Figure 1

(a) SEM images of isolated mature frustule of C. sp.; Gbs = girdle bands; Ep = Epitheca (bigger valve); Hy = Hypotheca (smaller valve); (b) isolated valve; Ra = raphe; Cn = central nodule; Pr = porous area; (c) individual girdle band (Gb); (d) porous area, Tr = transapical rib; Ar = areola Ce = cross extension; Da = distance between neighboring areolae within an array; Dp = distance between two areolae of two parallel arrays.