Environmental Variation on the Craniometrics of the Modern Portuguese

Previous research on the causes of craniometric variation within and among human populations has invoked both genetic and environmental explanations. Recent studies of modern populations in the United States and Portugal, among other populations, suggest that changes in environmental conditions have resulted in significant changes in cranial morphology. While similar changes in cranial morphology have been observed in genetically diverse populations, these populations do not appear to be converging on a common form. This study seeks to understand the role that population history and environmental variation play in explaining craniometric variation in the modern Portuguese. Using three-dimensional craniometric data collected from an identified skeletal collection from Lisbon, Portugal, this research examines the relationship between cranial morphology and place of birth. Two hypotheses are tested with regard to craniometric variation. The first asks whether phenotypic variation is related to geographic distance in the sample and therefore accurately represents genetic relationships. The second explores whether the significant secular changes observed in the sample obscure the population history reconstructed using craniometric data. The results demonstrate a significant relationship between geography and cranial morphology in the modern Portuguese sample. The clinal distribution to the craniometric variation is similar to what has been reported in some studies of molecular DNA from the Portuguese. The results show that cranial morphology reflects both the geography and genetic history of the sample and, furthermore, that secular changes in the population neither obscure nor erase this pattern. This study illustrates that even when secular changes have a significant impact on cranial morphology, they do not impede researchers' ability to reconstruct genetic relationships using craniometric data.

Cranial morphological variation among contemporary Mexicans: Regional trends, ancestral affinities, and genetic comparisons

Genetic research has documented geographical variation within Mexico that corresponds to trends in ancestry admixture from postcolonial times on. The purpose of this study is to determine whether craniometric variation among contemporary Mexicans is comparable to that reported in genetic studies. Standard osteometric measurements were taken on 82 male crania derived from forensic cases, with geographic origins of the specimens spanning over two-thirds of Mexico's states. To study similarities in regional clustering patterns with genetic data, k-means clustering analyses were performed, followed by chi-square tests of association between cluster assignments and geographic region of origin. Normal mixtures analyses were performed, centered on three "ancestral" sample proxies to estimate classification probability to each ancestry. The results demonstrate that the cranial morphological sample data cluster similarly to the regional groupings inferred from the genetic data. Additionally, the results indicate a gradient trend in population structure for contemporary Mexicans, with the proportion of Amerindian ancestry increasing from North to South while, conversely, European ancestry proportion estimates increase from South to North. Furthermore, the probabilities for classification of African ancestry remained low across the regions, again reflecting the results for the genetic data. Cranial morphological variation is well aligned with the genetic data for describing broad trends among Mexican populations, as well as yielding comparable estimates of general ancestry affiliations that reflect Mexico's history of Spanish contact and colonialism.

Variability and differences in the skulls of the common hamster (Cricetus cricetus) from several areas in Central Europe and from different time periods

The craniometric variability of skulls of the common hamster (Cricetus cricetus) from different countries (Belgium, the Netherlands, Austria, Germany) and different regions within Germany was studied. The aim was to study the variability in different regions and to see if differences between populations exist now and might have existed in former times also. The discriminant analyses were performed for females and males separately. The material was assigned to three different age classes and tests were attempted with all age classes. For the largest sample from Saxony-Anhalt, differences could also be observed between the three selected time periods (1900–1930, 1931–1960 and 1961–1990). Discriminant analyses were performed by keeping the sexes, age classes, and time periods separate wherever the material allowed for it. Regional samples differed to some degree (depending on the set of samples used). Particularly the samples from Austria, Belgium, and the Netherlands were more offset from the German samples; nevertheless, some overlap existed for the males of the third time period. The position of the small sample from the Rhineland was ambiguous in the different discriminant analyses but seemed rather to fall within the range of other German samples and not clearly in-between the German and the Dutch/Belgian samples. Overall variability, changes with time, and possible yearly fluctuations, as described in the literature, influenced the results and overlaid existing regional differences. The existence of a western subspecies could not be supported. The lack of substantial numbers of specimens illustrated the importance of collecting even the common species at all times for future research.

