Identification of the 48 distinct, non-chimeric eukaryotic phylotypes we obtained from our samples of the small river, the Seymaz (Geneva, Switzerland). (A) Phylogenetic positions of the 48 eukaryotic phylotypes we obtained. The tree shown is the result of a minimum evolution analysis of 68 partial SSU rRNA gene sequences, using the GTR + G model of evolution (see text). The number of phylotypes belonging to each higher-level eukaryotic group is indicated in brackets under the clade name. A fast-evolving lineage of undetermined taxonomic position is highlighted in blue. The tree was arbitrarily rooted on opisthokonts. Numbers at nodes are bootstrap support values following 10,000 replicates. All branches are drawn to scale. (B) Relative proportion of phylotypes belonging to each higher-level eukaryotic group.