Paraonis amazonica sp. n., SEM. A Anterior end, arrow point to the nuchal organ, dorsal view B Anterior parapodium of chaetiger 3, arrow point to the acicular lateral spine, dorsal view C Parapodium of setiger 35, acicular chaeta with a lateral spine (sl) hook-shaped chaeta with a terminal spine (st) D Acicular chaeta with a lateral spine enlarged. Scale bars: 0.1 mm (A), 20 µm (B), 10 µm (C), 1 µm (D).