Pleurotaenium trabecula Nägeli, 1849
Most likely ID: n.a.
Synonym: Pleurotaenium rectum
Sampling location: Schwemm Moor (Austria)
Phylogenetic tree: Pleurotaenium trabecula
Diagnosis:
- semi-cells straight, subcylindrical
- lateral margins sometimes slightly convex
- with distinct basal inflation
- each semi-cell with a terminal vacuole
- length 200–780 µm, width 18–48 µm
- apices smooth, flatly rounded
- chloroplasts several longitudinal ribbons
- pyrenoids scattered in chloroplasts
- cell wall smooth, very delicate punctate
The genus Pleurotaenium differs from the genus Haplotaenium by the presence of terminal vacuoles in the semicells, ribbon-shaped chloroplasts, and zygospores with a smooth cell wall without conical protuberances.
I found Pleurotaenium trabecula in the Schwemm Moor in Austria. The species has nearly cylindrical semi-cells with parallel or slightly convex sides. Each semi-cell has a basal thickening, which is sometimes accompanied by 1–2 shallow waves. The apices are broadly rounded and smooth. At the ends of each semicell, there is a terminal vacuole, often filled with crystals. The chloroplasts are ribbon-shaped and lie more or less parallel to the longitudinal axis of the cell. Pyrenoids are scattered within the bands.
Fig. 1 a-b: Pleurotaenium trabecula. L = 255 µm. Two focal planes of a specimen in DIC. Note the terminal vacuoles (TV) of the semi-cells. Obj. 60 X.
Fig. 2 a-b: Pleurotaenium trabecula. L = 255 µm. The same specimen as shown in fig. 1 a-b in brightfield illumination. TV = terminal vacuoles. Obj. 60 X.
Fig. 3 a-b: Pleurotaenium trabecula. A semi-cell in detail. BI = basal inflation, Chl= ribbon-shaped chloroplasts, PY = pyrenoids. Obj. 100 X.