The spines of P. pseudoconstruens are aligned with striae, in contrast to other species of Pseudostaurosira, which have spines aligned with costae.
The valves of P. parasitica are lanceolate, in contrast to the cruciform valves of P. pseudoconstruens. Pseudostaurosira robusta generally has two inflations in the valve outline, where P. pseudoconstruens has only one. Staurosira construens is similar in shape and areolae features, but the areolae may be elliptical in relation to the apical axis and more dense than 25 in 10 µm. The areolae of P. pseudoconstruens may be elliptical to the transapical axis and less dense than 20 in 10 µm. Staurosirella leptostauron has lineolate striae and the central area is smaller than in P. pseudoconstruens.
Ninastrelnikovia gibbosa is larger and a raphe is present, although cells are often linked together in similar colonies.