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The energy-sparing spring theory of the foot's arch has become central to interpretations of the foot's mechanical function and evolution. Using a novel insole technique that restricted compression of the foot's longitudinal arch, this study provides the first direct evidence that arch compression/recoil during locomotion contributes to lowering energy cost. Restricting arch compression near maximally (~80%) during moderate-speed (2.7 ms(-1)) level running increased metabolic cost by + 6.0% (p < 0.001, d = 0.67; unaffected by foot strike technique). A simple model shows that the metabolic energy saved by the arch is largely explained by the passive-elastic work it supplies that would otherwise be done by active muscle. Both experimental and model data confirm that it is the end-range of arch compression that dictates the energy-saving role of the arch. Restricting arch compression had no effect on the cost of walking or incline running (3°), commensurate with the smaller role of passive-elastic mechanics in these gaits. These findings substantiate the elastic energy-saving role of the longitudinal arch during running, and suggest that arch supports used in some footwear and orthotics may increase the cost of running.

The aim of this study was to determine the comparative accuracy of Demirjian's four dental development methods for forensic age estimation in the Western Australian population. A sample comprising 143 individuals aged 4.6 to 14.5 years were assessed using Demirjian's four methods for dental development (original 7-tooth: M(2), M(1), PM(2), PM(1), C, I(2), and I(1); revised 7-tooth: M(2), M(1), PM(2), PM(1), C, I(2), and I(1); 4-tooth: M(2), M(1), PM(2), and PM(1); and an alternate 4-tooth: M(2), PM(2), PM(1), and I(1)). When comparing all four methods, the 4-tooth method overestimated age in both males and females by 0.04 and 0.25 years, respectively. The original 7-tooth was least accurate for males, while the original 7-tooth, the revised 7-tooth, and the alternate 4-tooth were unsuitable for females. Therefore, we recommend the 4-tooth method to be used for forensic age estimation in Western Australian males and females, as it has the lowest overall mean deviation and the highest accuracy., (© 2011 American Academy of Forensic Sciences.)

Dental maturation and chronological age estimation were determined from 144 healthy Western Australian individuals aged 3.6-14.5 years. The results were compared with Farah et al.'s previous study which comprised a larger heterogeneous sample of Western Australian individuals (n = 1450). Orthopantomograms were analyzed with the application of Demirjian and Goldstein's 4-tooth method based on eight stages of dental mineralization. Analysis of variance revealed no significant differences in dental maturity scores in each age group among the males in both studies; similar results were seen in the females. Paired t-tests showed no statistical significance overall between chronological and estimated ages for the males in our sample (p = 0.181), whereas the females showed significant differences (p < 0.001). Our results show that smaller samples may be used when assessing dental maturity curves for forensic age estimation., (© 2011 American Academy of Forensic Sciences.)

Forensic anthropologists are frequently required to verify the human origin of complete and partial skeletal remains. This determination, however, can be difficult for bone fragments with few or no distinctive morphological markers. Current methods of distinguishing human from non-human bone fragments include microscopic, immunological and DNA testing, which are each limited to some degree (e.g. time consuming and expensive). The purpose of this study is to investigate an alternative morphometric approach to quantify the external structure of human long bones (humeri, femora, and tibiae) compared to quadrupedal (sheep, dog, and pig) and bipedal (kangaroo and emu) animals common to Australia. Eight traditional measurements were taken on a sample of 50 human and at least 10 of each of the five animal species; measurements were then analysed using linear discriminant analysis (LDA). The results expectedly indicate enough variation between species to correctly assign an unknown bone as that of a human or non-human, with cross-validated classification accuracy of 95% or better. More importantly, however, the technique also proved to be accurate if only a fragment of the diaphysis is analysed; classification accuracy 63-99%. The results of this study, therefore, outline a forensically useful non-invasive method to distinguish human from animal bones., (Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.)

We report here on new data examining cranial variation in 18 modern human sub-Saharan African populations. Previously, we investigated variation within southern Africa; we now extend our analyses to include a series of Central, East, and West African crania, to further knowledge of the relationships between, and variation and regional morphological patterning in, those populations. The sample comprises 377 male individuals; the three-dimensional coordinates of 96 landmarks are analyzed using Procrustes-based methods. Interpopulation variation is examined by calculating shape distances between groups, which are compared using resampling statistics and parametric tests. Phenotypic variance, as a proxy for genetic variance, is measured and compared across populations. Principal components and cluster analyses are employed to explore relationships between the populations. Shape differences are visualized using three-dimensional rendered models. Observed disparity patterns imply a mix of differences and similarities across populations, with no apparent support for genetic bottlenecks, which is likely a consequence of migrations that may have influenced differences in cranial form; supporting data are found in recent molecular studies. The Pygmy sample had the most distinctive cranial morphology; characteristically small in size with marked prognathism. These features characterized, although less strongly, the neighboring Bateke, and are possibly related to similar selective pressures in conjunction with interbreeding. Small cranial size is also involved in the considerable distinctiveness of the San and Khoikhoi. The statistical procedures applied in this study afford a powerful and robust means of quantifying and visualizing the magnitude and pattern of cranial variation between sub-Saharan African populations., (2009 Wiley-Liss, Inc.)

