Estimated Body Mass Research Articles

Middle Pleistocene Variations in the Diet of Equus in the South of France and Its Morphometric Adaptations to Local Environments

Equus is a very sensitive genus which has expanded over a large area and lived in Europe despite the climatic instability of the Pleistocene. Its persistence and abundance are helpful in understanding and describing environmental and climatic regional parameters. In this study, we present the result of dental mesowear and microwear analysis and post-cranial skeleton biometry on Equus populations located in two regions in the South of France from ten sites, corresponding to twelve assemblages dated from MIS 12 to MIS 5. The areas refer to two major climatic zones: the oceanic or subcontinental climate for the South West of France, and the Mediterranean for the South East. The first objective of this study is to integrate and compare biometric data, dental wear, and other already-published environmental proxies. The goal is to discuss the validity of horse body shape adaptations on a small geographical scale. The second objective is to describe the impact of environmental features on the horse population through time in the two regions. We observe that the Equus diet was quite diverse, according to microwear analysis which shows adaptations according to seasonal variations. However, they remained mostly grazers over a long period of time. Estimated body mass of Equus in the localities studied here varies from a mean of 468 up to a mean of 570 kg, but these variations failed to be correlated with the diet, the climatic period, or the geographical position of the horse population, probably because of the sample size or the restricted time-span or geographical scale. However, the conformation of the metapodials and the width of the third phalanges may have been linked with environmental and behavioural parameters. The width of the third phalange may be correlated with the recurrence of the snow cover, while the robustness of the metapodial co-occurs with a humid climate. Also, diet may influence the conformation of the bones, since the tall and slender horses seem to be preferentially grazers all year long and seasonally browser horses are tall and robust. Seasonally mixed-feeder horses, all coming from the Mediterranean area, were found to be smaller, perhaps in relation to a less productive environment. The correspondence of the dietary and morphometrical data could suggest high pressure on the horse population, which caused rapid body adaptation. Thus, the combination of these different proxies allows us to suggest more accurate large mammal paleoenvironmental reconstructions.

The diet of early birds based on modern and fossil evidence and a new framework for its reconstruction.

ABSTRACTBirds are some of the most diverse organisms on Earth, with species inhabiting a wide variety of niches across every major biome. As such, birds are vital to our understanding of modern ecosystems. Unfortunately, our understanding of the evolutionary history of modern ecosystems is hampered by knowledge gaps in the origin of modern bird diversity and ecosystem ecology. A crucial part of addressing these shortcomings is improving our understanding of the earliest birds, the non‐avian avialans (i.e. non‐crown birds), particularly of their diet. The diet of non‐avian avialans has been a matter of debate, in large part because of the ambiguous qualitative approaches that have been used to reconstruct it. Here we review methods for determining diet in modern and fossil avians (i.e. crown birds) as well as non‐avian theropods, and comment on their usefulness when applied to non‐avian avialans. We use this to propose a set of comparable, quantitative approaches to ascertain fossil bird diet and on this basis provide a consensus of what we currently know about fossil bird diet. While no single approach can precisely predict diet in birds, each can exclude some diets and narrow the dietary possibilities. We recommend combining (i) dental microwear, (ii) landmark‐based muscular reconstruction, (iii) stable isotope geochemistry, (iv) body mass estimations, (v) traditional and/or geometric morphometric analysis, (vi) lever modelling, and (vii) finite element analysis to reconstruct fossil bird diet accurately. Our review provides specific methodologies to implement each approach and discusses complications future researchers should keep in mind. We note that current forms of assessment of dental mesowear, skull traditional morphometrics, geometric morphometrics, and certain stable isotope systems have yet to be proven effective at discerning fossil bird diet. On this basis we report the current state of knowledge of non‐avian avialan diet which remains very incomplete. The ancestral dietary condition in non‐avian avialans remains unclear due to scarce data and contradictory evidence in Archaeopteryx. Among early non‐avian pygostylians, Confuciusornis has finite element analysis and mechanical advantage evidence pointing to herbivory, whilst Sapeornis only has mechanical advantage evidence indicating granivory, agreeing with fossilised ingested material known for this taxon. The enantiornithine ornithothoracine Shenqiornis has mechanical advantage and pedal morphometric evidence pointing to carnivory. In the hongshanornithid ornithuromorph Hongshanornis only mechanical advantage evidence indicates granivory, but this agrees with evidence of gastrolith ingestion in this taxon. Mechanical advantage and ingested fish support carnivory in the songlingornithid ornithuromorph Yanornis. Due to the sparsity of robust dietary assignments, no clear trends in non‐avian avialan dietary evolution have yet emerged. Dietary diversity seems to increase through time, but this is a preservational bias associated with a predominance of data from the Early Cretaceous Jehol Lagerstätte. With this new framework and our synthesis of the current knowledge of non‐avian avialan diet, we expect dietary knowledge and evolutionary trends to become much clearer in the coming years, especially as fossils from other locations and climates are found. This will allow for a deeper and more robust understanding of the role birds played in Mesozoic ecosystems and how this developed into their pivotal role in modern ecosystems.

