The phylogenetic tree resulting from maximum-likelihood analysis. (a) The interphotoreceptor retinoid-binding protein gene (IRBP) dataset under its best-fit model (GTR + G + I). (b) Growth hormone receptor gene (GHR) dataset under its best-fit model (K2P + G + I). Nodal support from a maximum-likelihood bootstrap analysis is indicated over the nodes (values less than 50 are not shown). For the Bayesian analysis, black circles indicate posterior probability values that exceed 0.8.