Fossil Homo femur from Berg Aukas, northern Namibia

Main morphological characteristics and sexual dimorphism of hominin adult femora from the Sima de los Huesos Middle Pleistocene site (Sierra de Atapuerca, Spain)

The excellent fossil record from Sima de los Huesos (SH) includes three well-known complete adult femora and several partial specimens that have not yet been published in detail. This fossil record provides an opportunity to analyze the morphology of European pre-Neandertal adult femur and its variation with different evolution patterns. Currently, there are a minimum of five adult individuals (males or females). In this study, we compiled previously published basic anatomical and biometric characteristics of SH adult femora, emphasizing the most relevant features compared to other recent and fossil hominins. The SH femora exhibited a primitive morphological pattern common to all non-Homo sapiens femora, as well as most of the Neandertal traits. Therefore, the complete Upper Pleistocene Neandertal pattern was well-established in Middle Pleistocene ancestors long before the proper Neandertals appeared. Additionally, we highlight that the SH and Neandertal femora share some morphological traits and proportions with modern humans that hold sexual significance in our species, regardless of size. Keeping this in mind, we discussed the sex determination of the complete SH specimens and re-evaluated sex allocation in two of them.

Exploring the morphology of adult tibia and fibula from Sima de los Huesos site in sierra de Atapuerca, Burgos, Spain

The analysis of the locomotor anatomy of Late Pleistocene Homo has largely focused on changes in proximal femur and pelvic morphologies, with much attention centered on the emergence of modern humans. Although much of the focus has been on changes in the proximal femur, some research has also been conducted on tibiae and, to a lesser extent, fibulae. With this in mind, we present one of the largest samples of the same population of human tibiae and fibulae from the Middle Pleistocene to determine their main characteristic traits and establish similarities and differences, primarily with those of Neanderthals and modern humans, but also with other Middle Pleistocene specimens in the fossil record. Through this study, we established that the Middle Pleistocene population from the Sima de los Huesos (Atapuerca, Burgos, Spain) had lower leg long bones similar to those of Neanderthals, although there were some important differences, such as bone length, which this fossil individuals resembled those of modern humans and not to Neanderthals. This fact is related to the crural index and leg length, even though we do not have any true association between femora and tibiae yet, it has implications for establishing locomotor efficiency and climate adaptation.

Mechanical and morphometric approaches to body mass estimation in rhesus macaques: A test of skeletal variables

OBJECTIVES

Estimation of body mass from skeletal metrics can reveal important insights into the paleobiology of archeological or fossil remains. The standard approach constructs predictive equations from postcrania, but studies have questioned the reliability of traditional measures. Here, we examine several skeletal features to assess their accuracy in predicting body mass.

MATERIALS AND METHODS

Antemortem mass measurements were compared with common skeletal dimensions from the same animals postmortem, using 115 rhesus macaques (male: n = 43; female: n = 72). Individuals were divided into training (n = 58) and test samples (n = 57) to build and assess Ordinary Least Squares or multivariate regressions by residual sum of squares (RSS) and AIC weights. A leave-one-out approach was implemented to formulate the best fit multivariate models, which were compared against a univariate and a previously published catarrhine body-mass estimation model.

RESULTS

Femur circumference represented the best univariate model. The best model overall was composed of four variables (femur, tibia and fibula circumference and humerus length). By RSS and AICw, models built from rhesus macaque data (RSS = 26.91, AIC = -20.66) better predicted body mass than did the catarrhine model (RSS = 65.47, AIC = 20.24).

CONCLUSION

Body mass in rhesus macaques is best predicted by a 4-variable equation composed of humerus length and hind limb midshaft circumferences. Comparison of models built from the macaque versus the catarrhine data highlight the importance of taxonomic specificity in predicting body mass. This paper provides a valuable dataset of combined somatic and skeletal data in a primate, which can be used to build body mass equations for fragmentary fossil evidence.

Sex estimation of the adult Neandertal Regourdou 1 (Montignac, France): Implications for sexing human fossil remains

Sex is a biological trait fundamental to the study of hominin fossils. Among the many questions that can be addressed are those related to taxonomy, biological variability, sexual dimorphism, paleoobstetrics, funerary selection, and paleodemography. While new methodologies such as paleogenomics or paleoproteomics can be used to determine sex, they have not been systematically applied to Pleistocene human remains due to their destructive nature. Therefore, we estimated sex from the coxal bone of the newly discovered pelvic remains of the Regourdou 1 Neandertal (Southwest France, MIS 5) based on morphological and metric data employing two methods that have been recently revised and shown to be reliable in multiple studies. Both methods calculate posterior probabilities of the estimate. The right coxal bone of Regourdou 1 was partially reconstructed providing additional traits for sex estimation. These methods were cross validated on 14 sufficiently preserved coxal bones of specimens from the Neandertal lineage. Our results show that the Regourdou 1 individual, whose postcranial skeleton is not robust, is a male, and that previous sex attributions of comparative Neandertal specimens are largely in agreement with those obtained here. Our results encourage additional morphological research of fossil hominins in order to develop a set of methods that are applicable, reliable, and reproducible.

Biomechanical and taxonomic diversity in the Early Pleistocene in East Africa: Structural analysis of a recently discovered femur shaft from Olduvai Gorge (bed I)

Recent Plio-Pleistocene hominin findings have revealed the complexity of human evolutionary history and the difficulties involved in its interpretation. Moreover, the study of hominin long bone remains is particularly problematic, since it commonly depends on the analysis of fragmentary skeletal elements that in many cases are merely represented by small diaphyseal portions and appear in an isolated fashion in the fossil record. Nevertheless, the study of the postcranial skeleton is particularly important to ascertain locomotor patterns. Here we report on the discovery of a robust hominin femoral fragment (OH 84) at the site of Amin Mturi Korongo dated to 1.84 Ma (Olduvai Bed I). External anatomy and internal bone structure of OH 84 were analyzed and compared with previously published data for modern humans and chimpanzees, as well as for Australopithecus, Paranthropus and Homo specimens ranging from the Late Pliocene to Late Pleistocene. Biomechanical analyses based on transverse cross-sections and the comparison of OH 84 with another robust Olduvai specimen (OH 80) suggest that OH 84 might be tentatively allocated to Paranthropus boisei. More importantly, the identification of a unique combination of traits in OH 84 could indicate both terrestrial bipedalism and an arboreal component in the locomotor repertoire of this individual. If interpreted correctly, OH 84 could thus add to the already mounting evidence of substantial locomotor diversity among Early Pleistocene hominins. Likewise, our results also highlight the difficulties in accurately interpreting the link between form and function in the human fossil record based on fragmentary remains, and ultimately in distinguishing between coeval hominin groups due to the heterogeneous pattern of inter- and intraspecific morphological variability detected among fossil femora.

