FIGURES 12–16 in Gyrosigma rostratum sp. nov. (Bacillariophyta) from the low intertidal zone, Xiamen Bay, southern China

FIGURES 12–16. Gyrosigma rostratum, sp. nov., external views, SEM. 12–13. Two types of valves (epitheca and hypotheca) with conopeum at each end (arrows), clockwise rotated raphe (12) and anticlockwise rotated raphe (13) in relation to apical axis. 14. Apex, showing noticeable conopeum, elongated narrow slits, round pores locating on the mantle (arrows), terminal raphe fissure, and five apical pores (black arrow). 15–16. Two central areas of epitheca and hypotheca, both with proximal raphe fissures turning in same direction (Fig. 15 central area of Fig. 12, Fig. 16 central area of Fig. 13). Scale bars = 10 μm (in Figs. 12–13), 1 μm (in Figs. 14–16).