Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species Author Adrianov, Andrey V. Author Maiorova, Anastassya S. text Zootaxa 2012 3166 41 58 journal article 45619 10.5281/zenodo.279772 32627594-388c-40b3-8481-0b241b850847 1175-5326 279772 Aspidosiphon ( Paraspidosiphon ) tenuis Sluiter, 1886 ( Fig. 5 R–S) Material. NhaTrang Bay: Mot Island, coral rubble, 7 m depth, 3 specimens ; Tre Island , coral rubble, 6 m depth, 6 specimens ; Tre Island , intertidal, fouling comunity, 5 specimens ; Diamond Bay, coral rubble, intertidal, 20 specimens . Description. Trunk 5–15 mm long, 2–3 mm wide, pale or light brown, semitransparent; introvert 1.5– 2 X trunk length. Anal shield green or brown-green, smooth and glossy, sometimes saddle-shaped or concave, composed of small dark units, with short marginal grooves; caudal shield brown-green, with radial grooves. Tentacles with white pigments; bidentate hooks 30 μm in height, arranged in rings on the distal introvert; unidentate hooks scattered on the proximal introvert. Pyramidal hooks absent. Longitudinal musculature splits into 23–25 anastomozing bands; retractor muscles originate 10% of trunk length from the caudal shield. Gut with 10–15 loops. Nephridia are about 80–90% of trunk length, unattached. Discussion. This species differs from other representatives of the subgenus Aspidosiphon (Paraspidosiphon) by the anal shield structure, the presence of both bidentate and unidentate hooks, and the absence of pyramidal hooks. This is a tropical Indo-West Pacific species known from Australia to Taiwan . It inhabits coral rocks and shells in shallow water.