"Heal the sick": Health status and caregiving during the 17th-18th century in Northern Italy (St. Biagio cemetery, Ravenna)

OBJECTIVE

The study of health-related care provision in archeology gives important indications on the culture and community organization of past populations. This study aims to assess the health status of the skeletal assemblage recovered from the burial site of St. Biagio (Ravenna, 17th-18th Centuries); next, we identified likely instances of need for and receipt of caregiving in response to the condition, to examine evidence of community attitudes toward disease and disability.

MATERIALS AND METHODS

The skeletal assemblage is composed of 133 individuals in a generally good state of preservation. Sex and age-at-death were estimated through classical anthropological methods. Health status was inferred through the biological index of frailty (BIF) and paleopathological analysis was performed through macroscopic and radiographic investigations. The "bioarcheology of care" approach was applied to individuals who showed evidence of impairment and disability.

RESULTS

The skeletal assemblage of St. Biagio was equally represented by males and females (50% males), with a higher percentage of adults (83.4%) than subadults (10.5%), and this is reflected in the high life expectancy at birth (40.3 years). No significant differences in health status emerged between age groups and sexes, with a generally high percentage of joint diseases, antemortem trauma, and infectious diseases. Evidence of care and compassion was found in some individuals with a high degree of impairment or disability, as in the case of probable Angelman syndrome.

DISCUSSION

This study provided important insights into the biological and social aspects of an Early Modern population in Northern Italy, showing that people with functional and/or visible abnormalities were probably cared for in life and were presumably considered full members of the society.

The estimation and evolution of hominin body mass

Body mass is a critical variable in many hominin evolutionary studies, with implications for reconstructing relative brain size, diet, locomotion, subsistence strategy, and social organization. We review methods that have been proposed for estimating body mass from true and trace fossils, consider their applicability in different contexts, and the appropriateness of different modern reference samples. Recently developed techniques based on a wider range of modern populations hold promise for providing more accurate estimates in earlier hominins, although uncertainties remain, particularly in non-Homo taxa. When these methods are applied to almost 300 Late Miocene through Late Pleistocene specimens, the resulting body mass estimates fall within a 25-60 kg range for early non-Homo taxa, increase in early Homo to about 50-90 kg, then remain constant until the Terminal Pleistocene, when they decline.

Variation in cross-sectional indicator of femoral robusticity in Homo sapiens and Neandertals

Variations in the cross-sectional properties of long bones are used to reconstruct the activity of human groups and differences in their respective habitual behaviors. Knowledge of what factors influence bone structure in Homo sapiens and Neandertals is still insufficient thus, this study investigated which biological and environmental variables influence variations in the femoral robusticity indicator of these two species. The sample consisted of 13 adult Neandertals from the Middle Paleolithic and 1959 adult individuals of H. sapiens ranging chronologically from the Upper Paleolithic to recent times. The femoral biomechanical properties were derived from the European data set, the subject literature, and new CT scans. The material was tested using a Mantel test and statistical models. In the models, the polar moment of area (J) was the dependent variable; sex, age, chronological period, type of lifestyle, percentage of the cortical area (%CA), the ratio of second moment areas of inertia about the X and Y axes (Ix/Iy), and maximum slope of the terrain were independent covariates. The Mantel tests revealed spatial autocorrelation of the femoral index in H. sapiens but not in Neandertals. A generalized additive mixed model showed that sex, %CA, Ix/Iy, chronological period, and terrain significantly influenced variation in the robusticity indicator of H. sapiens femora. A linear mixed model revealed that none of the analyzed variables correlated with the femoral robusticity indicator of Neandertals. We did not confirm that the gradual decline in the femoral robusticity indicator of H. sapiens from the Middle Paleolithic to recent times is related to the type of lifestyle; however, it may be associated with lower levels of mechanical loading during adolescence. The lack of correlation between the analysed variables and the indicator of femoral robusticity in Neandertals may suggest that they needed a different level of mechanical stimulus to produce a morphological response in the long bone than H. sapiens.

Belly fat or bloating? New insights into the physical appearance of St Anthony of Padua

Over the centuries, iconographic representations of St Anthony of Padua, one of the most revered saints in the Catholic world, have been inspired by literary sources, which described the Saint as either naturally corpulent or with a swollen abdomen due to dropsy (i.e. fluid accumulation in the body cavities). Even recent attempts to reconstruct the face of the Saint have yielded discordant results regarding his outward appearance. To address questions about the real appearance of St Anthony, we applied body mass estimation equations to the osteometric measurements taken in 1981, during the public recognition of the Saint’s skeletal remains. Both the biomechanical and the morphometric approach were employed to solve some intrinsic limitations in the equations for body mass estimation from skeletal remains. The estimated body mass was used to assess the physique of the Saint with the body mass index. The outcomes of this investigation reveal interesting information about the body type of the Saint throughout his lifetime.

The biological index of frailty: A new index for the assessment of frailty in human skeletal remains

OBJECTIVE

Frailty is the physiological stress that individuals suffer during their life. In past populations, frailty is conventionally assessed through the occurrence of different biomarkers of biological stress. Some efforts have been made to propose indexes that combine all biomarkers. However, these indices have some critical limitations: they cannot be used on incomplete skeletons, do not consider the severity and/or healing of lesions, and assign equal importance to different biomarkers. To address these limitations, we propose a new index to assess frailty in skeletal individuals.

MATERIAL AND METHODS

By statistically analyzing a large amount of osteological data available from the Museum of London, and using a Logit model, we were able to define a different weight for each reported biomarker of frailty, based on their importance in increasing the risk of premature death for the individuals.

RESULTS

The biological index of frailty (BIF) is the weighted mean of all biomarkers scored on the individuals, according to a different degree of importance assigned to each one. It also considers the severity and healing of the biomarkers when this is relevant to diagnose frailty. We applied BIF on a sample of Monastics and Non-Monastics from medieval England and compared it with the skeletal index of frailty (SFI).