Integration of tetrapod ichnofaunas and coastal dynamics for paleocommunity reconstruction in the Curtis and Summerville formations (Jurassic), eastern Utah

ABSTRACT The transition between the aeolian Moab Member of the Curtis Formation and the marginal marine upper tongue of the Summerville Formation, in the area of Arches National Park, Utah, facilitated the registration of the distinctive theropod-dominated Moab Megatracksite complex, which is something of an ichnological cause célèbre. The complex reveals three interpenetrating ichnofaunas each with distinctive ichnofacies characteristics. The present study focuses on the small theropod-dominated assemblages from the coastal dune facies and applies Walther’s Law of Facies to the sequence relationship between onshore ichnoassemblages, the late pulse of transgression by the Summerville sea, and the development of the shallow marine Pteraichnus ichnocoenosis. Together, these spatio-temporal facies relationship between onshore terrestrial, shoreline and shallow marine facies and their contained ichnofaunas shed useful light on the Late Jurassic tetrapod ecology of the region, in an area entirely lacking tetrapod body fossils. The small theropod dune ichnofauna has obvious precursors in other Jurassic dune facies. The shoreline and shallow marine ichnocoenosis also fit certain ichnofacies models, despite the lack of comparable ichnofaunas in the area. Abundant trackway size frequency data yield body mass estimates which allow testing of recently proposed palaeobiological theories on theropod ontogeny and community structure based on the skeletal record.

A proximal radius of Barberapithecus huerzeleri from Castell de Barberà: Implications for locomotor diversity among pliopithecoids

Pliopithecoids are a diverse group of Miocene catarrhine primates from Eurasia. Their positional behavior is still unknown, and many species are known exclusively from dentognathic remains. Here, we describe a proximal radius (IPS66267) from the late Miocene of Castell de Barberà (Vallès-Penedès Basin, NE Iberian Peninsula) that represents the first postcranial specimen of the pliopithecoid Barberapithecus huerzeleri. A body mass estimate based on the radius is compared with dental estimates, and its morphology is compared with that of extant and fossil anthropoids by qualitative means as well as by landmark-based three-dimensional geometric morphometrics. The estimated body mass of ∼5 kg for IPS66267 closely matches the dental estimates for the (female) holotype, thereby discounting an alternative attribution to the large-bodied hominoid recorded at Castell de Barberà. In multiple features (oval and moderately tilted head with a pronounced lateral lip and a restricted articular area for the capitulum; proximodistally expanded proximal radioulnar joint; and short, robust, and anteroposteriorly compressed neck), the specimen differs from hominoids and resembles instead extant nonateline monkeys and stem catarrhines. The results of the morphometric analysis further indicate that the Barberapithecus proximal radius shows closer similarities with nonsuspensory arboreal cercopithecoids and the dendropithecid Simiolus. From a locomotor viewpoint, the radius of Barberapithecus lacks most of the features functionally related to climbing and/or suspensory behaviors and displays instead a proximal radioulnar joint that would have been particularly stable under pronation. On the other hand, the Barberapithecus radius differs from other stem catarrhines in the less anteroposteriorly compressed and less tilted radial head with a deeper capitular fovea, suggesting a somewhat enhanced mobility at the elbow joint. We conclude that pronograde arboreal quadrupedalism was the main component of the locomotor repertoire of Barberapithecus but that, similar to other crouzeliids, it might have displayed better climbing abilities than pliopithecids.

