Staurosirella ovata has two apical pore fields, one at each pole, compared to the single apical porefield of S. martyi. Staurosirella ovata also has a higher stria density (6-9 in 10 µm). Staurosirella pinnata possesses both spines and a higher stria density (11-14 in 10 µm). Staurosirella subrobusta is broadly lanceolate, with a wider, more lanceolate sternum and tendency for more radiate striae at the poles. Note, however, that at the small end of the size spectrum, all of these taxa may be indistinguishable from one another.