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

Spiculophrys

Genus Spiculophrys Zlatogursky, 2016 Diagnosis: Centrohelids lacking silica scales but with numerous thin, pointed organic (without any traces of silica) scales tapering towards acute apices. 18S

Read More »

Acanthocystis drakena

From Zlatogursky, 2016 Acanthocystis drakena Zlatogursky, 2016 Diagnosis: Cells are 21.1-30.5 µm (ca. 26.7) in diameter. Cell is covered with oval plate-scales having a margin

Read More »

Choanocystis symna

From Zlatogursky, 2014 Choanocystis symna Zlatogursky, 2014 Diagnosis: Cell body ca. 6.7 µm in diameter. Axopodia three–five times longer than a cell diameter. Plate-scales dumbbell-shaped

Read More »

Acanthocystis costata

From Zlatogursky, 2014 Acanthocystis costata Zlatogursky, 2014 Diagnosis: Cell body ca 9.5 µm in diameter. Axopodia 2–3 times longer than cell diameter. Length of spine-scales

Read More »

Kinetocyst

Left: ultra-structure of a kinetocyst of Raphidiophrys contractilis); right: two kinetocysts in an axopodium. Kinetocysts In centrohelid heliozoa, extrusomes are called kinetocysts, and are present

Read More »

Yogsothoth carteri

Yogsothoth carteri, after Shishkin and Zlatogursky, 2018 Yogsothoth carteri Shishkin and Zlatogursky, 2018 Diagnosis: Individual cells in a colony have a diameter of 9.7-15.2 µm;

Read More »