The reliability of osteometric techniques for the sex determination of burned human skeletal remains

The influence of heat-induced shrinkage on the osteometric sexual dimorphism of human skeletons is still poorly known. In order to investigate this issue, a sample composed of 84 Portuguese individuals cremated at a modern crematorium was examined using standard measurements from the femur, the talus and the calcaneus. In addition, sex determination of the sample was attempted by using osteometric standards developed from the Coimbra collection of identified skeletons. This was carried out to assess the extent of the effect of heat-induced shrinkage on the correct classification of known-sex skeletons while using standards developed on unburned skeletons.Results demonstrated that sexual dimorphism was still observable in the sample of calcined bones despite shrinkage. However, the application of conventional osteometric standards was unsuccessful. As expected, shrinkage caused most females to be correctly classified according to sex, but the sex allocation of males was very poor for all standard measurements.The results were obtained on a small sample but suggest that univariate metric techniques specifically developed for calcined bones may be valuable for sex determination. This would bring new methodological possibilities for biological anthropology and would enlarge the set of techniques regarding sex determination of burned skeletal remains.     

Temporal trends in femoral diaphyseal torsional asymmetry among the Arikara associated with postural behavior

Average femoral torsion has been reported to differ among populations, and several studies have observed a relatively high prevalence of femoral anteversion asymmetry in Native Americans, especially females. This study investigates sexual dimorphism and temporal trends in femoral torsional asymmetry among the Arikara from the seventeenth to the early nineteenth century. To establish if there are population differences, femoral torsion was first measured using a direct method on a diverse comparative sample of Native Americans from the Southwest, Midwest, and Great Plains as well as American Whites and Blacks. To examine temporal trends among the Arikara, femoral torsion was examined using the orientation of the maximum bending rigidity at subtrochanteric in 154 females and 164 males from three temporal variants of the Arikara Coalescent tradition. There is significant sexual dimorphism in femoral torsional directional and absolute asymmetry among most Native American samples, but not among American Whites and Blacks. Among the Arikara there is significant sexual dimorphism in femoral torsional asymmetry in all three temporal variants, and asymmetry in femoral torsional asymmetry increased significantly from the protohistoric to the early historic period among females. The increased femoral torsional asymmetry is likely associated with a common side‐sitting posture observed in historic photographs of Great Plains females. Historic Arikara females may have habitually sat in this compulsory position for extended periods while conducting domestic chores. The dramatic change from the protohistoric to historic period suggests a cultural change in sitting posture among females that was widespread across the Northern Plains. Am J Phys Anthropol 154:512–524, 2014. © 2014 Wiley Periodicals, Inc.     

Odontometric profile of a prehistoric southeastern Florida population

This study analyzes and compares the dental size variation and sexual dimorphism of the Highland Beach Mound people, a late southeastern prehistoric aboriginal Florida population (ca. 800-1200 AD) with a somewhat earlier midwestern group (ca. 200-800 AD) and an Archaic sample (ca. 4160-2558 BC). The lengths and breadths of maxillary and mandibular permanent teeth of 99 individuals were measured, and crown surface areas were calculated for the molars. Results indicated that there was little sexual dimorphism. Only the mesiodistal dimensions of the upper P2 and lower C were significantly different at the P less than 0.05 level. In terms of dental size, what appears to be a chronologically based reduction in most points of comparison was seen in all three groups, with the exception of the molars, which were larger in the Highland Beach sample than in the earlier Schultz Mound.     