Research on the evolution and adaptive significance of primate craniofacial morphologies has focused on adult, fully developed individuals. Here, we investigate the possible relationship between the local stress environment arising from masticatory loadings and the emergence of the supraorbital torus in the developing face of the crab-eating macaque Macaca fascicularis. By using finite element analysis (FEA), we are able to evaluate the hypothesis that strain energy density (SED) magnitudes are high in subadult individuals with resulting bone growth in the supraorbital torus. We developed three micro-CT-based FEA models of M. fascicularis skulls ranging in dental age from deciduous to permanent dentitions and validated them against published experimental data. Applied masticatory muscle forces were estimated from physiological cross-sectional areas of macaque cadaveric specimens. The models were sequentially constrained at each working side tooth to simulate the variation of the bite point applied during masticatory function. Custom FEA software was used to solve the voxel-based models and SED and principal strains were computed. A physiological superposition SED map throughout the face was created by allocating to each element the maximum SED value from each of the load cases. SED values were found to be low in the supraorbital torus region throughout ontogeny, while they were consistently high in the zygomatic arch and infraorbital region. Thus, if the supraorbital torus arises to resist masticatory loads, it is either already adapted in each of our subadult models so that we do not observe high SED or a lower site-specific bone deposition threshold must apply., (Copyright 2009 Wiley-Liss, Inc.)

South Africa currently has a high homicide rate. This results in a large number of unidentified bodies being recovered each year, many of which are referred to the forensic examiner. This situation has resulted in considerable growth of forensic anthropological research devoted to devising standards for specific application in South African medico-legal investigations. The standards suitable for Black South Africans now encompass a wide variety of skeletal elements (e.g. cranium, humerus, pelvis, femur, patella, talus, calcaneus), each with differing degrees of accuracy. Apart from a preliminary investigation of the Zulu local population, however, we note that there appears to be no established metric mandible discriminant function standards for sex determination in this population. The purpose of the present study is to undertake a comprehensive analysis of sexual dimorphism in the mandible of Black South Africans, incorporating individuals from a selection of the larger local population groupings; the primary aim is to produce a series of metrical standards for the determination of sex. The sample analyzed comprises 225 non-pathological mandibles of Black South African individuals drawn from the R.A. Dart Collection. Nine linear measurements, obtained from mathematically transformed three-dimensional landmark data, are analyzed using basic univariate statistics and discriminant function analyses. All of the measurements examined are found to be sexually dimorphic; the dimensions of the ramus and corpus lengths are most dimorphic. The sex classification accuracy of the discriminant functions ranged from 70.7 to 77.3% for the univariate method, 81.8% for the stepwise method, and 63.6 to 84% for the direct method. We conclude that the mandible is a very useful element for sex determination in this population.

Fossils from Liang Bua (LB) on Flores, Indonesia, including a nearly complete skeleton (LB1) dated to 18kyr BP, were assigned to a new species, Homo floresiensis. We hypothesize that these individuals are myxoedematous endemic (ME) cretins, part of an inland population of (mostly unaffected) Homo sapiens. ME cretins are born without a functioning thyroid; their congenital hypothyroidism leads to severe dwarfism and reduced brain size, but less severe mental retardation and motor disability than neurological endemic cretins. We show that the fossils display many signs of congenital hypothyroidism, including enlarged pituitary fossa, and that distinctive primitive features of LB1 such as the double rooted lower premolar and the primitive wrist morphology are consistent with the hypothesis. We find that the null hypothesis (that LB1 is not a cretin) is rejected by the pituitary fossa size of LB1, and by multivariate analyses of cranial measures. We show that critical environmental factors were potentially present on Flores, how remains of cretins but not of unaffected individuals could be preserved in caves, and that extant oral traditions may provide a record of cretinism.