DISCUSSION

BIF is the first frailty index that gives a different weight to each skeletal biomarker of stress, considers both severity and healing of the lesions, and can be applied on partial skeletal remains. The comparison with SFI showed that BIF is applicable to a larger number of skeletal individuals, revealing new differences between the Monastic and the Non-Monastic groups.

Mobility in Ancient Egypt from the shape and strength of the femurs

The aim of the study was to establish the degree of robustness and to infer the level of mobility of a group from ancient Thebes (Middle Egypt). Seventy-one left femurs of adult individuals from the 1st century AD from the tomb of Monthemhat (Luxor) were studied.

Metrical, non-metrical variables, shape and size indices of femur were considered. Stature, body mass and Body Mass Index were calculated. All variables showed higher values in males, the vertical diameter of the femoral head was the variable with the highest sexual dimorphism. Non-metric variables also indicated low robustness, with heterogeneous sex distribution. The robustness, pilastric and platymeric indices indicated that the values were close to those of gracile populations in both sexes. Subtrochanteric size and shape showed no sexual dimorphism. The robustness, size and shape in the middle of the diaphysis suggested a mobility related to a daily occupation without intense physical activity in the legs. The results indicate a profile of low robustness, relative sedentarism with apparent sexual division in daily activities.

Adapting in the Arctic: Habitual activity and landscape interaction in Late Holocene hunter-gatherers from Alaska

OBJECTIVES

This study compares lower limb diaphyseal robusticity between Native Alaskan hunter-gatherers to reconstruct patterns of mobility and engagement with terrain.

MATERIALS AND METHODS

Ancestral remains included in this study date between 600 and 1800 C.E. and were divided into three regions: Coastal Bay, Far North Coastal, and Inland/Riverine. Cross-sectional properties were determined at femoral and tibial midshafts and standardized by powers of body mass and bone length.

RESULTS

Consistently elaevated areas and second moments of area were found in ancestral remains from the Far North Coastal, while the Coastal Bay remains had reduced diaphyseal robusticity. Individuals from the Inland/Riverine region were intermediate in robusticity for male femora, but similar to the Coastal Bay group for females. Sexual dimorphism was greatest in the Inland/Riverine ancestral remains and comparable between Coastal Bay and Far North Coastal regions.

CONCLUSIONS

Ancestral remains from the Far North Coastal region have the greatest diaphyseal robusticity in response to intensive hunting and travel over rugged terrain. Reduced sexual dimorphism in the Far North Coastal region suggest female participation in hunting activities. Intermediate diaphyseal robusticity among Inland/Riverine males and increased sexual dimorphism reflects diverse patterns of mobility in relation to the hunting cycle between males and females. Reduced diaphyseal robusticity and sexual dimorphism among the Coastal Bay group is associated with sedentary villages established around net fishing in regions with low relief. Such findings argue against technocentric views of sedentism in hunter-gatherer lifeways and generally reflect diverse adaptive strategies and interaction with local terrain among Indigenous Late Holocene hunter-gatherers of Alaska.

Age-related site-specific modifications in diaphyseal structural properties of the human fibula: Furrows and cross-sectional geometry

OBJECTIVES

Fibular structure is related to locomotor behavior, which allows an exploration of mobility in past human populations with diaphyseal cross-sectional geometry (CSG). However, bone structure depends on age-related changes. Nonmechanical alterations can affect biomechanical investigations. In this study, we examined how the cortical area and the variables used as functional markers in the fibular diaphysis (i.e., CSG and furrows) change with aging. We predict classic and specific modifications, and we discuss functional interpretations based on bone structure.

MATERIALS AND METHODS

The sample consisted of 124 individuals of known age in whom the fibular furrow depths were measured with calipers. Microcomputed tomography (micro-CT) scanning of 38 individuals provided CSG (e.g., cortical area, shape index, and robusticity) and fibular furrow indices. CSG was studied at five cross sections taken along the diaphysis. Linear regression analyses and age group comparisons were conducted.

RESULTS

The cross-sectional shape summary by fibular furrows and shape index and the total area did not change with aging; in contrast, the cortical area and the robusticity (Z_p-std) decreased with age.

DISCUSSION

The decrease in robusticity (Z_p-std) with aging is due to the maintenance of total area, which is related to the specific mechanical environment of the fibula, and to the loss of cortical bone and not to the decrease in mechanical stress. This finding is consistent with the lower bone modeling capacity in aged individuals, which also explains the lack of significant changes in the diaphyseal shape. Thus, fibular structure in older individuals is due to a combination of early bone adaptations to stress and aging effects.

An integrative approach to studying plasticity in growth disruption and outcomes: A bioarchaeological case study of Napoleonic soldiers

OBJECTIVES

The aim of this study was to investigate how much variation in adult stature and body mass can be explained by growth disruption among soldiers who served in Napoleon's Grand Army during the Russian Campaign of 1812.

METHODS

Linear enamel hypoplasia (LEH) were recorded as representations of early life growth disruption, while the impact on future growth was assessed using maximum femur length (n = 73) as a proxy for stature and maximum femoral head diameter (n = 25) as a proxy for body mass. LEH frequency, severity, age at first formation, and age at last formation served as explanatory variables in a multiple regression analysis to test the effect of these variables on maximum femur length and maximum femoral head diameter.

RESULTS

The multiple regression model produced statistically significant results for maximum femur length (F-statistic = 3.05, df = 5 and 67, P = .02), with some variation in stature (adjusted r² = 0.13) attributable to variation in growth disruption. The multiple regression model for maximum femoral head diameter was not statistically significant (F-statistic = 1.87, df = 5 and 19, P = .15).

CONCLUSIONS

We hypothesized stress events during early life growth and development would have significant, negative, and cumulative effects on growth outcomes in adulthood. The results did not support our hypothesis. Instead, some variables and interactions had negative effects on stature, whereas others had positive effects. This is likely due to catch-up growth, the relationship between acute and chronic stress and growth, resilience, and plasticity in human growth over the life course.

