(Phascolosoma) paci

Acd, 2000, Sipuncula from Hainan Island (China), Journal of Natural History 34, pp. 2187-2207 : 2197-2198

Phascolosoma (Phascolosoma) paci ®cum Keferstein, 1866

Material. Ximaozhu Island , 19 March 1992, one specimen; Ximaozhu Island ,

20 March 1992, one specimen; Yezhu Island , 26 March 1992, one specimen.

2014 February 14 34: 02 at] Bath of University [by Downloaded

Description. Uniformly dark coloured worms, 24±80 mm long, 9 mm wide for the largest specimen. Introvert is one to two times the trunk length. The integument is rough due to conical papillae distributed all over the body and a little posteriorly orientated in the pre-anal zone. Hooks in more than 50 rings and about 110 m m in height, have a hump-like secondary tooth on their concave side and many rectangular plates in their bases. Internally, an irregular clear streak with a separate triangle is present (®gure 5a, b). Four retractors and many bands of longitudinal musculature. Two long nephridia of about 100% the trunk length, totally attached to the body wall. Nephridiopores a little in front of the anus.

Discussion. Several features are diagnostic in the identi®cation of the species. The rough and sandpaper-like external appearance of the trunk, as well as the great length of its nephridia once the dissection is accomplished, catches the eye rapidly. On the other hand, the shape and structure of the hooks are diagnostic. The specimens of this species are well separated from P. (P.) scolops (Selenka and de Man, 1883) and P. (P.) nigrescens Keferstein, 1865 because they lack pigmented bands on the introverts.

The species shows a Western Indo-Paci®c distribution, from the Red Sea to Japan and Australia, which constitute its limits in the Paci®c Ocean. In the area investigated it has been recorded several times (Leroy, 1942; Chen, 1963; Li, 1982, 1989; Murina, 1989; Li et al., 1992b), in South China (including Hainan Island) as well as in Indochina and Vietnam.