Genus Pseudodifflugia Schlumberger, 1845
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 à têt brun-bleuâtre, encroûté et comme recouvert de petits grains de sable, ovoïde, plus ou moins allongé ou raccourci; expansions filiformes très longues." (= 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:
| 1 |
Shell compressed |
|
| - |
Shell not compressed |
2 |
| 2 |
Shell < 25 µm |
3 |
| - |
Shell > 30 µm |
5 |
| 3 |
Aperture very small, c. 4-5 µm |
P. microstoma |
| - |
Aperture larger |
4 |
| 4 |
Shell ovoid, without a neck |
|
| - |
Shell ovoid, tapering to a small distinct neck |
P. spec. |
| 5 |
Shell densely covered with xenosomes |
6 |
| - |
Shell loosely covered with xenosomes |
|
| 6 |
Plasmabody fills the shell completely |
|
| - |
Plasmabody doesn't fill the cell completely |