Trophomera sp.

Miljutin, Dmitry M. & Miljutina, Maria A., 2009, Description of Bathynema nodinauti gen. n., sp. n. and four new Trophomera species (Nematoda: Benthimermithidae) from the Clarion-Clipperton Fracture Zone (Eastern Tropic Pacific), supplemented with the keys to genera and species *, Zootaxa 2096 (1), pp. 173-196 : 189-190

Trophomera sp.

Fig. 9 ; Table 2

Material: One male in a bad condition though with most diagnostic features discernable.

Locality: 13°55.63’N, 130°12.20’W, 4900 m depth, 2–5 cm sediment layer, 28.05.2004, submersible “Nautile”, station 1597-5 CL 06.

Description: Body thread-like, cylindrical. Anterior end a slightly narrowing cone with rounded apex, posterior end a pointed cone shape. Transverse cuticular striation visible along whole body length. Cuticle thickness 3 µm along whole body length except terminal part of tail, where its thickness increasing to 6–10 µm, and 20 µm at caudal tip. Four submedian, short cephalic setae with rounded tips 4 µm long inserted in tiny pits. Two flat, cervical, lateral alae with a preamphidial part beginning at 1/3 distance from cephalic end to amphid and a postamphidial part (1/9 ala length). Amphidial aperture round, 6.0 µm in diameter. Short, somatic papillae approximately 1 µm long. Mouth opening reduced to a narrow apical tube. Pharynx a nonmuscular, cellular mass devoid of an internal lumen. Midgut an oligocellular trophosome without internal lumen and consisting of 1 row of cells. Borders between trophosomal cells distinct. Trophosomal cells consisting of large hyaline granules; density of these granules decreasing from anterior and posterior ends towards mid-body region. Spicules paired, almost straight. 15–16 mid-ventral, small, setiform supplementary organs present, from anterior to anus. Caudal glands absent.

Host unknown.

Females, juvenile stages unknown.

Remarks: The single specimen is in bad condition. Its body is strongly crumpled at the postamphidial part of the pharynx and beginning of the trophosome. The male reproductive system is wrinkled and collapsed, and it is impossible to ascertain its structure (number and arrangement of testes).

However, the described specimen evidently belongs to a new species of Trophomera because of its peculiar tail, characterized by a very thick cuticle. It only resembles T. gracilis ( Petter 1982a) in the shape and structure of cervical lateral alae (long pre-amphidial part and short, not bilobed post-amphidial part). But, unlike the male specimen described, T. gracilis possesses a rounded tail. Unfortunately, the poor condition of the specimen does not facilitate good description and makes the specimen unsuitable for the status of holotype.

Figures

FIGURE 9. Trophomera sp., male. A, B, cephalic end; C, posterior end; D, spicula. Abbreviations: l.a = lateral ala; a = amphid; v.d = vas deferens.