Bootstrap tests of significance and the case for humanlike skeletal-size dimorphism in Australopithecus afarensis

Most estimates of sexual size dimorphism in Australopithecus afarensis indicate that this early hominin was more dimorphic than modern humans. In contrast, a recent study reported that size variation in A. afarensis, as represented by postcranial remains from Hadar and Maka, Ethiopia, is statistically most similar to that of modern humans, indicating a humanlike level of sexual dimorphism. Here, we evaluate the evidence for humanlike dimorphism in A. afarensis. We argue that statistical support for this claim is not as robust as has been asserted for the following reasons: (1) the analysis from which the claim was derived does not distinguish the A. afarensis sample from either the human or chimpanzee samples; (2) for some of the comparisons made, the A. afarensis sample cannot be distinguished from the Gorilla sample using two-tailed tests; and (3) the A. afarensis postcranial sample used in the analysis may contain more male than female specimens, which precludes a straightforward interpretation of the statistical results. Thus, support for humanlike dimorphism is equivocal, and a greater level of dimorphism cannot be ruled out.     

Sexual dimorphism of the human corpus callosum from three independent samples: Relative size of the corpus callosum

Three independent autopsy samples of brains without apparent neuropathology were studied to ascertain whether there was sexual dimorphism in the human corpus callosum (CC). Using planimetric measurements on midsagittal brain sections, several morphometric features of the CC were studied: total callosal area, maximum dorsoventral splenial width, the posterior one fifth of the total area of the CC (mostly splenium), and brain weight. Ratio data correcting for brain size were also studied. In all samples, absolute brain size was larger in males, and significantly so. Measurements of splenial dorsoventral width were higher in females than males, but not significantly, except in the Australian sample. Total callosal area was absolutely higher in the Australian female sample than in males, and almost equal in the two American samples, without statistically significant differences. The posterior one-fifth area (splenium) was larger for females in each of the samples. The variables which were corrected for brain size were usually significantly larger in females, although this pattern varied in each sample. The statistical pattern of sexual dimorphism for the human CC differs from that found in most other neural structures, such as the amygdaloid nucleus, cerebellum, hippocampus, and thalamus. The absolute sizes of these structures are always significantly larger in males. When corrected for brain size, the relative sizes are not significantly larger. The CC is the only structure to show a larger set of relative measures in females. © 1993 Wiley-Liss, Inc.     

Changes in the sexual dimorphism of the human mandible during the last 1200 years in Central Europe

According to many investigations, changes in mandibular morphology can occur synchronously with changes in the environment, and sexual dimorphism of the mandible can be influenced by the environment. Sexual dimorphism during the last 1200 years was evaluated using geometric morphometric analysis of virtual cranial models. The method of geometric morphometrics allows differences in size and shape to be assessed separately. We analyzed groups of adult individuals dating to Early Middle Ages, High Middle Ages, Early Modern Ages and from a modern Czech population (21st century). Significant sexual dimorphism in mandibular size was found in all populations. A trend in the sexual dimorphism of size was seen, with differences between the sexes increasing gradually over time. Size changes in female mandibles were a better reflection of environmental conditions and climate than size changes in male mandibles. Regarding changes in the sexual dimorphism of shape, significant dimorphism was found in all four samples. However, the pattern of mandibular shape dimorphism was different and varied considerably between samples. There was only one stable shape trait showing sexual dimorphism across all four samples in our study: the gonion lies more laterally in male than in female mandibles and male mandibles are relatively wider than female mandibles. Sexual dimorphism of shape is not influenced by the climate; instead sexual selection might play a role. This research supports earlier studies that have found that the degree and pattern of sexual dimorphism is population-specific and the factors regulating sexual dimorphism today may not be the same as those in the past.     

Metric variation and sexual dimorphism in the dentition of Ouranopithecus macedoniensis

