FIGURES 16–20 in Pinnularia qinghainensis: a new diatom species (Bacillariophyta) found in the brackish Lake Qinghai, China

FIGURES 16–20. Pinnularia qinghainensis sp. nov., SEM external view. 16. Complete valve. 17. Detail of centre in Fig. 16, note hexagonal central area and slightly bent central raphe ends. 18, 19. Detail of pole in Fig. 16 showing curved distal raphe fissures and striae composed of 4 rows of small areolae. 20. Detail of striae showing small areolae occluded by silica plates. Scale bar = 10 μm (Fig. 16), 1 μm (Figs 17–20).