Ammotrypanella keenani sp. nov. A Lab images, whole specimens (holotype [specimen NHM_1250], post-staining, faded stain [left], paratype NHM_1871, unstained [right]) B Live images, whole specimens (holotype [left], paratype NHM_1871 [right]) C Lab image, prostomium (paratype NHM_1871, damaged, no = everted nuchal organ) D Lab image, prostomium (holotype, p = palpode) E Lab image, detail of palpode (holotype) F Lab image, posterior branchiae (paratype NHM_1871, br = branchiae) G Lab image, posterior branchiae (holotype, br = branchiae) H Live image, anterior (paratype NHM_1871, pp = parapodia, no = nuchal organ) I Lab image, detail of capillary chaetae (holotype) J Lab image, detail of anal funnel, ventro-distal (left) and latero-distal (right) views (holotype, stained, cp = cushioned pad, vc = ventral cirrus). Morphological features in plates C–H, J have been outlined with a fine white line to improve clarity of those features. Scale bars: 1 mm (A, F,G); 100 μm (E, I).