Cosmarium moniliforme f. panduriforme
Heimerl, 1891
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Schwemm Moor (Austria)
Phylogenetic tree: Cosmarium moniliforme f. panduriforme
Diagnosis:
- cells dumbbell-shaped
- length 12–33 µm, width 7–18 µm
- semi-cells almost spherical
- isthmus narrow, with concave margins
- chloroplast with one pyrenoid
- cell wall finely punctate
So far, I have only found Cosmarium moniliforme f. panduriforme in the Schwemm Moor in Austria. In the samples, this small Cosmarium species is inconspicuous and can easily be overlooked. The cells are distinctly dumbbell-shaped with almost spherical semi-cells. The specimens in my population were between 20-25 µm long, which fits very well with the data provided by von Lenzenweger (1999) of 12–33 µm. The parent form Cosmarium moniliforme and the variety Cosmarium moniliforme var. limneticum are larger (> 30 µm) and have an isthmus that tapers slightly inward.
Fig. 1 a-b: Cosmarium moniliforme f. panduriforme. L = 22 µm. Two focal planes of a specimen found in the Schwemm Moor. Note the isthmus with the concave margins. Obj. 100 X.
Fig. 2 a-b: Cosmarium moniliforme f. panduriforme. L = 24 µm. Two focal planes of a second specimen. Obj. 100 X.