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RUNX proteins, such as RUNX2, regulate the proliferation and differentiation of chondrocytes and osteoblasts. Haploinsufficiency of RUNX2 causes cleidocranial dysplasia, but a detailed analysis of Runx2+/− mice has not been reported. Furthermore, CBFB is required for the stability and DNA binding of RUNX family proteins. CBFB has two isoforms, and CBFB2 plays a major role in skeletal development. The calvaria, femurs, vertebrae and ribs in Cbfb2−/− mice were analyzed after birth, and compared with those in Runx2+/− mice. Calvarial development was impaired in Runx2+/− mice but mildly delayed in Cbfb2−/− mice. In femurs, the cortical bone but not trabecular bone was reduced in Cbfb2−/− mice, whereas both the trabecular and cortical bone were reduced in Runx2+/− mice. The trabecular bone in vertebrae increased in Cbfb2−/− mice but not in Runx2+/− mice. Rib development was impaired in Cbfb2−/− mice but not in Runx2+/− mice. These differences were likely caused by differences in the indispensability of CBFB and RUNX2, the balance of bone formation and resorption, or the number and maturation stage of osteoblasts. Thus, different amounts of CBFB and RUNX2 were required among the bone tissues for proper bone development and maintenance.

Purpose Improve understanding of the links between biological variables (sex, body size and anatomical position) and adaptive remodelling of autopodia, and the identification of traction use in the archaeological record. Methods A modified version of the recording system for identifying draught cattle in the archaeological record (Bartosiewicz et al., 1997) was applied to a sample of 1509 bones from six sites from medieval England. Analysis focused on identifying correlations between pathological and sub-pathological changes in lower-limb bones in relation to anatomy, sex and body mass. Results A correlation between sex, body mass and lower limb bone changes was demonstrated. The need to consider anterior and posterior limb bone elements separately to maximise the potential for identifying cattle used for traction was identified. Changes in hindlimb elements were highlighted as the most useful indicator of draught use. Contribution This study provides new, detailed evidence for a previously poorly understood correlation between the effects of anatomical position, sex and body size and the nature of skeletal changes traditionally associated with draught cattle. It pulls together findings and makes comprehensive suggestions for future studies. Limitations This is a purely methodological paper. Although general results are presented, there is insufficient space to include a full case study. This will be published separately within the results of the FeedSax project. Further research Future studies into the use of cattle for draught purposes in the past should take in to account the sex and size of the animals under consideration, and analyse anterior and posterior elements separately.

Terrestrial reptile remains are rare in Early Jurassic deposits from the UK but include important records of early dinosaurs and pterosaurs. Here we report an isolated limb bone from the Charmouth Mudstone Formation (upper Sinemurian) of Charmouth, Dorset that was previously misidentified as a referred specimen of the pterosaur Dimorphodon macronyx. Comparisons with other Early Jurassic tetrapods indicate that this element is the fibula of a neotheropod dinosaur, representing one of only a handful of theropod remains from the Lias Group. Although the material is limited the fibula is distinct from other penecontemporaneous European theropods and might represent a new – though currently undiagnosable – taxon. This, alongside other isolated discoveries, indicates that there might have been a higher diversity of theropod taxa in the Early Jurassic of Europe than is generally appreciated.

Reliable methods are needed to distinguish anthropogenic from non-anthropogenic causes of proboscidean limb bone breakage in fossil assemblages because of theoretical uncertainty about human-proboscidean relationships in the Pleistocene. This paper compares experimentally broken bones of African elephants (Loxodonta africana) and mammoths (Mammuthus spp.) after establishing that limb bone fracture dynamics are the same for those proboscidean taxa. We show that features thought exclusively diagnostic of percussive fracturing of green proboscidean long bones such as notched fracture edges, smooth fracture surfaces, and curvilinear fracture outlines also can be created on non-green bones and on bones affected by non-anthropogenic processes. The information reported here can be applied in analyses or re-analyses of fossil proboscidean bone assemblages and may either support or potentially alter current interpretations of hominin behavior.

The fore‐ and hindlimbs of birds are specialized to perform different functions. The growth patterns of limb bones and their relationship with the ontogeny of locomotion are critical to our understanding of variation in morphological, physiological and life‐history traits within and among species. Unfortunately, the ontogenetic development of limb bones has not been well explored, especially in altricial birds. In this study, we sampled the entire measurements of the pigeon (Columba livia) of individual skeletons, to investigate the ontogenetic allometry of limb bones by reduced major axis regression. The ulna and humerus were found to be positively allometric in relation to body mass, with the ulna growing more rapidly than the humerus. Together with previous data, this suggests that strong positive allometric growth in forelimb bones could be a common trend among diverse Carinatae groups. Hindlimb was dominated by positive allometry, but was variable in the growth of the tarsometatarsus which included three allometric patterns. A greater dorsoventral diameter in the midsection of the humerus and ulna confers superior bending resistance and is ideal for flapping/gliding flight. Shape variation in the midsection of different hindlimb components reflects different mechanical loading, and the markedly inverse trend between the tibiotarsus and tarsometatarsus before 28 days of age also suggests loading change before fledging. Before fledging, the growth of the leg bones was prior to that of the wing bones. This kind of asynchronous development of the fore‐ and hindlimbs was associated with the establishment and improvement of different functions, and with shifts in the importance of different functions over time., Post‐natal growth of limb bones was less explored, especially for altricial birds. We use detailed measurements, including width and depth of the proximal and distal ends, rather than the traditional focus on the length and midshaft width to investigate the ontogenetic allometry of the pigeon (Columba livia). The results of this study provide valuable information in poultry management, and are necessary for kinetics and kinematics studies.

