Aspidosiphon misakiensis Ikeda, 1904

Vargas, Rita & Kawauchi, Gisele Y., 2010, Sipunculans and Echiurans of Isla del Coco (Cocos Island), Costa Rica, Zootaxa 2557, pp. 60-68 : 64

Aspidosiphon misakiensis Ikeda, 1904

Material examined. Silverado, subtidal calcareous rock, 11 m, 23 May 2008, one specimen 6 mm.

Remarks: The shield is made up of closely set granular units of differing size; edge of shield demarcated by lighter colored units bordered with occasional small, papilla-like units. Comparison of this specimen with specimens from Japan (MCZ collection) showed that the anal shield was similar while the anal shield of specimens from the Azores had a wider, indistinct edge, grading to papilla-like units. Caudal shield offset dorsally and similar to anal shield; one specimen from Japan also had an offset caudal shield. Longitudinal muscle layer continuous, retractor muscles attach posteriorly at the caudal shield. Introvert with 32 rings of hooks, hooks bidentate or weakly bidentate, remainder bidentate; proximal introvert covered by many scattered unidentate hooks.

Aspidosiphon misakiensis has been previously reported from Japan and Australia in the Pacific Ocean as well as both sides of the Atlantic Ocean and the Mediterranean Sea ( Cutler 1994). This is the first report of this species in the eastern Pacific Ocean.