Difflugia brychtai Stepanek, 1967 (=D. mammillaris)
Diagnosis: Test pyriform. Fundus with a long thick spike located not on the longitudinal axis of the test, because of which the form of the test appears to be irregular. Covered with large mineral grains. Pseudostome round.
Dimensions: Stepanek, 1967: Length 81 µm, width 46 µm, pseudostome 24 µm, n=1; Opravilova and Stepanek, 1980: Length 120 µm, width 69 µm, pseudostome 28 µm; n=1.
Ecology: Freshwater. Europe.
Remarks: The description of this species is based on a single shell (see Opravilova and Stepanek, 1980). Therefore, it is somewhat surprising that the authors identified their second shell widely differing in shape and size and from another location as belonging to the same species. On the basis of these two morphologically quite different shells, it is difficult to conclude with certainty that they belong to the same species. However, I have observed such variation in populations of D. mammillaris, but only after studying multiple shells. Both forms of D. brychtai fall within the range of D. mammillaris and in my opinion D. brychtai is a junior synonym of D. mammillaris.