FIGURES 57–59 in The genus Afrocymbella (Bacillariophyceae) from lakes Malawi and Tanganyika, with description of new fossil and extant species

FIGURES 57–59. Afrocymbella nyassae sp. nov., SEM internal valve views. 57. View of the whole valve showing raphe structure and areolae without velum. 58. Detail of mid-valve of a broken valve showing proximal raphe ends covered by flap-like silica development and antler-like intermissio stigmoid. 59. Close view of valve apices showing APF with knobby jointed ridge of silica (white arrow) and distal raphe fissures slightly raised into small helictoglossae. Scale bars = 5 μm (Figs 57–58), 2 μm (Fig. 59).