Quadrulella deflandrei  Bankov, Todorov et Ganeva, 2021

Diagnosis: Shell large, colorless, ovoid or piriform in broad view, with sides tapering evenly and gradually from the rounded aboral region towards the aperture. Shell laterally compressed, with ovoid transverse section, and composed of quadrangular siliceous plates of very different sizes, primarily mixed, and most frequently arranged in irregular rows. Pseudostome ovoid, slightly convex frontally, and concave laterally, bordered by a thin collar of organic cement.

Dimensions: According to Bankov et al. (2021): Shell length 136–167 µm; width 85–102 µm; aperture33–47 µm.

Habitat: Sphagnum mosses.

Geographical distribution: Bulgaria, France.