Light micrographs of Promastobranchus variabilis sp. nov., holotype (A–C, E–K) and paratype (D) A anterior fragment showing MGSP B anterior thorax with areolated epithelium, ventro-lateral view C anterior end, lateral view D anterior end showing eyespots, dorsal view E transition between thorax and abdomen, lateral view F middle-posterior abdomen, dorso-lateral view G posterior abdomen, dorsal view H posterior abdomen, ventral view I posterior end, end view (anal cirri have been outlined with black lines) J hooded hooks at chaetiger 70, lateral view K hooded hooks, frontal view. Abbreviations: cc, capillary chaetae; ch, chaetiger; es, eyespot; hh, hooded hook; lo, lateral organ; neu, neuropodia; no, notopodia; per, peristomium; pro, prostomium. Scale bars: 1 mm (A, B, E–H); 0.5 mm (C); 0.2 mm (D, I); 50 μm (J); 10 μm (K).