Microworld

world of amoeboid organisms

Menu
Rhizamoeba timidum
Rhizamoeba timidum, characteristic shape, covered with detritus

 

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.

Rhizamoeba timidum
Rhizamoeba timidum with broad lamellapodium
Rhizamoeba timidum
This specimen moves from its polypodial shape into the monopodial from, leaving the detritus behind.
Rhizamoeba timidum
Broad monopodial form; nucleus visible and uroid with trailing filaments.
Rhizamoeba timidum
Rhizamoeba timidum
The same specimen, in phase contrast and in DIC.
Rhizamoeba timidum
A specimen leaving its covering of debris. Note the trailing filaments.
Rhizamoeba timidum
Rhizamoeba timidum, flattened polypodial form, covered with detritus.
Rhizamoeba timidum - Ferry Siemensma
Rhizamoeba timidum – Drawing: Ferry Siemensma, 1987
Rhizamoeba timidum
Rhizamoeba timidum – Drawing: Ferry Siemensma, 1987
Recent posts

Penardochlamys arcelloides

P. arcelloides – after Penard, 1904 Penardochlamys arcelloides  (Penard, 1904) Deflandre, 1953 Diagnosis: Colorless or very slightly yellowish envelope, bag or cauldron-shaped, very thin, chitinous,

Read More »

Reticulomyxa hannae

R. hannae, plasmodium – photomicrograph Steffen Clauss Reticulomyxa hannae Völcker and Clauß, 2020 Diagnosis: Trophozoites surrounded by a very thin mucous envelope, with slowly moving plasmodia, variable

Read More »

Velamentofex saxonensis

V. saxonensis, feeding (photomicrograph Steffen Clauss) Velamentofex saxonensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 30-95 μm, granuloreticulopodia up to 1000 μm long. with a hyaline, thin

Read More »

Velamentofex tyrolensis

V. tyrolensis (photomicrograph Steffen Clauss) Velamentofex tyrolensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 98-125 μm, with reticulopodia up to 300 μm long, with a hyaline,

Read More »

Velamentofex berolinensis

V. berolinensis Velamentofex berolinensis Völcker and Clauß, 2020 Diagnosis: Trophozoites ovoid, 50-300 µm, with a hyaline, extremely flexible, membranous test. Nuclei numerous, 11.6-16.2 µm in diameter,

Read More »

Lieberkuehniidae

 Lieberkuehniidae  Siemensma, Holzmann, Apothéloz-Perret-Gentil, Clauß, Voelcker, Bettighofer, Khanipour Roshan, Walden, Dumack and Pawlowski, 2020 Diagnosis: Multinucleate organic-walled monothalamous foraminifera. Test very flexible, elongated to broadly

Read More »