Sabatieria ornata Ditlevsen, 1918

Portnova, Daria, 2009, Free-living nematodes from the deep-sea Håkon Mosby Mud Volcano, including the description of two new and three known species *, Zootaxa 2096 (1), pp. 197-213 : 204-206

Sabatieria ornata Ditlevsen, 1918

Figures 3 , Table 4

Material studied: four males, three females. Glycerine slides. Males in glycerin slide Nos. from C-1/22 and C- 1/23; females from No. C-1/24.

Locality: Norwegian Sea, Håkon Mosby Mud Volcano, station 263B, 272. Sediment from the pogonophoran field and bare sediment from the centre of caldera.

Description: Body elongate, spindle-shaped to cylindrical. Cuticle transversally striated, but striation poorly visible. Cuticle bears transversal rows of punctation. Lateral dots slightly larger than median and submedian dots, arranged disorderly. Somatic setae distributed along the body, shorter than cephalic ones.

Cephalic end separated from the body, narrowing at the level of amphid. Labial setae short, 1 µm long. Cephalic setae 3–6 µm in males and 7 µm in females. Amphidial fovea coiled spirally in three turns, large, with precise cuticle edging. In males diameter of amphidial fovea 12–14 µm, i.e. 70–77 % of c.b.d., in females 12–14 µm, i.e. 70–87% of c.b.d. correspondly. Distance from the anterior end to the amphidial fovea 7–10 µm in males and 8–10 µm in females.

Cuticle at the anterior end thick. Stoma small and cup-shaped, walls not sclerotized. Small projection like denticles on the dorsal side at the base of stoma.

Oesophagus long, slightly muscular along its length, gradually extending to posterior end. Cardia small.

The glandular body of renetta cell sacciform, filled by granulated content. Ventral pore situated at the level of nerve ring, visible in one specimen. Distance between anterior end and excretory pore difficult to measure. Posterior part of renetta cell located below cardia. Distance between anterior end to the glandular body of renetta cell 153–168.3 µm in males and 153–183.6 µm in females.

except ratios a, b, c and c’).

Anterior and posterior testes outstretched and situated to the left of the intestine. Vas deferens lies to the right of intestine. Sperm cells inside the testes seed-like, filled very densely. Spicules short, arcuate, 61.2–76.5 µm (arch) and 53.5–61.2 µm (chord) with weakly visible thickenings at their ends. Proximally cephalic and distally acute. Gubernaculum with slightly arched dorso–caudal apophysis. Length of gubernaculum 22–25 µm. Long row of 17–18 midventral precloacal supplements present in males. All supplements bulging, cupola-shaped with axial canals. Distance from cloaca to the nearest cupola 11–12 µm. Five posteriormost supplements located very close to each other. The sixth supplements a little bit further from the fifth one; other 11 and 12 located at similar distance from each other. Additional precloacal setae (4–5 µm) located anterior to supplements.

Female reproductive system didelfic. Ovaries outstretched and of similar length. Anterior ovary to the left of intestine, the posterior one right. The width of the biggest egg in the oviduct is 84 µm in one female and 50 µm in the other two females.

Tail subdived into proximal conical and distal cylindrical parts. Length of the cylindrical part of tail more than 50% of the length of the conical one, with drop-like thickened tip. On the top of tail 3 caudal setae are visible. Short somatic setae sparsely distributed along conical part of the tail.

Remarks: Species from the Håkon Mosby resemble the Sabatieria-ornata- group based on the arrangement of precloacal supplements (5 supplements very close to each other), amphidial fovea with 3–4 turns, and slightly curved dorso-caudal apophyses. The male described by Ditlevsen (1918) was more slender than specimens from the mud volcano (a=47 vs. a=34.3), with 14 precloacal supplements vs. 17-18 supplements in individuals from Håkon Mosby. All other measurements in the original description and all other descriptions ( Platt 1985; Platt & Warwick 1988; Schuurmans Stekhoven 1946; Tchesunov 2000) are similar to those in the specimens from the Håkon Mosby mud volcano.

Figures

FIGURE 3. Sabatieria ornata Ditlevsen, 1918, details. A: male 1, total view; B: male 1, cephalic region; C: cloacal region; D: male 1, spicules. Scale bars: 100µm.