Methods for skeletal identification have a long history in physical and forensic anthropology. Recent literature demonstrates that new methods are constantly being developed, concurrent with refinements to those already commonly employed. The present study concerns the application of geometric morphometrics to assess the potential of mandibular morphology as a developmental marker for estimating age at death in subadult human skeletal remains. The sample comprises 79 known age and sex subadult individuals of South African Bantu and African American origin; 38 bilateral three-dimensional landmarks were designed and acquired using a portable digitizer. Linear regression was used to predict age using the multivariate descriptors of mandible size and shape based on configurations of three-dimensional landmarks. Our results show that the mandible can be used to predict age in the subadult skeleton with accuracy comparable to standards based on the dentition (standard error rates are between +/-1.3 and +/-3.0 years). These results closely parallel our previous study using the linear measurement of ramus height, but suggest that geometric morphometrics may be slightly more accurate when adolescents are included in the sample.

Humans alone among primates lack a superficial head of the temporalis muscle, although a complete superficial muscle is present in 1% of humans and an incomplete one in 8%. Yet the temporal fascia of normal humans contains all the fascial sheets associated with that head even though it is absent. The implication is that humans have lost the superficial temporal muscle, that this is evident from the retention of the fascial sheets, and that the muscular variations represent situations where the muscle has persisted to some degree. Molecular factors in the head domain that are responsible for the development of the muscles of mastication (myosin heavy chain 16) are likewise different in humans than in all non-human species and seem to be responsible for the reduction of those muscles in humans. Could the loss of the superficial portion of the temporalis muscle be a component of this reduction? Could the uncommon muscular variations result from some slight persistence of the prior molecular situation? Could the persistence of the fascial sheets, even when the muscle is absent, be because the molecular factors responsible for connective tissues are not the same as those responsible for muscles? How much of all this can be visualised in the fossil record? Skeletal dimensions of the temporal fossa, partly related to the temporal muscle size, imply that it may be possible to determine in which fossils temporal muscle reduction has occurred. Likewise, surface features of the bone in modern humans without a superficial muscular component but with a strong complex fibrous element suggest that it might be possible to determine, in any fossil in which the surface preservation is good enough, how far back this situation may have persisted. It is already known that myosin heavy chain molecular dating suggests that the muscle reduction may have occurred about 2.4 million years ago., (Copyright 2008 S. Karger AG, Basel.)

Many forelimb muscles (e.g. coracobrachialis, rhomboids, serratus sheet) are much less complex and much smaller in humans than in other primates. Yet human muscular variations and persistent fascial sheets indicate that increased size and complexity were once the norm. These muscular reductions are associated with equivalent skeletal gracilisation. Is it possible that molecular phenomena, not unlike those producing reduction of the jaw muscles and associated with gracilisation of the skull in species with reduced need for powerful mastication, may also have reduced forelimb muscles with gracilisation of its skeleton in species no longer using a forelimb for powerful locomotion? Could such molecular and skeletal changes be dated (as for the masticatory muscles) thus giving the time of origination of prehuman forelimb reduction and true bipedalism?, (Copyright 2008 S. Karger AG, Basel.)

This article forms part of an ongoing series of investigations designed to apply three-dimensional (3D) technology to problems in forensic anthropology. We report here on new morphometric data examining sexual dimorphism and population variation in the adult human mandible. The material is sourced from dissection hall subjects of South African and American origin consequently the sex and a statement of age are known for each individual. Thirty-eight bilateral 3D landmarks were designed and acquired using a Microscribe G2X portable digitizer. The shape analysis software morphologika (www.york.ac.uk/res/fme) is used to analyze the 3D coordinates of the landmarks. A selection of multivariate statistics is applied to visualize the pattern, and assess the significance of, shape variation between the sexes and populations. The determination of sex and identification of population affinity are two important aspects of forensic investigation. Our results indicate that the adult mandible can be used to identify both sex and population affinity with increased sensitivity and objectivity compared to standard analytical techniques.

There have been numerous attempts, with varying degrees of success, to differentiate males from females on the basis of the immature skeleton. We investigate here whether the mandible can discriminate immature individuals by sex; the techniques we apply are from the field of geometric morphometrics. The application of these methods in forensic anthropology is still relatively new; thus, an important aspect of this research is that it demonstrates potential applications in this discipline. The sample comprises 96 known age and sex subadult individuals; the three-dimensional coordinates of 38 landmarks are analyzed using the shape analysis software morphologika. Multivariate regressions indicated no significant sexual dimorphism in the subadult sample; this result is supported by poor cross-validated classification accuracy (59%). Our results suggest that the subadult mandible is not dimorphic (to the extent that dimorphism is not evident within the sample we studied); thus, sex determination using previously described criteria is likely to yield poor results.