Digital anthropometric volumes: Toward the development and validation of a universal software.

Anthropometry is a method for quantifying body size and shape often used to derive body composition and health risk prediction models. Recent technology advancements led to development of three-dimensional (3D) optical scanners that can overcome most of the limitations associated with manual anthropometric data collection. However, each of the currently available devices offers proprietary measurements that do not match conventional anthropometric definitions. The aim of the current study was to develop and then evaluate the precision and accuracy of new "universal" 3D optical analysis software that calculates digital anthropometric volumes using identical standard landmarks across scanners. Dual-energy x-ray absorptiometry (DXA) and air displacement plethysmography (ADP) total body and regional volume and fat mass reference measurements and 3D optical scans from two proprietary devices were collected from 356 participants to evaluate the robustness of total body and regional volume and fat mass measurements calculated by the developed software. Linear regression modeling with threefold cross validation was used to evaluate total body and regional fat masses from 3D scans. Total body and regional volumes measured by DXA and ADP had strong associations with corresponding estimates from the commercial 3D optical scanners coupled with the universal software (e.g., R2 =0.98 for Styku and R2 =1.00 for SS20, for both DXA and ADP comparisons). Regional body volumes also had strong correlation between DXA and the 3DO scanners (e.g., for arm, leg and trunk, respective R2 s of 0.75, 0.86, and 0.97 for Styku and 0.79, 0.89, and 0.98 for SS20). Similarly, there were strong associations between DXA- measured total body and regional fat mass and 3D optical estimates calculated by the universal software (e.g., for total body, arm, leg and trunk, respective R2 s of 0.86, 0.72, 0.77, and 0.88 for Styku and 0.84, 0.76, 0.78, and 0.85 for SS20). Absolute differences in volumes and fat mass between the reference methods and the universal software values revealed underlying proprietary scanner differences that can be improved when designing future devices. The current study suggests that, when compared against values calculated using DXA and ADP, the universal software was able to measure total and regional body volumes reliably from scans obtained by two different scanners. The universal software, with future refinements, combined with potential optical scanner design improvements, creates new opportunities for developing large multicenter anthropometric databases with uniformly defined body dimensions that can be used for modeling health risks. Shape Up! Adults Study, NCT0363785.

Volumetric Body Mass Estimate and in vivo Reconstruction of the Russian Pareiasaur Scutosaurus karpinskii

Pareiasaurs (Amniota, Parareptilia) were characterized by a global distribution during the Permian period, forming an important component of middle (Capitanian) and late Permian (Lopingian) terrestrial tetrapod biodiversity. This clade represents an early evolution of sizes over a ton, playing a fundamental role in the structure of middle and late Permian biodiversity and ecosystems. Despite their important ecological role and relative abundance around the world, our general knowledge of the biology of these extinct tetrapods is still quite limited. In this contribution we provide a possiblein vivoreconstruction of the largest individual of the speciesScutosaurus karpinskiiand a volumetric body mass estimate for the taxon, considering that body size is one of the most important biological aspects of organisms. The body mass ofScutosauruswas calculated using a 3D photogrammetric model of the complete mounted skeleton PIN 2005/1537 from the Sokolki locality, Arkhangelsk Region, Russia, on exhibit at the Borissiak Paleontological Institute, Russian Academy of Sciences (Moscow). By applying three different densities for living tissues of 0.99, 1, and 1.15 kg/1,000 cm3to reconstructed “slim,” “average” and “fat” 3D models we obtain average body masses, respectively, of 1,060, 1,160, and 1,330 kg, with a total range varying from a minimum of one ton to a maximum of 1.46 tons. Choosing the average model as the most plausible reconstruction and close to the natural condition, we consider a body mass estimate of 1,160 kg as the most robust value forScutosaurus, a value compatible with that of a large terrestrial adult black rhino and domestic cow. This contribution demonstrates that barrel-shaped herbivores, subsisting on a high-fiber diet and with a body mass exceeding a ton, had already evolved in the upper Palaeozoic among parareptiles, shedding new light on the structure of the first modern terrestrial ecosystems.

