taxonID	type	description	language	source
961D87E9AC45CB55FF0EFE02FDF2F98B.taxon	materials_examined	Localities and specimens found: 30 − 8 ♀, 1 ♀ ov, 9 j; 31 − 1 ♀, 1 j; 41 − 5 ♀, 1 ♀ ov, 8 j; 42 − 1 ♀, 1 j; 46 − 1 ♀; 50 − 1 ♀, 60 j; 51 − 41 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC45CB55FF0EFE02FDF2F98B.taxon	distribution	Distribution and ecology. Latonopsis australis s. lat. is a cosmopolitan species group distributed mainly in the tropics and subtropics around the world but also found in temperate areas of Europe, Asia and North America. To date, these crustaceans are known from all continents and biogeographic regions apart from Antarctica (Korovchinsky 2004, 2018; Kotov et al. 2013 a; Korovchinsky et al. 2021 b). This is one of the most frequently recorded (as L. australis, L. cf. australis or L. australis - group of species) cladocerans in Southeast Asia and the Oriental region generally (Fernando 1974, 1980; Chiang & Du 1979; Idris & Fernando 1981; Idris 1983; Sharma & Michael 1987; Michael & Sharma 1988; Sanoamuang 1998; Rane 2002, 2005, 2011; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Pascual et al. 2014; Sinev et al. 2015; Xiang et al. 2015; Lopez et al. 2017; Sharma & Sharma 2017; Gogoi et al. 2018; Sinev & Yusoff 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023), including Vietnam (Dang et al. 1980, 2002; Dang & Ho 2001; Sinev & Korovchinsky 2013; Gusakov et al. 2014). Latonopsis australis inhabits a wide range of biotopes, from littoral zones of large lakes and reservoirs (mainly with good vegetation) to various shallow and small, permanent and temporary water bodies: oxbow and floodplain lakes, little rivers, ponds, swamps, peat swamps, rice fields, etc. (Idris 1983; Dang & Ho 2001; Korovchinsky 2004, 2018; Lopez et al. 2017; Sinev & Yusoff 2018). This crustacean belongs to the few benthic representatives of the family Sididae, preferring bottom sediments for their habitat, although it also occurs in thickets of aquatic vegetation and in open pelagic parts of water bodies too (Korovchinsky 2004, 2018; Pascual et al. 2014). When disturbed, it is able to move unevenly for a short time (Korovchinsky 2018). According to Rane (2002), L. australis can be rather common among partially submerged floating plants. In our material, it was also found in the rhizosphere of a water hyacinth (Eichhornia crassipes (Martius )) and a floating moss (Salvinia sp.). Moreover, in these samples (Nos. 50, 51; here and beyond, see section “ Localities and specimens found ” and Appendix 1 for more detailed information on the number of specimens and locality characteristics of the taxon under discussion), it was the most abundant.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC45CB55FF0EFE02FDF2F98B.taxon	discussion	Remarks. Latonopsis australis s. str. was originally described from Australia (Sars 1888). Korovchinsky (2004, 2018) defines this taxon as a L. australis group of species that, in addition to the typical form, includes several close, poorly described congeners. The global population of this group (and the Oriental region is no exception) still needs a thorough review (Korovchinsky 2004, 2018; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Kotov et al. 2013 b; Lopez et al. 2017; Sinev & Yusoff 2018).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC45CB54FF0EF9CAFB57FD23.taxon	materials_examined	Localities and specimens found: 46 − 2 ♀; 49 − 1 ♀; 50 − 7 ♀, 3 j; 59 − 1 ♀; 60 − 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC45CB54FF0EF9CAFB57FD23.taxon	distribution	Distribution and ecology. According to modern concepts, this species is chiefly distributed in the tropics and subtropics of the Eastern Hemisphere. The northern limit of its range passes through Northern India, Central China and the Russian Far East (the Lower Amur River basin), whereas in the south it reaches New Guinea and north of Australia (Korovchinsky 2010, 2018; Korovchinsky et al. 2021 b). Pseudosida szalayi is well known in most Oriental and neighbouring countries under its original name (Korovchinsky 2010, 2013; Chatterjee et al. 2013; Kotov et al. 2013 b; Padhye & Dumont 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Xiang et al. 2015; Lopez et al. 2017; Sharma & Sharma 2017; Siboualipha et al. 2020; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In addition, in many sources (e. g., Shirota 1966; Fernando 1974; Idris & Fernando 1981; Idris 1983; Sharma & Michael 