Phylogeny of the Dictyostelia based on SSU rDNA sequences. The tree shown is the optimal topology obtained by both Bayesian inference and maximum likelihood searches. The tree identifies eight major taxonomic divisions, which are indicated by separate colors. The tree includes all known described and undescribed species of Dictyostelium (D), Polysphondylium (P) and Acytostelium (A). Branch lengths are the average of all trees recovered during the BI search after discarding a burn-in of 20% and are drawn to scale as indicated by the scale bar at the lower left. Support from BI posterior probabilities and 100 ML bootstrap replicates are respectively indicated to the left and right of slashes (/) on the relevant branches for values above 0.7 biPP and 50% mlBP. Values of 100% mlBP and 1.00 biPP are indicated as *. The tree is rooted according to .