title: Do constraints associated with the locomotor habitat drive the evolution of forelimb shape? A case study in musteloid carnivorans.
abstract: Convergence in morphology can result from evolutionary adaptations in species living in environments with similar selective pressures. Here, we investigate whether the shape of the forelimb long bones has converged in environments imposing similar functional constraints, using musteloid carnivores as a model. The limbs of quadrupeds are subjected to many factors that may influence their shape. They need to support body mass without collapsing or breaking, yet at the same time resist the stresses and strains induced by locomotion. This likely imposes strong constraints on their morphology. Our geometric morphometric analyses show that locomotion, body mass and phylogeny all influence the shape of the forelimb. Furthermore, we find a remarkable convergence between: (i) aquatic and semi-fossorial species, both displaying a robust forelimb, with a shape that improves stability and load transfer in response to the physical resistance imposed by the locomotor environment; and (ii) aquatic and arboreal/semi-arboreal species, with both groups displaying a broad capitulum. This augments the degree of pronation/supination, an important feature for climbing as well as grasping and manipulation ability, behaviors common to aquatic and arboreal species. In summary, our results highlight how musteloids with different locomotor ecologies show differences in the anatomy of their forelimb bones. Yet, functional demands for limb movement through dense media also result in convergence in forelimb long-bone shape between diverse groups, for example, otters and badgers.
authors.affiliation: Evolutionary Anthropology, Duke University, Durham, NC, USA.
authors.forename: Anne-Claire
authors.initials: AC
authors.lastname: Fabre
authors.affiliation: UMR CNRS/MNHN 7205, 'Origine, Structure et Evolution de la Biodiversité', Muséum National d'Histoire Naturelle, Paris, France.
authors.forename: Raphael
authors.initials: R
authors.lastname: Cornette
authors.affiliation: Department of Genetics, Evolution, and Environment and Department of Earth Sciences, University College London, London, UK.
authors.forename: Anjali
authors.initials: A
authors.lastname: Goswami
authors.affiliation: CR2P - UMR 7207 CNRS, MNHN, Univ Paris 06, Paris, France.
authors.forename: Stéphane
authors.initials: S
authors.lastname: Peigné
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology*; D000704:Analysis of Variance; D000818:Animals; D005075:Biological Evolution; D017753:Ecosystem; D005552:Forelimb / Q000033:anatomy & histology*; D008124:Locomotion / Q000502:physiology*; D015999:Multivariate Analysis; D045969:Mustelidae / Q000033:anatomy & histology*; D010802:Phylogeny
keywords: 3D geometric morphometrics; body mass; comparative analysis; convergence; ecomorphology