1987; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Rane 2011, etc.), it has been mistakenly reported in the region as a related Neotropical species P. bidentata Herrick, 1884 (see comments in Korovchinsky 2010, 2018; Chatterjee et al. 2013; Kotov et al. 2012, 2013 b; Xiang et al. 2015; Lopez et al. 2017; Sharma & Sharma 2017). In Vietnam, this crustacean has been recorded (including as P. bidentata) only in southern provinces so far (Shirota 1966; Dang & Pham 1979; Sinev & Korovchinsky 2013; present study). The lifestyle and ecology of P. szalayi are poorly studied. It lives mainly among aquatic vegetation, to which the crustacean apparently attaches itself by means of hook-shaped setae on its antennae (Korovchinsky et al. 2021 b). Pseudosida szalayi can also be found on the bottom. The species has been recorded in various water bodies and biotopes: littoral zones of lakes, ponds, ditches, channels, paddy fields, swamps, small pools, etc. (Idris 1983; Korovchinsky 2010; Sinev & Korovchinsky 2013; Sinev & Yusoff 2015, 2018; Siboualipha et al. 2020; Choedchim & Maiphae 2023). In our material, a few individuals of P. szalayi were registered only in shallow, vegetation-rich floodplain lakes, both on the bottom and among the roots of a water hyacinth (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC44CB54FF0EF9A7FC0DF833.taxon	materials_examined	Localities and specimens found: 101 − 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC44CB54FF0EF9A7FC0DF833.taxon	distribution	Distribution and ecology. This is a rare species discovered in Thailand (Kotov et al. 2005; Kotov & Štifter 2006), probably endemic to Southeast Asia. At present, it is known only from Thailand and Vietnam (Kotov & Štifter 2006; Maiphae et al. 2008; Jeong et al. 2012; Korovchinsky 2013; Choedchim & Maiphae 2023; Kotov et al. 2024). The lifestyle and ecology of this species are unstudied. Like other ilyocryptids (Kotov 2006; Kotov & Štifter 2006), it is obviously a typical bottom dweller. In Thailand, I. isanensis was recorded in a temporary pond and a rice field (Kotov et al. 2005; Choedchim & Maiphae 2023). The only female from our material was found in the Mekong Delta, in the channel zone of the Co Chien Branch (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC44CB54FF0EFD63FF74FA97.taxon	materials_examined	Localities and specimens found: 50 − 2 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC44CB54FF0EFD63FF74FA97.taxon	distribution	Distribution and ecology. This is a rare sidid from the Indo-Malaysian region that still requires additional investigation. To date, it has only been reported from a few habitats in central India, southern Thailand and southern Vietnam (Rane 1983, 2011; Korovchinsky 2011, 2018; Sinev & Korovchinsky 2013; present study). The lifestyle and ecology of the species are unstudied. It is probably (like Latonopsis australis) a predominantly bottom dweller that inhabits, judging by known finds, small water bodies and the littoral zones of lakes (Rane 1983; Korovchinsky 2011; Sinev & Korovchinsky 2013). In Vietnam, so far, Sarsilatona cf. fernandoi has been noted in two locations within Cat Tien National Park (Dong Nai Province): a semi-permanent forest pond and a flooded forest area (Korovchinsky 2011; Sinev & Korovchinsky 2013). Our only record (two adult females) was made in a permanent floodplain lake in the same territory, in a sample taken from the roots of water hyacinth (see Appendix 1). Thus, the species obviously lives among aquatic plants as well.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC44CB54FF0EFD63FF74FA97.taxon	discussion	Remarks. It is possible that S. fernandoi may have been previously confused with other related representatives in the region, most notably with S. serricaudata (Sars, 1901), now considered Neotropical. Therefore, the Asian findings of this and closely related forms need to be re-examined (Korovchinsky 2011, 2018; Van Damme & Sinev 2013).