Taxonomic Boundaries and Craniometric Variation in the Treeshrews (Scandentia, Tupaiidae) from the Palawan Faunal Region

The taxonomy of treeshrews (Order Scandentia) has long been complicated by ambiguous morphological species boundaries, and the treeshrews of the Palawan faunal region of the Philippines are no exception. Four named forms in the genus Tupaia Raffles, 1821, have been described from four island groups based on subtle qualitative morphological characters, and as many as three distinct species have been recognized. A recent molecular phylogenetic study of relationships among Tupaia species suggests that the two currently-recognized treeshrew species from the Palawan faunal region diverged very recently relative to other sister-species divergences within the genus and may not represent species-level taxonomic entities. Here we review the taxonomic and biogeographic histories of the Tupaia taxa from this region. We also collected craniodental data from 133 skulls of all four named forms, representing five island populations, and conducted univariate and multivariate analyses on these data. Our morphometric results are consistent with molecular results, further suggesting that there is insufficient evidence to recognize T. moellendorffi Matschie, 1898, as a separate species from T. palawanensis Thomas, 1894. Our analyses also revealed a craniodentally divergent population from the island of Balabac, which has never been considered a distinct subspecies (or species) from the population on Palawan. These results have conservation implications for the island populations in our analyses, but additional surveys and molecular evidence will be required to fully assess conservation priorities for the treeshrews of the Palawan faunal region.

Biological variation in a large sample of mouse lemurs from Amboasary, Madagascar: Implications for interpreting variation in primate biology and paleobiology

A thorough knowledge of biological variation in extant primates is imperative for interpreting variation, and for delineating species in primate biology and paleobiology. This is especially the case given the recent, rapid taxonomic expansion in many primate groups, notably among small-bodied nocturnal forms. Here we present data on dental, cranial, and pelage variation in a single-locality museum sample of mouse lemurs from Amboasary, Madagascar. To interpret these data, we include comparative information from other museum samples, and from a newly collected mouse lemur skeletal sample from the Beza Mahafaly Special Reserve (BMSR), Madagascar. We scored forty dental traits (n = 126) and three pelage variants (n = 19), and collected 21 cranial/dental measures. Most dental traits exhibit variable frequencies, with some only rarely present. Individual dental variants include misshapen and supernumerary teeth. All Amboasary pelage specimens display a “reversed V” on the cap, and a distinct dorsal median stripe on the back. All but two displayed the dominant gray–brown pelage coloration typical of Microcebus griseorufus. Cranial and dental metric variability are each quite low, and craniometric variation does not illustrate heteroscedasticity. To assess whether this sample represents a single species, we compared dental and pelage variation to a documented, single-species M. griseorufus sample from BMSR. As at Amboasary, BMSR mouse lemurs display limited odontometric variation and wide variation in non-metric dental traits. In contrast, BMSR mouse lemurs display diverse pelage, despite reported genetic homogeneity. Ranges of dental and pelage variation at BMSR and Amboasary overlap. Thus, we conclude that the Amboasary mouse lemurs represent a single species – most likely (in the absence of genetic data to the contrary) M. griseorufus, and we reject their previous allocation to Microcebus murinus. Patterns of variation in the Amboasary sample provide a comparative template for recognizing the degree of variation manifested in a single primate population, and by implication, they provide minimum values for this species' intraspecific variation. Finally, discordance between different biological systems in our mouse lemur samples illustrates the need to examine multiple systems when conducting taxonomic analyses among living or fossil primates.

Commentary on Derish and Sokal's “A Classification of European Populations Based on Gene Frequencies and Cranial Measurements: A Map-Quadrat Approach” (1988): Evidence for the Lack of Taxonomic Structure but the Congruence between Genetic and Morphometric Information

