Navicymbula Guide
  1. Asymmetry to apical axis slight
  2. Striae lineolate
  3. Distal raphe fissures dorsally deflected

The valve outline is very slightly asymmetric to the apical axis, so that valves are nearly naviculoid in appearance. The raphe is positioned in a nearly central position on valve. The distal raphe fissures are deflected dorsally. Each areola is, more specifically, a lineola. Therefore, striae are lineolate. Valves lack apical pore fields.

The genus is more closely allied with Navicula than Cymbella. Note the lineolae, a shared feature with Navicula. Navicymbula is considered monotypic. The species N. pusilla lives in brackish to saline waters, including in endorheic lakes of the Northern Great Plains.

The genus Navicymbula was designated by Krammer (2003) based on Cymbella pusilla Grunow. Later, it was treated in the genus Seminavis, as S. pusilla (Grunow) E.J.Cox and G.Reid 2004.