Sexual dimorphism in the fossil ground sloth Lestodon armatus (Xenarthra, Folivora)

ABSTRACT Mylodontidae (Mammalia, Xenarthra) is a family of ground sloths widely distributed in the South American fossil record, with members also present in Central and North America. Within the Mylodontidae, Lestodon armatus is the largest species, with an estimated body mass of more than three tonnes. This work focuses on the enlarged lower caniniforms of L. armatus as possibly exaggerated sexually dimorphic structures. Lower caniniforms from the late Pleistocene of Argentina, Uruguay, and Bolivia were studied using specimens from seven palaeontological collections. The possible sexual dimorphism in the caniniforms and its implications regarding the existence of sexual selection was assessed through morphometric analyses. The results support the existence of sexual dimorphism in L. armatus. Sexual dimorphism in an exaggerated structure in a large mammal suggests the existence of sexual selection, via competition between males or female mate choice, resulting in the evolution of the dimorphic structure. In L. armatus, the enlarged caniniforms would correspond to males and could have functioned as armaments in intraspecific fights or ornaments for sexual display. Based on observations in extant mammals, a polygynous mating system is proposed as highly probable in L. armatus, although the existence or composition of social groups cannot be certainly determined.

Allometric scaling and growth: Evaluation and applications in subadult body mass estimation.

Previously developed methods in subadult body mass estimation have not been tested in populations other than European-American or African-American. This study uses a contemporary Taiwanese sample to test these methods. Through evaluating their accuracy and bias, we addressed whether the allometric relationships between body mass and skeletal traits commonly used in subadult body mass estimation are conserved among different populations. Computed tomography scans of lower limbs from individuals aged 0-17 years old of both sexes were collected from National Taiwan University Hospital along with documented body weight. Polar second moment of area, distal femoral metaphyseal breadth, and maximum superior/inferior femoral head diameter were collected either directly from the scans or from reconstructed 3D models. Estimated body mass was compared with documented body mass to assess the performance of the equations. Current methods provided good body mass estimates in Taiwanese individuals, with accuracy and bias similar to those reported in other validation studies. A tendency for increasing error with increasing age was observed for all methods. Reduced major axis regression showed the allometric relationships between different skeletal traits and body mass across different age categories can all be summarized using a common fitted line. A revised, maximum likelihood-based approach was proposed for all skeletal traits. The results suggested that the allometric relationships between body mass and different skeletal traits are largely conserved among populations. The revised method provided improved applicability with strong underlying theoretical justifications, and potential for future improvements.

Body mass estimation from footprint size in hominins

Although many studies relating stature to foot length have been carried out, the relationship between foot size and body mass remains poorly understood. Here we investigate this relationship in 193 adult and 50 juvenile habitually unshod/minimally shod individuals from five different populations—Machiguenga, Daasanach, Pumé, Hadzabe, and Samoans—varying greatly in body size and shape. Body mass is highly correlated with foot size, and can be predicted from foot area (maximum length × breadth) in the combined sample with an average error of about 10%. However, comparisons among populations indicate that body shape, as represented by the body mass index (BMI), has a significant effect on foot size proportions, with higher BMI samples exhibiting relatively smaller feet. Thus, we also derive equations for estimating body mass from both foot size and BMI, with BMI in footprint samples taken as an average value for a taxon or population, estimated independently from skeletal remains. Techniques are also developed for estimating body mass in juveniles, who have relatively larger feet than adults, and for converting between foot and footprint size. Sample applications are given for five Pliocene through Holocene hominin footprint samples from Laetoli (Australopithecus afarensis), Ileret (probable Homo erectus), Happisburgh (possible Homo antecessor), Le Rozel (archaic Homo sapiens), and Barcin Höyük (H. sapiens). Body mass estimates for Homo footprint samples appear reasonable when compared to skeletal estimates for related samples. However, estimates for the Laetoli footprint sample using the new formulae appear to be too high when compared to skeletal estimates for A. afarensis. Based on the proportions of A.L. 288-1, this is apparently a result of relatively large feet in this taxon. A different method using a ratio between body mass and foot area in A.L. 288-1 provides estimates more concordant with skeletal estimates and should be used for A. afarensis.

