FIGURES 13–18 in Punctastriata altera sp. nov. (Bacillariophyta, Fragilariophyceae), a diatom from the United States of America

FIGURES 13–18. SEM images of Punctastriata altera sp. nov. from type material from the Cosumnes River, Sacramento County, U.S.A. 13, 14. Details of spines with skirt-like projections (white arrow heads). Neighboring valve connection is shown in Fig. 14. Also notice broken copulae in Fig. 14. 15, 16. Apical pore fields at head pole and foot pole, respectively (black arrows). Notice that skirt-like projections in Fig. 16 only go partially to the front of the spine (white arrow heads). 17, 18. Detail of valvocopulae. Fig. 17 shows apparent closed tips of a valvocopula that is broken on its side (white arrows). Notice lobed fimbriae (black arrow heads) and several broken copulae in the valve interior. Fig. 18 shows entire, apparently closed (white arrows), fimbriate valvocopula. Scale bars = 1 µm (Figs 13–16), 2 µm (Figs 17, 18).