Postcranial Measurements Research Articles

Postcranial sex estimation criteria for Mexican Hispanics.

Population-specific reference data are necessary for sex estimation in forensic anthropological practice. Currently, there are no population-specific data for Hispanics equivalent to data available for American Blacks and Whites. Individuals of Mexican origin represent the largest group of Hispanics in the United States (Spradley and Jantz. 2011. J Forensic Sci;56:289). This paper presents new population-specific sex estimation criteria for postcranial measurements for Mexican Hispanics. Metric data come from positively identified border-crossing fatalities at the Pima County Office of the Medical Examiner and documented cemetery collections curated at Universidad Nacional Autónoma de México and Universidad Autónoma de Yucatán. Stepwise variable selection procedures and discriminant function analyses were utilized to generate classification functions for postcrania. Sectioning points were also created for select measurements. Both the cross-validated classification rates and sectioning points achieved accuracy rates as high as 95% and 92%, respectively. These new criteria will improve sex estimation for US Mexico border crossers and Hispanics in the US.

Sexual dimorphism in human cranial trait scores: Effects of population, age, and body size

Sex estimation from the skull is commonly performed by physical and forensic anthropologists using a five-trait scoring system developed by Walker. Despite the popularity of this method, validation studies evaluating its accuracy across a variety of samples are lacking. Furthermore, it remains unclear what other intrinsic or extrinsic variables are related to the expression of these traits. In this study, cranial trait scores and postcranial measurements were collected from four diverse population groups (U.S. Whites, U.S. Blacks, medieval Nubians, and Arikara Native Americans) following Walker's protocols (total n = 499). Univariate and multivariate analyses were utilized to evaluate the accuracy of these traits in sex estimation, and to test for the effects of population, age, and body size on trait expressions. Results revealed significant effects of population on all trait scores. Sample-specific correct sex classification rates ranged from 74% to 94%, with an overall accuracy of 85% for the pooled sample. Classification performance varied among the traits (best for glabella and mastoid scores and worst for nuchal scores). Furthermore, correlations between traits were weak or nonsignificant, suggesting that different factors may influence individual traits. Some traits displayed correlations with age and/or postcranial size that were significant but weak, and within-population analyses did not reveal any consistent relationships between these traits across all groups. These results indicate that neither age nor body size plays a large role in trait expression, and thus does not need to be incorporated into sex estimation methods.

How large are the extinct giant insular rodents? New body mass estimations from teeth and bones

The island rule entails a modification of the body size of insular mammals, a character related with numerous biological and ecological variables. From the Miocene to human colonization (Holocene), Mediterranean and Canary Islands were unaltered natural ecosystems, with paleofaunas formed with endemic giant rodents among other mammals. Our aim is to create methods to estimate the body masses of fossil island rodents and address the nature of ecological pressures driving the island rule. We created regression equations based on extant rodent data and used these to estimate the body masses of the extinct species. Our results show strong correlations between teeth, cranial and postcranial measurements and body mass, except for the length of the long bones, the transversal diameter of the distal tibia and the anteroposterior diameter of the proximal tibia, where the equations were less reliable. The use of equations obtained from a more homogeneous group (suborder and family) is preferable when analyzing the area of the first molar. The new regressions were applied to estimate the body masses of some Mediterranean and Canarian fossil rodents (Canariomys, C. bravoi 1.5 kg and C. tamarani 1 kg; Hypnomys, H. morpheus 230 g and H. onicensis 200 g; and Muscardinus cyclopeus 100 g). Our results indicate that under absence of predation, resource availability (island area) is the key factor that determines the size of the Canariomys sp. However, under presence of specialized predators (birds of prey), body size evolution is less pronounced (Hypnomys sp.).

