Argynnia similis (Vucetich, 1973) comb. nov.
Basionym: Nebela similis Vucetich, 1973

Diagnosis: Shell oval-shaped, wide, with a rounded base and ending in a single short horn. Pseudostome oval and made up of rounded scales, without a chitinous lip. Shell elliptical in cross-section, transparent. Covering made up of circular and oval scales, sometimes juxtaposed.

Dimensions: Length 160-169 µm; width 135-145 µm; aperture 50-59 µm; horns = 6-10.

Habitat: Freshwater. Puelo lake, Argentina.