Figures 50–58 in Marine benthic diatoms of Guam: new records, Dictyoneis apapae sp. nov., and updates to the checklist

Figures 50–58. Dictyoneis apapae, sp. nov. (cont.), except Figs 51, 56, putative D. marginata from Gray's Reef National Marine Sanctuary, Georgia; SEM, cont. Figs. 50, 51. Comparison of the two species' exteriors with the following three points of distinction: 1. Central area; 2. Marginal pseudoloculi; 3. Apical groove. Fig. 52. Detail of an isolated valve apex. Fig. 53. Central region of isolated valve showing central nodule and poration on mantle with short intercalary striae, with a few longer (arrowhead), forming a denser band (arrow) before a hyaline border. Fig. 54. Fractured valve showing wall structure with large outer pores (arrow), smaller ridges defining smaller holes, and showing the slit-like inner foramina. Figs 55, 56. Comparison of the two species' interiors, both valves with valvocopula. Figs 57, 58. Opposite poles of a frustule in girdle view showing copulae. Arrow shows deep indent on end of valvocopula, which appears closed at that end as well as at the opposite; 2nd copula open and 3rd copula with large ligule that fills the indentation on the valvocopula. Scale bars: Figs 50, 51, 55–58 = 10 µm, Figs 52, 53 = 5 µm, Fig. 54 = 2 µm.