
Centropyxis pontifera Bartos, 1963
Diagnosis: Shell large, broadly oval, formed of a thick, solid, brownish-yellow organic matter. Shell with many larger irregularly scattered cuticular granules and many more covered with larger flat and polygonal mineral plates. Shell slightly translucent so that the inner shell opening bridges can also be clearly seen from the outside. Aperture large, pentagonal with rounded corners. The edges of the aperture curve inwards at four points deep in the shell, where gradually diverging from each other they reach the inner surface of the opposite shell dorsal side, to which they insert with much broader ends.
Dimensions: Length 124-150 µm, width 116-120 µm. Anterior part 34 µm high and posterior part 50 µm. Aperture about 30 µm with its leading edge away from the front end of the shell. Aperture at its widest point 50 µm wide, its trailing edge only 16 µm wide. Maximum height of the shell opening 45 um.
Habitat: Freshwater, sediment of the Vorderer Finstertaler See, Austria.
Remarks: Bartos (1963): “According to Thomas (1957) this species is closely related to C. ecornis (Ehrenberg 1838) Leidy 1879. It agrees with this species in the formation of the apertural bridges, in its construction from an organic mass, which lets the shell shine through and gives it a yellow-brownish color, and finally in its relatively low height. This species differs from C. ecornis, which is usually rounded to broadly oval but never regular, in that it is always broadly oval and symmetrical in shape and particularly in that it always has a pentagonal and regularly formed shell opening. Its dimensions fit well within Leidy’s size limit for this species (length 125-275 µm, width 100-230 µm). However, according to Thomas (1957), the sizes given for C. ecornis are much higher. However, according to all authors, C. ecornis is an aquatic form, while C. pontifera is a moss form.”