Meisterfeldia bitsevi  Bobrov and Mazei, 2021

Diagnosis: Shell bilaterally symmetrical, elongated oval, laterally not flattened, colorless, transparent. The dorsal side is slightly convex, posterior end curved to ventral side. The aperture is almost circular, placed on the ventral side, which is without any invagination and symmetrically convex as the dorsal side. Shell surface smooth, without mineral inclusions.

Dimensions: Shell length 30.43–33.40 μm, breadth 15.70–18.10 μm, depth 15.80–17.90 μm; aperture: width 5.10–6.20 μm, height 4.90–6.10 μm.

Ecology: Hollows in five trees at a height of 1.5 m. Semi-decomposed litter with a small number of mineral particles, mixed spruce-birchlindenforest. Urban park “Bitsevsky forest”, Moscow, Russia.

Differential diagnosis: From the other species of the genus Meisterfeldia this species can be distinguished by its larger size and lack of lateral compression (in contrast with M. chibisovi, M. wegeneri, M. polygonia), slightly elliptic aperture (in contrast with M. vanhoornei) and lack of pseudostomal neck and apertural collar (in contrast with M. turfacea).