New species of Yuomys (Rodentia, Ctenodactyloidea) from the upper Eocene of eastern Ningxia, China

ABSTRACT A new species, Yuomys robustus of the ctenodactyloid rodent Yuomys, is described in the paper. It is from the Western margin of the Ordos Basin District in eastern Ningxia Hui Autonomous Region, China. Yuomys robustus is characterized by a combination of features: large size, high tooth crown, having a postparacrista on M2 and lacking hypocone on P4. We also emended the diagnosis of type species of Yuomys, Y. cavioides. It is characterized by the absence of hypocone on P4, having a distinct ridge connecting the metaconule to the protocone on M1–M3, a postparacrista on M1, a mesostyle on M2, and a small ridge or spur on the mesial side of the protoloph on P4 and M1; the hypoconid smaller than the protoconid and is elongated, the paraconid absent and the mesostylid faintly visible on p4, but well developed on m1–m3; the talonid basin, sinusid, and posteroflexid are large and open on lower cheek teeth. The occurrence of Lophiomeryx angarae in the same stratigraphic layer as Y. robustus indicates that the horizon is possibly late Eocene in age, not early Oligocene as suggested by previous workers. Body mass estimations of Y. cavioides, Y. eleganes, and Y. robustus show that their weights are roughly in the range of 485–880 g, which is in between those of extant Myospalax and Ratufa. From the middle Eocene to the late Eocene, Yuomys exhibited a trend of gradually enlarging the cheek teeth, and increasing the tooth crown height and body mass.

Calcaneal allometry in humans and nonhuman primates

Body mass critically impacts locomotion because it largely determines the mechanical requirements for supporting and propelling the body against gravity. Primate long bone proportions relative to body mass and locomotion have been extensively studied; however, these relationships are less well understood in the foot. The scaling of the calcaneus is particularly important because of its weight-bearing role during locomotion. Here, we analyze calcaneal allometry in humans (n=120) and nonhuman primates (n=278) to investigate scaling relationships relative to known locomotor differences. Twelve linear measures, as well as articular facet surface areas, were collected on calcaneus surface models in Avizo Lite 9.0.1. Femoral head superoinferior breadth and established regression equations were used to estimate body mass (EBM). Calcaneal measures were regressed against EBM using phylogenetic least squares regression analyses conducted at different taxonomic levels to determine how the inclusion of multiple (sub)species within a genus impacted the presence of phylogenetic signal in our dataset. Reduced major axis ANCOVAs were used to test for significant differences between humans and (pooled) nonhuman primates. Residuals from isometry both among and within genera were evaluated with ANOVAs and post hoc multiple comparison tests. When analyzed at the (sub)species level, all but two dimensions relative to EBM exhibit phylogenetic signals. These signals are no longer apparent at the genus level, suggesting variation among the genera is driven by some factor other than phylogeny, such as body size or locomotion. Bipedally adapted humans display relatively larger calcaneal dimensions than nonhuman primates. Among nonhuman great apes, more arboreal taxa exhibit relatively larger cuboid facet surface areas, increasing midfoot mobility for movement over unpredictable substrates. More terrestrial taxa exhibit relatively longer calcaneal tubers for EBM, which serves to increase the muscle lever arm, and thus mechanical advantage, of the triceps surae muscle.

Scaling and relative size of the human, nonhuman ape, and baboon calcaneus.

