Phylum: Charophyta   Family: Desmidiaceae

Cosmarium turpinioides P.F.M. Coesel & R. Matthews 2024

This recently named species is a raise in rank of C. turpinii var. eximium W. & G.S. West 1908. It differs from C. turpinii Brébisson 1856 in having smaller dimensions with a single protuberance and a large isthmial granule.
Cell dimensions: L: 52.3-56.8 µm; B: 46.8-51.3 µm; Is: 14.8-15.7 µm; Th: c.28 µm; L/B: 1.08-1.12.
West & West (1908: 192) only managed to record it from a single site in Ireland. A rare variety that prefers circumneutral waters.

References: 
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.
Van Westen, M.C. (2024). Sieralgen in Drenthe.
West, W. & West, G.S. (1908). A Monograph of the British Desmidiaceae, Volume 3.