Family Alaimidae Micoletzky, 1922 6. Amphidelinae gen. sp.— {57} (0, 0, 8, 0; 1) Population structure and abundance. One male. Remarks. Nematodes of this subfamily can be identified to genus level and further only if females are present (Andrássy 2009b). 7. Alaimus de Man, 1880 spp.— {27, 50, 51, 53, 54, 68, 70} (0, 18, 0, 18; 10) Population structure and abundance. 1 to 2 juveniles, females, or males at each site. Ecology and distribution. The majority of the approximately 50 species of this genus known to date inhabit various terrestrial biotopes on all continents; about ten species occur in water bodies as well (Smol & Coomans 2006; Andrássy 2009b). Remarks. In Vietnam two representatives of this genus are known: the cosmopolitan A. primitivus de Man, 1880 and A. siddiqii Andrássy, 1970, originally described in Vietnam and not yet found elsewhere else (Andrássy 1970; Nguyen 2007). It seems that the solitary adult specimens found in our samples represent two or three different species. We failed to reliably identify our specimens either to the two species noted above or to any other representative of the genus. 8. * Paramphidelus Andrássy, 1977 sp.— {29} (0, 4, 0, 0; 1) Population structure and abundance. One female. Ecology and distribution. More than 20 valid species of this genus are known; these species inhabit predominantly terrestrial and semi-aquatic habitats all over the world. Seven species are known from bodies of water (Smol & Coomans 2006; Andrássy 2009b). Remarks. Previously, only P. monohystera (Heyns, 1962) Andrássy, 1977 has been recorded in Vietnam (Nguyen 2007; Gagarin & Nguyen 2008a). The female we found belongs to another unidentified species.

Published as part of Gusakov, Vladimir A. & Gagarin, Vladimir G., 2017, An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. I. Roundworms (Nematoda), pp. 1-43 in Zootaxa 4300 (1) on page 13, DOI: 10.11646/zootaxa.4300.1.1, http://zenodo.org/record/837117