Determination of individual's height by post-cranial measurements in Rewa region of Madhya Pradesh

Background: Stature estimation of an individual is an important in anthropological research. The identification of isolated extremities is an issue of great significance and plays a vital role in the investigation of the identity of victims of mass disasters and fatal assaults. Aims & Objectives: To determine individual’s height by post-cranial measurements in Rewa region of Madhya Pradesh. Materials and Methods: Present study is carried out in the Shyam Shah Medical College and S.G. Hospital, at Rewa city of Madhyapradesh. For this study, total 313 subjects were selected randomly which includes 194 males and 119 females, age between 22 to 27 years. Stature, shoulder breadth or biacromial breadth (a-a) Inter anterior superior iliac spine distance. (Inter asis distance) were measured using standard anthropometric instruments. Statistical analysis is done by using test of significance. Correlation, correlation co-efficient and regression equations for estimation of height is derived for males and females separately. Results: Results shows that individual’s height is extremely significantly correlated with biacromion breadth and very significantly correlated with inter anterior superior iliac spine distance. Conclusion: It is clear that if either of the measurement is known the other can be calculated and this fact may be of practical use in Medico-legal investigations and in Anthropometry.

Postcranial Sex Estimation of Individuals Considered Hispanic

When forensic anthropologists estimate the sex of Hispanic skeletal remains using nonpopulation specific metric methods, initial observations cause males to frequently misclassify as female. To help improve these methods, this research uses postcranial measurements from United States-Mexico border migrant fatalities at the Pima County Office of the Medical Examiner in Tucson, Arizona, as well as Hispanic individuals from the Forensic Anthropology Data Bank. Using a total of 114 males and 28 females, sectioning points and discriminant functions provide classification rates as high as 89.43% for Hispanic individuals. A test sample assessed the reliability of these techniques resulting in accuracy up to 99.65%. The clavicle maximum length measurement provides the best univariate estimate of sex, while the radius provides the best multivariate estimated of sex. The results of this research highlight the need for population specific data in the creation of a biological profile, especially when working with individuals considered Hispanic.

Postcranial morphology and the locomotor habits of living and extinct carnivorans

Members of the order Carnivora display a broad range of locomotor habits, including cursorial, scansorial, arboreal, semiaquatic, aquatic, and semifossorial species from multiple families. Ecomorphological analyses from osteological measurements have been used successfully in prior studies of carnivorans and rodents to accurately infer the locomotor habits of extinct species. This study uses 20 postcranial measurements that have been shown to be effective indicators of locomotor habits in rodents and incorporates an extensive sample of over 300 individuals from more than 100 living carnivoran species. We performed statistical analyses, including analysis of variance (ANOVA) and stepwise discriminant function analysis, using a set of 16 functional indices (ratios). Our ANOVA results reveal consistent differences in postcranial skeletal morphology among locomotor groups. Cursorial species display distal elongation of the limbs, gracile limb elements, and relatively narrow humeral and femoral epicondyles. Aquatic and semiaquatic species display relatively robust, shortened femora and elongate metatarsals. Semifossorial species display relatively short, robust limbs with enlarged muscular attachment sites and elongate claws. Both semiaquatic and semifossorial species have relatively elongate olecranon process of the ulna and enlarged humeral and femoral epicondyles. Terrestrial, scansorial, and arboreal species are characterized by having primarily intermediate features, but arboreal species do show relatively elongate manual digits. Morphological indices effectively discriminate locomotor groups, with cursorial and arboreal species more accurately classified than terrestrial, scansorial, or semiaquatic species. Both within and between families, species with similar locomotor habits converge toward similar postcranial morphology despite their independent evolutionary histories. The discriminant analysis worked particularly well to correctly classify members of the Canidae, but not as well for members of the Mustelidae or Ursidae. Results are used to infer the locomotor habits of extinct carnivorans, including members of several extinct families, and also 12 species from the Pleistocene of Rancho La Brea.

Limb-Bone Scaling Indicates Diverse Stance and Gait in Quadrupedal Ornithischian Dinosaurs

