Meeting Abstract

107.5  Sunday, Jan. 6  Ecomorphology in Modern and Fossil Birds MITCHELL, J.S.; The University of Chicago mitchelljs@uchicago.edu

The origin of the staggering ecological diversity of modern birds remains unresolved. A major limitation to studying the evolution of avian ecology has been the difficulty of determining the timing and overall rate of key ecological divergences in the avian tree of life. Here, I present results combining a recent molecular phylogeny with an extensive database of ecological characters (habitat, diet, foraging mode) and a very large morphological database (>1100 specimens, representing 451 genera in 138 families). Phylogenetic canonical correlations analysis of ecology and morphology yielded 3 statistically significant axes with Pearson’s r of 0.6, 0.48 and 0.4 each. The first axis mainly describes the distinction between large-bodied, ground foraging birds and small-bodied, aerially foraging birds. The second axis describes the distinction between aquatic and terrestrial foragers, and the third the separates leg locomotors (e.g., ostriches and loons) versus wing locomotors (e.g., hummingbirds and penguins). I also examined how disparity was partitioned along the avian tree and found substantial departures from Brownian motion expectations early and near the middle of the tree, with disparity on the higher end of the Brownian prediction for almost every node. This suggests that major breaks in ecomorphological evolution may have happened early in the avian tree, and that many of the major groups have retained ecological distinction from one another for an extended period of time.