The relative roles of adaptation and phylogeny in determination of larval traits in diversifying anuran lineages

I measured phenotypic traits important to the fitness of larval anurans to assess the relative roles of ancestral trait value and selective regime in determining present- day phenotypes. The positions of 14 species from three taxonomic families and three different habitats in a phenotypic space defi ned by 19 traits provided measures of taxonomic and ecological similarity. The distribution of phenotypic distances among species revealed that neithe r taxonomy nor habitat overwhelmingly determined phenotype. There appear to be multiple ways in which anurans can exploit pond types. However, the dir ection of phenotypic movement was not random from one species to the next. Independent contrasts revealed significant correlations in the evolution of traits that were consistent among lineages. These correlations reflected w ell- known trade- offs that result from functional relationships among the constituent traits. Although there is no simple pattern in the distribution of mean phenotypes across environments and lineages, the pattern of the ev olutionary trajectories that created that distribution is consistent with a predictive theory of multivariate evolution.