Rhizamoeba timidum (Bovee, 1972) Siemensma, 1987
Diagnosis: Small amoeba, which can spread very flat with numerous pseudopodia; pseudopodia conical or blunt; polypodial form usually covered with a layer of detritus; monopodial form ovoid-shaped or more elongated; nucleus spherical with central nucleolus; cytoplasm clear, with many very small granules; one large contractile vacuole; hyaloplasm at the anterior end with eruptive bulges; hyaloplasm may run back along the sides.
Dimensions: my measurements: monopodium 42-100 µm, polypodial form 35-60 µm; nucleus 6.5-8.0 µm.
Ecology: Fresh water. I found this species several times in the Netherlands.
Remarks: It is possible that this species can be split in more than one species. One location showed several specimens which strongly resembled R. timidum, but with a much larger nucleus, 9.6-12 µm.