Evidence for differential allometric effect on carnivoran scapular shape

TY - GEN

T1 - Evidence for differential allometric effect on carnivoran scapular shape

AU - Gálvez-López, Eloy

PY - 2013

Y1 - 2013

N2 - The effect of size on shape was tested in 213 scapulas from 101 carnivoran species, digitizing 34 3D-landmarks and using geometric morphometric methods. The sampled species spanned the whole size range of the order, and also covered all currently recognized families and all locomotor patterns and habitat preferences in Carnivora. As expected, a regression of shape on log-transformed centroid size revealed a significant allometric effect (size explained 17.2% of scapular shape variation). Furthermore, since significant evidences of phylogenetic signal in both the size and shape of the carnivoran scapula were found, the effect of size on shape was again tested after correcting for phylogenetic relatedness using phylogenetically independent contrasts. In this case, the allometric effect, although still significant, only explained 5.3% of shape variation, indicating that most of the allometric shape differences were related to size changes along phyletic lines. Finally, we tested whether the magnitude of the allometric effect varied among different subgroups within Carnivora. Indeed, the percentage of scapular shape variation explained by size varied among the different carnivoran families and among different locomotor types and habitat preferences, ranging from no significant effect on some subgroups to 50.0% in semifossorial carnivorans. Overall, the allometric effect found in ecological subgroups (locomotor type, habitat) exceeded the allometric effect found for the different families. However, after correcting for phylogenetic relatedness, the allometric effect was only significant in scansorial carnivorans and in those living in forest, mosaic and variable habitats. Furthermore, a reduction of its magnitude was observed in all cases. Thus, the results of the present study suggest that most of the allometric shape differences found in the carnivoran scapula are related to size changes ocurred during carnivoran evolution.

AB - The effect of size on shape was tested in 213 scapulas from 101 carnivoran species, digitizing 34 3D-landmarks and using geometric morphometric methods. The sampled species spanned the whole size range of the order, and also covered all currently recognized families and all locomotor patterns and habitat preferences in Carnivora. As expected, a regression of shape on log-transformed centroid size revealed a significant allometric effect (size explained 17.2% of scapular shape variation). Furthermore, since significant evidences of phylogenetic signal in both the size and shape of the carnivoran scapula were found, the effect of size on shape was again tested after correcting for phylogenetic relatedness using phylogenetically independent contrasts. In this case, the allometric effect, although still significant, only explained 5.3% of shape variation, indicating that most of the allometric shape differences were related to size changes along phyletic lines. Finally, we tested whether the magnitude of the allometric effect varied among different subgroups within Carnivora. Indeed, the percentage of scapular shape variation explained by size varied among the different carnivoran families and among different locomotor types and habitat preferences, ranging from no significant effect on some subgroups to 50.0% in semifossorial carnivorans. Overall, the allometric effect found in ecological subgroups (locomotor type, habitat) exceeded the allometric effect found for the different families. However, after correcting for phylogenetic relatedness, the allometric effect was only significant in scansorial carnivorans and in those living in forest, mosaic and variable habitats. Furthermore, a reduction of its magnitude was observed in all cases. Thus, the results of the present study suggest that most of the allometric shape differences found in the carnivoran scapula are related to size changes ocurred during carnivoran evolution.

M3 - Conference contribution

VL - 296

SP - 275

BT - Anatomical Record

T2 - 10th International Congress of Vertebrate Morphology

Y2 - 8 July 2013 through 12 July 2013

ER -