Cryptodifflugia fusca Penard, 1890
Basionym: Cryptodifflugia oviformis fusca Penard, 1890
Diagnosis: Differs from the typical form by its yellowish‑brown shell. Dimensions as in the typical form, with which it frequently co‑occurs. The taxon is polymorphous in both size and shape; elongated specimens are often recorded.
Dimensions: Shell length 13–26 μm; width 8–17 μm; aperture diameter 3–6 μm.
Ecology: Freshwater sediments; Sphagnum mosses; wet green mosses; aquatic plants; acid soils.
Distribution: Cosmopolitan.
References: 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.
*) Taxonomic Note: Cryptodifflugia oviformis var. fusca Penard, 1890, is changed to Cryptodifflugia fusca Penard, 1890.
No new name needs to be established in this case under the International Code of Zoological Nomenclature. Because the name was published before 1961 using the abbreviation var., it is deemed subspecific under Article 45.6.4, unless explicitly proposed as infrasubspecific. As a species-group name, it is simultaneously established at both species and subspecies rank under the Principle of Coordination (Art. 46.1), with the same author, date, and name-bearing type. Accordingly, when treated at species rank, the correct name is Cryptodifflugia fusca Penard, 1890.
