Trinema galeata (Penard, 1890) Jung, 1942
Diagnosis: Shell small, colourless, transparent, ovoid, compressed, with oval transverse section; composed of two types of shell-plates: large, circular, slightly overlapping, of about 10 µm in diameter, and small, oval, of about 3,1-3,4 x 2,4-2,7 µm, which haphazardly fill interstices between large plates. Aperture oval, sub-terminal, oblique, invaginated, surrounded by two or three rows small, circular, denticulate apertural-plates and three to four rows of small shell-plates, which clearly indicate the place of junction of the wide apertural visor with the main body. Cytoplasm granular, fills almost the whole shell; one large nucleus, placed posteriorly in the cell, with single central nucleolus. Pseudopodia numerous, thin, long, sometimes branching, usually well visible.
Dimensions: 41-84 um long; 22-49 µm wide; large scales about 10 µm in diameter, small ones 3,1-3,4 x 2,4-2,7 µm. Diameter of large shell-plates 5.6-10.3; aperture 11-24 µm (Todorov and Bankov, 2019).
Ecology: Mosses and soils, rare in Sphagnum. Probably cosmopolitan.
Remarks: Trinema galeata differs from T. complanatum by the well visible line indicating the place of junction of the wide apertural visor with the main body.