Putative Synedra crystallina var. bacillaris from Grunow’s Honduras material A–C specimen in external view with valvocopula, identified by the length, the straight sides and blunt pole, stria density (11 in 10 µm), and row of pores in the exterior of the valvocopula (arrows); small spines on apex (arrowheads on B) D fragment of valve, interior view, showing central longitudinal costa and transverse costae E–G fragment of frustule showing valvocopula and copula G showing transverse costae (arrow) and absence of inner wall, arrowhead shows additional pores on valvocopula pole. Scale bars: 25 µm (A, E); 10 µm (B–D, F); 5 µm (G).