Phascolosoma (Phascolosoma) stephensoni (Stephen, 1942)

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 : 16

Phascolosoma (Phascolosoma) stephensoni (Stephen, 1942)

( Figure 3 D, 4D)

Phascolosoma stephensoni: Saiz Salinas 1988a: 166 , fig. 2; Pancucci­Papadopoulou et al. 1999: 78–79, fig. 28.

Phascolosoma (Phascolosoma) stephensoni: Stephen & Edmonds 1972: 326 –327, figs 39g –h; Saiz Salinas 1986: 63 –70, fig. 24; Cutler & Cutler 1990: 719 –720, fig. 1; Saiz Salinas 1993b: 122 –125, figs 64, 65, 89b–d; Cutler 1994: 185, figs 44, 46e.

Material examined: ESFM – SIP /97–1, D1, dredge, 35°22.5' N – 33°05.2' E, 10 May 1997, 50 m, hard substratum, 2 specimens; ESFM – SIP /98–1, K4, Gazi Magosa Bay, 18 July 1998, 4 m, on Posidonia oceanica , 1 specimen; ESFM – SIP /98–2, K8, Limanbasi Cape, 20 July 1998, 3 m, on Cystoseira crinita , 1 specimen; ESFM – SIP /98–4, K9, Girne, 21 July 1998, 0–5 m, on C. crinita , 1 specimen; ESFM – SIP /98–3, K10, Malazgirt, 21 July 1998, 3 m, on P. oceanica , 1 specimen.

Remarks: Trunk 2.3–7.2 mm long, 1.2–3 mm wide. Introvert with irregular pigmented bands ( Figure 3 D), 4.8–6.3 mm long. Ratio between introvert and trunk lengths 0.5–1.1. Hooks arranged in more than 50 rings; 25–33 µm long, 25–40 µm wide at base on distal part of introvert; 18–38 µm long, 25–38 µm wide at base on proximal part of introvert. Hooks with a distinct streak, a triangular space, a crescent ( Figure 4 D). Most hooks with a distinct secondary tooth. Two black eye spots present. Two pairs of retractors present; ventral pair thicker than dorsal ones. Intestinal tract with about 7–8 coils, attached by spindle muscle. Longitudinal bands of musculature numbering 22–24. Preanal (40–180 µm long) and posterior papillae (60–190 µm long) cone­shaped, smooth, red in colour; those on mid­trunk small, hemispherical. Nephridia 2.8 mm long, 0.5 mm wide. Trunk 2.6 times nephridia length. Distance between posterior end of trunk and beginning of rectractors 0.5–2.2 mm long. Retractors originating from 22–31% of the distance to the end of trunk.

Distribution: Eastern Atlantic, western and northwestern Indian Ocean, western Pacific, Mediterranean Sea ( Cutler 1994). Depth range: 0–1445 m ( Cutler 1977; Cutler & Cutler 1996).

Figures

FIGURE 3. The species new to the eastern Mediterranean fauna. A. Trunk and partly everted introvert of the specimen (ESFM – SIP / 97 – 20) of Nephasoma (Nephasoma) constrictum. B. Trunk and partly everted introvert of the specimen (ESFM – SIP / 98 – 35) of Phascolosoma (Phascolosoma) agassizii agassizii. C. Trunk and partly everted introvert of the specimen (ESFM – SIP / 98 – 42) of Phascolosoma (Phascolosoma) scolops. D. Trunk and partly everted introvert of the specimen (E SFM – SIP / 98 – 2) of Phascolosoma (Phascolosoma) stephensoni. Scale line 1 mm

FIGURE 4. Hooks of Phascolosoma species from the Cypriot coast. A. Hooks of P. (P.) agassizii agassizii (ESFM – SIP / 98 – 35). B. Hook of P. (P.) granulatum (ESFM – SIP / 98 – 36). C. Hooks of P. (P.) scolops (ESFM – SIP / 98 – 39). D. Hooks of P. (P.) stephensoni (ESFM – SIP / 98 – 2). Scale line A 24 µm, B 30 µm, C 23 µm, D 15 µm