Micrasterias fimbriata Ralfs, 1848
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Schwemm Moor (Austria)
Phylogenetic tree: Micrasteria fimbriata
Diagnosis:
- cells subelliptical, deeply constriczed
- length 200–280 µm
- sinus open towards
- semi-cell 5 lobed
- polar lobes slightly elongated with each 6 spines
- lateral lobes near sinus elongated with 2 curved spines
- all secondary lobes with each 2 spines
- cell wall with several spines of different length
I first found only a few specimens of Micrasteria fimbriata in samples sent to me by Lenzenweger in August 1997. These were samples from the Schwemm Moor near Walchsee in Austria.
The main characteristics of Micrasterias fimbriata are the slightly elongated apical lobes and the lobes that are directly adjacent to the sinus. These elongated lobes have slightly curved spines at the distal ends. The apical lobes also have two small spines in the concave apex, but these are difficult to recognize. All other lobes also have spines, but these are somewhat shorter (s. fig. 1 a-b). The cell wall is covered with a few scattered spines, which can vary in length (s. fig. 2). These are not only located along the constrictions between the lobes, as is the case with Micrasteria papillifera.
Fig. 1 a-b: Micrasteria fimbriata. L = 242 µm. A specimen in DIC (a) and darkfield illumination (b). Obj. 20 X.
Fig. 2: Micrasteria fimbriata. Focal plane on the cell wall covered with several short spines (arrows). Obj. 100 X.