Phylum: Charophyta   Family: Desmidiacea

Cosmarium pseudogoniodes P.F.M. Coesel & K.J. Meesters 2023

In Europe this small taxon is regarded as widely distributed in acidic oligo-mesotrophic habitats. It was first recorded in the Outer Hebrides in 2023 but could easily be overlooked due to its small size.
Cell dimensions: L: 15-23 µm, B: 26-34 µm, Is: 7-11 µm; c.8-9 µm, L/B: 1.7-2.1.

References: 
Coesel, P.F.M. & Meesters, K.J. (2023 second edition). Desmids of the Lowlands.
Kouwets, F.A.C. (in manuscript). European Flora of the Desmid Genus Cosmarium.
Van Westen, M. (2024). Sieralgen in Drenthe.