Predicting body mass of bonobos (Pan paniscus) with human-based morphometric equations

A primate's body mass covaries with numerous ecological, physiological, and behavioral characteristics. This versatility and potential to provide insight into an animal's life has made body mass prediction a frequent and important objective in paleoanthropology. In hominin paleontology, the most commonly employed body mass prediction equations (BMPEs) are "mechanical" and "morphometric": uni- or multivariate linear regressions incorporating dimensions of load-bearing skeletal elements and stature and living bi-iliac breadth as predictor variables, respectively. The precision and accuracy of BMPEs are contingent on multiple factors, however, one of the most notable and pervasive potential sources of error is extrapolation beyond the limits of the reference sample. In this study, we use a test sample requiring extrapolation-56 bonobos (Pan paniscus) from the Lola ya Bonobo sanctuary in Kinshasa, Democratic Republic of the Congo-to evaluate the predictive accuracy of human-based morphometric BMPEs. We first assess systemic differences in stature and bi-iliac breadth between humans and bonobos. Due to significant differences in the scaling relationships of body mass and stature between bonobos and humans, we use panel regression to generate a novel BMPE based on living bi-iliac breadth. We then compare the predictive accuracy of two previously published morphometric equations with the novel equation and find that the novel equation predicts bonobo body mass most accurately overall (41 of 56 bonobos predicted within 20% of their observed body mass). The novel BMPE is particularly accurate between 25 and 45 kg. Given differences in limb proportions, pelvic morphology, and body tissue composition between the human reference and bonobo test samples, we find these results promising and evaluate the novel BMPE's potential application to fossil hominins.

Body mass estimation from dimensions of the fourth lumbar vertebra in middle-aged Finns

Although body mass is not a stable trait over the lifespan, information regarding body size assists the forensic identification of unknown individuals. In this study, we aimed to study the potential of using the fourth lumbar vertebra (L4) for body mass estimation among contemporary Finns. Our sample comprised 1158 individuals from the Northern Finland Birth Cohort 1966 who had undergone measurements of body mass at age 31 and 46 and lumbar magnetic resonance imaging (MRI) at age 46. MRI scans were used to measure the maximum and minimum widths, depths, and heights of the L4 body. Their means and sum were calculated together with vertebral cross-sectional area (CSA) and volume. Ordinary least squares (OLS) and reduced major axis (RMA) regression was used to produce equations for body mass among the full sample (n = 1158) and among normal-weight individuals (n = 420). In our data, body mass was associated with all the L4 size parameters (R = 0.093-0.582, p ≤ 0.019 among the full sample; R = 0.243-0.696, p ≤ 0.002 among the normal-weight sample). RMA regression models seemed to fit the data better than OLS, with vertebral CSA having the highest predictive value in body mass estimation. In the full sample, the lowest standard errors were 6.1% (95% prediction interval ±9.6 kg) and 7.1% (±9.1 kg) among men and women, respectively. In the normal-weight sample, the lowest errors were 4.9% (±6.9 kg) and 4.7% (±5.7 kg) among men and women, respectively. Our results indicate that L4 dimensions are potentially useful in body mass estimation, especially in cases with only the axial skeleton available.

Reevaluation of the body mass estimate for the KNM-ER 5428 Homo erectus talus

OBJECTIVES

In this study, we reexamined the body mass estimate for the Homo erectus specimen KNM-ER 5428 based on talus dimensions. Previous estimates of >90 kg for this fossil are large in comparison to body mass estimates for other H. erectus specimens.

MATERIALS AND METHODS

The study sample consisted of tali and femora of 132 modern cadaver males from a documented body mass skeletal collection. We recorded the talus trochlear mediolateral (TTML) breadth and femoral head diameter (FHD) for each modern human specimen, and obtained KNM-ER 5428's TTML values from the literature. We developed regression formulae based on TTML using the body mass estimated from FHD for the entire human sample and for known body masses from a normal-BMI subsample, and then used these formulae to calculate body mass for KNM-ER 5428. In addition, we examined the range of body masses for individuals with TTML measurements comparable to KNM-ER 5428.

RESULTS

The body masses of normal-BMI individuals with a TTML ≥32.3 mm (the smaller of the two fossil measurements from the literature) ranged between 60.3 and 86.2 kg and averaged 72.3 kg. The body masses of normal-BMI individuals with a TTML ≥33.7 mm (the larger measurement) ranged between 63.5 and 86.2 kg with a mean of 73.6 kg. The correlations between TTML and body mass are moderate. Revised body mass point estimates for KNM-ER 5428 ranged between 69.2 and 81.6 kg based on TTML, and average 70.5 and 76.0 kg.

DISCUSSION

Results suggest previously published body mass estimates of KNM-ER 5428's are too large. Its body mass was likely between 70 and 76 kg rather than >90 kg.

Femoral neck and shaft structure in Homo naledi from the Dinaledi Chamber (Rising Star System, South Africa)

The abundant femoral assemblage of Homo naledi found in the Dinaledi Chamber provides a unique opportunity to test hypotheses regarding the taxonomy, locomotion, and loading patterns of this species. Here we describe neck and shaft cross-sectional structure of all the femoral fossils recovered in the Dinaledi Chamber and compare them to a broad sample of fossil hominins, recent humans, and extant apes. Cross-sectional geometric (CSG) properties from the femoral neck (base of neck and midneck) and diaphysis (subtrochanteric region and midshaft) were obtained through CT scans for H. naledi and through CT scans or from the literature for the comparative sample. The comparison of CSG properties of H. naledi and the comparative samples shows that H. naledi femoral neck is quite derived with low superoinferior cortical thickness ratio and high relative cortical area. The neck appears superoinferiorly elongated because of two bony pilasters on its superior surface. Homo naledi femoral shaft shows a relatively thick cortex compared to the other hominins. The subtrochanteric region of the diaphysis is mediolaterally elongated resembling early hominins while the midshaft is anteroposteriorly elongated, indicating high mobility levels. In term of diaphyseal robusticity, the H. naledi femur is more gracile that other hominins and most apes. Homo naledi shows a unique combination of characteristics in its femur that undoubtedly indicate a species committed to terrestrial bipedalism but with a unique loading pattern of the femur possibly consequence of the unique postcranial anatomy of the species.

Morphology of the Homo naledi femora from Lesedi

OBJECTIVES

The femoral remains recovered from the Lesedi Chamber are among the most complete South African fossil hominin femora discovered to date and offer new and valuable insights into the anatomy and variation of the bone in Homo naledi. While the femur is one of the best represented postcranial elements in the H. naledi assemblage from the Dinaledi Chamber, the fragmentary and commingled nature of the Dinaledi femoral remains has impeded the assessment of this element in its complete state.

