Phylum: Charophyta   Family: Desmidiaceae

Cosmarium elevatiforme F.A.C. Kouwets 2025

This recently described species is based on C. phaseolus var. elevatum Nordstedt 1873 and its confusing description. The semicells support a central protuberance rather like a papilla. Compare with the similar-shaped C. elevatum (Nordstedt) Gutwinski 1895 but that species is larger without overlap.
Cell dimensions: L: 25.3-26.3 µm; B: 23.5-24.7 µm; Is: 7-7.5 µm; Th: 14.7-15 µm; L/B: 1.06-1.11.
Found in circumneutral waters such as lochs, moorland pools and abandoned peat-cuttings. Probably common but status little known due to earlier taxonomic confusion.

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