Aspidosiphon (Paraspidosiphon) laevis

Vargas, Rita & Kawauchi, Gisele Y., 2010, Sipunculans and Echiurans of Isla del Coco (Cocos Island), Costa Rica, Zootaxa 2557, pp. 60-68 : 65

Aspidosiphon (Paraspidosiphon) laevis de Quatrefages, 1865

Material examined. Bahia Chatham, subtidal calcareous rock, 15 m, 22 May 2008, two specimens, 15 & 29 mm; Punta María, subtidal calcareous rock, 20 m, SCUBA, rocks, 10 April 2008, one specimen, 18 mm; Punta Ulloa subtidal calcareous rock, 12 m, drag, 23 May 2008, one specimen, 25 mm; 8 m, 28 May 2008, one specimen, 24 mm; Silverado, subtidal calcareous rock, 11m 25 May 2008, four specimens, 4 to 30 mm.

Description. This species has a yellow to light tan body with a brown anal and caudal shield. The grooved anal shield has a pronounced ridge-like border posteriorly and is followed by scattered low shield units, which transition to numerous low papillae in the anal region; papillae absent in posterior half of body. Caudal shield with well developed concentric ridges radiating from its center and a distinct anterior border followed by several rows of rectangular units anterior to the ridge. Hooks are unidentate with a wide base. Retractor muscles are united until adjacent to their attachment at about 60% of body length as a broad sheet to the body wall; nerve cord passes through the narrow gap between the retractors at their separation. Anterior spindle muscle attaches along the rectum and sends a branch that attaches broadly anterior to the anus.

Habitat. Subtidal calcareous rock, 8- 20 m.

Remarks. This is a first record for Aspidosiphon (Paraspidosiphon) laevis in the eastern Pacific Ocean.

Distribution. Aspidosiphon (Paraspidosiphon) laevis is previously reported from the Indo-Pacific Ocean as well as the Caribbean and western Atlantic Ocean ( Cutler 1994).