FIGURES 136–139 in The genus Afrocymbella (Bacillariophyceae) from lakes Malawi and Tanganyika, with description of new fossil and extant species

FIGURES 136–139. Afrocymbella gibba sp. nov., SEM external valve views. 136. View of the whole valve showing raphe structure, slit-like areolae, and APF on footpole. 137. Detail footpole showing striae structure and distal raphe terminal fissure. 138. Detail of valve apex showing the slit-like areolae and APF of round poroids. 139. Detail of mid-valve showing dorsally deflected proximal raphe ends and slightly elongated stigmoid on the dorsal side of the large diamond-shaped central nodule. Scale bars = 10 μm (Fig. 136), 5 μm (Fig. 139), 2 μm (Figs 137–138).