Hannaea inaequidentata, normal vegetative valves, external view, SEM 60 displaced frustule 61 detail of Fig. 60, showing well-developed virgae and vimines (arrows), spines mostly located between two adjacent virgae, sometimes situated on virgae (arrowheads) 62, 63 apex details of Fig. 62 showing rimoportula configuration in two valves forming a cell: each cell with two rimoportulae, located diagonally at both apices of each cell (two arrows, respectively) 64, 65 another two apices showing a regular ocellulimbus and areolae occluded internally by hymens. Scale bars: 10 μm (60), 2 μm (61–63), 1 μm (64, 65).