Bayesian phylogeny of alveolates based on the analysis of 80 complete or nearly complete SSU rRNA gene sequences (1,325 positions), including 44 selected environmental phylotypes (indicated in bold). The number of phylotypes belonging to each of the five main alveolate lineages is indicated in brackets next to the clade name. Phylotypes previously considered as novel eukaryotic lineages, which are in fact fast-evolving members of known groups are highlighted in orange. Phylotypes that could be identified thanks to an increasing taxon sampling are highlighted in green. The tree is rooted with three stramenopile sequences. The GTR + G model of evolution was used, and the topology shown is a Bayesian consensus of 20,000 sampled trees (see text). The posterior probability of each resolved node is indicated. Branches are drawn to scale, except those marked with an asterisk (*), which were reduced by half for clarity.