Nephasoma diaphanes (Gerould, 1913)

Saiz-Salinas, J. I., 2007, Sipunculans and echiurans from the deep Angola Basin, Journal of Natural History 41 (45 - 48), pp. 2789-2800 : 2793

Nephasoma diaphanes (Gerould, 1913)

Material. Sta. EBS no. 318, two; Sta. AT no. 319, four; Sta. AT no. 321, five; Sta. AT no. 327, two; Sta. AT no. 333, one; Sta. AT no. 334, one; Sta. AT no. 337, 28; Sta. EBS no. 338, one? fragment; Sta. AT no. 339, 14+fragments; Sta. EBS no. 340, five; Sta. GKG no. 341/4, one; Sta. GKG no. 341/8, one; Sta. AT no. 343, six+fragments; Sta. EBS no. 344, three; Sta. AT no. 347, 218+one?; Sta. EBS no. 348, 14+one?; Sta. AT no. 349, 920+fragments; Sta. EBS no. 350, eight; Sta. AT no. 351, 289+fragments.

Description. Trunk 1.2–50 mm long and 0.5–2 mm wide. Introvert 2–24 mm in length and 0.2–1.5 mm in width. Scattered hooks, 20–60 Mm tall. Digitiform papillae 15– 30 Mm in height at the trunk end. Large specimens with brown pigmented papillae up to 100 Mm in diameter covering the posterior half of the trunk. In some everted introverts lobes instead of tentacles could be observed. Two retractors originate near the middle or posterior third of the trunk. One specimen coming from Sta. AT 349 lacks hooks.

Remarks. A cylindrical appearance and a trunk covered by papillae fits the description of this species in a broad sense. Diagnostic for the species is the reduction of tentacles to lobes, but unless the introverts are fully everted, it is practically impossible to assert this character with thin introverts and preserved material. In this way, identifications were achieved under the specific level. Many specimens have been found in abandoned tubes of polychaetes (nos 337, 339, 340, 343, 347, 349, 351) developing large and brown papillae up to 100 Mm in diameter. Other few specimens were found inside a sponge (nos 347, 349) and inside an abandoned scaphopod shell (no. 350).

Nephasoma diaphanes has been recorded as a cosmopolitan, deep-water species ( Cutler 1994). Similar to our findings, Cutler and Cutler (1987) have previously recorded the species inside polychaete tubes and at abyssal depths.