Crucial to the interpretation of the results of any finite element analysis of a skeletal system is a test of the validity of the results and an assessment of the sensitivity of the model parameters. We have therefore developed finite element models of two crania of Macaca fascicularis and investigated their sensitivity to variations in bone material properties, the zygomatico-temporal suture and the loading regimen applied to the zygomatic arch. Maximum principal strains were validated against data derived from ex vivo strain gauge experiments using non-physiological loads applied to the macaque zygomatic arch. Elastic properties of the zygomatic arch bone and the zygomatico-temporal suture obtained by nanoindentation resulted in a high degree of congruence between experimental and simulated strains. The findings also indicated that the presence of a zygomatico-temporal suture in the model produced strains more similar to experimental values than a completely separated or fused arch. Strains were distinctly higher when the load was applied through the modelled superficial masseter compared with loading an array of nodes on the arch. This study demonstrates the importance of the accurate selection of the material properties involved in predicting strains in a finite element model. Furthermore, our findings strongly highlight the influence of the presence of craniofacial sutures on strains experienced in the face. This has implications when investigating craniofacial growth and masticatory function but should generally be taken into account in functional analyses of the craniofacial system of both extant and extinct species.

Much of our understanding of population variation in southern Africa is derived from traditional morphometric research. In the search for new perspectives, this paper reports on new geometric morphometric data examining cranial variation in 12 modern human populations from southern Africa. In total, 298 male Bantu-speaking individuals were studied. In addition, a small Khoisan (Khoikhoi and San) series was also examined. The purpose of this study was to investigate Khoisan-Bantu morphological similarities and differences, and to examine variation within both the Bantu-speaking and Khoisan populations. The three-dimensional coordinates of 96 landmarks were analyzed, using the shape-analysis software morphologika. Interpopulation variation was examined by calculating Procrustes distances between groups; a cluster analysis was then used to summarize phenetic relationships. A principal components analysis explored the relationships between populations; shape differences were visualized and explored using three-dimensional rendered models, and further interpreted using thin-plate splines. Morphological differences are present within and between the crania of Bantu-speaking and Khoisan individuals. The Khoisan demonstrate features (e.g., a pentagonoid vault, more rounded forehead contour, and a small and less prognathic face) that clearly distinguish them from Bantu-speaking populations. Although southern African Bantu-speaking populations are clearly closely related, they show population-specific features (e.g., the crania of more southerly populations (Xhosa, Southern Sotho, and Zulu) are characteristically more brachycephalic and less prognathic). This study suggests that differential admixture with adjacent Khoisan peoples has contributed to diversity within southern African Bantu-speaking populations.

The determination of sex is a critical component in forensic anthropological investigation. The literature attests to numerous metrical standards, each utilizing diffetent skeletal elements, for sex determination in South A frican Blacks. Metrical standards are popular because they provide a high degree of expected accuracy and are less error-prone than subjective nonmetric visual techniques. We note, however, that there appears to be no established metric mandible discriminant function standards for sex determination in this population.We report here on a preliminary investigation designed to evaluate whether the mandible is a practical element for sex determination in South African Blacks. The sample analyzed comprises 40 nonpathological Zulu individuals drawn from the R.A. Dart Collection. Ten linear measurements, obtained from mathematically trans-formed three-dimensional landmark data, are analyzed using basic univariate statistics and discriminant function analyses. Seven of the 10 measurements examined are found to be sexually dimorphic; the dimensions of the ramus are most dimorphic. The sex classification accuracy of the discriminant functions ranged from 72.5 to 87.5% for the univariate method, 92.5% for the stepwise method, and 57.5 to 95% for the direct method. We conclude that the mandible is an extremely useful element for sex determination in this population.

Simple simulations of stresses and strains in several types of localised anatomical features have been modelled using basic biomechanical thinking, experimental stress analysis employing photo-elastic methods and theoretical stress and strain analysis using a finite elements approach where the computational program utilises fast LaGrangian analysis of continua. The studies are providing results showing that, for given load proportions, the particular forms of some bones and bony architectural features seem related to stresses and strains that are relatively evenly distributed across surfaces (and therefore mechanically optimal). The results particularly show how apparently opposite (paradoxical) situations can readily occur within anatomical systems. They also provide strong biological information relevant to the assessment of such features of bone architecture in phylogenetic investigations. They even give information relevant to clinical problems.

