FIGURES 21–23 in Sellaphora tanghongquii sp. nov. (Bacillariophyta, Sellaphoraceae), a new diatom species from the Southern China

FIGURES 21–23. Sellaphora tanghongquii sp. nov., SEM, external views. 21. External view of the entire valve. Arrow A in the figure indicates troughs extending to the apical area and progressively becoming shallower. Arrow B indicates areolae becoming smaller from the longitudinal ridge to the trough. Arrow C indicates a row of separated and small pores on the valve mantle. 22. Detail of valve apices showing, uniseriate striae extending into the mantle. 23. External view of valve centre showing central raphe endings with the drop-shaped pores. Scale bar = 1 μm.