FIGURES 12–16 in Two new Nitzschia species (Bacillariophyceae) from China, possessing a canal-raphe-conopeum system

FIGURES 12–16. Nitzschia arierae, sp. nov., internal views, SEM. 12. A whole valve, note the interspaces narrower towards the poles. 13. Apex, note the distinctive apical pore field and the poroids in the keel zone (two arrows). 14–16. Central areas, showing the subtended zone different from the uncovered zone (Fig. 14, double-head arrows), shortened striae (arrows), dichotomous striae (wavy arrows), and poroids present in the keel zone (Figs 14–15, arrowheads). Scale bars = 10 μm (Fig. 12), 1 μm (Figs 13–16).