| Division | Charophyta |
| Class | Zygnematophyceae |
| Order | Desmidiales |
| Family | Desmidiaceae |
| Basionym | Cosmarium trilobulatum var. excavatum Eichler & Gutwinski |
| Synonym | Cosmarium venustum f. ocellatum Ducellier 1918 |
Cells small size and longer than broad measure 23–32 μm in length and 20–25 μm width. Cells deeply constricted and sinus linearly closed; isthmus 6–8 μm. Semicell trapezoid shapes with rounded apical and basal angles. Lateral margin shows 2–3 undulations; the apex truncated apex with 2–3 undulations. Semicells covered with small granules; circular in lateral view and elliptical in vertical view.
Ecology
Thalli collected as plankton from acidic and oligotrophic water bodies.
Distribution in India
Tamil Nadu.