Adaptation to graviportality in Rhinocerotoidea? An investigation through the long bone shape variation in their hindlimb

Abstract Weight support is a strong functional constraint modelling limb bones in heavy quadrupeds. However, the complex relations between bone shape, mass, size and body proportions have been poorly explored. Rhinocerotoidea one of groups showing highest mass reached by terrestrial mammals through time. Here, we explore evolutionary variation shape hindlimb stylopod zeugopod its relationship with gracility this superfamily. Our results show that undergo general increase robustness towards high masses, associated reinforcements main muscle insertions. The femur, carrying marked phylogenetic signal, varies conjointly gracility, whereas tibia appears related to only. fibula does not vary according tibia. Moreover, congruent distal part femur complete underlines potentially covariation elements constituting knee joint. These results, coupled those previously obtained from forelimb study, allow better comprehension among Rhinocerotoidea, refining concept ‘graviportality’