MATERIALS AND METHODS

Here we analyze and provide descriptions of three new relatively well-preserved femoral specimens of H. naledi from the Lesedi Chamber: U.W. 102a-001, U.W. 102a-003, and U.W. 102a-004. These femora are quantitatively and qualitatively compared to multiple extinct hominin femoral specimens, extant hominid taxa, and, where possible, each other.

RESULTS

The Lesedi femora are morphologically similar to the Dinaledi femora for all overlapping regions, with differences limited to few traits of presently unknown significance. The Lesedi distal femur and mid-diaphysis preserve anatomy previously unidentified or unconfirmed in the species, including an anteroposteriorly expanded midshaft and anteriorly expanded patellar surface. The hypothesis that the Lesedi femoral sample may represent two individuals is supported.

DISCUSSION

The Lesedi femora increase the range of variation of femoral morphology in H. naledi. Newly described features of the diaphysis and distal femur are either taxonomically uninformative or Homo-like. Overall, these three new femora are consistent with previous functional interpretations of the H. naledi lower limb as belonging to a species adapted for long distance walking and, possibly, running.

Variation in pelvic shape and size in Eastern European males: a computed tomography comparative study

Background

The significantly accelerated development of human society in the last millennium has brought about changes in human behavior and body mass that may have influenced human bone morphology. Our objective was to analyze the variation in pelvic shape and size in males from modern and medieval populations.

Methods

We obtained 22 pelvic girdles of adult males from a medieval cemetery located in Cedynia, Poland. The control group comprised 31 contemporary male pelves from individuals inhabiting the same region. The analyzed parameters were: interspinous distance (ISD), intercristal distance (ICD), intertuberous distance (ITD), anatomic conjugate of the pelvis, height of the pelvis (HP), iliac opening angle (IOA), iliac tilt angle (ITA), and ISD/ITD/HP ratio. Geometric morphometrics was used to analyze differences in shape in the pelves. All analyses were carried out on three-dimensional CT reconstructions of pelves.

Results

ISD, ICD, and IOA were significantly greater in modern pelves than in those from Cedynia, but no significant differences were seen between the two groups in ITD, anatomical conjugate, HP, or ITA. ISD/ITD/HP ratios were significantly lower in the Cedynia group. Geometric morphometrics revealed significant differences in pelvic shape between the analyzed groups.

Discussion

The pelves of modern males are larger, wider, and flatter than those of medieval males. Changes in the set of daily activities that produce mechanical loading and estimated body mass may constitute the main factors explaining pelvic variability. However, differences in ontogenesis should also be taken into consideration, especially since growth in past populations is often found to be reduced relative to modern populations.

Femur associated with the Deep Skull from the West Mouth of the Niah Caves (Sarawak, Malaysia)

The skeletal remains of Pleistocene anatomically modern humans are rare in island Southeast Asia. Moreover, continuing doubts over the dating of most of these finds has left the arrival time for the region's earliest inhabitants an open question. The unique biogeography of island Southeast Asia also raises questions about the physical and cultural adaptations of early anatomically modern humans, especially within the setting of rainforest inhabitation. Within this context the Deep Skull from the West Mouth of the Niah Caves continues to figure prominently owing to its relative completeness and the greater certainty surrounding its geological age. Recovered along with this partial cranium in 1958 were several postcranial bones including a partial femur which until now has received little attention. Here we provide a description and undertake a comparison of the Deep Skull femur finding it to be very small in all of its cross-sectional dimensions. We note a number of size and shape similarities to the femora of Indigenous Southeast Asians, especially Aeta people from the Philippines. We estimate its stature to have been roughly 145-146 cm and body mass around 35 kg, confirming similarities to Aeta females. Its extreme gracility indicated by low values for a range of biomechanical parameters taken midshaft meets expectations for a very small (female) Paleolithic East Asian. Interestingly, the second moment of area about the mediolateral axis is enlarged relative to the second moment of area about the anteroposterior axis, which could potentially signal a difference in activity levels or lifestyle compared with other Paleolithic femora. However, it might also be the result of sexual dimorphism in these parameters as well as possibly reflecting changes associated with aging.

The impact of terrain on lower limb bone structure

OBJECTIVES

Lower limb diaphyseal geometry is often used to evaluate mobility in past populations. Diaphyseal dimensions such as high shape (I_X /I_Y ) indices generally thought to reflect high mobility may also result from walking over rough terrain. This study investigates the possible effects of terrain on lower limb diaphyseal cross-sectional geometric dimensions.

MATERIALS

The sample (N = 3,195) comprises adult skeletons from Europe, Africa, North America, and Asia, spanning from around 30,000 BP to mid-twentieth century.

METHODS

Femoral and tibial shape and bending/torsional strength dimensions were gathered either as part of a previous project or were generously provided by researchers. Local terrain for each site was quantified with ArcGIS mapping software using geographic coordinates and USGS elevation data, and characterized as flat, hilly, or mountainous.

RESULTS

Analysis of variance shows significant differences (p < .05) in midshaft femoral and tibial shape ratio and relative bending/torsional strength among the three terrain categories, with more AP oriented diaphyseal shapes and greater relative strength in hilly and mountainous groups, even after correcting for the effect of subsistence. As expected, the impact of terrain is much more marked for hunter-gatherers and agriculturalists than for more mechanized recent populations. Interestingly, the effect of terrain is confounded in higher latitude individuals that exhibit increased ML bending strength, probably reflecting larger body breadth.

DISCUSSION

This study underscores the mechanical significance of traveling over rough terrain and highlights the complex interactions of mobility, terrain, and body shape that contribute to shaping lower limb bone diaphyseal structure.

Cross-sectional properties of the humeral diaphysis of Paranthropus boisei: Implications for upper limb function

A ∼1.52 Ma adult upper limb skeleton of Paranthropus boisei (KNM-ER 47000) recovered from the Koobi Fora Formation, Kenya (FwJj14E, Area 1A) includes most of the distal half of a right humerus (designated KNM-ER 47000B). Natural transverse fractures through the diaphysis of KNM-ER 470000B provide unobstructed views of cortical bone at two sections typically used for analyzing cross-sectional properties of hominids (i.e., 35% and 50% of humerus length from the distal end). Here we assess cross-sectional properties of KNM-ER 47000B and two other P. boisei humeri (OH 80-10, KNM-ER 739). Cross-sectional properties for P. boisei associated with bending/torsional strength (section moduli) and relative cortical thickness (%CA; percent cortical area) are compared to those reported for nonhuman hominids, AL 288-1 (Australopithecus afarensis), and multiple species of fossil and modern Homo. Polar section moduli (Z_p) are assessed relative to a mechanically relevant measure of body size (i.e., the product of mass [M] and humerus length [HL]). At both diaphyseal sections, P. boisei exhibits %CA that is high among extant hominids (both human and nonhuman) and similar to that observed among specimens of Pleistocene Homo. High values for Z_p relative to size (M × HL) indicate that P. boisei had humeral bending strength greater than that of modern humans and Neanderthals and similar to that of great apes, A. afarensis, and Homo habilis. Such high humeral strength is consistent with other skeletal features of P. boisei (reviewed here) that suggest routine use of powerful upper limbs for arboreal climbing.

