Phylum: Charophyta   Family: Desmidiaceae

Cosmarium pseudoconnatum Nordstedt 1870

A rarely recorded species of oligotrophic waters such as peat bogs, shallow lochs and moorland pools. It has a predominantly north-western distribution in the British Isles.
Cell dimensions (2): L: 53-56 µm, B: 40-43 µm, Is: 37-40 µm; L/B: 1.31-1.32.
A large cell with very shallow sinuses, which are open widely. Semicells are sub-semicircular with a broadly rounded apex, cell-wall covered with pores. West & West (1908: 27) record it from the Outer Hebrides but note it’s a rare desmid.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.
West, W. & West, G.S. (1908). A Monograph of the British Desmidiaceae, Volume 3