A phylogenetic analysis of the SSU rRNA from members of the plasmodiophorida and phagomyxida

The Plasmodiophorida and Phagomyxida are orders of zoosporic eukaryotes of uncertain phylogenetic affinities. We have obtained ribosomal DNA sequence information from several species in these groups. Phylogenetic analyses of these sequences have confirmed that they form a monophyletic grouping that clusters most closely with a rhizopod assemblage consisting of sarcomonads and chlorarachneans. The Phagomyxida sequences appear distant enough from those of the Plasmodiophorida to justify a separate order. The relationships between the Plasmodiophorida remain unclear, with species from the same genus showing significant degrees of divergence.