Zonomyxa violacea, 450 µm

 

 

Genus Zonomyxa Nüsslin, 1882

 

Diagnosis: Test discoid in resting stage, 140 to 160 µm; locomotive form pyriform or oblong, 220 to 250 µm long. Test chitinoid pellicle, without mucilaginous envelope, flexible, follows the movements of the cell. Surface with small temporal perforations through which thin plasma threads emerge. Pseudopods single, clear, conical, from slit-like pseudostome. Endoplasm granular, violet-tinted. Up to 32 vesicular nuclei. Crystalloid bodies, 3 to 5 µm. Feeding: herbivorous. Habitat: sphagnum mosses. Monospecific.

 

 

Zonomyxa violacea Nüsslin, 1882

 

Diagnosis: As for the genus. The description is almost identical as for Amphizonella violacea. According to Meisterfeld (2006) Zonomyxa violacea can be distinguished from A. violacea by the following characters:

- a thinner membrane,
- no external mucus layer,
- and most significantly: numerous nuclei.

Zonomyxa normally has 4 nuclei (Meisterfeld, 2006), but Penard (1906) reports up to 32. These are smaller (~20 m) than the single large nucleus of Amphizonella violacea. I found an average of 7 nuclei per cell.

 

Dimensions: my measurements 360-450 µm, nuclei c. 28 µm.

 

Ecology: in Sphagnum. Tirol, France.

 

Remarks: I have only found cells with about seven spherical nuclei. Nuclei are hard to detect in living specimen. I crushed cells in order to push the nuclei out of the cell membrane. My specimens came from Sphagnum from Tirol, Austria. I've also found this species in Sphagnum from the Vosges in France.

 

Zonomyxa violacea
Zonomyxa violacea, 220 µm
Zonomyxa violacea
Cell with several pseudopodia

 

Zonomyxa violacea

Compare the above specimen with the original drawing below made by Nüsslin (1884). This drawing shows much better the common shape of this organism as the one which is usually used in textbooks, a drawing made by Penard.

 

Zonomyxa violacea

 

The drawing above was made by Penard (1906) and is usually used in textbooks, adding more confusion than clarity to the identity of this amoeboid. Penards drawing closely resembles the one of Nüsslin in the upper right corner of the drawing below, where it has the shape of a <. Remarkable are the thin 'hairs' around the cell. I've seen similar 'hairs' in specimens of A. violacea, where they were bacteria along wires of mucus.

 

Zonomyxa violacea
Zonomyxa violacea
Zonomyxa violacea
Pseudopods
Amphizonella violacea
Amphizonella violacea
A small pseudopod and some seconds later.
Zonomyxa violacea
Zonomyxa violacea, pseudopod - Mittermoor, Tirol
Zonomyxa violacea
Zonomyxa violacea
Nuclei, each 28 µm
Zonomyxa violacea
Three nuclei (arrows); this specimen contained seven nuclei, 28 µm each - Mittermoor, Tirol
Zonomyxa violacea
Zonomyxa violacea
Zonomyxa violacea, 36 µm
Zonomyxa violacea
Food vacuoles
Zonomyxa violacea
Food particles
Zonomyxa violacea
Food particles