FIGURES 174–179 in Novel diatom species (Bacillariophyta) from the freshwater discharge site of Laguna Diablas (Island Isabela = Albemarle) from the Galapagos

FIGURES 174–179: Pinnularia valdecontroversa sp. nov. SEM internal valve views. Figs 174, 177: striae radiate in the proximal part of valve, in the distal part becoming strongly asymmetrical about the apical axis. Fig. 175: proximal raphe ends small, slit-shaped, bent in the same direction towards valve secondary side (arrows). Figs 176, 178, 179: distal raphe ends terminate in small helictoglossae (arrow in Fig. 179). Note the open alveolae (Fig. 176 arrow).