Among human and nonhuman apes, calcaneal morphology exhibits significant variation that has been related to locomotor behavior. Due to its role in weight-bearing, however, both body size and locomotion may impact calcaneal morphology. Determining how calcaneal morphologies vary as a function of body size is thus vital to understanding calcaneal functional adaptation. Here, we study calcaneus allometry and relative size in humans (n=120) and nonhuman primates (n=278), analyzing these relationships in light of known locomotor behaviors. Twelve linear measures and three articular facet surface areas were collected on calcaneus surface models. Body mass was estimated using femoral head superoinferior breadth. Relationships between calcaneal dimensions and estimated body mass were analyzed across the sample using phylogenetic least squares regression analyses (PGLS). Differences between humans and pooled nonhuman primates were tested using RMA ANCOVAs. Among (and within) genera residual differences from both PGLS regressions and isometry were analyzed using ANOVAs with post hoc multiple comparison tests. The relationships between all but two calcaneus dimensions and estimated body mass exhibit phylogenetic signal at the smallest taxonomic scale. This signal disappears when reanalyzed at the genus level. Calcaneal morphology varies relative to both body size and locomotor behavior. Humans have larger calcanei for estimated body mass relative to nonhuman primates as a potential adaptation for bipedalism. More terrestrial taxa exhibit longer calcaneal tubers for body mass, increasing the triceps surae lever arm. Among nonhuman great apes, more arboreal taxa have larger cuboid facet surface areas for body mass, increasing calcaneocuboid mobility.

Improving estimates of body mass in American black bears using morphometrics and non-linear models

Measuring the body mass of American black bears (Ursus americanus) can be challenging because of their large size, and if equipment to weigh individuals is undersupplied. Our purpose was to estimate body mass of Florida black bears (U. a. floridanus) by developing models (linear and non-linear) that use morphometrics that can be reasonably easy to obtain (e.g., chest girth and body length). We compared our models with a previously published model for Florida black bears to determine whether prediction of body mass could be improved. Our models were built with current data (2012–2018; n = 532) collected across Florida, USA, by the Florida Fish and Wildlife Conservation Commission. We partitioned the data into training and test subsets using 10-fold cross-validation with 100 iterations. Model fit was assessed by comparing root mean square error (RMSE), mean absolute error (MAE), and coefficient of determination (R2) of observed and predicted values. Based on RMSE, MAE, and R2, our optimal regression model for predicting mass (M) of both female and male bears used both chest girth (G) and total body length (L) as predictors in the non-linear form M = aGb × Lc. Our optimal model was a better fit than the previously published model when both were applied to the full data sets from the current and previous study and to an independent data set. We applied our optimal non-linear regression models built from live bear data to morphological data collected from bear carcasses (n = 544), mainly road mortalities. We found that the live-bear models acceptably estimated mass of dead bears for both sexes. Estimating the mass of live and dead bears can expedite handling time of individuals, fill in data gaps, and provide valuable information on the Florida black bear; our approach may be applicable to American black bears range-wide.

Association between parental socioeconomic status and offspring overweight/obesity from the China Family Panel Studies: a longitudinal survey

ObjectiveTo examine the association between parental socioeconomic status (SES) and the risk of offspring overweight/obesity and the changes of the association that occur as children grow older.DesignWe used data from...

Human and hutia (Isolobodon portoricensis) interactions in pre-Columbian Hispaniola: The isotopic and morphological evidence

