FIGURES 9–14. Stephanodiscus neoaegypticus, SEM. Fig. 9. Iconotype, external valve showing small concentric convex undulation with out spines. Fig. 10 in Stephanodiscus Ehr. species from Holocene sediments in the Faiyum Depression (Middle Egypt)

FIGURES 9–14. Stephanodiscus neoaegypticus, SEM. Fig. 9. Iconotype, external valve showing small concentric convex undulation with out spines. Fig. 10. External valve showing small concentric concave undulation and external rimoportula opening (arrowed). Fig. 11. Internal valve showing sub-marginal rimoportulae (arrowed). Fig. 12. Detail of the same valve showing two sub-marginal rimoportulae and marginal ring fultoportulae. Fig. 13. Detail of the central ring of fultoportulae (each with two satellite pores). Stephanodiscus neoaegypticus v. fekrii SEM. Fig. 14. Iconotype, external valve with a concave central area, marginal ring of fultoportula apertures and external opening of a rimoportula (arrowed). Scale bars = 10 µm (Figs 9–11, 14), 1 µm (Fig. 12), and 2 µm (Fig. 13).