Human variation in the shape of the birth canal is significant and geographically structured

The human birth canal shows a tight fit with the size of the neonate, which can lead to obstetric complications. This is not the case in other apes, and has been explained as the outcome of conflicting evolutionary pressures for bipedal locomotion and parturition of a highly encephalized fetus. Despite the suggested evolutionary constraints on the female pelvis, we show that women are, in fact, extremely variable in the shape of the bony birth canal, with human populations having differently shaped pelvic canals. Neutral evolution through genetic drift and differential migration are largely responsible for the observed pattern of morphological diversity, which correlates well with neutral genetic diversity. Climatic adaptation might have played a role, albeit a minor one, with populations from colder regions showing a more transversally oval shape of the canal inlet. The significant extent of canal shape variation among women from different regions of the world has important implications for modern obstetric practice in multi-ethnic societies, as modern medical understanding has been largely developed on studies of European women.

Earliest Known Hominin Calcar Femorale in Orrorin tugenensis Provides Further Internal Anatomical Evidence for Origin of Human Bipedal Locomotion

The calcar femorale (CF), a plate of dense bone internal to the lesser trochanter, is visible on computed tomographic images of the 6 million-year-old femoral fragment BAR 1003'00 (from the taxon Orrorin tugenensis), among the oldest specimens relevant to reconstructing the evolution of human bipedal locomotion. A strongly expressed CF has been used previously as an indicator of bipedality. If true, then there should be a quantifiable difference in the CF among hominoids. Absolute and normalized CF lengths were measured from computed tomographic images at five anatomical locations along the proximal portion of BAR 1003'00 in addition to samples of nine H. sapiens and ten P. troglodytes femora. The span of the CF superiorly to inferiorly within the proximal femur was measured by counting the number of cross-sections on which the CF occurred. A Bayesian approach was used to classify the BAR 1003'00 sample based on normalized lengths. The P. troglodytes femora were more variable both in the occurrence of the trait and, where present, its span in the proximal femur. The H. sapiens sample exhibited CF lengths that were consistently larger at each location than the P. troglodytes in absolute terms, but the normalized lengths overlap substantially. The Bayesian posterior probability test classifies the CF of BAR 1003'00 with H. sapiens. The BAR 1003'00's calcar femorale has a strong anatomical similarity to the H. sapiens sample, supporting the conclusion that O. tugenensis is an early bipedal hominin. Anat Rec, 301:1834-1839, 2018. © 2018 Wiley Periodicals, Inc.

Exploring bone volume and skeletal weight in the Middle Pleistocene humans from the Sima de los Huesos site (Sierra de Atapuerca, Spain)

Body mass estimation in fossil human species is a crucial topic in paleoanthropology as it yields information about ecologically relevant characteristics. Nevertheless, variables crucial to body mass estimation such as bone volume and skeletal weight have never before been calculated in a fossil human species. The exceptional state of preservation of several fossil human long bones from the Sima de los Huesos (SH) Middle Pleistocene site, in the Sierra de Atapuerca, makes it possible to calculate for the first time the absolute bone volume in five complete long bones (two femora and three humeri) of a fossil human species, an approach not possible in fragmentary or poorly preserved fossils. We have relied on computed tomography scans and 3D reconstructions to calculate bone volume. A sample of 62 complete bones of robust recent humans was also used for comparative purposes. The male SH femora (weight-bearing bones) and humeri (non-weight-bearing bones) have, relative to their size, greater bone volume (volume of bone tissue over total bone volume) than the equivalent bones in our recent human sample. As mass is volume × density, and bone tissue density (as a material) is similar across mammals, we calculate bone mass, and our results show that the SH hominins had on average heavier long bones than extant humans of the same size. From the femoral weight at hand, we have estimated the total skeletal weight in two SH individuals, which is about 36% heavier than in the recent humans of the equivalent body size. Using different methods and skeletal variables, including skeletal weight, to estimate body mass in these two SH humans, we highlight the considerable differences in body mass estimates we obtained, and that the largest body mass estimate is the one based on the skeletal weight. Our results suggest that we cannot assume the same relative proportion of bone volume and bone and skeletal weight characterized the entire genus Homo. Given that skeletal weight has a significant influence on body mass, current body mass estimates of fossil Homo specimens could be systematically underestimated. Thus, the significantly larger bone volume and heavier bones, probably throughout the entire skeleton, of SH humans could have had consequences for many biological parameters in this Pleistocene population and considerable importance for studies focusing on adaptive and ecologically relevant characteristics. Although more recent human samples should be analyzed, in our view, the high skeletal robusticity of the SH sample, including larger bone volume and skeletal weight, is part of their adaptive body type selected for throughout the Pleistocene to support different mechanical and activity regimes and formed under tight genetic control, including control over bone formative and regulatory processes.

A diachronic examination of biomechanical changes in skeletal remains from Tombos in ancient Nubia

Using morphometric assessment, we diachronically analyse mechanical stress and limb function at the Tombos (modern Sudan) archaeological site through time and changing socioeconomic circumstances. Based on previous research, we expect that during the Third Intermediate/Napatan (c. 1070-656 BCE) people were larger and more physically active than in the New Kingdom (∼1400-1070 BCE). On the appendicular skeleton of adults 57 measurements were obtained on individuals from 67 discrete burials and 370 commingled skeletal elements. These raw measurements were analysed statistically. Individuals from the discrete burials were used to calculate body mass and estimate mechanical behaviour (torsional and bending rigidity of long bones) modeled using beam theory across several bones of the upper and lower limbs. Body mass estimates for both sexes show people during the Third Intermediate/Napatan period were statistically significantly larger. On the upper limb for both sexes, variation reflects joint stabilisation and actions of flexion and extension at the elbow and/or supination/pronation of the forearm. On the lower limb, females show variation related to weight bearing activities and foot flexion; male variation is related to weight bearing activities, joint movement and stabilisation. These data point to altered habitual behaviour and physical activity for both sexes at Tombos through time. Suggested causes for both sexes include increased agricultural activities, and for males increased granite quarrying and equestrian activities. Using analyses of multiple bones of the upper and lower limbs in conjunction with biomechanical analyses, this study demonstrates the importance of the examination of physical activities in past populations, highlighting changes that can occur with sociopolitical transitions.

