Onchnesoma steenstrupii steenstrupii Koren & Danielssen, 1875

Açik, S., Murina, G. V., Çinar, M. E. & Ergen, Z., 2005, Sipunculans from the coast of northern Cyprus (eastern Mediterranean Sea), Zootaxa 1077, pp. 1-23 : 11-12

Onchnesoma steenstrupii steenstrupii Koren & Danielssen, 1875

Onchnesoma steenstrupii steenstrupii: Saiz Salinas & Villafranca Urchegui 1990: 1164 ; Cutler 1994: 138 –139; Pancucci­Papadopoulou et al. 1999: 68–69, fig. 23.

Onchnesoma steenstrupii: Stephen & Edmonds 1972: 163 –164, figs 19a–c; Murina & Zavodnik 1985 /1986: 61–62, fig. 24; Saiz Salinas 1993b: 113 –115, fig. 59.

Material examined: ESFM – SIP /97–15, T7, trawl, start: 35°40.3'N – 34°39.1'E, finish: 35°39.7'N – 34°37.8'E, 16 May 1997, 275– 337 m, mud, 4 specimens; ESFM – SIP /97–14, D10, dredge, 35°08.9'N – 33°58.6'E, 19 May 1997, 92 m, mud, 1 specimen.

Remarks: Body pear­shaped, or barrel­shaped. Trunk spherical, various coloured: grey, orange, rusty red. In a few specimens, introvert partly reddish in colour. Trunk 0.8–1.5 mm long, 0.6–1.1 mm wide. Introvert partly everted, 0.3–6.7 mm long, 0.2–0.5 mm wide. When fully extended, introvert 6 times trunk length. Small wart­like papillae on surface of trunk; 10–18 µm long, 13–35 µm in diameter. Posterior part of trunk with 22–24 longitudinal keel­like structures. Chitin plate including of these keel­like structures 15–33 µm long. Inner layer of musculature continuous. Spindle and wing muscle absent. Anus located near mouth. Intestine with several coils. Only one retractor attached at posterior part of body. Caudal end of body sightly pointed. The nephridia single, elongate. Oral disc couldnt be observed owing to the retraction of their introverts. Some specimens with eggs in coelom cavity, elliptical; longer axis 95–148 µm in diameter, smaller axis 50–115 µm in diameter.

Distribution: Common in the North Atlantic, also present in the southeastern Atlantic, higher latitudes of the western Pacific and southwestern Indian Ocean, Mediterranean Sea ( Cutler 1994). Depth range: 0–3362 m ( Saiz Salinas 1988b).