BackgroundThe most primitive ornithischian dinosaurs were small bipeds, but quadrupedality evolved three times independently in the clade. The transition to quadrupedality from bipedal ancestors is rare in the history of terrestrial vertebrate evolution, and extant analogues do not exist. Constraints imposed on quadrupedal ornithischians by their ancestral bipedal bauplan remain unexplored, and consequently, debate continues about their stance and gait. For example, it has been proposed that some ornithischians could run, while others consider that none were cursorial.Methodology/Principal FindingsDrawing on biomechanical concepts of limb bone scaling and locomotor theory developed for extant taxa, we use the largest dataset of ornithischian postcranial measurements so far compiled to examine stance and gait in quadrupedal ornithischians. Differences in femoral midshaft eccentricity in hadrosaurs and ceratopsids may indicate that hadrosaurs placed their feet on the midline during locomotion, while ceratopsids placed their feet more laterally, under the hips. More robust humeri in the largest ceratopsids relative to smaller taxa may be due to positive allometry in skull size with body mass in ceratopsids, while slender humeri in the largest stegosaurs may be the result of differences in dermal armor distribution within the clade. Hadrosaurs are found to display the most cursorial morphologies of the quadrupedal ornithischian cades, indicating higher locomotor performance than in ceratopsids and thyreophorans.Conclusions/SignificanceLimb bone scaling indicates that a previously unrealised diversity of stances and gaits were employed by quadrupedal ornithischians despite apparent convergence in limb morphology. Grouping quadrupedal ornithischians together as a single functional group hides this disparity. Differences in limb proportions and scaling are likely due to the possession of display structures such as horns, frills and dermal armor that may have affected the center of mass of the animal, and differences in locomotor behaviour such as migration, predator escape or home range size.

Morfometría de dos ejemplares de Foca de Ross, Ommatophoca rossii, de la Colección Nacional de Mastozoología del Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”

Morphometrics of two specimens of Ross Seal, Ommatophoca rossi , housed at the Mammals collection of the Museo Argentino de Ciencias Naturales Bernardino Rivadavia. The description of material housed in collections contribute to the knowledge and conservation of species, specially those that are scarcely represented due to the relatively difficult access to their distribution range. The Ross seal is an example of this, even though this species is not threatened in its conservation status, the apparent changes in the ice pack extension may affect the state of the populations. The Mammals National Collection of the Museo Argentino de Ciencias Naturales Bernardino Rivadavia (MACN-Ma, Buenos Aires, Argentina) houses two specimens belong- ing to this species: an adult female, represented by the skull, post-cranial skeleton and extended skin, and the pup, represented by the skull and extended skin. In this paper we report information on the skull and post-cranial measurements of the two O. rossii specimens. In addition, a brief description of its skull morphology is given.

The giant hyena Pachycrocuta brevirostris: Modelling the bone-cracking behavior of an extinct carnivore

The giant hyena Pachycrocuta brevirostris was the largest bone-cracking carnivore that ever existed. With the mass of a lioness, it had massive limbs with shortened distal bones and a heavy, powerfully built mandible with robust, well-developed premolars. All these features reflect its adaptation for dismembering ungulate carcasses, transporting large pieces of them without dragging to the denning site and fracturing bones. This paper estimates the relative contribution of hunting and scavenging to the diet of this extinct hyena, using a combined biomechanical and taphonomic approach. Analysis of the bone-cracking behavior of P. brevirostris was based on the abundance of skeletal elements in the large mammals assemblage from Venta Micena (Guadix-Baza basin, southeast Spain), a locality currently interpreted as an early Pleistocene hyena den. The distribution of major limb bones of ungulates among complete elements, isolated epiphyses and diaphyses were analyzed using contingency tables and correspondence analysis. Results obtained showed that the bones with greater marrow contents (femur, humerus and tibia) were preferentially fractured by the hyenas, while those others with less nutritional value (radius and metapodials) were better represented as complete elements in the assemblage. The quantitative analysis of the preservational state of skeletal elements allowed testing specific patterns of bone modification by the giant hyenas, such as a proximodistal sequence of consumption for humerus and tibia, thus revealing the highly specialized bone-cracking behavior of P. brevirostris. Regression equations adjusted with modern carnivores for body size on craniodental and postcranial measurements provide an average estimate of mass of ∼110 kg for the giant hyena. The high moment arms for masseter and temporalis muscles indicate a substantial strength for bone fracturing with the well-developed premolar teeth. Jaw depth provided resistance against dorsoventral loads during bone-cracking activities. However, the moment arm of resistance for an object positioned at the canines reveals a loss of bite strength compared with spotted hyenas and thus less predatory abilities. These results are in agreement with the scavenging niche deduced for P. brevirostris from taphonomic analysis.

