Meeting Abstract

P1.152  Saturday, Jan. 4 15:30  Patterns of morphological evolution during a locomotor transition: Lessons from the evolution of wing-propelled diving in penguins PROFFITT, JV*; MIDDLETON, KM; CLARKE, JA; University of Texas, Austin; University of Missouri, Columbia; University of Texas, Austin jvproffitt@gmail.com

Evolutionary transitions in locomotion provide excellent opportunities for exploring patterns of whole-organism morphological change associated with shifts in ecology. More specifically, these scenarios can act as investigatory frameworks for examining differential rates of evolution in separate anatomical regions, informing our understanding of the relationship between adaptation, anatomical form, and biological function. The evolution of wing-propelled diving in penguins represents a model system in which to pursue these questions due to penguins’ distinctive modes of locomotion relative to immediate outgroups, robust fossil record, and well-constrained phylogeny. New morphological characters developed through study of fossils and dissection of extant taxa were combined with previously developed character matrices to form the most complete dataset of penguin osteological characters to date. Patterns of character change in the forelimb and hind limb of penguins were assessed in parsimony and Bayesian frameworks to infer relative rates of evolutionary change in each anatomical region across penguin phylogeny. In contrast to hypotheses of sequential modification for forelimb and hind limb morphology, we find similar rates of character change early in penguin evolution. Our results emphasize the importance of examining whole-organism patterns of change rather than approaches only based on single character complexes or key innovations. These data, when combined with further anatomical and functional data obtained from extant penguins, will provide greater insight into the evolution of ecological and morphological diversification within birds.