Difflugia australis (Playfair, 1917) Gauthier-Lièvre & Thomas, 1958
Basionym: Difflugia bacillariarum var. australis Playfair 1917

Diagnosis: The shell is broadly ovate, with a rounded dome and convex sides that converge closely towards the aperture, where they suddenly diverge into a slight rim. The shell is often asymmetrical, with one side more inflated than the other, and the tail slanting. The fundus features a tail-like appendage. A collar of very small, evenly sized plates surrounds the aperture..

Dimensions: Playfair (1917): Shell length 100-120 µm; width 57-72 µm; pseudostome 23-36 µm; collar 6 µm. Vucetich: Length 100-120 µm; width 58-75 µm; pseudostome 25-35 µm; collar 6-8 µm.

Habitat: Freshwater. Sphagnum. Australia, Argentina.

Remarks: Chardez (1978) described some shells with a length 110-166 µm, width 60-79 µm, pseudostome 25-35 µm and collar 0-6 µm, but this is probably a different species.