FIGURES 28–34 in Taxonomic revision and morphological cladistics analysis of the diatom genus Anorthoneis (Cocconeidaceae), with description of Anorthoneis arthus-bertrandii sp. nov.

FIGURES 28–34. Anorthoneis dulcis specimens from Hein (1991), original material #4138, Withlacoochee River, Fla, U.S.A, ANSP Material Collection, Philadelphia Academy of Natural Sciences, SEM images. (28) External raphe-sternum valve with faint, hyaline, submarginal areas (arrow); (29) External coaxial, expanded, pore-like proximal raphe endings; (30) External distal raphe ending terminating in a roundish submarginal hyaline area; (31) Proximal raphe endings hooked in opposite directions and to the central nodule; (32) Internal distal raphe ending terminating in vestigial helictoglossa; (33) Internal view of raphe-sternum valve; (34) Tilted internal view (60°) of raphe-sternum valve showing the thickened raphe-sternum, central nodule and submarginal hyaline area. Scale bars: Figs 28, 33, 34 = 5 μm; Fig. 31 = 2 μm; Figs 29, 30, 32 = 1 μm.