The fossil sample attributed to the late Miocene hominoid taxon Ouranopithecus macedoniensis is characterized by a high degree of dental metric variation. As a result, some researchers support a multiple-species taxonomy for this sample. Other researchers do not think that the sample variation is too great to be accommodated within one species. This study examines variation and sexual dimorphism in mandibular canine and postcanine dental metrics of an Ouranopithecus sample. Bootstrapping (resampling with replacement) of extant hominoid dental metric data is performed to test the hypothesis that the coefficients of variation (CV) and the indices of sexual dimorphism (ISD) of the fossil sample are not significantly different from those of modern great apes. Variation and sexual dimorphism in Ouranopithecus M(1) dimensions were statistically different from those of all extant ape samples; however, most of the dental metrics of Ouranopithecus were neither more variable nor more sexually dimorphic than those of Gorilla and Pongo. Similarly high levels of mandibular molar variation are known to characterize other fossil hominoid species. The Ouranopithecus specimens are morphologically homogeneous and it is probable that all but one specimen included in this study are from a single population. It is unlikely that the sample includes specimens of two sympatric large-bodied hominoid species. For these reasons, a single-species hypothesis is not rejected for the Ouranopithecus macedoniensis material. Correlations between mandibular first molar tooth size dimorphism and body size dimorphism indicate that O. macedoniensis and other extinct hominoids were more sexually size dimorphic than any living great apes, which suggests that social behaviors and life history profiles of these species may have been different from those of living species.     

Effect of mobility on femur midshaft external shape and robusticity

This study investigates differences in femur midshaft shape, robusticity, and sexual dimorphism derived from external measurements between a broad range of prehistoric and historic North American populations with different subsistence strategies and inferred levels of mobility. The sample was divided into six groups to test whether observed femur midshaft variables follow the patterns predicted based on archaeologically and historically determined subsistence and mobility data. The results suggest significant variation in femur midshaft shape and robusticity in all populations, and that inferred mobility levels do not correspond consistently with femur midshaft structure in either males or females. Results do, however, support the prediction that sexual dimorphism is generally greater in more mobile populations.     

Finite Element Analysis of Foot and Ankle Impact Injury: Risk Evaluation of Calcaneus and Talus Fracture

IntroductionFoot and ankle impact injury is common in geriatric trauma and often leads to fracture of rearfoot, including calcaneus and talus. The objective of this study was to assess the influence of foot impact on the risk of calcaneus and talus fracture via finite element analysis.MethodsA three-dimensional finite element model of foot and ankle was constructed based on magnetic resonance images of a female aged 28. The foot sustained a 7-kg passive impact through a foot plate. The simulated impact velocities were from 2.0 to 7.0 m/s with 1.0 m/s interval.ResultsAt 5.0 m/s impact velocity, the maximum von Mises stress of the trabecular calcaneus and talus were 3.21MPa and 2.41MPa respectively, while that of the Tresca stress were 3.46MPa and 2.55MPa. About 94% and 84% of the trabecular calcaneus and talus exceeded the shear yielding stress, while 21.7% and 18.3% yielded the compressive stress. The peak stresses were distributed around the talocalcaneal articulation and the calcaneal tuberosity inferiorly, which corresponded to the common fracture sites.ConclusionsThe prediction in this study showed that axial compressive impact at 5.0 m/s could produce considerable yielding of trabecular bone in both calcaneus and talus, dominantly by shear and compounded with compression that predispose the rearfoot in the risk of fracture. This study suggested the injury pattern and fracture mode of high energy trauma that provides insights in injury prevention and fracture management.     

Sexual differences in European Neanderthal crania with special reference to the Krapina remains

Problems relating to the identification of sex in Neanderthal specimens are discussed. Three morphological features—morphology of the mastoid process and surrounding area, form of the supraorbital torus at glabella and the superciliary region, and the rugosity of the nuchal plane—were selected as most indicative of sex in Neanderthal crania based on observations from the Krapina collection and on those European specimens with pelvicly determined sex. Thirteen Neanderthal crania (eight males, five females) are sexed on the basis of these criteria, and the pattern and degree of sexual dimorphism determined for this sample is compared to those exhibited by other samples of more recent European hominids. It is concluded that the degree of sexual dimorphism in Neanderthal crania, as defined by this study, is consistent with that observed in the other fossil samples and that Neanderthals exhibit slightly more cranial sexual dimorphism than more recent Europeans. Models for explaining this are discussed as is the difference in pattern of change and degree of sexual dimorphism between the cranium and postcranium during later prehistoric hominid evolution in Europe.     

