Euglypha filifera Penard, 1890

Diagnosis: Shell elongate oviform, slightly compressed, lateral margins and fundus with a few long spines, usually 6-15 in number, 15-25 µm long, attached to the shell by small hemispherical nodules; spines are often paired, located more or less symmetrically on top and on the sides up to half the height of the shell. Aperture circular, bordered by usually eight finely dentated scales; body scales oval; nucleus large, with several nucleoli.

Dimensions: Shell length 55—70 µm; width 25—35 µm; thickness 12—21 µm; aperture diameter 10—14 µm.

Ecology: Freshwater., Sphagnum and aquatic plants. Common species.

Remarks: The spines can be solitary or arranged in tufts of 3 or 4.

Infraspecific taxa.

E. filifera spinosa Wailes, 1912
​​The shell is more compressed than the typical form, the entire surface is covered with numerous spines. The length of the shell is 60—90 µm, the width of the shell is 26—40 µm, the diameter of the aperture is 10—15 µm, the length of the spines is 10—30 µm.

E. filifera pyriformis Wailes, 1913
The shell is pear-shaped in plan (with an elongated neck), more compressed in cross section than the typical form. On the sides of the shell there are 5—7 large spines. The length of the shell is 48—50 µm, the width of the shell is 24—30 µm, the thickness of the shell is 17—23 µm, the diameter of the aperture is 6—10 µm, the length of the spines is 17—23 µm.

E. filifera cylindracea Playfair, 1918
Differs from the typical form in the cylindrical shape of the shell, the sides are almost parallel or only slightly converge toward the aperture. The length of the shell is 65—68 µm, the width of the shell is 23—24 µm, the diameter of the aperture is 9-10 µm, the length of the spines is 21—23 µm.

E. filifera magna Van Oye, 1958
Differs from the typical form in its larger size. The number of periapical idiosomes is 12—14. The length of the shell is 106 µm, the width of the shell is 63—78 µm, the diameter of the aperture is 20—30 µm.