Synedrosphenia bikarensis sp. nov. (all from Bikar sample BA5) A–C holotype whole valve, basal and apical portions, respectively (LM) D–F external SEM views of apical, middle and basal portions, respectively, of a frustule, showing valve structure. Oval in D highlights area where break in striae across the annulus can be seen, even though the annulus is not readily visible G, H internal views of apical pole with pseudoseptum (arrow) and middle portion (H) showing transverse costae and the lack of a longitudinal costa under the annulus I, J frustule in girdle view, apical and basal portions, respectively, showing heteropolarity and girdle bands of the epicingulum. Arrows mark the notches visible on the hypovalvocopula at the apical pole and epivalvocopula at the basal pole, indicating the asymmetry. Scale bars: 25 µm (A); 10 µm (B, C, H); 5 µm (D–G, I, J).