Oligobregma whaleyi sp. nov. holotype (specimen NHM_822). A Lab (upper) and live (lower) images, whole specimens [lab image] B Lab image, mid-body segments and annulation C Lab image, ventral midbody (vm = ventral midline) D Live (left) and lab (right) images of prostomium (pe = peristomial ring, h = prostomial horns) E Lab images, midbody and posterior parapodia, chaetigers 15 (left) and 24 (right) (dc = dorsal cirrus, vc = ventral cirrus, ip = interramal papilla) F Lab image, detail of dorsal cirrus and internal gland (dc = dorsal cirrus, ig = internal gland) G Lab image, detail of notopodial spines on chaetiger 1 H Lab image, detail of capillary chaetae (lc = lyrate chaetae) I Lab image, detail of lyrate chaetae. Morphological features in plates B–D, F, G, H have been outlined with a fine white or black line to improve clarity of those features. Scale bars: 1 mm (A); 100 μm (F–H); 50 μm (I).