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC47CB57FF0EFF22FC6CFCFB.taxon	materials_examined	Localities and specimens found: 8 − 2 ♀, 3 ♀ ov, 2 ♀ em, 1 j; 25 − 25 ♀, 21 ♀ ov, 50 ♀ em, 95 j; 26 − 51 ♀, 33 ♀ ov, 26 ♀ em, 116 j; 27 − 1 j; 32 − 1 ♀, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC47CB57FF0EFF22FC6CFCFB.taxon	distribution	Distribution and ecology. Ilyocryptus raridentatus s. str. was described from Australia in insufficient specification and has only recently been redescribed in detail (Kotov & Štifter 2006; Dadykin et al. 2024 a). The currently known range of the species, in addition to Australia, covers a number of countries in Southeast and East Asia, penetrating north up to Korea, Japan and the Russian Far East (Kotov & Sanoamuang 2004 b; Kotov & Štifter 2006; Kotov et al. 2011, 2012, 2024; Korovchinsky et al. 2021 b; Choedchim & Maiphae 2023; Dadykin et al. 2023, 2024 a). In Vietnam, this ilyocriptid was first recorded in the course of the present studies of the meiobenthos as I. cf. raridentatus (Gusakov et al. 2014, 2024). This crustacean is a typical bottom dweller, like other representatives of the genus. It is found in various lentic and lotic water bodies (swamps, puddles, ponds, lakes, reservoirs, rivers, river floodplains, etc.) but its ecological preferences are still not fully understood (Kotov & Štifter 2006; Choedchim & Maiphae 2023; Dadykin et al. 2023, 2024 a). In our material, I. raridentatus was found in the inshore biotopes of a natural lake, a sand quarry and two reservoirs. In qualitative samples from the open and plant-filled littoral of a small reservoir (Nos. 25, 26; see Appendix 1), on silt-clay sand, it was especially numerous.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC47CB57FF0EFF22FC6CFCFB.taxon	discussion	Remarks. According to the latest revision (Dadykin et al. 2024 a), some previously published finds of I. cf. sarsi Stingelin, 1913 and I. sordidus (Liévin, 1848) from East Asia might obviously also be attributed to I. raridentatus, but the results need additional verification, preferably by molecular methods.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC46CB56FF0EFC8CFD12F95D.taxon	materials_examined	Localities and specimens found: 8 − 15 ♀, 9 ♀ ov, 3 ♀ em; 15 − 1 ♀, 1 ♀ em; 32 − 4 ♀, 1 ♀ ov, 7 j; 45 − 1 ♀; 46 − 1 ♀; 49 − 3 ♀, 3 ♀ ov; 50 − 3 ♀, 1 j; 51 − 2 ♀ em, 1 j; 60 − 1 j; 65 − 2 ♀ ov, 3 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC46CB56FF0EFC8CFD12F95D.taxon	distribution	Distribution and ecology. Ilyocryptus spinifer is one the most common and well known members of the genus, especially in the tropics and subtropics worldwide. It is nearly cosmopolitan, only absent in the northern Palaearctic regions and Antarctica (Kotov & Dumont 2000; Kotov & Štifter 2006; Kotov et al. 2013 a; Korovchinsky et al. 2021 b; Dadykin et al. 2024 b). This ilyocryptid had been recorded frequently in the majority of countries within the Oriental area, including under the synonymized names: I. halyi Brady, 1886, I. longiremis Sars, 1888, I. verrucosus Daday, 1905, or as I. cf. spinifer specimens (Fernando 1974, 1980; Idris & Fernando 1981; Rajapaksa & Fernando 1982 a; Idris 1983; Michael & Sharma 1988; Sanoamuang, 1998; Rane 2002, 2005, 2011; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Korovchinsky 2013; Van Damme et al. 2013; Padhye & Dumont 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015, 2020; Xiang et al. 2015; Lopez et al. 2017; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023; Kotov et al. 2024). In Vietnam, this cladoceran was noted (at first as I. halyi, later as I. spinifer) in various types of water bodies throughout the country, from plains to mountains, in both benthic and planktonic samples (Dang et al. 1980, 2002; Dang & Ho 2001; Duong et al. 2008; Sinev & Korovchinsky 2013; Gusakov et al. 2014; Zhdanova 2014; Phan et al. 2015; present study). Ilyocryptus spinifer occurs in almost all types of freshwater bodies and in a wide range of physical and chemical conditions. This ilyocryptid can also be found in saline estuaries. It is a typical benthic crustacean, spending most of its life in the upper layer of bottom sediments (mainly silty and clay). However, the species is not devoid of the ability to swim and therefore can sometimes be encountered in plankton, as well as among thickets of aquatic vegetation (Paranaguá et al. 2005; Kotov & Štifter 2006; Sinev & Korovchinsky 2013; Korovchinsky et al. 2021 b). In our material, I. spinifer was the most common representative among all registered Cladocera, although not very numerous.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC46CB56FF0EFC8CFD12F95D.taxon	discussion	Remarks. Despite the fact that the last worldwide revision showed no differences between I. spinifer populations from different continents (Kotov & Dumont 2000), this taxon still needs further comparative studies, including using molecular methods. It is possible that, nevertheless, this is a complex of very similar relatives (Kotov & Štifter 2006; Lopez et al. 2017; Kotov et al. 2024).