Phylum: Charophyta   Family: Desmidiaceae

Cosmarium druimnahimrichense C.D.N. Johnson 2025

Cells medium-sized, about 1.35 times as long as broad, broadly elliptic in outline, sinus linear and slightly dilate at the apex. Semicells broadly semicircular, basal angles tightly rounded, sides slightly convex and crenate converging upwards and blending easily into the small truncate apex. The semicells’ margin has 20-22 crenae; the cell-wall is ornamented with five concentric radiating series of granules, crossing the sides, the outer two in face view are geminate. There are two noticeable supraisthmial granules, above these is a circular group of granules in five vertical rows, the middle three comprise 6 granules that become adjacent farther away from the isthmus. The outer rows comprise 3 or 4 granules. Between these granules and the concentric series is an unsculptured zone. Side view of the semicell is subcircular with the basal half protruding (resembling an eggcup), apical view elliptic with a pronounced central protuberance. Chloroplast axile with two pyrenoids.
Cell dimensions: L: 47.1-52.6 µm; B: 36.2-39.0 µm; Is: 12.6-13.8 µm; Th: 26.0-26.9 µm; L/B: 1.28-1.39.
Only known from a shallow, silty, meso-oligotrophic loch.

References: 
Johnson, C.D.N. (2025). Cosmarium druimnahimrichense. C.D.N. Johnson spec. nov.
Kouwets, F.A.C. (2025). European Flora of the Desmid Genus Cosmarium. Part 1: Text. Part 2: Plates.