Phylum: Charophyta   Family: Desmidiaceae

Cosmarium coeselii F.A.C. Kouwets, M.F. van Westen & B.F. van Tooren 2021

This is a recently described species based on the poorly known and described C. pachydermum var. aethiopicum (West & West) West & West 1905. It is smaller than C. pachydermum in all dimensions with no overlap. The cell-wall is densely covered in fine pores.
Single cell dimensions: L: 84.5 µm. B: 67.7 µm. Is: 31.3 µm. L/B: 1.25.
Found in quaking bogs and other moorland bogs. It’s described as widespread but not common in Europe. The status in the Outer Hebrides in unknown.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium.
Van Westen, M.C. (2024). Sieralgen in Drenthe.