Micrasterias apiculata
Meneghini ex Ralfs, 1848
Most likely ID: n.a.
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Synonym: n.a.
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Sampling location: Holzöster See (Austria), Schwemm (Austria)
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Phylogenetic tree: Micrasterias apiculata
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Diagnosis:Â
- cells broad ellipsoid, sinus widened towards margin
- length 120–300 µm
- semi-cells 5 lobed
- lobes deeply contricted
- polar lobes longer than lateral lobes
- all lobed covered with short, conical spines
I found Micrasterias apiculata in 1995 in the Holzöster See (Austria) and then again in 2003 and 2025 in the Schwemm Moor (Austria). In my sampling sites in the region of Lake Constance I have not yet been able to find this species.
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Micrasterias apiculata is somewhat similar in outline to Micrasterias papillifera. However, Micrasterias apiculata has many short spines distributed over the entire surface of the lobes (s. figs. 2 and 3 b), whereas Micrasterias papillifera has them exclusively in rows along the incisions between the lobes.
Fig. 1: Micrasterias apiculata. L = 230 µm. A specimen found in July 2025 in the Schwemm Moor. Obj. 60 X.
Fig. 2: Micrasterias apiculata. L = 230 µm. The same specimen as shown in fig. 1 with focal plane on the spines covering the semi-cells. Obj. 60 X.
Fig. 3 a-b: Micrasterias apiculata. L = 230 µm. A second specimen in darkfield illumination. Obj. 40 X.