Trophomera senckenbergi, Miljutin & Miljutina, 2009

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 : 187-189

Trophomera senckenbergi sp. n.

Fig. 8 ; Table 2

Type material: Holotype: one virgin female, collection number MNHN-BN497 .

Type locality: 14°02.55’N, 130°05.35’W, 5035 m depth, 31.05.2004, multicorer #8, corer #2.

Etymology: In honour of Senckenberg Research Institute ( Germany).

Description: Female known only. Body slightly fusiform, with thickest body part at first half of body. Anterior and posterior ends in shape of a cone with rounded tip. Cuticular, very thin, transverse, striation along whole body length being hardly visible except at caudal region. Cuticle thickness 1.5 µm at anterior tip and approximately 1 µm in rest body parts. Amphids located at 0.88 c.b.d. from anterior end; amphidial apertures pore-like, 1.5 µm in diameter. Four submedian, papilloid, cephalic setae 2 µm long inserted in tiny pits. Mouth opening reduced to a narrow, apical channel in cuticle. Pharynx looking like a non-muscular string devoid of an internal lumen. Cardia absent. Midgut an oligocellular trophosome without visible internal lumen and consisting of one row of big cells in longitudinal optical section. Borders between trophosomal cells distinct. Anus and rectum present. Female reproductive system didelphic, amphidelphic. Ovaries outstretched or hologonic (non-reflected) in single virgin specimen. No spermathecae nor sperm observed. Hyaline ring representing a circular vaginal sphincter visible around vagina. Caudal glands absent.

Host unknown.

Males, juvenile stages unknown.

Differential diagnosis: The female of Trophomera senckenbergi sp. n. is characterized by a non-reflected ovary (it is impossible to clarify the certain construction because of immaturity of the type specimen). There are only five described Trophomera species , which have non-reflected ovaries: T. megala ( Petter, 1987) and T. turpicauda Miljutin, 2004 possessing hologonic ovaries, as well as T. laubieri ( Petter, 1987) , T. pacifica sp. n. and T. pseudominuta Miljutin, 2004 possessing telogonic outstretched ovaries.

T. senckenbergi sp. n. differs from T. megala by its shorter body length (1.5 mm vs. 65–170 mm), body shape (fusiform vs. cylindrical), design of trophosome (oligocellular vs. multicellular), and its tail shape (conical with rounded tip vs. rounded with long terminal spine).

T. senckenbergi sp. n. differs from T. turpicauda by its shorter body length (1.5 mm vs. 3.4–6.1 mm), the body shape (fusiform vs. cylindrical), and its tail shape (conical with rounded tip vs. rounded with terminal, cuticular process of irregular shape).

T. senckenbergi sp. n. differs from T. laubieri and T. pacifica by its shorter body length (1.5 mm vs. 5.2–6.4 mm), the body shape (fusiform vs. cylindrical), and its tail shape (conical with rounded tip vs. conical with an edged elongated tip).

T. senckenbergi sp. n. differs from T. pseudominuta by its shorter body length (1.5 mm vs. 2.8 mm), its longer tail (c = 44.6 vs. 86.9), and its tail shape (conical with rounded tip vs. rounded).

Remarks: The ovary of T. senckenbergi sp.n. is probably non-reflected. The reflected structure of ovaries is usually clearly visible even in virgin specimens (e.g. in T. tchesunovi ( Miljutin, 2004) or in T. petterae ( Miljutin, 2004)) , whereas the structure of ovaries of virgin female of T. turpicauda (possessing a hologonic ovaries) was clearly non-reflected.

Figures

FIGURE 8. Trophomera senckenbergi sp. n., female, holotype. A, cephalic end, lateral view; B, primordial genital system; C, posterior end; D, total view. Abbreviation: a = amphid.