A three-dimensional analysis of the morphological evolution and locomotor behaviour of the carnivoran hind limb

Background: The shape of the appendicular bones in mammals usually reflects adaptations towards different locomotor abilities. However, other aspects such as body size and phylogeny also play an important role in shaping bone design. We used 3D landmark-based geometric morphometrics to analyse the shape of the hind limb bones (i.e., femur, tibia, and pelvic girdle bones) of living and extinct terrestrial carnivorans (Mammalia, Carnivora) to quantitatively investigate the influence of body size, phylogeny, and locomotor behaviour in shaping the morphology of these bones. We also investigated the main patterns of morphological variation within a phylogenetic context. Results: Size and phylogeny strongly influence the shape of the hind limb bones. In contrast, adaptations towards different modes of locomotion seem to have little influence. Principal Components Analysis and the study of phylomorphospaces suggest that the main source of variation in bone shape is a gradient of slenderness-ro...