Nephasoma pellucidum (Keferstein, 1865)

Adrianov, Andrey V. & Maiorova, Anastassya S., 2012, Peanut worms of the phylum Sipuncula from the Nha Trang Bay (South China Sea) with a key to species, Zootaxa 3166, pp. 41-58 : 44

Nephasoma pellucidum (Keferstein, 1865)

( Fig. 2 A–B )

Material. Nha Trang Bay: Hon Rock, 10–15 m depth, coral rubble, 10 specimens; Mung Island, 7–15 m depth, sand, 1 specimen.

Description. Trunk spindle-shaped, 20–25 mm long and 3–4 mm wide; introvert shorter than trunk, with scattered hooks of two types – small, about 50 μm, and large, up to 300 μm in height. Tentacular crown with 20–30 whitish transparent tentacles. Trunk is translucent, pale tan, with large uniformly distributed digitiform papillae. Body wall with continuous muscle layers; two retractor muscles originate in the mid trunk. Gut with 25–30 loops; spindle muscle not attached posteriorly; contractile vessel with vesicular swellings. Nephridia free, about 35–40% of trunk length, nephridiopores adjacent to anus.

Discussion. This is the only species of Nephasoma that is common in shallow waters of the Indo-West Pacific. In the West Pacific, it has been found inhabiting sandy bottoms and dead corals from Australia and Indonesia to southern Japan.

Figures

FIGURE 2. A – B. Nephasoma pellucidum. A) lateral view, introvert everted; B) hook. C) Thysanocardia catharinae, lateral view, introvert everted. D) Themiste cymodoceae, dorsal view, introvert everted. Scale bars: A, 5 mm; B, 100 µm; C – D, 2.5 mm.