Intrageneric taxonomic distinction based on morphological variation in the macaque (Macaca) skeleton.

Taxonomic classification is important for understanding the natural world, yet current methods for species assessment often focus on craniodental morphology rather than the entire skeleton. Moreover, it is currently unknown how much variation could, or should, exist intragenerically. Here, we tested whether taxonomy can be accurately predicted based on patterns of morphological variation in macaques (H ) and whether postcranial bones reflect subgeneric macaque taxonomy similarly, or better, than the cranium (H ).

Patterns of integration and modularity in the primate skeleton: a review.

The question of how complex morphologies evolve, given constraints imposed by genetic, developmental and functional factors, has been a topic of inquiry for many decades. In the mid-twentieth century the study of morphological trait covariation, and the implications of this for evolutionary diversification, was developed under the general concept of "morphological integration". Given the polygenic inheritance model underlying quantitative skeletal traits, and the existence of differential pleiotropic effects, it is assumed that variation in the genotype to phenotype map will lead to the emergence of semi-autonomous "modules" that share relatively stronger covariance (integration) among traits within them.

Morphological modularity in the anthropoid axial skeleton.

Previous research has found that hominoids have stronger modularity between limb elements than other anthropoids, suggesting that there is less constraint on morphological diversification (e.g., limb proportions) in hominoids in terms of evolutionary independence.

Morphological integration of the hominoid postcranium.

Previous research has suggested that magnitudes of integration may be distinct in the postcranium of hominoids when compared to other primate species. To test this hypothesis, we estimated and compared magnitudes of integration of eight postcranial bones from three-dimensional surface scans for 57 Hylobates lar, 58 Gorilla gorilla, 60 Pan troglodytes, 60 Homo sapiens, 60 Chlorocebus pygerythrus, and 60 Macaca fascicularis. We tested the hypotheses that 1) magnitudes of integration would be distinct in the postcranium of hominoids compared to cercopithecoids, with the explicit prediction that magnitudes of integration would be lower in hominoids than in cercopithecoids, and 2) girdle elements (scapula, os coxa) would have lower magnitudes of integration across all taxa.

An integrative skeletal and paleogenomic analysis of stature variation suggests relatively reduced health for early European farmers.

Human culture, biology, and health were shaped dramatically by the onset of agriculture ∼12,000 y B.P. This shift is hypothesized to have resulted in increased individual fitness and population growth as evidenced by archaeological and population genomic data alongside a decline in physiological health as inferred from skeletal remains.

Examination of magnitudes of integration in the catarrhine vertebral column.

The evolution of novel vertebral morphologies observed in humans and other extant hominoids may be related to changes in the magnitudes and/or patterns of covariation among traits. To examine this, we tested magnitudes of integration in the vertebral column of cercopithecoids and hominoids, including humans. Three-dimensional surface scans of 14 vertebral elements from 30 Cercopithecus, 32 Chlorocebus, 39 Macaca, 45 Hylobates, 31 Pan, and 86 Homo specimens were used.

Ontogenetic changes in magnitudes of integration in the macaque skull.

Objectives: Magnitudes of morphological integration may constrain or facilitate craniofacial shape variation. The aim of this study was to analyze how the magnitude of integration in the skull of Macaca fascicularis changes throughout ontogeny in relation to developmental and/or functional modules.

Materials And Methods: Geometric morphometric methods were used to analyze the magnitude of integration in the macaque cranium and mandible in 80 juvenile and 40 adult M.

The relative efficacy of the cranium and os coxa for taxonomic assessment in macaques.

Objectives: The cranium is generally considered more reliable than the postcranium for assessing primate taxonomy, although recent research suggests that pelvic shape may be equally reliable. However, little research has focused on intrageneric taxonomic discrimination. Here, we test the relative taxonomic efficacy of the cranium and os coxa for differentiating two macaque species, with and without considering sexual dimorphism.

Morphological variation of the early human remains from Quintana Roo, Yucatán Peninsula, Mexico: Contributions to the discussions about the settlement of the Americas.

