FIGURES 21–25 in Chelonicola and Poulinea, two new gomphonemoid diatom genera (Bacillariophyta) living on marine turtles from Costa Rica

FIGURES 21–25. Poulinea lepidochelicola. SEM pictures taken from the holotype population from the olive ridley sea turtle carapace collected on Ostional Beach, Costa Rica. 21. External view of an entire valve showing the raphe structure, the striae composed of two enlarged areolae and the fascia with only one reduced stria. 22. External detail of a headpole with the siliceous covering of the distal raphe fissure and the lack of an apical pore field. 23. External detail of a footpole with the thickened siliceous covering of the distal raphe fissure and the presence of several areolae surrounding the apex. 24. External detail of the central area showing the spatulate proximal raphe endings. 25. External detail of the striae. Note the hymenate coverings in the areolae canals. Scale bar represents 1 μm except for Fig. 21 where scale bar = 10 μm.