Paraplehnia seisuiae sp. nov., ICHUM 5345 (holotype), sagittal sections (A–G) and schematic diagram (H). A Spermiducal bulb B–D connection between spermiducal bulb and prostatic vesicle E, F copulatory apparatus G genital pit H schematic diagram of copulatory complex. Abbreviations: cex canal of extra-vesicular grand cg cement glands cov common oviduct dl duct of Lang’s vesicle dsb duct of spermiducal bulb fa female atrium fg female gonopore gp genital pit lv Lang’s vesicle ma male atrium mb muscular bulb mg male gonopore ph pharynx pp penis papilla pv prostatic vesicle sb spermiducal bulb v vagina. Scale bars: 600 μm (A, E, F, H); 300 μm (B–D, G). Staining: hematoxylin and eosin stain (A–E); Mallory’s triple stain (F, G).