Taxonomy and phylogeny of three heterotrich ciliates (Protozoa, Ciliophora), with description of a new Blepharisma species

Abstract

The morphology and phylogeny of three heterotrich ciliates, Anigsteinia clarissima (Anigstein, 1912) Isquith, 1968, Blepharisma penardi sp. nov., and Blepharismaundulans Stein, 1867, were investigated based on living morphology, infraciliature, and small subunit (SSU) rDNA sequence data. The new species B. penardi sp. nov. is recognized by the following combination of characters: size about 150-180×45-55μm in vivo, cell colour variable from colourless to pale pink to dark brownish; peristome extending to middle of body; 36-63 adoral membranelles; 24-34 somatic kineties; single macronucleus; cortical granules tiny and colourless; freshwater habitat. Anigsteinia clarissima and B.undulans are both reported from China for the first time and are redescribed based on a combination of previous descriptions and new data from the Chinese populations. Phylogenetic analyses based on SSU rDNA sequence data show that B.penardi sp. nov. and B. undulans are both located within a clade comprising only congeners, thus supporting the monophyly of the genus Blepharisma. Anigsteinia clarissima clusters with its only congener forming a clade that is sister to the Spirostomum assemblage. Both the morphological and the molecular data support the placement of Anigsteinia in the family Spirostomidae.