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The arboreal environment is complex and irregular and imposes significant constraints on the locomotor ability of vertebrates, resulting in morphological adaptations. Carnivorans are of particular interest because they radiated several times independently into the arboreal milieu, leading to convergence in long bone anatomy. We investigated whether the forelimb muscles show differences in arboreal vs. terrestrial species and tested for convergence in muscle architecture. To do so, we studied the forelimb muscles in 17 species of carnivorans with different locomotor modes (arboreal and terrestrial). Our results showed that the forelimb musculature evolved in a convergent manner in arboreal species, resulting in more forceful and heavier wrist rotators and elbow flexors, even when accounting for phylogeny. This suggests that selective forces imposed by the environment drive the evolution of the muscular system towards a convergent phenotype that provides a functional advantage for locomotion in the complex threedimensional arboreal habitat.

The lack of bone morphological markers associated with the human control of wild animals has prevented the documentation of incipient animal domestication in archaeology. Here, we assess whether direct environmental changes (i.e. mobility reduction) could immediately affect ontogenetic changes in long bone structure, providing a skeletal marker of early domestication. We relied on a wild boar experimental model, analysing 24 wild-born specimens raised in captivity from 6 months to 2 years old. The shaft cortical thickness of their humerus was measured using a 3D morphometric mapping approach and compared with 23 free-ranging wild boars and 22 pigs from different breeds, taking into account sex, mass and muscle force differences. In wild boars we found that captivity induced an increase in cortical bone volume and muscle force, and a topographic change of cortical thickness associated with muscular expression along a phenotypic trajectory that differed from the divergence induced by selective breeding. These results provide an experimental proof of concept that changes in locomotor behaviour and selective breeding might be inferred from long bones morphology in the fossil and archaeological record. These trends need to be explored in the archaeological record and further studies are required to explore the developmental changes behind these plastic responses.

Objectives The locomotor repertoire of the olive baboon (Papio anubis) changes during ontogeny from a diversified pattern in infancy to a stereotyped pattern in adults. On the assumption that the femoral diaphysis adapts to variations in the loading regime, we aimed to evaluate the impact of locomotor changes on femoral biomechanical properties during the ontogeny of olive baboons. Materials and Methods We used the cross‐sectional geometry of 50 three‐dimensional‐reconstructed olive baboon femora of an ontogenetic sample including individuals from birth to 28 years of age and belonging to a single social group. Cross section parameters were extracted, and cortical thickness maps were produced from 20% to 80% of the femoral length. Results Newborns present a distribution of cortical thickness that is longitudinally symmetric and anteroposterior shaped cross sections at midshaft. From this condition, infants, juveniles and adults femoral diaphyses are all characterized by a proximal shift in cortical thickness and a mediolateralization of bending rigidity and strength at midshaft. Discussion As soon as locomotor autonomy is established and despite a combination of several significant locomotor modes, the biomechanical pattern remains stable during ontogeny. Our results do not reflect the changes in locomotor repertoires that occur during ontogeny of Papio anubis. We therefore advise caution when inferring complex locomotor behavior from femoral biomechanical properties.

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