Meisterfeldia polygonia  Bobrov, 2016

Diagnosis: Shell is very small, bilaterally symmetrical, narrowly ovate, slightly compressed, almost circular in a transverse section, brown, non-transparent. Dorsal side weakly convex, posterior end evenly curved, anterior end with aperture slightly cut obliquely towards ventral side. Aperture elliptical, subterminal. Shell surface smooth, without mineral inclusions.

Dimensions: shell length 6.75–7.50 μm; shell breadth 3.75–4.50 μm; shell depth 3.75–4.00 μm; axis of aperture 2.50–3.00 μm.

Ecology: Tundra, North-Russia. Sphagnum, peat tussock

Remarks: The species differs morphologically from Cryptodifflugia vanhoornei by its smaller size: the shell is nearly twice smaller, it is more graceful and always stained with brown.