Spirotaenia condensata (Brebisson, 1848)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Ibmer Moor (Austria)
Phylogenetic tree: Spirotaenia condensata
Diagnosis:
- cell cylindroid or spindle-shaped with rounded apices
- length 120 – 270 µm
- often enveloped in mucilaginous sheath
- two chloroplasts ribbon-shaped, helicoidal twisted
- between the ends of the chloroplasts a gap is visible
- irregularly spaced pyrenoids in the chloroplasts scattered
I have found Spirotaenia condensata only once before in June 1995 in specimens from the Ibmer Moor in Austria. This desmid algae is easy to recognize by the spiralized chloroplast. The nucleus is located in the middle of the cell, attached to the cell wall in a plasma pocket (see fig. 1b). Some descriptions state that only one chloroplast is present. However, this is not the case. In order for a gap to form between the ends of the chloroplasts in the middle of the cell (s. fig. 1a), there must be two chloroplasts, as Förster has drawn it (s. drawing above).
More pictures and information about Spirotaenia condensata: Michael Plewka – Freshwater life – Spirotaenia condensata
Fig. 1 a-b: Spirotaenia condensata. L = 158 µm. Two focal planes of a medium sized specimen. Note the gap (Gp) between the ends of the two twisted chloroplasts. Nu = nucleus, PY = pyrenoid. Obj. 40 X.