There are certain animal candidates for which researchers have long speculated as having been managed, or possibly domesticated, by indigenous peoples in the pre-Columbian Caribbean, the primary candidate being some members of a group of caviomorph rodents known as hutia (Capromyinae). This study comprises an isotopic and morphological investigation of the potential management of an extinct species endemic to Hispaniola, the Puerto Rican hutia (Isolobodon portoricensis). For comparisons, isotopic analysis was conducted of bone collagen samples examining carbon (∂13Cco) and nitrogen (∂15N) values of I. portoricensis with two other species of endemic hutia, guinea pig (Cavia porcellus), Antillean slider (Trachemys stejnegeri), rhinoceros iguana (Cyclura cornuta) and edible rat (Brotomys sp.) from four sites in the Dominican Republic: El Flaco, El Carril, El Cabo and La Entrada. This data was compared to human and dog collagen values available from El Flaco to assess similarities between these groups. Osteometric data was recorded for hutia mandibles, allowing for body mass estimations (n = 230). The findings suggest that some Isolobodon portoricensis specimens possessed carbon (δ13Cco) values similar to humans and dogs at El Flaco, possibly associated with the consumption of agriculturally produced maize. This research does not indicate whether domestication or management of this species was occurring, at least not in a systematic way. Concurrence with palaeoenvironmental and zooarchaeological data from the region in which El Flaco and El Carril are located indicate that indigenous agricultural practices may have affected populations of hutia, perhaps by attracting them and supporting them within anthropogenic mosaic landscapes. The data also suggests that some degree of either purposeful feeding or scavenging from human agricultural plots was occurring and supports some degree of commensalism between humans and Puerto Rican hutia at these sites.

Estimation of body mass in white-tailed deer (Odocoileus virginianus) using cross-sectional geometry of the metapodial

Zooarchaeologists have developed and used several techniques for estimating the body mass of individual prey animals. Many of these are based on skeletal variables such as minimum number of individuals, weight of remains, or linear dimensions of long bone articular ends. All of these techniques fail to account for individual variability in body mass across the lifespan driven by the primary productivity of the landscape, sex, ontogeny, and season of individual death. Because skeletons are weight-bearing, they constantly remodel in response to changes in body mass, making long bone cross-sectional properties an ideal metric for predicting body mass. Cross-sectional geometric properties of distal limb bones and body mass of white-tailed deer (Odocoileus virginianus) were measured in a sample of 64 recently harvested individuals. Best-fit regressions between cross-sectional skeletal dimensions and dressed body weight produce higher R-squared values and lower standard errors of the estimate than regressions between dressed body weight and linear dimensions of long bone articular ends. Cross-sectional geometry can provide new useful line of evidence for estimating body mass of prey animals, when available.

Juvenile Body Mass Estimation from the Femur Using Postmortem Computed Tomography Data.

Skeletal estimation methods to reconstruct the juvenile biological profile are largely limited to those estimating age and, to a lesser extent, sex. While body mass is not generally estimated as part of the biological profile in forensic investigations, this is a logical candidate for inclusion in the forensic biological profile, as it has long been of interest in paleoanthropology and several methods to estimate juvenile body mass currently exist. To explore the performance of body mass estimation for juveniles, the authors tested the accuracy and precision of previously published panel regression formulae using two femoral measurements: the breadth of the distal metaphysis and the cross-sectional polar moment of inertia (J). The test sample consisted of measurements of 94 individuals from birth to 12.5 years of age, taken from postmortem computed tomography scans housed at the Office of the Medical Investigator, New Mexico, USA. Results indicate that body mass estimates are more accurate when estimated from cross-sectional than from metaphyseal measures. Both formulae, however, consistently underestimated weight, and the magnitude of the underestimation increased exponentially with age. This suggests that, contrary to what others have argued, body mass estimation is complicated by population variation in body composition. This study reinforces the importance of documenting and investigating the ontogeny of human variation. The global increase in medical imaging in clinical settings can be leveraged to obtain skeletal data for juveniles from a wide range of ontogenic environments, marking an exciting time for the study of human variation.

A new parapithecine (Primates: Anthropoidea) from the early Oligocene of Libya supports parallel evolution of large body size among parapithecids

