Prestauroneis Guide
Credit: Karen Neil
  1. Central striae radiate
  2. Central striae widely spaced
  3. Pseudoseptae present

Valves are lanceolate to lanceolate-elliptical. The raphe extends the length of the valve, onto the valve mantle. Pseudosepta are present at the apices. The striae are radial at the center of the valve, becoming nearly parallel at the apices. The striae are uniseriate and composed of small, round or elliptical areolae. At the center of the valve, striae are separated by robust interstriae (virgae). The external proximal raphe ends are expanded, while the internal proximal raphe ends are simple and slightly curved. The distal raphe ends are deflected unilaterally. The cingulum is composed of several open, porous bands with one or two rows of small, round poroids.

Prestauroneis includes the former Navicula integra W. Smith and recently described taxa including P. tumida Levkov and Williams 2011, and species from China (Liu et al. 2014). Prestauroneis appears to be most closely related to Stauroneis (Bruder & Medlin 2008), but has been superficially compared to Parilibellus (Witkowski et al. 2000).