Stauroneis Guide
Credit: Loren Bahls
  1. Stauros present
  2. Pseudosepta may be present
  3. Striae distinctly punctate

Stauroneis has naviculoid and mostly solitary cells with two chloroplasts, one on each side of the cell against the cingulum. Valves range from almost linear to lanceolate to elliptic-lanceolate. The central area is a prominent transverse fascia, known as a “stauros”. The central fascia typically extends to the valve margins, where one to several short striae may be present. The striae are uniseriate and punctate. The areolae are usually round but are transversely elongate in some species. Pseudosepta are present in some species. Variable and useful diagnostic features for identifying species include: presence or absence of pseudosepta, valve size and shape, width of the axial area, size and shape of the central area, number of striae in 10 µm, shape of areolae and number of areolae in 10 µm, raphe structure, and size and shape of the external proximal raphe ends.

Stauroneis is a diverse freshwater genus found mostly in the benthos of wetlands and small lakes and ponds. Some species are also found in stream benthos and on moist soils and moss.