Omanicotyle heterospina n. gen. et n. comb. from the gills of Argyrops spinifer (Forsskål). a, Scanning electron micrograph (SEM) of an entire specimen. b, close up of the opening of one of the paired, dorsally positioned vaginae. c, desiccated specimen prepared for SEM to reveal the crown of 16–18 spines within each vagina. d, laser scanning confocal microscope image of the vaginal spines stained with a chromotrope 2R based stain (see). Scale bars: a = 100 μm; b = 20 μm; c = 50 μm; d = 41.8 μm.