PSEUDOSTAUROSIRA ELLIPTICA HAS NOT BEEN VERIFIED IN NORTH AMERICA
Pseudostauirosira elliptica should be compared with P. brevistrata, P. neoelliptica, and Staurosira construens var. venter. Note that smaller specimens of these taxa may not be distinguishable in LM. Larger specimens of P. brevistrata are more lanceolate in valve outline than P. elliptica. The striae are shorter and composed of a few, wider areolae than in P. neoelliptica, which has longer striae composed of narrower areolae. Also, apical pore fields in P. neoelliptica are more developed than in P. elliptica, which has reduced apical pore fields. The spines of Staurosira construens var. venter are also hollow, but they are positioned in line with the costae. In contrast, the spines of P. elliptica are positioned in line with the striae.