Terschellingia longicaudata De Mann, 1907

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 : 202-204

Terschellingia longicaudata De Mann, 1907

Figures 2 , Table 3

Material studied: Three males, four females. Glycerine slides. Males in glycerin slide from Nos. M-1/35 to M-1/38; females from Nos. M-1/35 to M-1/37.

Locality: Norwegian Sea, Håkon Mosby Mud Volcano, station 283A. Sediment from the pogonophoran field.

stated, except ratios a, b, c and c’).

Description: Body slender, long and fusiform. Cuticle with disappearing thin striation, which is poorly visible under light microscope. Head anteriorly rounded and slightly truncate on the top. Six inner, labial papillae 1µm long. Six outer, labial, setiform sensilla 2–3 µm long. Four cephalic setae 3–4 µm long, forming a circle slightly under the amphid. These setae located 17–18 µm and 16–19 µm from the anterior end in males and females, respectively. Somatic setae scattered irregularly at pharyngeal part of the body, untill excretory pore of ventral gland. Amphidial fovea circular and sclerotized. Diameter of amphidial fovea 9–10 µm, i.e. ca. 41–50 % of c.b.d. Distance from apex to anterior border of the amphidial fovea 5–7 µm, identical in males and females. Buccal cavity small, saucer-shaped, unarmed, 6–7 µm wide and 2 µm long. Oesophagus narrow, cylindrical, muscular along its entire length, posteriorly forming a well-pronounced bulb. The diameter of the bulb is 37–40 µm in males and 40–48 µm in females. Intestine gleam easily visible.

Cardia oval, 20 µm long. Renetta big, easily visible, consisting of 2 spheres connected with each other by a thin channel. Glandular body with nuclei of renetta clearly seen below the cardia. Renetta ampulla slightly widens and oval. Excretory pore located ventrally, beyond the level of the nerve ring.

The reproductive system of males diorchic. Outstretched anterior testis and reflexed posterior are similar in length. Both testes lie to the left of intestine. Vas deferens long and thin, with granulated content. Spermatozoa oval with easily visible nuclei. Spicules bent, strongly arched, 30.5–36.6 µm (arch) or 24.4–27.5 µm (chord), distally acute, proximally broadened and cephalic. Gubernaculum short with wide, pointed, caudal apophysis, 12.2–15 µm long. One precloacal seta, 2–3 µm long. Precloacal supplements absent.

Females reproductive system didelphic, with two outstretched ovaries. Posterior and anterior ovaries of similar length. Ovaries located to the left of intestine. The width of the biggest egg in the oviduct was 41–60 µm.

Tail elongate-filiform, with basal conical part, containing three caudal glands. Tail length 7–12 a.b.d. Ventral and dorsal sides of conical part of the tail with scattered somatic setae, 4µm long.

Remarks: The Håkon Mosby specimens fit the original description by De Mann (1907). Specimens from the mud volcano also correspond well to the redescription of T. longicaudata by Chitwood (1951) based on nematodes from the sea weeds of Copano Bay, Texas. Distinction only between lengths of spicules. The spicules on the specimens of T. longicaudata from the Håkon Mosby mud volcano were shorter than on the specimens from Chitwood’s description (30.5–36.6 µm vs. 40µm).

Figures

FIGURE 2. Terschellingia longicaudata De Mann, 1907, details. A: male 1, total view; B male 2, cephalic end; C: posterior end; D: vulva. Scale bars: 100 µm.