Brachonella fastigata was first described in 1926 by Kahl as Metopus fastigatus. Later the species was transferred to the genus Brachonella by Jankowski (1964).

So far I could detect Brachonella fastigata exclusively in the Simmelried where the species is quiete common. Brachonella fastigata can be easily identified by the strongly overhanging bulge of the apical dome on the left side of the body. The right side of the body, on the other hand, is continuous with the apical dome without such a bulge. This gives the effect of a “peaked cap” in lateral view. Brachonella fastigata swims slowly with rowing movements of the long cilia. The very long, soft caudal cilia are also conspicuous. I had the impression that the posterior pole of the cell is free of cilia, which arise in a ring around it. The specimens in my population were 50 – 58 µm long, which is slightly larger than described by Kahl, who states “maximum 50 µm”. Otherwise all characteristics agree with the description of Kahl.