Cosmarium vogesiacum (Lemaire, 1883)
Most likely ID: n.a.
Synonym: n.a.
Sampling location: Simmelried
Phylogenetic tree: Cosmarium vogesiacum
Diagnosis:
- semi-cell trapezoidal with flattened apex
- length 19–23 µm, width 18–22 µm
- sinus narrow, dilated to the margin
- lateral margins of semi-cells with 5–7 granules
- parallel to margin von semi-cells 2–3 rows of granules
- in the center of the semi-cells 2 elliptical warts
- parallel to sinus two rows of granaules
- one pyrenoid per semi-cell
So far I have only found Cosmarium vogesiacum in the Simmelried. However, I have only been able to find it there in the last 2 years. I cannot rule out the possibility that Cosmarium vogesiacum was already present before, but then only sporadically at most. In the meantime, the species has become very stubborn and I mainly find it in a shallow siltation zone. The specimens shown below are from July and September 2023.
Fig. 1 a-d: Cosmarium vogesiacum. L = 32 µm. Different focal planes of a slightly squashed specimen. Obj. 100 X.
Fig. 2 a-b: Cosmarium vogesiacum. L = 33 µm. A second, slightly squashed specimen. Obj. 100 X.