Microworld

world of amoeboid organisms

Menu

 

Diagnosis: Shell oval or pyriform, rigid test without collar, densely or sparsely agglutinated with mineral xenosomes;  xenosomes attached to the surface of the test, or embedded into and surrounded by a structureless, sheath like organic cement matrix; aperture may be circular and regularly ag­glutinated with xenosomes; it may have an organic rim, or it may be narrow and irregular; test not filled entirely by the cytoplasm; filopodia branching.

Type species: Pseudodifflugia gracilis Schlumberger, 1845.

Ecology: freshwater, soil and marine littoral sands.

Remarks: About 20 species, often with incomplete descriptions. Even the type species needs a much more accurate description: Animal test brown-bluish, encrusted and covered with small sand grains, ovoid, more or less elongated, with very long filipods”. That’s all, without any images.

Probably this genus is a “Sammelgruppe”, a taxon that contains a number of not closely related amoeboids. Some species may belong to the genus Plagiophrys, like P. compressa.

 

Key to some species:

1Shell compressed

P. compressa

Shell not compressed

2

2Shell < 25 µm

3

Shell > 30 µm

5

3Aperture very small, c. 4-5 µmP. microstoma
Aperture larger

4

4Shell ovoid, without a neck

P. klarae

Shell ovoid, tapering to a small distinct neckP. spec.
5Shell densely covered with xenosomes6
Shell loosely covered with xenosomes

P. fascicularis

6Plasmabody fills the shell completely

P. archeri

Plasmabody doesn’t fill the cell completely

P. virescens

Pseudodifflugia virescens
Pseudodifflugia virescens
Recent posts

Euglyphidion

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, Y., Xei, S., Gu, Y. and Zhou, X., 2008 Diagnosis: Shell is brown, laterally uncompressed,

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 »

Puytoracia bonnetti

Puytoracia bergeri, from Nicholls, 2006 Puytoracia bergeri   Nicholls, 2006 Diagnosis: Shell an oblong flattened cylinder, with rounded anterior and posterior ends. An invaginated pseudostome

Read More »