Thalassomonhystera oxycephalata Tchesunov et Miljutina, sp. n.

• Main Authors: Tchesunov, Alexei V., Miljutina, Maria A.
• Format: Other/Unknown Material
• Language: unknown
• Published: Zenodo 2005
• Subjects: Biodiversity; Taxonomy; Animalia; Nematoda; Adenophorea; Monhysterida; Monhysteridae; Thalassomonhystera; Thalassomonhystera oxycephalata; Arctic; Arctic Ocean; Greenland; Svalbard
• Online Access: https://doi.org/10.5281/zenodo.5658417; http://treatment.plazi.org/id/E535B46CFFAAFFCAC707FB8D29571DCE

Thalassomonhystera oxycephalata Tchesunov et Miljutina sp. n. Table 1, Figs 3, 4 Material . One holotype male, four paratype males and two paratype females. The slides are deposited in the nematode collection of the Shirshov Institute of Oceanology of Russian Academy of Sciences, Moscow. Type locality. Arctic Ocean, area between Greenland and Svalbard, 79°8.2'N & 02°53.6'E, depth 5569 m (Molloy Deep), silt, 16 August, 2000. Etymology . The name oxycephalata reflects a narrowing cephalic end. Description . Body slender, elongate spindle­shaped. Cuticle smooth. Cephalic end narrowed. Labial region set off slightly. Mouth opening surrounded with six small lips. Labial papillae not discernible. The outer labial setae and cephalic setae are jointed in one circle of ten equal tiny setae approximately 1.5 µm long. Amphid at a considerable distance from the head apex, well posterior to the stoma ending. Amphid large, circular to slightly longitudinally oval, with fine but distinct cuticular edging, very fine concentric striation and more or less certain central spot. No other sensilla visible posterior to the amphid along the body. Buccal cavity elongate tubular and very narrow, its walls hardly differ from internal cuticular lining of the esophagus. Esophagus slender and weak. Cardia small, surrounded with intestinal tissue. No indications of a renette cell. Vulva not sclerotised. Female gonad singular, outstretched and situated entirely to the right of the midgut. Uterus can contain a single egg 30–47 µm long and 8.5–11 µm wide, with coarsely granulated cytoplasm. No postvulvar sac. There are a few round cells with light cytoplasm and small dense nuclei (spermatozoa or spermatides?) in the posterior prevaginal portion of the gonad. Male gonad singular, outstretched and situated entirely to the right of the midgut. Spermatocytes relatively large and arranged in one row in the anterior part of the gonad. Ripe spermatozoa (or spermatides?) look like tiny light­refracted crumbs in the posterior part of the male gonad. ...