32.5 Friday, Jan. 4 Getting a grip on grasping in carnivorans: a three-dimensional analysis of forelimb shape FABRE, A-C*; SLATER, G; CORNETTE, R; PEIGNé, S; GOSWAMI, A; POUYDEBAT, E; CNRS and MNHN, France ; University College London, UK ; Smithonian Institution, Washington, DC; MNHN, Paris, France; CNRS and MNHN, Paris, France; University College London, UK; CNRS and MNHN, Paris, France email@example.com
The ability to manipulate and grasp is often considered a hallmark of the humans associated with their bipedal locomotion and tool use. Yet, many other mammals use their forelimbs to manipulate food or objects. Carnivorans, and especially procyonids such as raccoons, are well known for their manipulation ability. Given that manipulation of objects often involves complex rotations of the lower forelimb we predict that species capable of manipulation show strong differences in the shape of the radius and ulna. Here we examine for a data set comprising eight species of procyonids, one ailurid and eight mustelids whether species with good manipulative skills differ from others in the shape of the forelimb elements. To do so we used a surface sliding semi-landmark approach capable of characterizing the articulations between bones in their full 3D complexity. The results analysed in a phylogenetic context show that carnivorans with high manipulative skills differ markedly from others in the shape of the forelimb bones. Both the proximal and distal articulation areas of ulna (axis 1) and radius (axes 1 and 2) discriminated between species with and without manipulative skills. The humerus also showed significant differences between manipulators and non-manipulators, but only on the second shape axis. Thus, our results confirm our prediction and illustrate that the functional signal of manipulation ability is stronger for the lower forelimb bones, which are most strongly implicated in the movement. Moreover, our results demonstrate the importance of using surface methods to capture non-discrete aspects of morphology related to complex movements.