Published in 1988, the paper by Derish and Sokal on the “classification on European populations” represented a methodological turning point in the assessment of the possible relationships (co-variation extent) among genotype (gene frequencies), phenotype (morphometrics), culture (language), and geography within a relatively limited and coherent eco-spatial unit. Notably, this exploratory study examined the variation patterns expressed by 59 gene frequencies (sampling 22 genetic loci) and 10 selected cranial measurements in population samples from 97 European localities encompassing (at that time) 29 countries, the investigated area having been arbitrarily structured into 85 unitary quadrats. By simply reading the first introductory sentences, the main critical question was: How can it work? This is the question mostly because the tools commonly used at the time for combined data analysis— the NT-SYS library of numerical taxonomy programs set by Rohlf (1985)—were in their “infancy” stage (the electronic version for PC was made available only later; see Rohlf 1990). In addition, previous work from the same Sokal, as well as from other researchers (e.g., Guglielmino-Matessi et al. 1979), had pointed out the complex nature and not yet fully understood background of morphometric (notably, craniometric) variation, which represented an additional complicating factor in such an investigation. Finally, the quadratting procedure appeared to give little hope for a consistent picture of spatial correlation between gene frequencies and morphometric record—how could the use of a grid with cells of 5 5 degrees (each roughly covering 240,000 km), where both gene frequencies and craniometric data were only available for a subset of cells and sample sizes varied considerably, have been a reliable background for a successful analytical work? The nature itself of the investigated topic, dealing with the “classificatory schemes for organizing human variation”—that is, indirectly with the concept of

Craniometrical variability of the Eurasian otter (Lutra lutra: Carnivora: Mustelidae) from the Northern Eurasia

The analysis of morphometric variability of the Eurasian otter (Lutra lutra) was carried out based on 350 skulls from geographically distant localities throughout the distribution range of this species, including China, Japan, and India. Our study revealed minor craniometric variability in L. lutra, which increases in tropical regions, and also symmetrical change of size and proportions of the skulls in the eastern and western parts of the Northern Eurasia as well as the change of the latitudinal trend in the skull variation approximately between 50 and 55° N. The correlation between the value of the morphological diversity and climatic variables is demonstrated. The Caucasian otter (L. l. meridionalis) shows significant similarity with otters from Europe (L. l. lutra). On the contrary, otters occurring in Honshu Island (L. l. nippon) are well differentiated morphologically from the continental populations. The results of our analysis suggest that L. simplicidens from the Middle Pleistocene of Europe probably represents a fossil subspecies of the Eurasian otter, L. lutra. The hypotheses are formulated about influence of ecological conditions on the the value of the parameters of morphological diversity as well as on the intensity of sexual dimorphism in the L. lutra. The results of our study siggest the higher level of genetic diversity of the Eurasian otter in the eastern part of the Northern Eurasia in comparison with the western part of its distribution range.

Craniometric diversity of the common vampire bat (Desmodus rotundus) in Central and South America

The common vampire bat, Desmodus rotundus Geoffroy, 1810, is a species with an extensive geographical distribution, occurring in a wide variety of habitats. A recent phylogeographical study using molecular markers described a scenario in which this species is formed by 5 distinct geographically circumscribed mitochondrial clades. Here we studied the craniometric variation of the common vampire bat to assess the amount of subdivision within this species and to test for the possibility of distinct morphological patterns associated with geographical lineages. We used 16 measurements from 1,581 complete skulls of adult D. rotundus representing 226 localities in South America and Mesoamerica. The assessment of morphological diversity between groups was done by the estimation of minimum FST values. Overall, the results show that most of the within-species variation is a result of the size component. Both shape data and size data are correlated with geographic distances. Our results favor the origin of biological diversity as the outcome of genetic drift and stepping-stone pattern of gene flow instead of local adaptations to local environmental conditions. The FST analyses also support male-biased dispersal. The results give little evidence to support previous suggestions that the common vampire bat may be composed of 2 or more species.

Geographic Patterns of Craniofacial Variation in Pre-Hispanic Populations from the Southern Cone of South America

In this study we analyzed the relationships and patterns of spatial variation from morphological cranial variability of 17 population samples representing the ancient inhabitants of the central territory of Argentina (archaeologically known as “Sierras Centrales”) and other pre-Hispanic populations from different ecological and geographic regions of the Southern Cone of South America (Argentina and Uruguay), based on the analysis of 10 craniofacial measurements. Results obtained from D2 distances can be interpreted as evidence of a similar biological history for the populations that inhabited the Sierras Centrales and the population of Santiago del Estero. Matrix correlation analysis demonstrated that craniometric variation is significantly influenced by geography, suggesting that populations that lived at lower geographical distance share more biological similarity. Global spatial autocorrelation analysis suggests a clinal pattern for the biological variation, although Moran's I estimates calculated for each variable demonstrate that only nasal height and breadth show this spatial pattern of variation. Results from spatial regression techniques show a significant effect of altitude modeling nasal shape, in agreement with previous studies suggesting that nasal morphology is strongly influenced by environment variables.

