FIGURES 21–26 in A new species of Punctastriata (Bacillariophyta, Fragilariophyceae) from temporary streams in southern Portugal

FIGURES 21–26. SEM images of Punctastriata obstinata sp. nov. from type material BR-4654, Oeiras Stream, Portugal. 21. Valve view showing second row of spines on valve mantle (white arrows) and open copula (white arrowheads). 22. Valve internal view showing apical pore fields (dashed arrows), the volae that are well-developed, and the raised axial area-virgae together with the recessed striae. 23. Girdle, tilted view of frustule showing second row of spines on mantle (white arrows), and skirt-like, flared projection of the spines (black arrow). 24. Close up on valve mantle showing spines with skirt-like, flared projections in formation (black arrows) and open copula (white arrowhead). 25. Internal view of striae showing multiseriate striae with very small areolae and volae extending inwards, accumulating mineral material. Notice the striae lies in a single internal depression running from valve face to mantle. 26. Close up on internal elliptic opening of the apical pore field (dashed arrow). Notice small round poroids. Scale bars: 0.5 µm (Figs 25, 26), 1 µm (Figs 21–24).