Microgromia minor de Saedeleer, 1934

Most likely ID: n.a.

 

Synonym: n. a.

 

Sampling location: Simmelried

 

Phylogenetic tree: Microgromia minor

 

Diagnosis:

  • shell retort-shaped, outline circular sometimes elongated with a dorsal tip
  • length of shell 14–25 µm
  • shell hyaline and thin
  • short neck, obliquely oriented to shell outline
  • one side of the neck is a slightly concave transition of the shell outline
  • neck with a septum
  • nucleus central with a spherical nucleolus
  • contractile vacuole near neck
  • granuloreticulopodia very thin, anastomosing, arising from a peduncle
Microgromia-minor
Microgromia minor

I found Microgromia minor between 2005 and 2014 in the Simmelried. Mostly the specimens were found there on gelatinous colonies of cyanobacteria (probably Aphanothece spec.), on which it fed. I have not been able to find any more specimens after 2014.

 

Microgromia minor looks similar to Microgromia haeckeliana, but one side of the neck is an extension of the shell outline, with a slightly concave indentation (s fig. 1). In my population there were also some specimens with an elongately deformed shell, which terminated in a short tip at the dorsal margin (s. figs. 2 and 5 a-b). Otherwise the outlines of the shells were mostly circular.

Microgromia-minor

Fig. 1: Microgromia minor. L = 17 µm. Lateral view of specimen. Note the slightly concave transition of the shell outline into the neck (arrow). Obj. 100 X.

Microgromia-minor

Fig. 2: Microgromia minor. L = 17 µm. A second specimen feeding on cyanobacteria (likely Aphanothece spec.). Note the dorsal tip of the shell. Obj. 100 X.

Microgromia-minor

Fig. 3: Microgromia minor. L = 14 µm. A third specimen feeding on cyanobacteria. Obj. 100 X.

Microgromia-minor

Fig. 4: Microgromia minor. L = 13 µm. A fourth specimen feeding on cyanobacteria. Obj. 100 X.

Microgromia-minor

Fig. 5 a-b: Microgromia minor. L = 15 µm. Two focal planes of a specimen feeding on cyanobacteria. Obj. 100 X.

Microgromia-minor

Fig. 6: Microgromia minor. L = 16 µm. Two specimens in a feeding community. Obj. 100 X.