A new test of the sex of the Lake Mungo 3 skeleton

ABSTRACT The Lake Mungo 3 skeleton has been the subject of controversy since its discovery in 1974. Brown (2000) has alleged that the sex of this individual cannot be determined from the available evidence, since the skeleton lacks the most diagnostic areas of the skull and pelvis. In an effort to reexamine the sex diagnosis of Lake Mungo 3 our team collected an exhaustive battery of postcranial measurements from the skeleton. These measurements are compared to a number of Australian samples of known sex, both from the Pleistocene as well as the Holocene. In all, approximately 55 postcranial measurements are used for these comparisons. Many of the measurements sampled for Lake Mungo 3 fall at the extreme high end of the Holocene male sample, sometimes beyond the observed Holocene male range, and likewise fall well outside the Holocene female range. Lake Mungo 3 is also very similar in size to ‘robust’ Pleistocene and early Holocene males and larger than a known Pleistocene female. These results support the assignment of male sex to Lake Mungo 3. However, they also lead us to question the attribution of Lake Mungo 3 to a ‘gracile’ category amongst early Australians.

Estimación de la masa corporal de las especies de osos fósiles y actuales (Ursidae, Tremarctinae) de América del Sur

Body mass estimation of extinct and extant South American bears (Ursidae, Tremarctinae). Precise estimates of body mass in fossil taxa are elementary to paleobiological reconstruction. Using demonstrated relationships between body mass and anatomical measurements in modern mammals, several authors proposed prediction equations to estimate the body mass of fossil taxa. We calculate the body mass of extant and fossil South American bears (Tremarctos ornatus and Arctotherium respectively) applying 61 selected allometric equations to 19 cranial, dental and postcranial measurements. We also estimate the body mass ranges of the five Arctotherium species by simple size comparison to size and weight of extant bears. Extrapolating on the basis of geometric similitude with T. ornatus we further estimated the body mass of Arctotherium in order to know if our estimations, bias published equations, were feasible. Also we test the prediction equations results with a specimen of Tremarctos ornatus of known body mass. We found that the best prediction equations for all Arctotherium species are based on femoral (8 equations) and cranial (one equation) measurements. In turn the best prediction equations for T. ornatus are based on cranial (one equation), first lower molar (one equation), femoral (two equations) and humeral measurements (three equations).

The estimation of body weight of the reindeer (Rangifer tarandus L.) from skeletal measurements: preliminary analyses and application to archaeological material from 17th- and 18th-century northern Finland

In this study, a variety of postcranial skeletal measurements of reindeer (Rangifer tarandus L.) are used to predict the body mass. Regression equations for estimating the body weight of females as well as correction factors for estimating the weight of males are generated. These are applied to archaeological reindeer bones from 17th- and 18th-century Northern Finland. Predicted weights of archaeological reindeer correspond well with the weight of modern reindeer. Sexual dimorphism, however, caused problems in this analysis, since the criteria used for sex assessment affect the body weight prediction and thus the results of inter-assemblage comparisons.

Limb-size proportions in Australopithecus afarensis and Australopithecus africanus

Previous analyses have suggested that Australopithecus africanus possessed more apelike limb proportions than Australopithecus afarensis. However, due to the errors involved in estimating limb length and body size, support for this conclusion has been limited. In this study, we use a new Monte Carlo method to (1) test the hypothesis that A. africanus had greater upper:lower limb-size proportions than A. afarensis and (2) assess the statistical significance of interspecific differences among these taxa, extant apes, and humans. Our Monte Carlo method imposes sampling constraints that reduce extant ape and human postcranial measurements to sample sizes comparable to the fossil samples. Next, composite ratios of fore- and hindlimb geometric means are calculated for resampled measurements from the fossils and comparative taxa. Mean composite ratios are statistically indistinguishable ( α = 0.05) from the actual ratios of extant individuals, indicating that this method conserves each sample's central tendency. When applied to the fossil samples, upper:lower limb-size proportions in A. afarensis are similar to those of humans ( p = 0.878) and are significantly different from all great ape proportions ( p ≤ 0.034), while Australopithecus africanus is more similar to the apes ( p ≥ 0.180) and significantly different from humans and A. afarensis ( p ≤ 0.031). These results strongly support the hypothesis that A. africanus possessed more apelike limb-size proportions than A. afarensis, suggesting that A. africanus either evolved from a more postcranially primitive ancestor than A. afarensis or that the more apelike limb-size proportions of A. africanus were secondarily derived from an A. afarensis-like ancestor. Among the extant taxa, limb-size proportions correspond with observed levels of forelimb- and hindlimb-dominated positional behaviors. In conjunction with detailed anatomical features linked to arboreality, these results suggest that arboreal posture and locomotion may have been more important components of the A. africanus behavioral repertoire relative to that of A. afarensis.