Background: In terms of structure and function, the skull is one of the most complicated organs in the body. It is also one of the most important parts in terms of developmental and evolutionary origins. This complexity makes it difficult to obtain evolutionary assessments if, as is usually the case with fossils, only part of the skull is available. For this reason this study involves a set of comparisons whereby the smallest functional units are studied first, and these built up, through a triple-nested hierarchical design, into more complex anatomical regions and eventually into the skull-as-a-whole. This design has been applied to macaques (Macaca) in order to reveal patterns of variation at the different levels. The profiles of such variation have been obtained both within and between species. This has lead to a search for the skull parts that have undergone similar selection pressures during evolution and comparable development patterns in both ontogeny and phylogeny., Results: Morphometric analysis (Principal Components) was used to obtain these profiles of species and sex separations based on 77 cranial variables from 11 species of macaques. The results showed that 7 functional units could be aggregated into three functionally reasonable anatomical regions on the basis of similarities in profiles. These were: the masticatory apparatus containing mandible, lower teeth and upper teeth, the face as a whole combining maxilla (actually lower face) and upper face, and the cranium as a whole involving cranium and calvaria. Twenty-six variables were finally selected for analyzing the morphology of the whole skull. This last showed an overall profile similar to that revealed in the masticatory apparatus but also contained additional information pertaining to individual species and species-groups separations., Conclusions: The study provides a model for carrying out analysis of species separations and sex variation simultaneously. Through this design it seems possible to see cranio-dental elements that may result from similar developmental processes, have similar functional adaptations, and show an appropriately integrated structure morphologically. This study also implies that the biological information drawn from part of skull alone, e.g. as in studies of incomplete fossils may provide misleading information.

The internal architecture of the vertebral bodies spanning the levels T1 to L5 in seven male columns was studied using mammographic-resolution radiographs of 2.5-mm-thick planar parasagittal slices. The overlapping radiographic shadows of vertebral trabeculae combined in the image to form a series of 'elements', broadly representative of the cancellous structure. The orientations and sizes of these elements were analysed by applying the Fast Fourier transform (FFT) to the digitized radiographic images. Elements aligned in the 'vertical' orientation, along the long axis of the column, were the most prominent for all vertebral levels. The relative prominence of horizontal to vertical elements was generally constant along the column below T5. In contrast, the relative prominence of oblique to vertical elements declined in the cranio-caudal direction, particularly in individuals aged > or = 60 years. The ratio of 'large' (x > 0.3 mm) to 'small' (0.15 mm < or = x < or = 0.3 mm) elements was unchanged cranio-caudally in specimens < 60 years. However, in individuals > or = 60 years, large elements increased in relative prominence in the caudal direction. These results suggest that a basic orthogonal pattern of trabeculae is found along the male human spine, regardless of differences in vertebral body size. Power-spectral analysis is shown to yield information summarizing the predominant orientations and sizes of radiographically rendered architectural elements of vertebral cancellous bone, to define the effects of ageing on architecture, and to identify broad structural differences between vertebral levels in the adult male spine.

A suite of measurements was collected from the talus, calcaneus, navicular, and cuboid of humans from Southern China, Victorian Britain, Roman Britain, and Zulu tribes people from the Republic of South Africa. Univariate and multivariate statistical analyses of dimensions of individual foot bones revealed subtle but distinct patterns of morphological discrimination on the basis of sex and size on the one hand, and geographical relationships on the other. These differences are largely expressed in the first three canonical variates of the multivariate analyses: the first axis expresses both sex and size differences, and the second and third, geographical group differences. Confirmation of morphological patterns obtained from individual multivariate analyses was provided by an integrated analysis of the four tarsal elements together. However, the integrated analysis also gave larger separations with discriminations along different axes. Thus the three geographical groups (Zulus, Southern Chinese, and the two British groups together) were separated by first and third variates. The discrimination of sex and size differences was found in the second axis, mirroring what was found in the first axes of the individual studies. This axis reversal implies that in examining all bones together, there is enough redundant information about sex and size in each individual bone that they are relegated to a second axis. It likewise implies that the data referring to geographic discriminations provided by each individual bone are not redundant; they sum in the integrated analysis, and therefore contribute to the overall analysis to a greater extent, with increased clarity., (Copyright 2002 Wiley-Liss, Inc.)

The sizes of mammalian brain components seem to be mostly related to the sizes of the whole brain (and body), suggesting a one-dimensional scale of encephalization. Previous multivariate study of such data concludes that evolutionary selection for enlargement of any one brain part is constrained to selection for a concerted enlargement of the whole brain. However, interactions between structurally related pairs of brain parts confirm reports of differential change in brain nuclei, and imply mosaic rather than concerted evolution. Here we analyse a large number of variables simultaneously using multi-dimensional methods. We show that the relative proportions of different systems of functionally integrated brain structures vary independently between different mammalian orders, demonstrating separate evolutionary radiations in mammalian brain organization. Within each major order we identify clusters of unrelated species that occupy similar behavioural niches and have convergently evolved similar brain proportions. We conclude that within orders, mosaic brain organization is caused by selective adaptation, whereas between orders it suggests an interplay between selection and constraints.

