Pinnularia substomatophora Hust. in A. S. Atlas Diat., pl. 392, fig. 14. 1934. Arch. Hydrobiol. Suppl., 14:160, pl. 2, fig. 14. 1935(Patrick and Reimer 1966)
This taxon has linear valve or slightly swollen sides and rounded ends. It is distinguished from P. stomatophora by the lack of the characteristic markings in the central area and the more strongly divergent and convergent striae.
. (Patrick and Reimer 1966).