An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. I. Roundworms (Nematoda) Gusakov, Vladimir A. Gagarin, Vladimir G. Zootaxa 2017 4300 1 1 43 de Man, 1876 De Man 1876 [246,529,1876,1902] Adenophorea Ironidae Animalia Enoplida 10 11 Nematoda family   Population structure and abundance.1 to 2 juvenile specimens and/or females at each site.   Ecology and distribution.Hydrobiont. Registered in reservoirs and lakes in countries of Central Asia( Azerbaijan, Kyrgyzstan) and Europe ( Ukraine) ( Tsalolikhin 1987; Gagarin 1993, 2001), as well as in rivers and small waterbodies in Southeast Asia ( Vietnam, Thailand, Malaysia) ( Nguyen & Nguyen 2005; Tsalolikhin 2009). Presumably, this species has wider distribution in the waters of Eurasia, and possibly on other continents (see Remarks).   Remarks. Tsalolikhin (2009)presumes that  I. gagarinialso occurs in North and SouthAmerica but has been identified there as a similar species,  I. longicollisDaday, 1899. At the same time, Andrássy (2007)considers  I. longicollisto be a synonym of  I. ignavusBastian, 1865. It is thus possible that both before and after the description of  I. gagarini, many occurrences of this species have been identified as either  I. longicollisor  I. ignavus. 2.   Ironus ignavusBastian, 1865—{23, 24, 31, 36} (11, 4, 8, 0; 6)  Population structure and abundance.At sites 23, 24, and 36—a few (2 to 5) juvenile specimens and females including one with eggs (estimated total abundance 1–2 x10 3/m2), at 31—numerous (about 100) juveniles, females and gravid females in equal proportion (36 x10 3individuals/m2).   Ecology and distribution.Amphibiont. Dwells in water, wet soil and mosses. Cosmopolitan. Recorded from all continents except Antarctica ( Andrássy 2007). Frequently observed in Vietnam ( Nguyen & Nguyen 2005; Nguyen 2007; Gagarin & Nguyen 2008a). 3. *  Ironus paludicolaSchneider, 1937—{8} (5, 0, 0, 0; 1)  Population structure and abundance.Some juvenile specimens (5), females (6) and gravid females (2) (5 x10 3/m2).   Ecology and distribution.Hydrobiont. Found in various waterbodies in Indonesia( Sumatra), North ( Mexico), Central(Costa-Rica) and South(Surinam) America and Africa ( Mauritania, Tanzania, Ethiopia) ( Tsalolikhin 1996; Andrássy 2011). First record from Vietnam.   Remarks.Males are unknown ( Andrássy 2011). 1585189550 Azerbaijan Central Asia 11 12 1 1585189565 Indonesia Sumatra 11 12 1 Sumatra