Cranial and Postcranial Measurements of the Early Modern Edo People from 19 Archeological Sites in the Tokyo Urban Area and the Suburbs

Cranial and Postcranial Measurements of the Early Modern Edo People from 19 Archeological Sites in the Tokyo Urban Area and the Suburbs

Indo-Pacific bottlenose dolphins Tursiops aduncus in Amakusa, western Kyushu, Japan

A year-round resident population of bottlenose dolphins is known in the coastal waters of Amakusa-Shimoshima Island, western Kyushu (130 ∞ 07 ¢ E, 32 ∞ 33 ¢ N). 1 There are two types of bottlenose dolphins, the aduncus and the truncatus types, in the Indo-Pacific regions. 2–4 In Japanese waters, bottlenose dolphins with ventral spotting and small body size, which are characteristics of the aduncus type, 2–4 are reported from the Amami Islands (129 ∞ 22 ¢ E, 28 ∞ 18 ¢ N), 5,6 Kagoshima Bay (130 ∞ 37 ¢ E, 31 ∞ 30 ¢ N; Kishiro T. pers. comm., 2000), Mikura Island (139 ∞ 36 ¢ E, 33 ∞ 52 ¢ N) 7 and the Bonin Islands (142 ∞ 11 ¢ E, 26 ∞ 05 ¢ N). 8 Recent taxonomic re-examinations of bottlenose dolphins have indicated that the two types are separate species, Tursiops aduncus and T. truncatus . 9–13 The objective of the present paper is to identify the species of bottlenose dolphins off Amakusa. During our population studies of bottlenose dolphins in the coastal waters of Amakusa-Shimoshima Island, which were initiated in 1994, we were able to obtain samples and data from two carcasses. Both of the specimens were male; MIE001, taken incidentally by a gill net on 26 July 1995; and MIE003, stranded on a beach on 3 May 1998. The age of the two specimens was determined by reading the number of layers on decalcified and hematoxylin-stained tooth sections after Kasuya and Matsui. 14 We took a total of 34 cranial and postcranial measurements following Perrin. 15

Interobserver Variation of Selected Postcranial Skeletal Measurements

Osteometric data are of great importance for analytical purposes in the field of forensic anthropology, and it is critical that interobserver concordance is high in order for the results of these analyses to be reliable. Significant interobserver variation of skeletal measurements is cause for concern since it may result in conflicting conclusions. The range of interobserver variation of selected postcranial measurements is addressed. Thirteen standard measurements familiar to most forensic anthropologists were examined, as well as nine nonstandard measurements that were unfamiliar to most participants in the study. Sixty-eight individuals participated in the study, the majority of whom considered themselves to be forensic anthropologists with various levels of experience. In general, interobserver variation of the tested standard postcranial measurements was found to be minimal, with the exception of pubis length and subtrochanteric femur measurements. The difficulties that can lead to measurement error are discussed and possible solutions are recommended.