Estimating body mass and composition from proximal femur dimensions using dual energy x-ray absorptiometry

Body mass prediction from the skeleton most commonly employs femoral head diameter (FHD). However, theoretical predictions and empirical data suggest the relationship between mass and FHD is strongest in young adults, that bone dimensions reflect lean mass better than body or fat mass and that other femoral measurements may be superior. Here, we generate prediction equations for body mass and its components using femoral head, neck and proximal shaft diameters and body composition data derived from dual-energy x-ray absorptiometry (DXA) scans of young adults (n = 155, 77 females and 78 males, mean age 22.7 ± 1.3 years) from the Andhra Pradesh Children and Parents Study, Hyderabad, India. Sex-specific regression of log-transformed data on femoral measurements predicted lean mass with smaller standard errors of estimate (SEEs) than body mass (12-14% and 16-17% respectively), while none of the femoral measurements were significant predictors of fat mass. Subtrochanteric mediolateral shaft diameter gave lower SEEs for lean mass in both sexes and for body mass in males than FHD, while FHD was a better predictor of body mass in women. Our results provide further evidence that lean mass is more closely related to proximal femur dimensions than body or fat mass and that proximal shaft diameter is a better predictor than FHD of lean but not always body mass. The mechanisms underlying these relationships have implications for selecting the most appropriate measurement and reference sample for estimating body or lean mass, which also depend on the question under investigation.

The effect of ontogeny on estimates of KNM-WT 15000's adult body size

The Homo erectus specimen KNM-WT 15000 has played a critical role in our understanding of body size evolution. New interpretations suggest that KNM-WT 15000 had a younger age-at-death and a more rapid ontogenetic trajectory than previously suggested. Recent fossil discoveries and new interpretations suggest a wide range of body size and shape variation in H. erectus. Based on these new insights, we argue that KNM-WT 15000's adult stature and body mass could have been much smaller than has been traditionally presented in the literature. Using chimpanzee and modern human growth trajectories, we bracketed the range of possibilities for KNM-WT 15000's adult body size between 160.0 and 177.7 cm (5'3″-5'10″) for stature and 60.0 and 82.7 kg (132-182 lbs.) for body mass. These estimates put KNM-WT 15000 near the mean rather than among the largest known H. erectus specimens.

Relationship between body mass, lean mass, fat mass, and limb bone cross-sectional geometry: Implications for estimating body mass and physique from the skeleton

OBJECTIVES

Estimating body mass from skeletal dimensions is widely practiced, but methods for estimating its components (lean and fat mass) are poorly developed. The ability to estimate these characteristics would offer new insights into the evolution of body composition and its variation relative to past and present health. This study investigates the potential of long bone cross-sectional properties as predictors of body, lean, and fat mass.

MATERIALS AND METHODS

Humerus, femur and tibia midshaft cross-sectional properties were measured by peripheral quantitative computed tomography in sample of young adult women (n = 105) characterized by a range of activity levels. Body composition was estimated from bioimpedance analysis.

RESULTS

Lean mass correlated most strongly with both upper and lower limb bone properties (r values up to 0.74), while fat mass showed weak correlations (r ≤ 0.29). Estimation equations generated from tibial midshaft properties indicated that lean mass could be estimated relatively reliably, with some improvement using logged data and including bone length in the models (minimum standard error of estimate = 8.9%). Body mass prediction was less reliable and fat mass only poorly predicted (standard errors of estimate ≥11.9% and >33%, respectively).

DISCUSSION

Lean mass can be predicted more reliably than body mass from limb bone cross-sectional properties. The results highlight the potential for studying evolutionary trends in lean mass from skeletal remains, and have implications for understanding the relationship between bone morphology and body mass or composition.

Rich table but short life: Diffuse idiopathic skeletal hyperostosis in Danish astronomer Tycho Brahe (1546-1601) and its possible consequences

The exhumation of Danish astronomer Tycho Brahe (1546–1601) was performed in 2010 to verify speculative views on the cause of his death. Previous analyses of skeletal and hair remains recovered from his grave refuted the presumption that he died from poisoning. These studies also outlined the possibility that he actually died from an acute illness, echoing the rather vague and inaccurate testimony of some historical records. We performed a detailed paleopathological analysis of Tycho Brahe’s skeletal remains, along with a reconstruction of his diet based on carbon and nitrogen stable isotopes analysis and an estimate of his physical status (relative body fat) based on medullar and cortical dimensions of the femoral shaft. The astronomer’s remains exhibit bone changes indicative of diffuse idiopathic skeletal hyperostosis (DISH). The study further allows us to classify him as obese (100% reliability according to our decision tree designed from Danish males), and points out his rich diet (high input of animal protein and/or marine resources) and high social status. Comorbidities of DISH and obesity are reviewed, and their influence on health status is discussed. We further consider some conditions associated with metabolic syndrome as possible causes of Tycho Brahe’s final symptoms (urinary retention, renal failure and coma), including diabetes, alcoholic ketoacidosis and benign prostatic hypertrophy. Although a definite and specific diagnosis cannot be established, our study points to today’s civilization diseases often associated with DISH and metabolic syndrome as the possible cause of death of Tycho Brahe.

