Ditrema mukrous, empty shell
Ditrema mukrous De Saedeleer, 1934
Diagnosis: Shell hyaline, small, with one side fastened to the substrate, with an open base, resembling an iglo; outline circular, often irregular. Shell usually with two opposite apertures, each with a short neck. Young shells colorless, older shells yellow to brown. Pseudopodia granular, fine, extending along the substrate. Nucleus globular with a central nucleolus.
Dimensions: De Saedeleer 12-14 µm; my measurements: 21-28 µm, from aperture to aperture; 9-15 µm in diameter.
Ecology: in water with Sphagnum-contact. Diepveen, Crailoo, Laegieskamp the Netherlands.
Diagram of Ditrema mukrous. The shell resembles an iglo with two apertures; there is no bottom.
All above shells are from the same sample. It shows the variation in shape and color. One shell has three apertures.
Apertural view and side view (right): the test resembles an iglo.
This specimen with one aperture was present in the same wet-mount as the two specimens above. No other specimens were present after two weeks in a wet chamber. It is likely that this specimen is a Ditrema mukrous with one aperture.