Gonatozygon kinahanii
(W. Archer) Rabenhorst, 1868
Most likely ID: n.a.
Synonym: Leptocystinema kinahanii
Sampling location: Simmelried
Phylogenetic tree: Gonatozygon kinahanii
Diagnosis:
- cells elongate cylindrical with with parallel sides
- truncate apices
- length 150–500 µm, width 10–20 µm
- cells often in long filametes
- cell wall smooth, without ornamentation
- two ribbon-shaped chloroplasts
- 4–10 pyrenoids per chloroplast
- end of cells transparent, often with vacuoles containing some crystals
- spherical nucleus centrally between the chloroplasts
I find Gonatozygon kinahanii regularly, but rarely in the Simmelried. Up to now I find exclusively single cells and a pair of cells (s. fig. 5). Filaments with several cells I have not found yet.
Gonatozygon kinahanii can be identified by the smooth cell wall and that not widened or narrowed cell ends. The cell ends are transversely truncated. Sometimes the cell ends are still convexly rounded (s. fig. 1 a). The two chloroplasts are equally aligned in both halves of the cell. That they are flat and ribbon-shaped can be seen by carefully rotating the cell under the coverslip (s. figs. 1 a and 1 b).In the cytoplasm, there are often small, colorless crystals, which collect especially in the terminal vacuoles (s. figs 4 and 5).
Fig. 1 a-b: Gonatozygon kinahanii. L = 266 µm. Focal planes of a single cell on the front side of the ribbon-shaped chloroplasts (a) and on the narrow side of the chloroplasts after turning of the cell by 90° (b). Nu = nucleus, PY = pyrenoids, TV = terminal vacuoles. Obj. 60 X.
Fig. 2: Gonatozygon kinahanii. Detail of the cell shown in fig. 1 a-b. The nucleus (Nu) is located in the middle between the two chloroplasts (Chl 1, Chl 2). PY = pyrenoids. Obj. 100 X.
Fig. 3: Gonatozygon kinahanii. Focal plane on the crystals floating in the cytoplasm of the cell (arrows). Some of them have the shape of square tiles. Obj. 100 X.
Fig. 4: Gonatozygon kinahanii. Focal plane on the floating crystals (FC) in one of the terminal vacuoles of the cell. Obj. 100 X.
Fig. 5: Gonatozygon kinahanii. 228 and 236 µm. A pair of cells, probably after a cell division. Obj. 40 X.