Trinema parmularius  Łuców & Siemensma, 2025

Diagnosis. In ventral view, shell elongated-ovoid, usually with a very faint indication of a neck or narrowing towards the aperture. In cross-section, shell elliptical, colorless and transparent. In lateral view, the shell has a biconvex outline, interrupted on the ventral-anterior side by the aperture. Large scales broadly elliptical, touching or slightly overlapping, and smaller scales oblong to elliptical, varying greatly in size. Aperture circular, invaginated, and bounded by one row of small denticulate apertural scales.

Dimensions: Łuców et al. (2024): Shell length 44.7—66.9 µm; width 17.9—32.9 µm; depth 17.0—29.7 µm; aperture 7.4—16.0 µm; large scales 3.7—9.1 µm.

Habitat: Freshwater, peatland.

Geographical distribution: Type locality: Khar Zurkhnii Khukh Nuur fen, Mongolia.

Differential diagnosis: Trinema parmularius differs from all known Trinema species by the presence of broadly elliptical scales. In ventral view, it resembles T. clipelina Rauenbusch, 1987, but that species is half the size of T. parmularius and in lateral view it has a broad rounded fundus.

References: Łuców, D., Siemensma, F., Avirmed, D., Obremska, M., Słowiński, M., Zawiska, I., 2025. Morphological and morphometric investigations on testate amoebae from Mongolia with descriptions of a new genus and four new species. European Journal of Protistology 97, 126128. https://doi.org/10.1016/j.ejop.2024.126128