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC46CB59FF0EF8F8FEE2FE2F.taxon	materials_examined	Localities and specimens found: 62 − 1 ♀ ov, 1 j; 67 − 13 ♀, 7 ♀ ov, 6 ♀ em, 9 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC46CB59FF0EF8F8FEE2FE2F.taxon	distribution	Distribution and ecology. This is a rare species, perhaps an endemic to Southeast Asia. It was described from Thailand (Kotov & Sanoamuang 2004 b), and later this species was also recorded in Laos (Kotov et al. 2013 b). In Vietnam, I. thailandensis was recently discovered during the present studies of the bottom meiofauna (Gusakov et al. 2024; Kotov et al. 2024). The species lifestyle and ecology are unstudied. Obviously, they are similar to those in other congeners. Hitherto, I. thailandensis has been found in a permanent pond, puddle and peat swamp (Kotov & Sanoamuang 2004 b; Kotov & Štifter 2006; Choedchim & Maiphae 2023). In Vietnam, we registered it in two temporary water bodies: a small floodplain forest lake and a roadside pool (see Appendix 1). In the second habitat, the species was relatively abundant.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC49CB59FF0EFE6FFE4CFBE4.taxon	materials_examined	Localities and specimens found: 8 − 4 ♀, 3 ♀ ov, 4 ♀ em; 12 − 1 j; 25 − 2 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC49CB59FF0EFE6FFE4CFBE4.taxon	distribution	Distribution and ecology. Ilyocryptus yooni is a recently described member of the genus distributed in East and Southeast Asia. Today, the ascertained range of the species extends from the Russian Far East and Japan, through Korea and China, to Vietnam and Malaysian Borneo (Jeong et al. 2012, 2014; Sinev & Yusoff 2015; Sinev et al. 2015; Xiang et al. 2015; Korovchinsky et al. 2021 b; Dadykin et al. 2023; Kotov et al. 2024). Before the present studies on meiobenthos, I. yooni was not known in Vietnam (Gusakov et al. 2024; Kotov et al. 2024). Ilyocryptus yooni is a benthic species that apparently prefers permanent lentic and lotic water bodies. To date, it has been recorded in large lakes with broad shallow areas rich in aquatic vegetation, in the backwater of a small river and in its channel with a slow current, in a small stream, in ponds and in rice fields (Jeong et al. 2012; Sinev & Yusoff 2015; Sinev et al. 2015; Dadykin et al. 2023). In Vietnam, we found it in the open littoral of three reservoirs on clay and silty-sandy sediments (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC49CB59FF0EFE6FFE4CFBE4.taxon	discussion	Remarks. In East Asia (China and further south), prior to its description I. yooni was usually identified as its close congener I. agilis Kurz, 1878 (Jeong et al. 2012, 2014; Xiang et al. 2015; Kotov et al. 2024). Our initial findings of I. yooni individuals in Vietnam (samples Nos. 8 and 12; see Appendix 1) were also documented as I. cf. agilis (Gusakov et al. 2014).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC49CB58FF0EFB68FD66FF5F.taxon	materials_examined	Localities and specimens found: 60 − 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC49CB58FF0EFB68FD66FF5F.taxon	distribution	Distribution and ecology. Until recently, it was believed that G. brazzai is the only representative of the genus that has a circumtropical distribution (Smirnov 1992; Kotov et al. 2013 a). According to modern concepts, this species lives only in the tropical regions of the Old World (Africa, Asia, Australia), while in the New World (tropics and subtropics of South, Central and North America) the genus is represented by a close species G. freyi Neretina et Kotov, 2017 (Neretina & Kotov 2017). Despite the relatively wide distribution, finds of G. brazzai populations in nature are relatively rare and, as a rule, limited to a few specimens. To date, the species had been noted in most countries of South and Southeast Asia (Fernando 1974, 1980; Idris & Fernando 1981; Rajapaksa & Fernando 1982 a; Idris 1983; Michael & Sharma 1988; Maiphae et al. 2008; Tanaka & Ohtaka 2010; Rane 2011; Chatterjee et al. 