In this paper we examine metamerism in the vertebral column of certain mammals from the perspectives of development and adaptation. To this end we examine the patterns of metameric variation of dimensions of the neural (vertebral) canal, vertebral body and spinous process in man and inbred strains of mice. The data from inbred strains of mice indicate that variability in dimensions within a strain reflects the temporal ordering and nature of developmental influences on vertebral morphogenesis. Differences between strains parallel the within-strain findings. These findings are attributed to somatic and neural influences on morphogenesis. Comparisons between mice and man indicate that these same influences can be invoked to explain and interpret the mosaic nature of vertebral column evolution. These findings lead us to conclude that different vertebral elements and levels are subject to different interactions of evolutionary and morphogenetic influences. The study of these influences and their interactions should prove fruitful in developing an understanding of the relationship between adaptation, development, growth and function in the skeleton generally.

The changes that occur in the normal human incus with age have been investigated. Evidence for age-related changes in this ossicle, especially in the region of the long process, has been accumulating over the last 30-40 years and yet they have neither been confirmed quantitatively nor explained satisfactorily. In this study the results of a morphometric study of the long processes of a series of normal incudes are presented. These demonstrate that the lenticular and long processes undergo progressive symmetric resorption with advancing age. We consider these findings in the light of previous considerations of incudal remodelling and propose that these remodelling changes may reflect a normal adaptive response to the biomechanical milieu of the human middle ear.

The combined use of architectural and stress technologies in osteological studies is starting to provide the basic biomechanical underpinnings to both evolutionary and applied medical investigations of bone. The architectural investigations, though tested using invasive methods, are aimed at non-invasive ways of obtaining information from radiographs of bones, fossils and people. They include optical (Fourier) data analysis (ODA) and computational Fourier transformations (FFT). The stress studies, though initially involving older techniques such as photoelastic stress analysis, now employ finite element analysis (FEA) and, most recently, fast Lagrangian analysis of continua (FLAC). Taken together, these methods are capable of providing more detailed knowledge of bone form and function that is important (a) in revealing functional adaptation in evolutionary studies of fossils and (b) for making early diagnosis and understanding pathological fractures in the late stages of osteoporosis.

The subgeneric relationships of savannah baboons have long been a point of contention among taxonomists. Recent documentation of morphological clines and evidence of interspecific hybridization have further complicated this problem. In this investigation, the dental dimensions of 443 savannah baboons, representing three of the generally recognized species, Papio anubis, P. cynocephalus, and P. ursinus, were analyzed using univariate and multivariate statistical procedures. A small number of possible P. ursinus/P. cynocephalus hybrids was included in the analysis. The results suggest that the three morphotypes are clearly distinct. Furthermore, the hybrid group possesses a dentition incorporating different elements of the two interbreeding species. However, these individuals are not simply intermediate but quite different. These findings, considered in conjunction with other morphological and distributional data, tend to warrant maintenance of the present specific distinctions., (Copyright © 1990 Wiley‐Liss, Inc., A Wiley Company.)

Although most studies emphasise the similarity of the australopithecines to modern man, and suggest, therefore, that these creatures were bipedal tool-makers at least one form of which (Australopithecus africanus--"Homo habilis", "Homo africanus") was almost directly ancestral to man, a series of multivariate statistical studies of various postcranial fragments suggests other conclusions. Their locomotion may not have been like that of modern man, and may, though including a form or forms of bipedality, have been different enough to allow marked abilities for climbing. Bipedality may have arisen more than once, the Australopithecinae displaying one or more experiments in bipedality that failed. The genus Homo may, in fact, be so ancient as to parallel entirely the genus Australopithecus thus denying the latter a direct place in the human lineage.

