Arcella jurassica Olivier, 1944
Diagnosis: Test pyramid-shaped but strongly truncated, in lateral view trapezium-shaped, with 5-8 planes; pseudostome surrounded by about 15 pores, each 1-2 µm in diameter. In dorsal view, there are 5-7 ribs, resembling a star. Dorsal plane polygonal, ventral plane circular.
Dimensions: Length 90 µm.
Ecology: Freshwater. In peat bogs between Hypnaceae, Doubs, France.
M. ovalistoma – after Bartos, 1963 Metaheleopera Bartos, 1963 Diagnosis: Shell clearly narrowing towards the pseudostome, which can be seen even more clearly on the narrower sides
M. radixicola – after Chardez, 1974 Matsakision radixicola Chardez, 1974 Diagnosis: Shell ovoid, slightly compressed, transparent; pseudostome oval, truncated perpendicularly, with a slight neck. Shell
M. cassagnaui – after Bonnet, 1967 Matsakision cassagnaui Bonnet, 1967 Diagnosis: Shell hyaline, elongated ovoid, very little compressed, truncated perpendicularly or very slightly obliquely in
Matsakision – after Bonnet, 1967 Matsakision Bonnet, 1967 Diagnosis: Shell hyaline, elongated ovoid, very little compressed, truncated perpendicularly or very slightly obliquely in the region
Arcella marginata, after Deflandre, 1929 Arcella marginata Daday, 1905 Diagnosis: Shell roughly hemispherical, rather overhanging, with a flattened, smooth edge. In dorsal view showing a
Arcella lobostoma, after Deflandre, 1929 Arcella lobostoma Deflandre, 1929 Diagnosis: Shell hemispherical. In ventral view, irregular circular outline, often a little elliptical; pseudostome irregularly lobed: