Synedrosphenia gomphonema cont. A apical pole of frustule in polar view tilted 60°, showing the valvocopula and copula of the hypocingulum (HVC and Hcop) largely hidden under the epicingulum bands (EVC and Ecop); the pleurae are missing and in the space where they were the tips of the newly formed valves are visible (long arrows). Short white arrows point to the apical notches slightly off-center in opposite directions; black arrow shows some slit formation in the copula (GU44BJ-4) B–E valvocopula with apical pole in advalvar view (B) showing recurved pars interior at the tip, abvalvar view (C), basal pole (D) and middle (E), all showing fimbriae (B, D, E from same specimen in GU44BI-4, C from TK4) F, G copula middle and apical pole, respectively, external view, showing fimbriae developing on the abvalvar edge of the pars exterior (arrow) (TK4). Scale bars: 10 µm (A, E, F, G); 5 µm (B–D).