world of amoeboid organisms


Raphidocystis marginata

From Siemensma (1991)

Raphidocystis marginata  (Siemensma, 1981) Zlatogursky, 2018
Basionym: Raphidiophrys marginata Siemensma, 1981
Diagnosis: Plasma body 24-27 µm in diameter, surrounded by a layer of numerous loosly distributed plate-scales without a clear structure, only with a few granules on the surface, and with a thick, hollow edge, which shows a band of fine teeth on the inside. Scales are ovate, but larger scales tend to be naviculoid. Scales are 5.9-10.0 x 2.5-3.9 µm, L/B ratio 1.9-2.6 (mean 2.2). Axopodia strongly granulated and numerous. One to three strongly bulging contractile vacuoles.

Ecology: In sapropel, not uncommon. Holland (Siemensma 1981), Chile, New Zealand, Sri Lanka, Canada (Ntcholls & Dürrschmidt 1985).

Remarks: The species resembles a Heterophrys species, as the scales are only visible as fine lines around the cell. The hollow edge is clearly noticeable after embedding in e.g. Canadabalsem.

Recent posts

Actinosphaeridium spec.

Actinosphaeridium spec. Diagnosis: Cell surrounded by a membranous shell, with an outer mucous layer. Filopodia with granules, sometimes branching. Cell stalked. Ecology: I found this

Read More »


Euglyphidion enigmaticum – after Bonnet, 1960 Genus Euglyphidion Bonnet, 196 Diagnosis: Shell hyaline, ovoid, pseudostome circular or slightly elliptical. Shell loosely covered with two types of

Read More »

Leptomyxa spec.

Leptomyxa sp., slowly retracting in response to the light of the microscope Leptomyxa sp. Diagnose: This is a very large amoeba which I found in

Read More »

Zivkovicia spec.

Zivkovicia spec., 200 µm long; the right image is viewed through the aperture Zivkovicia spec.  Diagnosis: Shell pyriform, circular in oral view, with a clear

Read More »

Pontigulasia pentangulostoma

P. pentangulostoma, after Quin et al., 2008 Pontigulasia pentangulostoma Quin et al., 2008 Diagnosis: Shell is brown, laterally uncompressed, parted to neck and body regions

Read More »

Flabellula citata

Flabellula citata, from Dykova et al., 2008 Flabellula citata Schaeffer, 1926 Diagnosis: Length in locomotion 15-75 µm; width 25-55 µm. Shape very variable, from a

Read More »