SEM micrographs of Craspedostauros nazmii sp. nov. A external view of entire valve B external view of central area C, D external view of valve apex showing wing-like silica flap E internal view of entire valve F internal view of central area showing raphe terminate G–H internal view of valve apex. Scale bars: 10 μm (A, E); 2 μm (B–D, F–H).