Diplophrys mutabilis Takahashi, Yoshida, Inouye and Watanabe, 2014

Diagnosis: Cell shape orbicular to fusiform, asymmetrical to the axis connecting the polar ends, exhibiting an irregular gliding motility by means of fine filamentous, branching ectoplasmic elements extending up to 150µfrom both polar ends of the cell. Hyaline cytoplasm containing one to several colorless, or yellow, orange, or amber-colored conspicuous refractive granules. Nucleus located subcentrally with an evident nucleolus. One to several vacuoles, one of which is a contractile vacuole. Cells grow by repeated binary fission. Sporangia, spores, and cysts were not observed.

Ultrastructure. Unidentified cytoplasmic membranes of various forms, including ring-like, single-helical, or double-helical structures, are present. Cell wall composed of overlapping Golgi-derived circular scales (0.8-1.5 µm diameter) displaying an incrassate rim.

Dimensions: 3.1-8.3 x 3.4-10.3 µm diameter.

Ecology: fresh water, Japan

Remarks: The species’ SSU rDNA sequence places it in the Diplophrys clade, but it was separated from any known species.