Cryptodifflugia oviformis fusca (Penard, 1890) Bonnet et Thomas, 1956
Diagnosis: Differs from the typical form by yellowish-brown shell. Dimensions as in the typical form, with which it rather often co-occurs. The taxon is polymorphous in both size and shape; elongated specimens are frequently recorded.
Dimensions: Shell length 13–26 μm, shell width 8–17 μm, aperture diameter 3–6 μm.
Ecology and distribution: Freshwater sediments, Sphagnum mosses, wet green mosses, aquatic plants, acid soil. Cosmopolitan.
Reference: Bobrov, A., Mazei, Y., 2017. A review of testate amoeba genus Cryptodifflugia Penard, 1890 (Phryganellina: Cryptodifflugiidae) with a key to species. Zootaxa 4282 (2): 292–308.