The pattern of overall dental dimensions in over 900 teeth of ramapithecines from Lufeng in China is examined using frequency distribution histograms and fitted normal curves, and compared with data for extant hominoids. A prior study has demonstrated unequivocally that at least two groups of animals must have existed at Lufeng [Wu and Oxnard, 1983; Oxnard, 1983a]. The present investigation confirms this finding in more detail. In addition it shows that one fossil group possesses smaller teeth with a lesser degree of sexual dimorphism and approximately equal numbers of adult males and females, and the other possesses larger teeth with a rather larger degree of sexual dimorphism and a female-male ratio that may have approximated from as low as 2:1 to as high as 4:1. Comparisons of patterns of difference along the tooth row demonstrate that both these forms differ from modern apes in their sexual dimorphism, the smaller form being more like humans than the larger, which is more like apes, especially orangutans. Comparisons of the areas of the canine teeth with each of the other functional segments of the tooth row again show that the smaller form is basically similar to modern humans and that the larger resembles extant great apes. Comparisons of other functional dental areas seem to relate to dietary and masticatory functions. Thus the cutting areas are large relative to the chewing areas in omnivorous humans, whereas in the essentially vegetarian great apes this ratio is smaller. The smaller fossil resembles the human condition and may have been somewhat omnivorous; the larger one more resembles the apes and may have been somewhat more vegetarian. However, these comparisons also show that the way in which the larger form resembles the apes is associated with special development of the canines, which is different from that in any modern ape. Comparisons show that the canines in the larger form project far beyond the normal line of tooth crowns. Finally, comparisons show that canine sexual dimorphism in height is marked in the larger form. Neither of these last two features is true of the smaller fossil. These findings have implications for our understanding of the evolution of early pongids and hominids, and for the evolution of primate sexual dimorphisms and dental mechanisms., (Copyright © 1983 Wiley‐Liss, Inc., A Wiley Company.)

Morphometric analysis of Professor A.H. Schultz's data on the overall proportions of primates reveals differences between the sexes. Univariate examinations of these data confirm the existence of the spectrum of sexual dimorphism already well known. This spectrum relates mainly to differences in the proportions of the trunk. It has a differential expression with largest differences between the sexes in species such as orangutans and boboons, and smallest in species such as spider monkeys and douroucoulis. Multivariate statistical study of these same data reveal, however, further unsuspected sexual dimorphisms. Although differences between the sexes are only small when measures of the relative lengths of bodily parts are examined, they are big when bodily breadths are studied. Investigation of breadths alone reveals that the primates display two major patterns of sexual dimorphisms and seven unique sexual dimorphisms among the 18 genera examined. Such findings mean that sexual dimorphism of bodily structure is not a single phenomenon with differential expression, a concept widely noted in the literature and most recently associated with social organization. There are several different sexual dimorphisms and this suggests that their causation is likely to be multifactorial with multiple complex interactions among the factors. Some of the sexual dimorphisms must have evolved in parallel a number of times, and, given that chimpanzees, gorillas, and humans each display a different sexual dimorphism, at least some of the evolutionary changes in different sexual dimorphisms must be very recent. The findings even imply the possibility of further unique patterns of sexual dimorphism in some fossils. By further extension, the findings may have some implications for our understanding of nonstructural dimorphisms in humans., (Copyright © 1983 Wiley‐Liss, Inc., A Wiley Company.)

Dental dimensions and distributions of dental dimensions of males and females were compared for great apes (Pan, Gorilla, and Pongo, and humans (Homo). The results were examined and discussed with reference to fossil primates Sivapithecus and Ramapithecus. The analyses focused on patterns of sexual dimorphism, both with regard to mean dimensions and the distribution of those dimensions. Sex differences in mean canine dimensions were large and significant for Gorilla and Pongo, significant but smaller for Pan, and small but occasionally significant for Homo. The dispersions of measures were greater for males than for females in Gorilla and Pan but did not differ significantly for Pongo or Homo. Examination of the noncanine teeth revealed complex sex differences. In the anterior teeth, sex differences in mean dimensions were generally apparent for Gorilla and Pongo, less so for Pan, and least of all in Homo. The patterns of dispersion of measures of anterior teeth differed markedly from those of the canines. Pan exhibited the same pattern for anterior and canine teeth. Gorilla showed the opposite pattern. Pongo and Homo showed similar dispersions for males and females in many cases. Sex differences in posterior teeth followed the pattern of the canines for Gorilla and were absent for Pan. Pongo exhibited mean differences in dimensions across sex, but dispersions were similar. The pattern for Homo was most like that of Pongo, but with fewer significant differences. The genera differed with regard to the number of significant differences in means or dispersions along the tooth row. It is clear that the patterns of dimorphism differ qualitatively across all extant genera of great apes and humans. It appears that the pattern for Homo most closely resembles that of Ramapithecus, whereas Pongo most closely resembles Sivapithecus. The patterns for Gorilla and Pan appear to be unlike either of the fossil forms. It is suggested that the qualitatively distinct patterns of dental sexual dimorphism indicate substantial flexibility during recent primate evolution and that the degree of structural flexibility demonstrated provides a basis for appreciating potential for plasticity of gender differences in behavioral, social, and cultural systems., (Copyright © 1985 Wiley‐Liss, Inc., A Wiley Company.)

