Euglypha acanthophora (Ehrenberg, 1841) Perty, 1849
Diagnosis: Shell ovoid or slightly elongated towards the aperture, not compressed; fundus with 1-9 long, usually with long, straight or slightly curved, backward-directed spines, in numbers from 3 to 9, which are in fact elongated scales; aperture circular, bordered by up to three rows of serrated scales; body scales elliptical or nearly circular with a tooth-like projection on the posterior edge; plasma and pseudopodia normal.
Dimensions: Measurements in the literature: 55—84 µm; my measurements 66—97 µm.
Habitat: Freshwater. In sediment and between aquatic plants, in Sphagnum and other moist mosses.
Remarks: The scales are scutiform, with a small tooth-like projection on the posterior part. The spines are elongated shell scales, tapering towards a sharp point. Also shells without spines can be found.
Infraspecific taxa.
E. acanthophora brevispina Penard, 1902
Differs from the typical form in having shorter spines. Sometimes more slender and less wide. Size and ecology as in the type.
E. acanthophora cirrata Wailes, 1912
The aperture is surrounded by two rows of peri-apical scales. At the fundus of the shell there are two spines, located at an angle to the longitudinal axis and directed towards each other. The length of the shell is 50-78 µm, the width of the shell is 21-43 µm, the diameter of the aperture is 13-14 µm, the length of the spines is 10-20 µm.
E. acanthophora cylindracea (Playfair, 1918) Decloitre, 1962
Differs from the typical form in the cylindrical shape of the shell and slightly larger dimensions. The length of the shell is 100-133 µm, the width of the shell is 53-76 µm, the diameter of the aperture is 38-44 µm, the length of the spines is 28-34 µm. 4.
E. acanthophora deflandrei Decloitre, 1956
Differs from the typical form by the presence of 2 straight, long spines on the fundus of the shell, parallel to its longitudinal axis. Shell length 52 µm, width 26 µm, diameter of the aperture 20 µm.
E. acanthophora equeis Decloitre, 1956.
Differs from the typical form by the presence of spines located all over the shell, directed forward. The length of the shell is 56 µm, the width of the shell is 36 µm, the diameter of the aperture is 14 µm, the length of the spines is 10-11 µm.
E. acanthophora flexuosa Penard, 1902
Differs from the typical form by the presence of long and curved spines in the back of the shell. The shell length is 60-70 µm, the shell width is 28-32 µm, the aperture diameter is 18-20 µm, the length of the spines is 18-20 µm.
E. acanthophora heterospina Decloitre, 1949
Differs from the typical form by the presence of spines of varying length on the fundus. The shell length is 52-56 µm, the shell width is 26-28 µm, the aperture diameter is 13-15 µm, the length of the short spines is 2-8 µm, the length of the long spines is 20-22 µm.
