BIOLOGIYA MORYA, 2016, Vol. 42, No. 6, pp. 439-448

Two new species of free-living marine nematodes (Nematoda) from an area near the mouth of the Yen River of Vietnam

© 2016 Nguyen Dinh Tu¹, V. G. Gagarin², Phan Ke Long³, Nguyen Thi Xuan Phuong¹, Nguyen Vu Thanh¹

¹Nematology Department, Institute of Ecology and Biological Resources, Vietnam Academy of Science and Technology, Hanoi, Vietnam;
²Institute for Biology of Inland Waters, Russian Academy of Sciences, Borok 152742;
³Vietnamese National Museum of Nature, Vietnam Academy of Science and Technology, Hanoi, Vietnam

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Two new species of free-living marine nematodes were found in a mangrove forest near the mouth of the Yen River, northern Vietnam. Metachromadoroides obscura sp. n. is morphologically close to M. complexa Timm, 1961, but differs from it in having a larger pharyngeal bulb, longer spicules, shorter gubernacula, and a smaller number of precloacal supplements. Oxystomina minor sp. n. is morphologically close to O. vipriensis Gagarin et Nguyen Vu Thanh, 2014, but is distinguished from the latter in having a shorter and thicker body, a longer tail in the males, shorter spicules, longer gubernacula, and the excretory pore located further from the anterior body end.

Key words: Vietnam, free-living marine nematodes, new species, Metachromadoroides obscura sp. n., Oxystomina minor sp. n.