A–F Decussiphycus sinensis sp. nov. SEM, internal view. Slide 09153 (from strain Ca68) A the entire valve B details of striae structure near the valve margin; note the shallow margin (white arrows) C details of the central area; note proximal raphe fissures (white arrows) and ribs of the quincunx system (black arrowheads) D, E details of the valve apex; note the shallow valve margin (black arrows) with striae continuing onto it (white arrows), areolae with round occlusions near the sternum (black arrowheads) and oval occlusions towards the margin (white arrowheads). Apical expansions of the sternum indicated by asterisks F details of the valve apex; note the horseshoe-shaped helictoglossa (white arrow) and apical expansion of the sternum (asterisk). Scale bars: 10 µm (A); 2 µm (B–F).