Cylindrifflugia bacillariarum
(Perty) González-Miguéns et al., 2022
Most likely ID: n.a.
Synonym: Difflugia bacillariarum
Sampling location: Simmelried, Sima Moor (Austria)
Phylogenetic tree: Cylindrifflugia bacillariarum
Diagnosis:
- shell ovoid or spherical, with a posterior spine
- shell colorless or yellowish brown, covered with siliceus scales and diatom frustules
- length 57–133 µm
- aperture of shell circular (often covered by diatom frustules)
- nucleus spherical, located posterior
So far I have only found Cylindrifflugia bacillariarum twice. The first time in April 1997 in Simmelried and the second time in Sima Moor (Austria) in June 2024. Since 1997 I have not found any further specimens in the Simmelried.
The shell of Cylindrifflugia bacillariarum is completely covered with empty frustules of diatoms and it has an elongated spike at the posterior end, which makes it very characteristic. Penard (1902) considered Cylindrifflugia bacillariarum to be a variant of Difflugia elegans (meanwhile Cylindrifflugia elegans (Penard) n. comb. González-Miguéns et al., 2022), but points out that it was declared as Difflugia bacillariarum by Perty (1849). In fact, the two species are very similar and have often been confused in the past. However, the shell of Cylindrifflugia elegans is not completely covered with diatom frustules, but also with a high proportion of mineral grains (s. Ferry Siemensma – Microworld- Cylindrifflugia elegans). Since the specimens in my population were completely covered with diatom frustules, they must be Cylindrifflugia bacillariarum.
More information and images on Cylindrifflugia bacillariarum: Ferry Siemensma-Microworld-Cylindrifflugia bacillariarum
Fig. 1 a-c: Cylindrifflugia bacillariarum. L = 96 µm. Three focal planes of a specimen with extended pseudopodia (PP). Diatom frustules intended for assembling in the shell or for creating a daughter shell are gathered around the cytostome. Obj. 60 X.
Fig. 2 a-b: Cylindrifflugia bacillariarum. L = 96 µm. The slightly squashed specimen as shown in fig. 1 a-c. The spherical nucleus (Nu) is located in the posterior third and the shell is exclusively covered with diatom frustules (DF). Obj. 60 X.