Geographic Patterns of Craniofacial Variation in Pre-Hispanic Populations from the Southern Cone of South America

In this study we analyzed the relationships and patterns of spatial variation from morphological cranial variability of 17 population samples representing the ancient inhabitants of the central territory of Argentina (archaeologically known as "Sierras Centrales") and other pre-Hispanic populations from different ecological and geographic regions of the Southern Cone of South America (Argentina and Uruguay), based on the analysis of 10 craniofacial measurements. Results obtained from D2 distances can be interpreted as evidence of a similar biological history for the populations that inhabited the Sierras Centrales and the population of Santiago del Estero. Matrix correlation analysis demonstrated that craniometric variation is significantly influenced by geography, suggesting that populations that lived at lower geographical distance share more biological similarity. Global spatial autocorrelation analysis suggests a clinal pattern for the biological variation, although Moran's I estimates calculated for each variable demonstrate that only nasal height and breadth show this spatial pattern of variation. Results from spatial regression techniques show a significant effect of altitude modeling nasal shape, in agreement with previous studies suggesting that nasal morphology is strongly influenced by environment variables.

A probabilistic approach to the craniometric variability of the genus Homo and inferences on the taxonomic affinities of the first human population dispersing out of Africa

There is probably no paleoanthropological issue with deeper disagreements than the taxonomic status of the Early–Middle Pleistocene members of the genus Homo One reason could be the difficulty of estimating the relationship between morphological and taxonomic diversity. In an attempt to contribute new evidence to this debate, bootstrapping techniques are used for analyzing the cranial variability of Homo. The results indicate that: (i) the size of the neurocranium relative to the viscerocranium discriminates better among extant hominoid species than skull size; (ii) no cluster of fossil specimens of Homo exceeds the morphological variability of Gorilla gorilla, with the only exception of the one that comprises all members of Homo except modern humans; and (iii) some clusters are taxonomically more consistent than others, as long as they show a range of morphological variability similar to that found in both Pan troglodytes and Homo sapiens. According to these results, three taxa are tentatively suggested for Homo: (i) anatomically modern humans; (ii) an “erectine” morphotype plus Neanderthals; and (iii) a “habiline” cluster. Finally, the results indicate a greater taxonomic affinity for the human population involved in the first dispersal “Out of Africa” with the “habiline” group, which agrees with the early age reported for Dmanisi (1.77 Ma), a Georgian site placed at the gates of Europe.

Migrations in the Eurasian Steppes in the Light of Paleoanthropological Dat

Cranial series provide vital clues about human history. The purposes of this analysis is to investigate the biological interactions between the population of Western Eurasia and that of the Armenian uplands, reconstructed on the basis of phenetic affinities between separate populations. Measurements of the neurocranium and facial skeleton have been used for many years to provide an assessment of the degree of biological relatedness among samples from past and living populations. Although these measurements are influenced by an unknown combination of hereditary and environmental factors (Cavalli-Sforza et al. 1971), and may be affected by masticatory mechanics (Van Gerven 1982) and environmental variation (Beals 1972, Guglielmino-Matessi et al. 1979), twin studies (Clark 1956, Orczykowska-Swiatkowska et al. 1975, Saunders et al. 1980), familial studies (Devor 1987, Howells 1966), and worldwide comparisons of craniometric variation have revealed a moderate degree of genetic control (Susanne 1977), and have demonstrated the utility of such variables for reconstructing patterns of biological interaction between populations (Howells 1973, 1989, Abdueshvili 1982, Alexeev 1986). Our study involved the multidimensional craniometrical analysis of more than 204 cranial series from the fifth to the second millennia BC in Eurasia. These were analyzed using canonical variates analysis of Mahalanobis D2 generalized distances between each pair of samples. New anthropological data allowed identification of alien Mediterranean characteristics influencing various ethnic Eurasian groups and revealed evidence of a migratory stream from the Armenia, the Middle East, and the Caucasus. This research provided new evidence of patterns of ethnic contact and intermixture in Western Eurasia.

