FIGURES 51–64 in Novel diatom species (Bacillariophyta) from the freshwater discharge site of Laguna Diablas (Island Isabela = Albemarle) from the Galapagos

FIGURES 51–64: Luticola darwinii sp. nov. Figs 51–60: LM images. Valve views, showing size diminution series. Fig. 54 is of the holotype. Figs 51, 55, 57–59: with DIC, differential interference contrast, remaining bright field. Scale bar = 10 μm for LM figures. Figs 61–64: SEM external valve views. Figs 61, 62: narrow axial area expanded at the centre to form a wide rectangular fascia, extended to the valve margins, with 4–5 striae on either side. Fig. 63: radiate striae with irregularly spaced areolae. Proximal raphe ends strongly bent towards the valve primary side (arrows), distal raphe ends strongly hooked into one side. Fig. 64: note the punctiform stigma, clearly set off from the shortened marginal striae (arrow).