Two New Species of the Order Monhysterida Filipjev, 1929 (Nematoda) from the Van Uc River Mouth in Vietnam

• Published in: Inland water biology Vol. 14; no. 5; pp. 517 - 527
• Main Authors: Gagarin, V. G., Tú’, Nguyễn Đình
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.09.2021; Springer Nature B.V
• Subjects: Animal cuticle; Biodiversity; Biology; Biomedical and Life Sciences; Bottom sediments; Fluvial sediments; Freshwater & Marine Ecology; Geoecology/Natural Processes; Identification; Life Sciences; Males; Monhysterida; Morphology; Morphometry; Nematodes; New species; River mouth; River mouths; Rivers; Sediments; Spicules; Stomata; Systematics of Hydrobionts; Vietnam; new species; Vietnam; marine free-living nematodes; sp. n
• ISSN: 1995-0829; 1995-0837
• DOI: 10.1134/S1995082921050059

Two new species of free-living nematodes of the order Monhysterida have been described from bottom sediments of the Van Uc River, Vietnam. Amphimonhystrella major sp. n. resembles A. parva Gagarin, Nguyen Vu Thanh, 2009 by the structure of the spicular apparatus, but differs by a longer body, shorter tail, longer stoma, and larger spicules. Thalassomonhystera lepta sp. n. is morphologically close to T. elegans Gagarin, Nguyen Vu Thanh, 2013, but has a shorter body, smooth cuticle, tail of different shape, and larger spicules. A table of the main morphometric characters of males of the valid species of the genus Amphimonhystrella and a dichotomous key for their identification and the table of the main morphometric characters in males of seven valid species of the genus Thalassomonhystera found in water bodies of Vietnam and a dichotomous key for their identification are presented.