In the last few years, many models have been proposed to link microevolutionary processes to macroevolutionary patterns, defined by comparative data analysis. Among these, Brownian motion and Ornstein-Uhlenbeck (O-U) processes have been used to model, respectively, genetic drift and stabilizing selection. Since these models produce different curves of pairwise variance between species against time since divergence, different profiles in phylogenetic correlograms must appear. In this paper, we analyzed variation in body weight among 17 species of South American carnivores by means of phylogenetic correlograms, constructed using Moran's I coefficients in four distance classes. Phylogeny among species was based on molecular data. The observed correlogram was then compared with 400 simulated correlograms of Brownian motion and O-U over the same phylogeny. The observed correlogram indicates a phylogenetic gradient up to 8 mya, when coefficients tend to stabilize, and autoregressive model indicates that around 74% of the interspecific variance in body size can be explained by phylogenetic inertia. This is expected by considering that body size is usually correlated with many ecological and life-history traits, being subjected to many constraints that can be modeled by O-U process expressing stabilizing selection.
carnivores; body size; phylogeny; autocorrelation; correlograms; stabilizing selection
