Phylum: Charophyta   Family: Desmidiaceae

Cosmarium owencashlaense F.A.C. Kouwets 2025

A recently described species named after the Owencashla River in County Kerry, Munster, Ireland, located on the Dingle Peninsula, near Castlegregory. This is where the type material was collected. It needs to be carefully compared with C. exiguum Archer 1864, but that species is on average slightly broader giving a smaller L/B ratio, apparently without overlap.
Single cell dimensions: L: 26 µm, B: 11 µm, Is: 5.4 µm; Th: c.8 µm, L/B: 2.37.
Because of earlier taxonomic confusion, its status in the Outer Hebrides is unknown. It reportedly preferred acidic habitat such as moorland pools and bogs, especially with Sphagnum.

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