Anthropometric variation in West-Central Mexico

Anthropometric data from five indigenous Mexican groups, collected by Carlos and Manuel Basauri in 1933, were reanalyzed and compared with serological and cranial non-metric data. Ten cranial and 14 postcranial measurements were used, both separately and together. Bias-corrected r0 and FST values were slightly higher for the postcranial analysis (0.033) than for the cranial analysis (0.024). Given the degree of linguistic differentiation among the Mexican populations, not to mention the different histories of the communities sampled, this result is surprisingly low. The two groups which were closest linguistically and geographically, the Cora and Huichol, were also close biologically. The other three groups, Tarascan, Aztecan, and Otomi, were not closely related to each other or to the Cora-Huichol pair. More interesting than the relationship between populations in this case are those within them. The Aztecas of Tuxpan, Jalisco, exhibit high rii values and lower-than-expected phenotypic variance, suggesting the pronounced action of genetic drift. The Otomi of Ixmiquilpan and Cora of the Sierra de Nayarit, despite their very different histories, both exhibit low rii values and higher-than-expected phenotypic variance, indicating a high level of gene flow. Despite the phenotypic similarities between the Cora and Huichol, their residual variance is very different; this mirrors serological investigations of relative admixture. Over all, recent population history, and especially non-indigenous admixture, are at least as explicative of the observed biological variation as historical linguistic ties are.

Estimating missing data: an iterative regression approach

The problem of missing data is common in all fields of science. Various methods of estimating missing values in a dataset exist, such as deletion of cases, insertion of sample mean, and linear regression. Each approach presents problems inherent in the method itself or in the nature of the pattern of missing data. We report a method that (1) is more general in application and (2) provides better estimates than traditional approaches, such as one-step regression. The model is general in that it may be applied to singular matrices, such as small datasets or those that contain dummy or index variables. The strength of the model is that it builds a regression equation iteratively, using a bootstrap method. The precision of the regressed estimates of a variable increases as regressed estimates of the predictor variables improve. We illustrate this method with a set of measurements of European Upper Paleolithic and Mesolithic human postcranial remains, as well as a set of primate anthropometric data. First, simulation tests using the primate data set involved randomly turning 20% of the values to “missing”. In each case, the first iteration produced significantly better estimates than other estimating techniques. Second, we applied our method to the incomplete set of human postcranial measurements. MISDAT estimates always perform better than replacement of missing data by means and better than classical multiple regression. As with classical multiple regression, MISDAT performs when squared multiple correlation values approach the reliability of the measurement to be estimated, e.g., above about 0·8.

A New Method for Discriminating African-American from European-American Skeletons Using Postcranial Osteometrics Reflective of Body Shape

A discriminant function analysis based on seven postcranial measurements for the metric assessment of race is presented. A sample from the Terry Collection (NMNH) was used to create independent functions for African-American males and females, and European-American males and females. The functions were tested using known forensic cases from the Maxwell Museum of Anthropology and the C.A. Pound Human Identification Laboratory. Based on the Terry Collection sample, correct classification of race for males was 87.0%, and for females 100.0%. For the independent test population, correct classification for males was 81.8%, and for females only 57.1%. The low classification for females is most likely due to sample bias.

ESTIMATING BODY LENGTH OF PYGMY RIGHT WHALES (CAPEREA MARGINATA) FROM MEASUREMENTS OF THE SKELETON AND BALEEN

AbstractVarious parts of the skeleton and/or the longest baleen plate of 46 specimens of Caperea marginata from Australia and New Zealand were measured and related to body length. Of the 32 skull, postcranial and baleen‐plate measurements available, eight were analysed and seven found to be good predictors of body length, by using a curvilinear model describing their relationship with body length. Greatest skull width, supraoccipital length and mandible length had the smallest prediction limits (± 0.28‐0.33 m in small animals, ±0.44‐0.58 m in large animals) when compared with postcranial measurements (scapula length, vertebra 7 centrum width). Baleen‐plate length was also a useful predictor of body length (±0.32‐0.77 m). There was a substantial increase in the arch of the skull as body length increased. Bulla length was not a good predictor of body length, because measurements were highly variable and because the bulla grew little during postnatal life. Physical maturity occurred at body lengths of at least 5.9 m, also the shortest length at which both epiphyses of the humerus and proximal epiphyses of the radius and ulna were fused. Weaning appears to occur at about 3‐3.5 m. The following approximate relative age/length classes were erected: dependent calves, <3.6 m; subadults, 3.6‐5.5 m; adults, >5.5 m. Females were significantly longer than males in the sample of 22 animals greater than 5.9 m, length of the smallest recorded physically mature animal.