Phylum: Charophyta   Family: Desmidiaceaa

Cosmarium pseudosuborthogonum F.A.C. Kouwets 2025

A small desmid with semicells about semicircular with undulate sides, about 8 undulations per semicell. Apices truncate and retuse.
Cell dimensions (2): L: 22-22.5 µm; B: 16-16.3 µm; Is: 5.9-7 µm; Th: c.10 µm; L/B: 1.35-1.40.
Found in mesotrophic vegetated loch-margins. Status in the Outer Hebrides unknown due to taxonomic confusion.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.