Meeting Abstract
Often, a predictable relationship exists between an organism’s habitat and its locomotor biomechanics. Lizards use a range of vertical and horizontal substrates (e.g. arboreal, or terrestrial habitats) where selection is expected to optimize morphological and functional performance on their dominate substrate type. Thus, studying the functional evolution of the axial skeleton aids our understanding of the degree of coupling between phenotypic variation and various habitats or locomotor modes. This study quantified the variation of scapular shape across 28 lizard species that vary across four substrate types. A lateral view of the scapula was photographed from specimens. Pictures were imported into MorphoJ along with a pruned phylogeny. Specimens were coded by substrate (terrestrial, arboreal, saxicolous, or generalist) to perform a canonical variate analysis of scapular shape in light of phylogenetic history. Using a Brownian motion model of evolution, minimal phylogenetic signal was detected, however additional models will be examined. The width of the articulation between the suprascapula and scapula accounted for 56% of the shape variation, while scapula height accounted for 28.6% of the variation. The scapular shape of terrestrial lizards was significantly different from arboreal and generalists, while saxicolous was intermediate in morphospace. Terrestrial locomotion likely generates the basal condition, but newly invaded substrates may lead to a shift in scapular shape. The lack of phylogenetic signal, coupled with distinct separation in terrestrial lizards, suggests that scapular shape responds to the functional demands of locomotion on particular substrate types within this clade.