Primate limb morphology is often described as either generalized, that is, suited to a range of locomotor and positional behaviors, or specialized for unique locomotor behaviors such as brachiation or bipedalism. The evolution of highly specialized limb morphology may result in loss of evolvability, that is, in a decreased capacity of the locomotor skeleton to evolve in response to selection towards alternative ecomorphological niches. Using evolutionary simulations, I show that the highly specialized limb anatomy of hominoids is associated with a significant loss of evolvability, defined as the number of generations to reach alternative adaptive peaks, and in parallel an increased risk of extinction, particularly in simulated evolution toward generalized quadrupedal limb proportions. Loss of evolvability in apes and humans correlates with three factors: (1) decreased correlation among limb bone lengths (i.e., integration), which slows the rate of change along lines of least evolutionary resistance; (2) limb specialization, which places apes and humans in relatively remote areas of morphospace; and (3) increased skeletal size as a proxy for body size. Thus, locomotor over-specialization can lead to evolutionary dead-ends that significantly increase the probability of hominoid populations going extinct before evolving new adaptive morphologies.

Diaphyseal cross-sectional geometry (CSG) is an effective indicator of humeral bilateral asymmetry. However, previous studies primarily focused on CSG properties from limited locations to represent the overall bilateral biomechanical performance of humeral diaphysis. In this study, the complete humeral diaphyses of 40 pairs of humeri from three Chinese archaeological populations were scanned using high-resolution micro-CT, and their biomechanical asymmetries were quantified by morphometric mapping. Patterns of humeral asymmetry were compared between sub-groups defined by sex and population, and the representativeness of torsional rigidity asymmetry at the 35% and 50% cross-sections (J35 and J50 asymmetry) was testified. Inter-group differences were observed on the mean morphometric maps, but were not statistically significant. Analogous distribution patterns of highly asymmetrical regions, which correspond to major muscle attachments, were observed across nearly all the sexes and populations. The diaphyseal regions with high variability of bilateral asymmetry tended to present a low asymmetrical level. The J35 and J50 asymmetry were related to the overall humeral asymmetry, but the correlation was moderate and they could not reflect localized asymmetrical features across the diaphysis. This study suggests that the overall asymmetry pattern of humeral diaphysis is more complicated than previously revealed by individual sections.

Limb bone articular and diaphyseal proportions have been shown to relate to locomotor behavior in broad comparisons across catarrhines, but comparisons among phylogenetically and functionally more closely related species may be particularly useful in investigating form-function relationships that can be applied to fossil taxa. Here we compare inter- and intra-limb proportions of diaphyseal strength and articular surface area and breadth of the femur and humerus with frequencies of leaping and vertical climbing behavior in 13 cercopithecid species. Leaping frequency is highly positively correlated with femoral/humeral diaphyseal strength, moderately positively correlated with femoral/humeral articular breadth, and less highly correlated with femoral/humeral articular surface area. These results are consistent with predicted higher bending loads as well as joint reaction forces on the femora of leapers. Surface areas may show a weaker association because they also directly impact joint excursion and are thus more influenced by other aspects of locomotion, including climbing. Climbing frequency is positively correlated with humeral head articular surface area/diaphyseal strength, but weakly negatively correlated with femoral head articular surface area/diaphyseal strength. These combined trends lead to a strong negative association between climbing and femoral/humeral head surface area. Femoral/humeral diaphyseal strength and distal articular breadth are not correlated with climbing frequency. The climbing results are consistent with greater shoulder mobility in more frequent vertical climbers. The lack of such a relationship in the femur among these taxa contrasts with earlier findings for catarrhines more generally, including hominoids, and may be a result of different climbing kinematics in cercopithecoids involving less hip abduction than in hominoids. Different use of the forelimb during climbing in cercopithecoids and hominoids may also explain the lack of association between femoral/humeral diaphyseal strength and climbing in the present study, in contrast to comparisons across catarrhines more generally.

In this paper we analyse the taphonomic signatures of captive jaguars (Panthera onca) in order to explore the potential of experimental frameworks to distinguish between different felid agents in carnivore-altered palaeontological and archaeological bone assemblages. Many papers have considered carnivore ecology and the bone altering behaviour of different animals since the development of taphonomic research since the 1980's, as part of the hunter vs scavenging debate to understand early hominin sites. Hyenas have been the most studied carnivore, followed by felids and lastly canids. Within felids, lions and leopards have been the focus of most research, whereas other agents, such as jaguars or tigers are still relatively uncharacterised taphonomically. Here we present the results of an experimental feeding program to assess the nature and extent of alterations that captive jaguars can produce on horse (Equus ferus caballus) appendicular bones. Working with captive animals has some limitations, namely the generally greater extent of alterations on captive-analysed assemblages in relation to their wild counterparts. Despite this issue, we aim to start developing a broader referential framework of felid ethology that includes jaguars, a relevant taphonomic agent for understanding bone assemblages of the European and American Pleistocene. Therefore, in this preliminary study on the taphonomy of jaguars, we aim to show their prowess as bone-altering agent, capable of generating tooth-marks on long limb bone diaphyses and epiphyseal deletion. The taphonomic behaviour of jaguars has not been documented experimentally in any detail so far.