Monoraphidium griffithii
(Berkeley) Komárková-Legnerová, 1969
Most likely ID: n.a.
Synonyms: Ankistrodesmus acicularis, Rhaphidium aciculare, Closterium griffithii, Rhaphidium polymorphum var. aciculare, Dactylococcopsis acicularis, Rhaphidium fasciculatum var. aciculare, Ankistrodesmus falcatus var. acicularis, Rhaphidium falcatum var. aciculare
Sampling location: Simmelried
Phylogenetic tree: Monoraphidium griffithii
Diagnosis:
- cells slender, straight spindle-shaped
- length 50–72 µm, width 2–4.5 µm
- one chloroplast, parietal
- pyrenoids absent
- nucleus in central notch of chloroplast
I have only found Monoraphidium griffithii in the Simmelried, although it is also supposed to occur in plankton. The cells are straight, very thin, and spindle-shaped. There is only one chloroplast, which does not contain pyrenoids. If pyrenoids are present, then it is the similar species Closteriopsis acicularis.
Most of the time, the cells of Monoraphidium griffithii are longer than 50 µm. If the cells are shorter than 40 µm, then they belong to other species of the genus Monoraphidium, such as Monoraphidium litorale or Monoraphidium tortile.
Fig. 1 a-b: Monoraphidium griffithii. L = 56 µm. Two focal planes of a specimen found in October 2024 in the Simmelried. Obj. 100 X.