Meeting Abstract
The locomotor apparatus is, as is the whole organism, an integrated structure. The co-variation of its parts is regulated. In this context, evolutionary response to a functional demand on a part is limited by the functional demands on the other parts. The integration pattern itself may, however, evolve to allow differential changes in its parts. Specialization of pair of limbs to locomotion in a particular environment should induce a reduction of the overall integration while maintaining a strong integration within the limb itself. We investigated changes in the long bone co-variation pattern in mustelids belonging to four different locomotor ecologies (terrestrial, semi-arboreal, semi-fossorial, and semi-aquatic). Despite the differences in locomotor ecology, mustelids show a strong integration and changes in the co-variation patterns are scaling with the between-species divergence time, with the exception of the (Mustela putorius, M. eversmanni, M. lutreola) clade where changes in the co-variation pattern increased strongly in a short amount of time. Allometries have only a low impact on the pattern. The co-variation patterns differ between locomotor ecologies, but few of these variations match the hypothesis of a reduction of integration due to functional specialization. As the definition of the functional modules found in literature comes from the study of terrestrial locomotion, we suggest that future studies on the functional modules during locomotion in other environments might shed a new light on the results of this study.