Odontometric variation among American black, European, and Mongoloid populations

Quantified dental parameters (including root and pulp areas and shape variables) derived from periapical radiographs were used to make comparisons among a sample of American Black (8 males--124 teeth, 9 females--138 teeth), European derivative (31 males--304 teeth, 43 females--497 teeth) and Mongoloid populations (12 males--166 teeth, 19 females--252 teeth). The magnitude of sexual dimorphism within each ethnic stock was also examined. Teeth from American Black males were robust. Sexual dimorphism was unambiguous in all groups although a hierarchical order existed from the highly dichotomous American Black sample to the more homogeneous European sample. The female dental phenotype was down-scaled from their male counterparts, but not gracile in form. Easily obtained area and shape parameters derived from dental radiographs proved useful as discriminators among racial groups and the sexes. The relationships among these data lend further support to the hypothesis of an African origin of modern humans.     

Sexual dimorphism in the Atapuerca-SH hominids: the evidence from the mandibles

The pattern of sexual dimorphism in 15 mandibles from the Atapuerca-SH Middle Pleistocene site, attributed to Homo heidelbergensis, is explored. Two modern human samples of known sex are used as a baseline for establishing sexing criteria. The mandible was divided for analysis into seven study regions and differential expression of sexual dimorphism in these regions is analysed. A total of 40 continuous and 32 discrete variables were scored on the mandibles. The means method given in Regh & Leigh (Am. J. phys. Anthrop.110, 95-104, 1999) was followed for evaluating the potential of correct sex attribution for each variable.On average, the mandibles from the Atapuerca-SH site present a degree of sexual dimorphism about eight points higher than in H. sapiens samples. However, mandibular anatomy of the European Middle Pleistocene hominid records sexual dimorphism differentially. Different areas of the Atapuerca-SH mandibles exhibit quite distinct degrees of sexual dimorphism. For instance, variables of the alveolar arcade present very low or practically no sexual dimorphism. Variables related to overall size of the mandible and symphysis region present a medium degree of sex differences. Finally, ramus height, and gonion and coronoid process present a high degree of sexual dimorphism (indexes of sexual dimorphism are all above 130%). Whether this marked sexual dimorphism in specific anatomical systems affects sexual differences in body size is not completely clear and further studies are needed.Sexual differences detected in the mandible of modern humans have at least two components: differences related to musculo-skeletal development and differences related to a different growth trajectory in males and females (relative development of some of the basal border features). The Atapuerca-SH mandibles display little variation in the basal border, however. The limited variation of this mandibular region may indicate that the pattern of sexual variation in H. heidelbergensis is different enough to that of H. sapiens to caution against simple extrapolation of criteria from one pattern to the other.     

Skeletal indicators of subsistence patterns and activity régime in the Mesolithic sample from Grotta dell’Uzzo (Trapani,Sicily): a case study

The skeletal sample from Grotta dell’Uzzo, Sicily (2 adult females and 5 adult males) was compared to a number of more representative population samples from Western Europe and the Mediterranean Basin. The majority of these were from Italian pre- and protohistoric sites. The research protocol analyzed skeletal indicators of labour activity and sexual division of labour (body size and proportions, sexual dimorphism, limb lateralization, bone robustness, the development of muscular attachments, accessory articular facets, signs of muscular hyperfunction). Sexual dimorphism and limb lateralization showed some regular patterns of possible general significance in all the samples examined here. A general pattern of gracilization and de-specialization of physical activity is observed in the Mesolithic as compared to the Upper Palaeolithic samples. The main features of the Mesolithic samples are: a reduction of body size and bone robustness, a lower degree of sexual dimorphism and limb bone asymmetry, a reduction of the mechanical stress on the lower limbs indicated by less pronounced muscular attachments and reduced talar flattening. This trend is reversed towards the Neolithic period. The main features of these variations are discussed in relation to economic and environmental changes. The Uzzo sample fits well into the general picture of the Western European Mesolithic, although showing some intermediate features between the Mesolithic and the Neolithic samples. This paper is dedicated to the memory of the late Roland Menk, who made significant contribution to our understanding of the Mesolithic transition.     

