Pteromonas

Pteromonas is a genus of green algae in the family Phacotaceae. It has a cosmopolitan distribution, and mainly occurs in nutrient-rich freshwaters.

Pteromonas is a unicellular, motile organism with two flagella; the protoplast of the cell is contained in a transparent, flattened shell called a lorica. The two flagella emerge from separate openings in the anterior of the lorica. The lorica consists of two equal parts pressed together at their margins, forming a keel. The lorica is variously shaped, and may be undulate or spiny. The protoplast is pyriform, ovoid or globose and compressed. Cells contain a cup-shaped chloroplast with one or more pyrenoids and usually an stigma. Two contractile vacuoles are present at the base of the flagella.