Microgromia haeckeliana

 

 

Microgromia haeckeliana De Saedeleer, 1934

 

Diagnosis: Shell hyaline, small, retort-shaped, double-sided symmetrically, with one side fastened to the substrate; outline circular, sometimes irregular or angular. Shell with a distinct, often thickened neck. Septum clear, usually with a shorter kind of septum at the base of the neck, thus forming a V-shape. Septum oriented from left to right. Cytoplasm asymmetrical, with a bundle of pseudopodia. Pseudopodia granular, very thin, and anastomosing, thus forming a network. Nucleus relatively large, globular with a central nucleolus. One contractile vacuole.

 

Dimensions: De Saedeleer (1934): shell 13.6-17.0 µm, nucleus 4 µm. Kreutz (2012): 11-14 µm, nucleus 3.6 µm. My measurement: 16.9 µm, nucleus 4.4 µm.

 

Ecology: in iron rich water, on mucous layers of cyanobacteria.

 

Remarks: All pictured specimens on this page were attached to the cover slip. However, it is not clear what De Saedeleer means with a septum oriented from left to right. What if the shell is fastened to the cover slip or to the slide? Is the orientation than reversed? Further observations are needed.

 

Microgromia haeckeliana
Microgromia haeckeliana
Living specimen with V-shaped septum; drawing by De Saedeleer, 1934. Note the V-shaped septum.
Microgromia haeckeliana
Microgromia haeckeliana
The same specimen as at the top.
Microgromia haeckeliana
Microgromia haeckeliana, shell 16.9 µm, nucleus 4.4 µm, with long "Pseudopodienstiel".
Microgromia haeckeliana
Microgromia haeckeliana
Irregular shell with a long septum and empty shell
Microgromia haeckeliana
Microgromia haeckeliana
Shell 16 µm, with distinct V-shaped septum and shell 18 µm
Microgromia haeckeliana
Microgromia haeckeliana
Both shells 18 µm
Microgromia haeckeliana
Microgromia haeckeliana, 16.9 µm