The human settlement of the Americas has been a topic of intense debate for centuries, and there is still no consensus on the tempo and mode of early human dispersion across the continent. When trying to explain the biological diversity of early groups across North, Central and South America, studies have defended a wide range of dispersion models that tend to oversimplify the diversity observed across the continent. In this study, we aim to contribute to this debate by exploring the cranial morphological affinities of four late Pleistocene/early Holocene specimens recovered from the caves of Quintana Roo, Mexico.

Biological diversity in an Islamic archaeological population: A radiogenic strontium isotope and craniometric analysis of affinity in Ottoman Romania.

Objectives: Written accounts, as well as a previous craniometric study, indicate that migrations of non-Europeans and conversions of Europeans to Islam define Ottoman communities in Early Modern Europe. What is less clear are the roles of migration and admixture in generating intra-communal variation. This study combines craniometric with strontium isotope data to compare the cranial affinities of locally born and immigrant individuals.

Diachronic changes in craniofacial morphology among the middle-late Holocene populations from Hehuang region, Northwest China.

Objectives: This study analyzes craniofacial shape variation in the Hehuang region of Northwest China within a population genetic framework, and takes a diachronic approach to explore the relationship betwee cultural discontinuity and biological continuity/discontinuity in the Hehuang region during the middle to late Holocene.

Materials And Methods: The sample comprises 76 adult skulls from five archaeological sites, ranging from 4,500 to 1,530 BP. 3D geometric morphometrics, multivariate statistics, quantitative evolutionary genetic and biodistance analyses were performed to study the diachronic variation in craniofacial morphology.

Multivariate morphometrics, quantitative genetics, and neutral theory: Developing a "modern synthesis" for primate evolutionary morphology.

Anthropologists are increasingly turning to explicit model-bound evolutionary approaches for understanding the morphological diversification of humans and other primate lineages. Such evolutionary morphological analyses rely on three interconnected conceptual frameworks; multivariate morphometrics for quantifying similarity and differences among taxa, quantitative genetics for modeling the inheritance and evolution of morphology, and neutral theory for assessing the likelihood that taxon diversification is due to stochastic processes such as genetic drift. Importantly, neutral theory provides a framework for testing more parsimonious explanations for observed morphological differences before considering more complex adaptive scenarios.

Comparison of cranial fluctuating asymmetry between normal and pathological specimens from a modern Thai skeletal group.

The purpose of this study was to compare fluctuating asymmetry (FA) levels across cranial modules of normal and pathological cranial specimens. It was examined whether pathological specimens have significantly higher FA scores than normal specimens in cranial regions affected by a developmental disorder. For this study, a modern Thai skeletal sample from Chulalongkorn University was analyzed.

Morphological integration of anatomical, developmental, and functional postcranial modules in the crab-eating macaque (Macaca fascicularis).

Objectives: Integration and modularity reflect the coordinated action of past evolutionary processes and, in turn, constrain or facilitate phenotypic evolvability. Here, we analyze magnitudes of integration in the macaque postcranium to test whether 20 a priori defined modules are (1) more tightly integrated than random sets of postcranial traits, and (2) are differentiated based on mode of definition, with developmental modules expected to be more integrated than functional or anatomical modules.

Materials And Methods: The 3D morphometric data collected for eight limb and girdle bones for 60 macaques were collated into anatomical, developmental, and functional modules.

Assessing the relative impact of historical divergence and inter-group transmission on cultural patterns: a method from evolutionary ecology.

In the study of cultural evolution, observed among-group affinity patterns reflect the effects of processes such as mutation (e.g. innovation and copying error), between-group interaction (culture flow), drift and selection.

The evolution of hominoid cranial diversity: A quantitative genetic approach.

Hominoid cranial evolution is characterized by substantial phenotypic diversity, yet the cause of this variability has rarely been explored. Quantitative genetic techniques for investigating evolutionary processes underlying morphological divergence are dependent on the availability of good ancestral models, a problem in hominoids where the fossil record is fragmentary and poorly understood. Here, we use a maximum likelihood approach based on a Brownian motion model of evolutionary change to estimate nested hypothetical ancestral forms from 15 extant hominoid taxa.