Growth patterns in the modern human skeleton

This study investigates cross sectional growth patterns in the human skeleton using a recent skeletal sample of known age and sex. Measurements were selected to reflect different functional regions of the cranium, mandible and post cranial skeleton, and growth is evaluated using a single phase Gompertz curve. Different parts of the skeleton vary in the proportion of adult size attained at birth and in their subsequent rate of attainment of adult size. The paper introduces a method for the objective and quantitative comparison of the growth of different samples, and is used in this instance to analyze sexual differences in the growth of the post cranial skeleton. The development of sexual dimorphism is evaluated in terms of differences in the rate and duration of male and female growth. Adult sexual dimorphism is generally lower in early growing variables than in later-growing variables. There is considerable diversity in the ontogenetic basis of sexual dimorphism in the human skeleton demonstrating that the development of sexual dimorphism within a species should not be regarded as a uniform phenomenon. Am J Phys Anthropol 105:57–72, 1998. © 1998 Wiley-Liss, Inc.     

Degree of pelvic sexual dimorphism in human populations. A greene t-test application

The knowledge of sexual dimorphisms is important in many aspects of paleodemography and paleobiology. One major problem lies in a correct sexual diagnosis. However, due to the different methodologies employed to estimate the degree of sexual dimorphism, the comparison of the results remains difficult. The Greene t-test (1989) is accurate for a comparative analysis of raw data. On the basis of 18 measurements of theos coxae the test is made to evaluate the degree of sexual dimorphism. The data collected are employed to investigate the pelvic sexual dimorphism within a recent sample of known sex, and among the Afalou-bou Rhummel — Taforalt (Epipaleolithic of Northern Africa) and the Teviec — Hoedic samples (Mesolithic of France). A comparative analysis is applied to a few recent samples. The results indicate the stability of sexual dimorphism pattern in recent and past populations.     

Patterns of size sexual dimorphism in Australopithecus afarensis: Another look

Size sexual dimorphism is one of the major components of morphological variation and has been associated with socioecology and behavioral variables such as mating patterns. Although several studies have addressed the magnitude and pattern of sexual dimorphism in Australopithecus afarensis, one of the earliest hominids, consensus has yet to be reached. This paper uses assigned resampling method, a data resampling method to estimate the magnitude of sexual dimorphism without relying on individual sex assessments, to examine the fossil hominid sample from Hadar. Two questions are asked: first, whether sexual dimorphism in a selected sample of skeletal elements of A. afarensis is the same as that in living humans, chimpanzees, or gorillas; and second, whether different skeletal elements reflect variation in sexual dimorphism in the same way. All possible metric variables were used as data in applying the method, including seven variables from three elements (mandibular canine, humerus, femur). Analyses show that A. afarensis is similar in size sexual dimorphism to gorillas in femoral variables, to humans in humeral variables, and to chimpanzees in canine variables. The results of this study are compatible with the hypothesis that the pattern of sexual dimorphism in A. afarensis is different from any that are observed in living humans or apes.     

Methodological considerations on the study of sexual dimorphism in past human populations

The degree of sexual dimorphism in human populations is influenced by stress, social role and by labour division. However, studies on ethnographic populations provided contradictory results. Unfortunately, most of these studies were based on stature only, which, as we could observe in a survey on pre-protohistoric circum-Medirerranean samples, is a poor indicator of functionally related dimorphism. A number of skeletal measurements were examined: skull, stature, transverse trunk diameters, long bones length, circumference and section, in order to assess their usefulness as indicators of functionally related dimorphism. The best indicators were represented by section and circumference of the long bones of the limbs, followed by cross-shoulder breadth (biclavicular length), stature and limb bone length, facial measurements, cranial measurements and sacral breadth. From the methodological point of view, it was found that:

1. It is better to calculate the index of dimorphism for each trait or set of traits within each sample. Then a weighted average of all the available samples is taken. The index derived from pooling a number of samples does not make biological sense. In pooled samples the distinction of between versus within sample differences is obscured;
2. It is better to combine an index which is based on the difference between averages and one which takes variability into account, because variability can also be an aspect of sexual dimorphism;
3. It is better to apply some allometric correction to the measurements used. For instance, the log transformation produces clearer trends of differential dimorphism among the various traits.

