Guide to Gomphosinica

Valves are clavate, or club-shaped, in valve view. In girdle view, frustules are cuneate. Striae are composed of 2-3 rows of areolae. Internally, the proximal raphe ends are unilaterally curved. A prominent stigma is present in the central area. Externally, the stigma has a round opening. Internally, the stigma has many small, round openings. An apical pore field is present at the footpole. The pore field has with numerous porelli, similar in shape to the areolae. The apical pore field is bisected by external distal raphe. Both septa and pseudosepta are present at the apices.

Gomphosinica was described to include a group of species formerly included in Gomphonema and Gomphoneis (Kociolek et al. 2015). In North America, the genus includes G. geitleri (Kociolek and Stoermer) Kociolek et al., G. glaceriana Kociolek et al., G. robusta Kociolek et al., G. subtilis Kociolek et al. and G. capitata Kociolek et al.

The genus also includes a number of species from Tibet, Nepal and China, including G. hedinii (Hustedt) Kociolek et al. 2015. Note that the only difference in morphology between Gomphosinica and Gomphonella is the number of stigmata (Tuji 2020). Molecular data is needed to determine the relationship of taxa in these genera.