Phylum: Charophyta   Family: Desmidiaceae

Cosmarium bioculatiforme F.A.C. Kouwets 2025

The open, acute-angled sinus is a key character, but the degree of opening is variable. Because of the taxonomic confusion regarding Cosmarium bioculatum J. Ralfs 1848, Kouwets has rename this taxon C. bioculatiforme.
Kouwets' Cell dimensions: L: 11-19 µm, B: 10.5-21.5 µm, Is. 3.5-4.5 µm; Th. 7-9 µm L/B: 0.84-1.13.
(Mine fall within these.)
The current finds are from shallow pools rich in vegetation and vegetated loch-margins which are neutral to slightly acidic.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium.