Hannaea cf. arcus, SEM 18 complete valve with valvocopula. 19–21 details of Fig. 18, note valvocopula with sawtooth-shaped projections attached to valve (19, 20, arrows), valvocopula open at one pole (21, arrow). Scale bars: 10 μm (18), 2 μm (19–21).

 
 
  Part of: Liu B, Williams DM (2020) From chaos to order: the life history of Hannaea inaequidentata (Lagerstedt) Genkal and Kharitonov (Bacillariophyta), from initial cells to vegetative cells. PhytoKeys 162: 81-112. https://doi.org/10.3897/phytokeys.162.56136