Diatoma sinensis sp. nov., SEM, valvocopula A, B two valvocopulae showing the sawtooth-shaped projections and the open nature C–E details of A showing the two rows of poroids, note one open end (C, two arrows), a third very short row of poroids present at the middle (D, arrow) and one closed end (E) F–H details of B showing the two rows of poroids, note one open end (F, arrow), a third very short row of poroids present at the middle (G, arrow), and the different poroid shapes of the two rows of poroids. Scale bars: 5 μm (A, B); 2 μm (C–H).