Family: Small, less than 50 μm; oblong to ovate; ridges faint or absent.
Genus: Body ovate in locomotion, longer than broad, with clear zone as anterior part; uninucleate (Illustrated Guide, 1985).

Clydonella sp. 2 clips Japan, 1998

Clydonella sp. 2 clips Torinome Kuroiso Tochigi, 1998

Clydonella sp. 2 clips Gifu Gifu, 1998