Craniometric Variation in the Aleutians: Integrating Morphological, Molecular, Spatial, and Temporal Data

Several hypotheses have been put forward about the origins and evolution of the inhabitants of the Aleutian Islands. Both Hrdlička [The Aleutian and Commander Islands and Their Inhabitants (Philadelphia: Wistar Institute of Anatomy and Biology, 1945)] and Laughlin ["The Alaska gateway viewed from the Aleutian Islands," in Papers on the Physical Anthropology of the American Indian, W. S. Laughlin, ed. (New York: Viking Fund, 1951), 98-126] analyzed cranial morphology and came to somewhat different conclusions using a typological approach and limited analytical methods. Subsequent investigations using morphological data have not significantly improved our understanding of Aleut prehistory. More recently, radiocarbon dating and mitochondrial DNA analyses have shed light on Aleut genetic variation and changes over time, but better morphological methods using multivariate statistical analysis have not yet been used. We analyzed craniometric data using multivariate procedures and found that Aleuts demonstrate significant changes in cranial morphology over time, and these changes correspond to Hrdlička's observations but may not necessarily reflect in-migration. The morphological changes were concentrated in the very aspects of morphology that are easily observable and that Hrdlička most often measured, namely, cranial length, breadth, and height, but they were obscured when craniometric variation as a whole was analyzed. Also, we found that the morphological changes over time were not related to the changes in haplogroup frequencies over time, suggesting that migration into the Aleutians did not play a significant role in producing the morphological changes. However, craniometric variability apparently increases over time, suggesting in-migration, localized selection, and/or greater environmental heterogeneity. Our results contradict Laughlin's observations but may be more in line with his hypothesis of in situ evolutionary changes absent gene flow. In addition to selection, gene flow, and gene drift, however, sociocultural changes must also be considered as a factor in why morphology changed over time.

Craniometric variation of some Mediterranean and Atlantic populations of Stenella coeruleoalba (Mammalia, Delphinidae): A three‐dimensional geometric morphometric analysis

AbstractThe variability of cranial features of Atlantic and Mediterranean samples of Stenella coeruleoalba was examined using a three‐dimensional geometric morphometric approach. Data were collected on 79 skulls from the upper and middle Mediterranean Sea, the Atlantic French coasts, and Scotland. Three‐dimensional x, y, and z coordinates of 27 landmarks were recorded on each left half skull using a Microscribe 3‐D digitizer. All configurations were rotated, centered, and scaled, and residuals from the mean configuration were analyzed through multivariate analyses of variance. Mahalanobis distances among populations were used to evaluate phenetic relationships. Consensus configurations were compared to visualize shape differences among samples. Analyses revealed significant differences among populations, a clear distinction of the Scottish coasts dolphins from the other samples, and a closer relationship of the dolphins from the French coasts to the Mediterranean populations than to the Scottish one. Shape differences are mainly concentrated in the rostral and in the occipital regions of the skull. Phylogenetic and adaptive factors were invoked as possible causes of the variation patterns.

Cranial Differentiation of Fruit-Eating Bats (GenusArtibeus) Based on Size-Standardized Data

Size-standardized craniometric variation was investigated among species of the genus Artibeus. Eleven extant and one extinct species were examined using geometric and linear morphometric analyses to evaluate morphological differences among species. Based on 19 landmarks located in the ventral side of the cranium, 29 size-standardized linear measurements were calculated and used for statistical multivariate analyses. Discriminant Function Analysis showed major interspecific differences in shape between A. anthonyi and A. concolor with respect to the remaining extant species of Artibeus. These two species are described as morphologically unique morphotypes with a broader rostrum, enlarged squamosal region, and wider basicranium. Specifically, a broader premaxilla is the character that better discriminates A. anthonyi from all other species, whereas a broader squamosal region (particularly the deep mandibular fossa, and elongated squamosal) and wider braincase are the main characters differentiating A. concolor. All other species of the genus overlap to varying extents in their morphology showing high shape similarities. The least variant shape features include the pterygoid fossa, the glenoid (mandibular) fossa, the maxillae, and the occipital region; these regions in all cases contribute to mechanical aspects of jaw function and bite. The fact that the least variant aspects of skull shape all involve feeding is consistent with the hypothesis that selection has favored a specific diet-associated morphology rather than divergence or character displacement in Artibeus.

