Onchnesoma steenstrupii steenstrupii Koren and Danielssen, 1876

Saiz-Salinas, J. I., 2007, Sipunculans and echiurans from the deep Angola Basin, Journal of Natural History 41 (45 - 48), pp. 2789-2800 : 2794

Onchnesoma steenstrupii steenstrupii Koren and Danielssen, 1876

Material. Sta. EBS no. 318, two.

Description. Trunk 2–4.5 mm long and 1–2 mm wide. Introvert 3–5 mm in length and 1 mm in width. Pyriform in appearance with the posterior end finished in a blunt point. Over the surface of the trunk are conspicuous small wart-like papillae. Several longitudinal keel-like structures on the end of the trunk. A single retractor originates from the end of the trunk.

Remarks. The presence of small papillae covering the surface of the trunk and the keel-like structures on the posterior end of the trunk are diagnostic for this species. The species is common in the North Atlantic Ocean and is known also in the South Atlantic, Indian and Pacific Oceans at depths of 0–2990 m. It has been found previously in the investigated area by Cutler and Cutler (1987), but at bathyal depths. Finding our specimens at 5126 m extends the vertical known range of this species to abyssal depths.