The phylogenetic position of an unusual Protoperidinium species, P-bipes (Peridiniales, Dinophyceae), based on small and large subunit ribosomal RNA gene sequences

摘要

Protoperidinium bipes is a minute heterotrophic dinoflagellate with a very distinctive shape and a tabulation unique for the genus, resulting in its placement into the subgenus Minusculum. The small subunit rDNA and the large subunit rDNA sequences of this species were determined using the single-cell polymerase chain reaction technique and analyzed to estimate its phylogenetic position. The results of the phylogenetic analyses revealed that P. bipes positioned in the clade corresponding to the section Protoperidinium of the subgenus Protoperidinium. Although the species occasionally has been regarded to belong to a different genus, our molecular analysis clearly confirmed that it is a true member of the genus Protoperidinium. It was inferred from our analysis that the reduction of the number of precingular plates took place relatively recently during the course of evolution of Protoperidinium.