Family & Genus: Under 100 μm long;
oblong to ovate; with several, longitudinal, parallel ridges; uninucleate .
Species: Locomotive, 30-50 μm long, 20-30 μm wide, pseudopods rare; uroid none; ectoplasm pale; 3-5 dorsal ridges and clear, antero-lateral margin; endoplasm finely granular; nucleus spherical, 5-6 μm, endosome as a band or 2-3 pieces; contractile vacuole 8-12 μm (Illustrated Guide, 1985). Ovate; 30-80 μm long; 3-4 dorsal ridges; nucleus with 2 or 3 ribbon-like endosomes (How to know the protozoa, 1979).
Images of collecting locality:
No.2, Saiko (Lake Sai) at Doman-green park, Toda city, Saitama Pref., Japan, December 2, 2007 by Y. Tsukii