A craniometric analysis of early modern Romania and Hungary: The roles of migration and conversion in shaping European Ottoman population history.

Objectives: Debate persists regarding the biological makeup of European Ottoman communities settled during the expansion of the Ottoman Empire during the 16th and 17th centuries, and the roles of conversion and migration in shaping demography and population history. The aim of this study was to perform an assessment of the biological affinities of three European Ottoman series based on craniometric data.

Materials And Methods: Craniometric data collected from three Ottoman series from Hungary and Romania were compared to European and Anatolian comparative series, selected to represent biological affinity representative of historically recorded migration and conversion influences.

Evolutionary population history of early Paleoamerican cranial morphology.

The nature and timing of the peopling of the Americas is a subject of intense debate. In particular, it is unclear whether high levels of between-group craniometric diversity in South America result from multiple migrations or from local diversification processes. Previous attempts to explain this diversity have largely focused on testing alternative dispersal or gene flow models, reaching conflicting or inconclusive results.

Transmission of biology and culture among post-contact Native Americans on the western Great Plains.

The transmission of genes and culture between human populations has major implications for understanding potential correlations between history, biological, and cultural variation. Understanding such dynamics in 19th century, post-contact Native Americans on the western Great Plains is especially challenging given passage of time, complexity of known dynamics, and difficulties of determining genetic patterns in historical populations for whom, even today, genetic data for their descendants are rare. Here, biometric data collected under the direction of Franz Boas from communities penecontemporaneous with the classic bison-hunting societies, were used as a proxy for genetic variation and analyzed together with cultural data.

11,000 years of craniofacial and mandibular variation in Lower Nubia.

The transition to agriculture was a key event in human history. The extent to which this transition is associated with biological changes in different world regions remains debated. Cultural and osteological records in Lower Nubia throughout the Holocene have been interpreted as a result of in situ differentiation or alternatively as migratory events and possible admixture with surrounding populations.

Testing the equivalence of modern human cranial covariance structure: Implications for bioarchaeological applications.

Objectives: Estimation of the variance-covariance (V/CV) structure of fragmentary bioarchaeological populations requires the use of proxy extant V/CV parameters. However, it is currently unclear whether extant human populations exhibit equivalent V/CV structures.

Materials And Methods: Random skewers (RS) and hierarchical analyses of common principal components (CPC) were applied to a modern human cranial dataset.

Are human hands and feet affected by climate? A test of Allen's rule.

Objectives: In recent years, several studies have shown that populations from cold, high-latitude regions tend to have relatively shorter limbs than populations from tropical regions, with most of the difference due to the relative length of the zeugopods (i.e., radius, ulna, tibia, fibula).

The relative correspondence of cranial and genetic distances in papionin taxa and the impact of allometric adjustments.

The reconstruction of phylogenetic relationships in the primate fossil record is dependent upon a thorough understanding of the phylogenetic utility of craniodental characters. Here, we test three previously proposed hypotheses for the propensity of primate craniomandibular data to exhibit homoplasy, using a study design based on the relative congruence between cranial distance matrices and a consensus genetic distance matrix ("genetic congruence") for papionin taxa: 1) matrices based on cranial regions subjected to less masticatory strain are more genetically congruent than high-strain cranial matrices; 2) matrices based on cranial regions developing earlier in ontogeny are more genetically congruent than matrices based on regions that develop later; and 3) matrices based on cranial regions with greater anatomical/functional complexity are more genetically congruent than matrices based on anatomically simpler regions. Morphological distance matrices based on the shape of 15 different cranial regions, delineated on the basis of previous catarrhine studies, were statistically compared to a matrix of known genetic distances in papionins.

Incongruity between affinity patterns based on mandibular and lower dental dimensions following the transition to agriculture in the Near East, Anatolia and Europe.

While it has been suggested that malocclusion is linked with urbanisation, it remains unclear as to whether its high prevalence began 8,000 years earlier concomitant with the transition to agriculture. Here we investigate the extent to which patterns of affinity (i.e.