Phascolosoma nigrescens (Keferstein, 1865)

Vargas, Rita & Kawauchi, Gisele Y., 2010, Sipunculans and Echiurans of Isla del Coco (Cocos Island), Costa Rica, Zootaxa 2557, pp. 60-68 : 63

Phascolosoma nigrescens (Keferstein, 1865)

Material examined. Punta Ulloa, 12–15 m, subtidal calcareous rock, 14 October 2007, three specimens, 13– 15 mm; 12–15 m, April 2008, one specimen 20 mm; 3 m, 23 May 2008, reef, two specimens, 19 & 22 mm; 28 May 2008, one specimen, 28 mm; Bahía Chatham, 11m, 26 May 2008, two specimens, 16 & 27mm; Silverado, 11 m, 25 May 2008, 7 mm.

Additional material. Bahía Chatham, intertidal, April 2008, 1 specimen, 22mm.

Description: The largest specimen was brownish yellow with numerous papillae over the body surface while the smaller specimens had light tan bodies with scattered papillae which were denser on the dorsal surface posterior to the anus and at the caudal end. There were more than 100 rows of hooks interrupted by a short bare region about 40% from the distal end; the hooks had a small secondary tooth, five basal warts, and showed a very distinctly swollen clear streak similar to that described for this species by Cutler (1994). One specimen had numerous ova in the body cavity.

Habitat. Intertidal-subtidal calcareous rock, 0– 15 m.

Distribution. P. nigrescens is widespread in tropical regions and has been reported previously from the Gulf of Nicoya and Golfo Dulce on the Pacific coast of Costa Rica by Cutler et al. (1992) and Dean (2001).