Population‐specific deviations of global human craniometric variation from a neutral model

Past studies have revealed that much of human craniometric variation follows a neutral model of population relationships. At the same time, there is evidence for the influence of natural selection in having shaped some global diversity in craniometrics. In order to partition these effects, and to explore other potential population-specific influences, this article analyzes residuals of craniometric distances from a geographically based neutral model of population structure. W.W. Howells' global craniometric data set was used for these analyses, consisting of 57 measurements for 22 populations around the world, excluding Polynesia and Micronesia because of the relatively recent settlement of these regions. Phenotypic and geographic distances were derived between all pairs of populations. Three-dimensional multidimensional scaling configurations were obtained for both distance matrices, and compared using a Procrustes rotation method to show which populations do not fit the geographic model. This analysis revealed three major deviations: the Buriat, Greenland Inuit, and Peru. The deviations of the Buriat and Greenland Inuit appear to be related to long-term adaptation to cold environments. The Peruvian sample is more similar to other New World populations than expected based on geographic distance alone. This deviation likely reflects the evolutionarily recent movement of human populations into South America, such that these populations are further from genetic equilibrium. This same pattern is seen in South American populations in a comparative analysis of classical genetic markers, but not in a comparative analysis of STR loci, perhaps reflecting the higher mutation rate for the latter.

Discrepancy between cranial and DNA data of early Americans: implications for American peopling.

Currently, one of the major debates about the American peopling focuses on the number of populations that originated the biological diversity found in the continent during the Holocene. The studies of craniometric variation in American human remains dating from that period have shown morphological differences between the earliest settlers of the continent and some of the later Amerindian populations. This led some investigators to suggest that these groups—known as Paleomericans and Amerindians respectively—may have arisen from two biologically different populations. On the other hand, most DNA studies performed over extant and ancient populations suggest a single migration of a population from Northeast Asia. Comparing craniometric and mtDNA data of diachronic samples from East Central Argentina dated from 8,000 to 400 years BP, we show here that even when the oldest individuals display traits attributable to Paleoamerican crania, they present the same mtDNA haplogroups as later populations with Amerindian morphology. A possible explanation for these results could be that the craniofacial differentiation was a local phenomenon resulting from random (i.e. genetic drift) and non-random factors (e.g. selection and plasticity). Local processes of morphological differentiation in America are a probable scenario if we take into consideration the rapid peopling and the great ecological diversity of this continent; nevertheless we will discuss alternative explanations as well.

Modern human cranial diversity in the Late Pleistocene of Africa and Eurasia: Evidence from Nazlet Khater, Peştera cu Oase, and Hofmeyr

The origin and evolutionary history of modern humans is of considerable interest to paleoanthropologists and geneticists alike. Paleontological evidence suggests that recent humans originated and expanded from an African lineage that may have undergone demographic crises in the Late Pleistocene according to archaeological and genetic data. This would suggest that extant human populations derive from, and perhaps sample a restricted part of the genetic and morphological variation that was present in the Late Pleistocene. Crania that date to Marine Isotope Stage 3 should yield information pertaining to the level of Late Pleistocene human phenotypic diversity and its evolution in modern humans. The Nazlet Khater (NK) and Hofmeyr (HOF) crania from Egypt and South Africa, together with penecontemporaneous specimens from the Peştera cu Oase in Romania, permit preliminary assessment of variation among modern humans from geographically disparate regions at this time. Morphometric and morphological comparisons with other Late Pleistocene modern human specimens, and with 23 recent human population samples, reveal that elevated levels of variation are present throughout the Late Pleistocene. Comparison of Holocene and Late Pleistocene craniometric variation through resampling analyses supports hypotheses derived from genetic data suggesting that present phenotypic variation may represent only a restricted part of Late Pleistocene human diversity. The Nazlet Khater, Hofmeyr, and Oase specimens provide a unique glimpse of that diversity.