     

Sexual dimorphism of the dental tissues in human permanent mandibular canines and third premolars

Methods of measuring tissue area from images of longitudinal thin tooth sections have been used to assess sexual dimorphism in the permanent dentition. The aim of this study was to demonstrate the extent of sexual dimorphism within the coronal tissue proportions of permanent mandibular canines and premolars, using area measurements of the enamel and dentine-pulp core. The sample consisted of embedded "half-tooth" sections from 45 individuals, all of known age-at-death and sex, collected from the St. Thomas' Anglican Church historic (1821-1874) cemetery site in Belleville, ON, Canada. The relative dentine-pulp area of the third premolars and canines displayed high levels of sexual dimorphism, as well as statistically significant mean differences between the sexes. The male canines and premolars have significantly more dentine than their female counterparts, as well as relatively more dentine with respect to overall crown size. The female canines and premolars have significantly more enamel relative to overall crown area than those of the males. These results suggest that relative area measures of crown tissues are more predictable measures of sexual dimorphism than absolute measures, and tissue proportions may remain constant despite intrasex variation in overall tooth crown size.     

A Lack of Sexual Dimorphism in Width-to-Height Ratio in White European Faces Using 2D Photographs, 3D Scans, and Anthropometry

Facial width-to-height ratio has received a great deal of attention in recent research. Evidence from human skulls suggests that males have a larger relative facial width than females, and that this sexual dimorphism is an honest signal of masculinity, aggression, and related traits. However, evidence that this measure is sexually dimorphic in faces, rather than skulls, is surprisingly weak. We therefore investigated facial width-to-height ratio in three White European samples using three different methods of measurement: 2D photographs, 3D scans, and anthropometry. By measuring the same individuals with multiple methods, we demonstrated high agreement across all measures. However, we found no evidence of sexual dimorphism in the face. In our third study, we also found a link between facial width-to-height ratio and body mass index for both males and females, although this relationship did not account for the lack of dimorphism in our sample. While we showed sufficient power to detect differences between male and female width-to-height ratio, our results failed to support the general hypothesis of sexual dimorphism in the face.     

Cortical bone remodeling rates in a sample of African American and European American descent groups from the American Midwest: comparisons of age and sex in ribs

This study employs regression analysis to explore population and sex differences in the pattern of age-associated bone loss, as reflected by histomorphometric variables that are measures of intracortical and endocortical bone remodeling. A comparison of an African American sample from the Washington Park Cemetery in St. Louis, Missouri, and a European American rib sample composed of cadavers, autopsies, and forensic cases from Missouri reveals the existence of complex age-associated patterns for differences in measures of intracortical remodeling and cortical area. Females from the two samples express similar bone dimensions and dynamics. The African American females appear to lose more bone than their male counterparts, but this difference is absent in the European American sample. When age-associated patterns are considered, it is in the younger cohorts that African Americans exhibit greater relative cortical area than European Americans, but this is reversed in the older ages, when the latter group manifests greater bone mass. The European American males consistently differ in the slopes and intercepts for the variables compared to the other groups, and differences are highly significant with African American females, with the former group maintaining bone mass while the latter exhibit a more rapid bone loss. Achieving larger relative cortical area due to smaller endosteal area, coupled with better bone quality due to lower intracortical porosity early in life, may be a mechanism by which African Americans, especially females, maintain adequate bone mass in older ages, which buffers them from bone loss and related fragility fractures despite higher rates of intracortical remodeling and endosteal expansion later in life. These results suggest that both genetic and environmental factors are responsible for the differences in bone remodeling and bone mass observed between these samples.