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Sinev & Yusoff 2015, 2018; Lopez et al. 2017; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In Vietnam, G. brazzai has been recorded only in the southern regions so far, including the Mekong Delta (Shirota 1966; Sinev & Korovchinsky 2013; Le & Phan 2019; present study). Grimaldina brazzai is a bottom dweller, living among detritus on the surface of sediments (Kotov 2006). In large water bodies (lakes, reservoirs), it prefers plant-filled littoral areas but occurs in shallow open zones too. The species is also recorded in other permanent and temporary water bodies: floodplains, rice fields, ponds, channels, etc. (Idris & Fernando 1981; Tanaka & Ohtaka 2010; Sinev & Korovchinsky 2013; Sinev & Yusoff 2015; Neretina & Kotov 2017; Le & Phan 2019; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In our material, a single female of G. brazzai was registered in a small temporary forest lake (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC49CB58FF0EFB68FD66FF5F.taxon	discussion	Remarks. The status of the Asian and Australian populations of G. brazzai still needs to be carefully re-checked. Perhaps, this is a group of close species (Chatterjee et al. 2013; Sinev & Korovchinsky 2013; Van Damme et al. 2013; Sinev & Yusoff 2015; Neretina & Kotov 2017).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB58FF0EFEFFFEDBFB63.taxon	materials_examined	Localities and specimens found: 32 − 2 ♀, 2 ♀ ov, 1 ♀ em, 7 j; 42 − 1 ♀ ov; 46 − 1 ♀; 50 − 14 ♀, 9 j; 51 − 12 ♀, 1 ♀ ov, 7 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB58FF0EFEFFFEDBFB63.taxon	distribution	Distribution and ecology. Currently, M. flabelligera is known from Australia and the Neotropical and Oriental regions (Smirnov 1992; Güntzel et al. 2003; Kotov et al. 2013 a). Among the Oriental countries, the M. flabelligera - like populations have been recorded in Thailand, Cambodia and Vietnam (Sanoamuang 1998; Maiphae et al. 2005; Tanaka & Ohtaka 2010; Korovchinsky 2013; Van Damme et al. 2013; Gusakov et al. 2014; Choedchim & Maiphae 2023). However, at the moment, the presence of this species in Southeast Asia is considered controversial (see Remarks for details). The lifestyle and ecology of M. flabelligera are poorly covered in the literature. Obviously, as in most other macrothricids, its life is mainly associated with the surface of bottom sediments and aquatic vegetation (Kotov 2006; Korovchinsky et al. 2021 b). The species has been found in different types of water bodies, from lakes and reservoirs to rivers and swamps (Güntzel et al. 2003; Tanaka & Ohtaka 2010; Van Damme et al. 2013; Choedchim & Maiphae 2023). In Vietnam, we detected the M. flabelligera - like specimens in a man-made pond and two natural lakes, on the bottom and among the roots of floating plants (see Appendix 1). In the rhizosphere, they were more numerous.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB58FF0EFEFFFEDBFB63.taxon	discussion	Remarks. The individuals of M. flabelligera that we found in Vietnam correspond to Smirnov’s (1992) description according to the general diagnostic characteristics. For the first time this macrothricid was noted in the fauna of the country in the work of Gusakov et al. (2014). At the same time, a number of researchers consider the presence of this species in Southeast Asia to be highly questionable (Kotov et al. 2013 b; Van Damme & Sinev 2013; A. Y. Sinev’s personal communication). They suggest that populations from Southeast Asia identified as M. flabelligera may actually represent a morphotype of another widespread relative in the region, M. triserialis Brady, 1866, which has additional spine-like setules on the segments of antenna II, similar to the typical form of M. flabelligera. Thus, there is a clear need for a thorough comparative surveys of the Asian “ flabelligera – triserialis ” forms. Unfortunately, there are no such studies yet. So far, we are presenting the specimens we have discovered as in this checklist.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB58FF0EFAA3FD60F9AF.taxon	materials_examined	Localities and specimens found: 2 − 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB58FF0EFAA3FD60F9AF.taxon	distribution	Distribution and ecology: This specimen was found in the shallow central part of a reservoir on clay-silty bottom (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB58FF0EFAA3FD60F9AF.taxon	discussion	Remarks. An accurate species identification of this single juvenile is tough. It differs from the juveniles of other representatives of the genus that we have found.