Microcorycia flava (Greeff, 1866) Cockerell, 1911
Diagnosis: Upper test part more or less rigid, dome-shaped, mostly covered more or less by xenosomes. Individuals without xenosomes also occur. The upper test part is yellow to yellowish brown, the lower test part light yellow to hyaline. Xenosomefree portions of the upper test part appear darkly punctuate in the light microscope. As REM photography shows, the dots are irregularly distributed alveolae.
Dimensions: Bartos (1963): 90-100 µm , Penard (1902): 80-100 µm, Badewitz (2004): mean 103.8 (78-130) µm (n=18). My measurements: 102-115 µm (n=5)
Ecology: Microcorycia flava populates terrestrial and limnetic habitats. Terrestrial habitats mainly include mosses and soils. Based on their locality, mosses comprise both soil mosses and epiphytic as well as epilithic mosses. The moisture degree of mosses ranges from submersed mosses to moist mosses to xerophile mosses at extreme locations such as rocks, walls and roofs. Microcorycia flava is the species most commonly observed.
Remarks: Cytoplasm does not fill up the test; it is granulate and contains numerous food particles, excreta as well as contractile vacuoles, 3-12 or more being located near the upper periphery according to Penard (1902). Digiform lobopodia are obviously not formed or only by way of exception. Only Archer is reported to have observed them (quoted from Penard 1902). However, it can be observed with many individuals where the cell is in a vital state that a widely rotund pseudopodium is outside the test. Penard (1902) observed the formation of this type of pseudopodium: The extrusion of the ectoplasmic pseudopodium occurred in an eruptive way, seemed to grow stiff on the surface and was slowly retracted back into the cell body. According to Badewitz (2004) pseudopodia of this type are mainly lasting. Only one is formed per individual, which spreads on a flat surface. No observations exist on the function of these pseudopodia, uptake of food and locomotion. Penard (1902) has seen epipodia that fix the protoplast in the test only with “young” individuals.
The cell is mononuclear. Penard (1902) reported also on binuclear cells. Nuclei are spherical or ovular and contain a number of nucleoli of irregular shape. Penard (1902) ascertained the diameter of four nuclei of four individuals to be 19 µm. Badewitz (2004) measured nuclei sized between 13 µm and 18 µm. Nuclei are always difficult to recognize in the living cell; they are masked by cell inclusions and under the test. Penard (1902) therefore recommended to crush the organisms.