Smaller long bone cross-sectional size in people who died of tuberculosis: Insights on frailty factors from a 19th and early 20th century Finnish population

There is little research on how individuals suffering from tuberculosis may differ from those not infected in terms of overall skeletal morphology. Tuberculosis was endemic in 19th and early 20th century Finland making documented skeletal collections of Finns ideal to study effects of the disease on bone. The present study compares long bone cross-sectional total area between individuals who died of tuberculosis and those with another recorded cause of death in a Finnish sample. Adult male individuals (N = 105) were selected for analysis. Complete humeri (N = 56), femora (N = 66) and tibiae (N = 64) were 3D scanned using a laser scanner and total cross-sectional areas calculated with AsciiSection software. Individuals who died of tuberculosis (N = 24, 15 humeri, 14 femora, 13 tibiae) had, when standardized for body size, significantly smaller total cross-sectional femoral and humeral, but not tibial, areas. The mechanisms behind the observed relationship may reflect a combination of biological 'frailty' in terms of susceptibility to infection, reduced childhood activity and/or vitamin D deficiency, which possibly influenced both subperiosteal development during adolescence and, later, susceptibility to contracting and dying of TB. Due to the relatively small sample future studies are needed to further investigate the relationship between TB and bone cross-sectional size.

Assessing the accuracy of body mass estimation equations from pelvic and femoral variables among modern British women of known mass

Femoral head diameter is commonly used to estimate body mass from the skeleton. The three most frequently employed methods, designed by Ruff, Grine, and McHenry, were developed using different populations to address different research questions. They were not specifically designed for application to female remains, and their accuracy for this purpose has rarely been assessed or compared in living populations. This study analyzes the accuracy of these methods using a sample of modern British women through the use of pelvic CT scans (n = 97) and corresponding information about the individuals' known height and weight. Results showed that all methods provided reasonably accurate body mass estimates (average percent prediction errors under 20%) for the normal weight and overweight subsamples, but were inaccurate for the obese and underweight subsamples (average percent prediction errors over 20%). When women of all body mass categories were combined, the methods provided reasonable estimates (average percent prediction errors between 16 and 18%). The results demonstrate that different methods provide more accurate results within specific body mass index (BMI) ranges. The McHenry Equation provided the most accurate estimation for women of small body size, while the original Ruff Equation is most likely to be accurate if the individual was obese or severely obese. The refined Ruff Equation was the most accurate predictor of body mass on average for the entire sample, indicating that it should be utilized when there is no knowledge of the individual's body size or if the individual is assumed to be of a normal body size. The study also revealed a correlation between pubis length and body mass, and an equation for body mass estimation using pubis length was accurate in a dummy sample, suggesting that pubis length can also be used to acquire reliable body mass estimates. This has implications for how we interpret body mass in fossil hominins and has particular relevance to the interpretation of the long pubic ramus that is characteristic of Neandertals.

Body mass prediction from femoral volume and sixteen other femoral variables in the elderly: BMI and adipose tissue effects

OBJECTIVES

The frequently used prediction equations of body mass do not seem appropriate for elderly individuals. Here, we establish the relationship between femoral dimensions and known body mass in elderly individuals in order to develop prediction formulas and identify the factors affecting their accuracy.

MATERIALS AND METHODS

The body mass linear least-squares regression is based on 17 femoral dimensions, including femoral volume, and 66 individuals. Body proportion and composition effects on accuracy are analyzed by means of the body mass index (BMI) and on a subset sample (n = 25), by means of the masses of adipose, bone and muscle tissues.

RESULTS

Most variables significantly reflect body mass. Among them, six dimensions (e.g., biepicondylar breadth, femoral volume, and head femoral diameter) present percent standard errors of estimate ranging from 9.5 to 11% (r = 0.72-0.81) in normal BMI samples. Correlations are clearly lower in samples with normal and abnormal BMI [r = 0.38-0.58; % of standard error of estimate (SEE) = 17.3-19.6%] and not significantly correlated in females (femoral volume) who present high proportions of abnormal BMI and adipose tissue. In the subset, femoral volume is well correlated with bone mass (r = 0.88; %SEE = 7.9%) and lean body mass (r = 0.67; %SEE = 17.2%).

DISCUSSION

Our body mass estimation equations for elderly individuals are relevant since relatively low correlations are recurrent in studies using younger individuals of known body mass. However, age, sex, lifestyle, and skeleton considerations of studied populations can provide information about the relevance of the body mass estimation, which is dependent on the BMI classification and the proportion of adipose tissue. Our general considerations can be used for studies of younger individuals.

Lower limb articular scaling and body mass estimation in Pliocene and Pleistocene hominins

Previous attempts to estimate body mass in pre-Holocene hominins have relied on prediction equations derived from relatively limited extant samples. Here we derive new equations to predict body mass from femoral head breadth and proximal tibial plateau breadth based on a large and diverse sample of modern humans (avoiding the problems associated with using diaphyseal dimensions and/or cadaveric reference samples). In addition, an adjustment for the relatively small femoral heads of non-Homo taxa is developed based on observed differences in hip to knee joint scaling. Body mass is then estimated for 214 terminal Miocene through Pleistocene hominin specimens. Mean body masses for non-Homo taxa range between 39 and 49 kg (39-45 kg if sex-specific means are averaged), with no consistent temporal trend (6-1.85 Ma). Mean body mass increases in early Homo (2.04-1.77 Ma) to 55-59 kg, and then again dramatically in Homo erectus and later archaic middle Pleistocene Homo, to about 70 kg. The same average body mass is maintained in late Pleistocene archaic Homo and early anatomically modern humans through the early/middle Upper Paleolithic (0.024 Ma), only declining in the late Upper Paleolithic, with regional variation. Sexual dimorphism in body mass is greatest in Australopithecus afarensis (log[male/female] = 1.54), declines in Australopithecus africanus and Paranthropus robustus (log ratio 1.36), and then again in early Homo and middle and late Pleistocene archaic Homo (log ratio 1.20-1.27), although it remains somewhat elevated above that of living and middle/late Pleistocene anatomically modern humans (log ratio about 1.15).

Can we refine body mass estimations based on femoral head breadth?

Femoral head breadth is widely used in body mass estimation in biological anthropology. Earlier research has demonstrated that reduced major axis (RMA) equations perform better than least squares (LS) equations. Although a simple RMA equation to estimate body size from femoral head breadth is sufficient in most cases, our experiments with male skeletons from European data (including late Pleistocene and Holocene skeletal samples) and the Forensic Anthropology Data Bank data (including the W. M. Bass Donated Skeletal Collection sample) show that including femoral length or anatomically estimated stature in an equation with femoral head breadth improves body mass estimation precision. More specifically, although directional bias related to body mass is not reduced within specific samples, the total estimation error range, directional bias related to stature, and temporal fluctuation in estimation error are markedly reduced. The overall body mass estimation precision of individuals representing different temporal periods and ancestry groups (e.g., African and European ancestry) is thus improved.