Scanning electron micrographs of two different morphotypes of Rhadinorhynchus cololabis. (A) Morphotype I of male: anterior trunk possessing fewer spines, divided by a distinct aspinose zone into anterior and posterior fields, ventral view; (B) Morphotype I of female: anterior trunk possessing fewer spines, divided by a distinct aspinose zone into anterior and posterior fields, ventral view; (C) Morphotype II of male: anterior trunk possessing more spines, lacking distinct aspinose zone (red circle showing two lateral spines connecting the anterior and posterior fields together), ventral view; (D) Morphotype II of female: anterior trunk possessing more spines, lacking a distinct aspinose zone (red circle showing two lateral spines connecting the anterior and posterior fields together), ventral view.