MASS ESTIMATION OF EXTINCT TAXA AND PHYLOGENETIC DATA BOTH INFLUENCE ANALYSES OF CHARACTER EVOLUTION IN A LARGE CLADE OF BIRDS (TELLURAVES)

Incorporating extinct taxa in phylogenetic comparative methods is rapidly becoming invaluable in studies of character evolution. An increasing number of studies have evaluated the impact of including extinct taxa on model selection and parameter estimation. However, these analyses are conditional on accurate estimation of ancestral phenotypes. In particular, it is potentially underappreciated how different estimates of body mass may bias subsequent analyses. Here, we perform an analysis of character evolution of body size in a large clade of birds, incorporating 76 extinct species, and evaluate how different methods for including estimates of body masses of extinct taxa and different phylogenetic hypotheses affect the results. Our results show that model selection can vary dramatically depending on the phenotypic and phylogenetic data used in the reconstruction. As a result, the inferred evolutionary history can vary substantially. Some models infer a pre-K-Pg diversification in body size, where as others suggest that this process occurred after the boundary. These results provide additional insight into the application of comparative models of evolution, as well as the evolutionary history of one of the most spectacular vertebrate radiations.