Micrasterias apiculata
(Meneghini ex Ralfs, 1848)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Holzöster See (Austria), Schwemm (Austria)
Phylogenetic tree: Micrasterias apiculata
Diagnosis:
- 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 in the Schwemm (Austria). In my sampling sites in the region of Lake Constance I have not yet been able to find this species.
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. 1 b and 2), whereas Micrasterias papillifera has them exclusively in rows along the incisions between the lobes.
Fig. 1 a-b: Micrasterias apiculata. L = 210 µm. Two focal planes of a specimen found 2003 in the Schwemm (Austria). Note the short spines covering the lobes (b). Obj. 20 X.
Fig. 2: Micrasterias apiculata. L = 210 µm. The spines covering the lobes in detail of the specimen as shown in fig. 1 a-b. Obj. 40 X.
Fig. 3 a-b: Micrasterias apiculata. L = 240 µm. A second specimen found 1995 in the Holzöster See (Austria) in DIC (a) and darkfield illumination (b). Obj. 20 X.