Parapithecines are an extinct subfamily of stem anthropoid primates previously known only from the Jebel Qatrani Formation in Egypt. Here, we describe isolated teeth pertaining to Simonsius harujensis sp. nov., a relatively small-bodied parapithecine from strata near Zallah Oasis in the Sirt Basin of central Libya that is estimated to date to ∼31 Ma on the basis of mammalian biostratigraphy. The dental morphology of S. harujensis sp. nov. is generally intermediate between that of the closely related parapithecines Parapithecus fraasi and Simonsius grangeri, highlighting some of the anatomical features distinguishing the latter taxa and providing further support for their generic separation. A phylogenetic analysis using parsimony methods was performed on a character-taxon matrix incorporating data from the new Libyan parapithecine, virtually all other parapithecids and the proteopithecid Proteopithecus sylviae. Results of this analysis suggest that parapithecids comprise a basal clade consisting of three species of Biretia and a more derived clade including Parapithecinae (Parapithecus and Simonsius) and Qatraniinae (Qatrania, Ucayalipithecus, and Apidium). Body mass estimates for parapithecids were calculated on the basis of regression equations generated to predict body mass from the occlusal area of upper and lower cheek teeth in extant anthropoids. The relatively small body mass of S. harujensis sp. nov. and its reconstructed phylogenetic position as the sister group of S. grangeri, which is the largest known parapithecid, support the convergent acquisition of body mass larger than 500 g among multiple clades of early Oligocene African anthropoids. The new Libyan parapithecine augments previously reported evidence supporting a substantial degree of faunal provincialism across northern Africa/Arabia during the early Oligocene.

Testing Equid Body Mass Estimate Equations on Modern Zebras—With Implications to Understanding the Relationship of Body Size, Diet, and Habitats of Equus in the Pleistocene of Europe

The monodactyl horses of the genusEquusoriginated in North America during the Pliocene, and from the beginning of the Pleistocene, they have been an essential part of the large ungulate communities of Europe, North America and Africa. Understanding how body size ofEquusspecies evolved and varied in relation to changes in environments and diet thus forms an important part of understanding the dynamics of ungulate body size variation in relation to Pleistocene paleoenvironmental changes. Here we test previously published body mass estimation equations for the family Equidae by investigating how accurately different skeletal and dental measurements estimate the mean body mass (and body mass range) reported for extant Grevy's zebra (Equus grevyi) and Burchell's zebra (Equus quagga). Based on these tests and information on how frequently skeletal elements occur in the fossil record, we construct a hierarchy of best practices for the selection of body mass estimation equations inEquus. As a case study, we explore body size variation in Pleistocene EuropeanEquuspaleopopulations in relation to diet and vegetation structure in their paleoenvironments. We show a relationship between diet and body size inEquus: very large-sized species tend to have more browse-dominated diets than small and medium-sized species, and paleovegetation proxies indicate on average more open and grass-rich paleoenvironments for small-sized, grazing species ofEquus. When more than one species ofEquusco-occur sympatrically, the larger species tend to be less abundant and have more browse-dominated diets than the smaller species. We suggest that body size variation in PleistoceneEquuswas driven by a combined effect of resource quality and availability, partitioning of habitats and resources between species, and the effect of environmental openness and group size on the body size of individuals.

Macaca ulna from new excavations at the Notarchirico Acheulean site (Middle Pleistocene, Venosa, southern Italy)

In this article, we describe an almost complete macaque mandible from the Middle Pleistocene locality Marathousa 1 in the Megalopolis Basin of southern Greece. The mandible belonged to a male individual of advanced ontogenetic age and of estimated body mass ∼13 kg. Comparative metric analysis of its teeth permits its attribution to the Barbary macaque Macaca sylvanus, a species that was geographically widely distributed in Western Eurasia during the Plio-Pleistocene. The dental dimensions of the Marathousa 1 macaque fit better within the variation of the Early Pleistocene M. s. florentina and the Middle to Late Pleistocene M. s. pliocena rather than with the extant representative M. s. sylvanus. Moreover, principal component analysis reveals a better match with M. s. pliocena. However, because no clear-cut diagnostic criteria have been defined to differentiate these European fossil subspecies, we attribute the Marathousa 1 specimen to M. s. cf. pliocena, in agreement with the chronology of the locality. Previously known only from the Early Pleistocene of Greece by some isolated teeth, this is the first record of Macaca in the Middle Pleistocene of the country and one of very few in the eastern sector of the peri-Mediterranean region. We discuss the presence of macaques in the paleolake environment of Marathousa 1, as well as their predation risks from both carnivores and hominins present at the locality.