Previous observations on twelve fossil foot bones (Olduvai 8: Day and Napier, '64) together with multivariate morphometric studies of one of them, the talus (Day and Wood, '68) suggested human-like bipedality for this foot. Subsequent studies showed the conclusions on the talus to be wrong: The fossil talus, as defined by eight measures, does not resemble that of man but is reminiscent of those of creatures known (extant--orangutans) or believed (extinct--some fossil apes and monkeys) to be arboreal in habitus (Oxnard '72; Lisowski, et al., '74, '76). A reassessment of the entire Olduvai 8 foot is therefore necessary to answer the problem posed by a foot that has a non-human talus with, apparently, a human arched pattern of the remaining tarsal and metatarsal bones. The dry bones of a series of feet of extant hominoids have been rearticulated and are found to be close to the actual relationships presented by dissected specimens in which ligaments, articular cartilages and soft tissues are present. Similar rearticulation applied to casts of the individual Olduvai foot bones produces a structure that is not arched in the same manner as the human foot; it displays features that ally it more closely with the feet of various apes. Sections of casts of the already rearticulated Olduvai foot (from both the Wenner Gren Foundation and the Kenya National Museums) show that the human-like appearance of the original rearticulation is due to a series of incorrect osteological alignments. Although casts do not permit study of surface features, the dimensions of the casts are sufficiently accurate to permit rearticulation in this manner. It is thus clear, a) that the Olduvai foot is not adated for bipedality in the manner of man, and b) that it displays features in which it resembles the feet of arboreal creatures. Such anatomical characters as relate to bipedality in the fossil suggest usage as in an arboreal species that also walks bipedally with flattened arches (like a chimpanzee or gorilla) rather than with the high arches of man.

Data obtained from ramapithecine specimens found in Asia, Africa and Europe have suggested the existence of two major subgroups, Ramapithecus and Sivapithecus, with Ramapithecus having pre-human status. Recently, however, it has been proposed that the fossils all belong to a single group, Sivapithecus, which is more closely related to the apes, in particular the orang-utan. Here we analyse data from a series of similar fossils which have been found in late Miocene coalfields in Lufeng, Yunnan Province, China. These include a number of almost complete jaws and five partial skulls which are more complete than any others so far known. A statistical analysis of the overall dimensions of the large number of teeth included in these finds shows that the differences between the groups previously assigned to Ramapithecus and Sivapithecus are greater than those found between the sexes in the most sexually dimorphic of the living great apes. Within the groups the distribution is bimodal and we suggest each group contains sex subgroups.

A recent discussion by Corruccini and Ciochon ('76) implies that previous multivariate morphometric studies of the shoulder, reviewed in Oxnard ('73), have been misinterpreted because due allowance was not made for the overall sizes of the specimens. Results that were given functional significance in the earlier investigations are cited as being due at least in part to overall bodily size. Although examination of the range of genera selected for mention by corruccini and Ciochon seems superficially to support this view, it is demonstrated here that examination of the full range of genera in the earlier studies refutes, unequivocally, that suggestion. The discussion by Corruccini and Ciochon ('76) also implies that the more complex size correction applied in their study produces a result different from that of the previous workers. Again, although perusal of the particular part of the earlier study selected for discussion by Corruccini and Ciochon would appear to bear that out, it is demonstrated here that comparisons with all parts of the earlier results provide a different picture. Thus the main result of Corruccini and Ciochon replicates rather closely a more restricted part of the earlier result not mentioned by Corruccini and Ciochon. The difference between Corruccini and Ciochon's principal result and the main result of the prior authors is shown to rest upon the difference between the more restricted earlier study of "residual" shoulder dimensions and the other broader studies; i.e., not upon any multivariate manipulation, but upon the inclusion in the broader study of a wider range of information about the shape of the primate shoulder. Knowledge of these and other points is important in assessing the overall contribution of the discussion of Corruccini and Ciochon.

Locomotor morphology, it is recognized, cannot be understood without an understanding of locomotor behavior. The interaction of locomotor anatomy and behavior has been successfully analyzed for single species and species pairs. Broader generalizations, however, require the demonstration of anatomical/behavioral associations for numerous sets of species. To accomplish this it is necessary to develop a method for the simultaneous quantitative description and comparison of many different parameters of the locomotor niche: locomotor behaviors, habitat usages, and diets. As a start towards achieving this we present a multidimensional approach to the description of functional parameters of the niche for prosimians. We derive quantitative evaluations of locomotor activity, habitat utilization, and diet for each of 27 species, using field data, film and video records, and the available literature. These parameters are then displayed graphically and clustered to provide profiles for comparisons both of species and variables. The multidimensional profiles reveal valuable information about activity, environment and diet, and their interactions. They permit closer comparisons with equivalent multidimensional information about prosimian structure, based on morphometric studies. The method gives useful graphical and statistical techniques for interspecific comparisons of morphometrics and niche metrics.