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB5BFF0EF9EFFA15FEE7.taxon	description	(Fig. 3 A – D)	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB5BFF0EF9EFFA15FEE7.taxon	materials_examined	Localities and specimens found: 25 – 4 ♀, 2 ♀ ov, 1 j; 26 – 2 ♀, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB5BFF0EF9EFFA15FEE7.taxon	distribution	Distribution and ecology. This uncertain Macrothrix member was discovered in the open and plant-filled littoral of one of the reservoirs (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC48CB5BFF0EF9EFFA15FEE7.taxon	discussion	Remarks. At the moment, the exact species identity of these individuals is not clear. More material and further research are needed to resolve this issue. It is possible that this is a new, not-yet-described representative of the genus. Based on the key diagnostic characteristics (dilating distally antennules, short distal segments of setae natatoriae, specific armament of the setae of the outer lobe of the limb I), the Vietnamese Macrothrix sp. 2 is most similar to M. spinosa King, 1853, which is widely known in the Oriental region, and to the Australian M. breviseta Smirnov, 1976 (Smirnov 1992). As in the first species, our individuals have the entire dorsal margin of valves clearly serrated (Fig. 3 A, C). At the same time, the structure of their antennules, bearing distally several transverse groups of relatively long setules on the anterior side (Fig. 3 A, B), is more similar to those of M. breviseta. However, the dorsal margin of valves of M. breviseta has serrulations mainly in the area of the head pore. In addition, the Vietnamese Macrothrix sp. 2 also differs from both named species by an even shorter distal segment of the natatoriae setae (Fig. 3 A, D).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4BCB5AFF0EFA20FBEBFF73.taxon	materials_examined	Localities and specimens found: 25 – 4 ♀, 1 ♀ ov, 13 j; 26 – 1 ♀, 2 j; 32 – 2 ♀, 1 ♀ em, 1 j; 51 – 2 ♀, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4BCB5AFF0EFA20FBEBFF73.taxon	distribution	Distribution and ecology. Macrothrix spinosa is one of the best-known representatives of the genus, especially in tropical and subtropical regions around the world (Smirnov 1992; Korovchinsky et al. 2021 b). Kotov et al. (2013 a) indicate it for all biogeographic zones except Antarctica. This macrothricid is very common in the Oriental and adjacent states (Chiang & Du 1979; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Rane 2002, 2005, 2011; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Ji et al. 2015; Sinev et al. 2015, 2020; Sinev & Yusoff 2015, 2018; Lopez et al. 2017; Sharma & Sharma 2017; Choedchim & Maiphae 2023), including Vietnam (Dang & Pham 1979; Dang et al. 1980, 2002; Dang & Ho 2001; Duong et al. 2008; Sinev & Korovchinsky 2013; Gusakov et al. 2014; Zhdanova 2014; Phan et al. 2015). Note that in a number of the afore-cited sources, M. spinosa is given under the synonymous name, Macrothrix goeldi Richard, 1897 (Smirnov 1992; Kotov et al. 2013 a). Macrothrix spinosa is a littoral species primarily associated with plant-filled areas. It occurs in almost all types of water bodies, both in plankton and benthos (Idris 1983; Phan et al. 2015; Sinev et al. 2015, 2020; Choedchim & Maiphae 2023). In our material, this crustacean was found in a reservoir and a natural lake, including a sample from the roots of floating moss (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4BCB5AFF0EFA20FBEBFF73.taxon	discussion	Remarks. It is possible that populations of M. spinosa from different parts of the world represent a complex of similar species. This issue requires further detailed research (Korovchinsky et al. 2021 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ACB5AFF0EFE03FA8BFBFF.taxon	materials_examined	Localities and specimens found: 41 – 12 ♀, 4 ♀ ov, 3 ♀ em, 2 j; 95 – 1 ♀, 1 ♀ ov, 1 ♀ em, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ACB5AFF0EFE03FA8BFBFF.taxon	distribution	Distribution and ecology. Alona intermedia has an almost cosmopolitan distribution (Kotov et al. 2013 a; Sinev 2016, 2017). It is relatively widely known (mainly as A. intermedia or as a synonym, Biapertura intermedia (Sars, 1862 )) in the Oriental region (Fernando 1974; Chiang & Du 1979; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Maiphae et al. 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Van Damme et al. 2013; Ji et al. 2015; Sinev 2016; Lopez et al. 2017; Sharma & Sharma 2017; Choedchim & Maiphae 2023), not excluding Vietnam (Dang et al. 1980, 2002; Dang & Ho 2001; Sinev 2017; present study). The lifestyle and ecology of this crustacean are still not fully understood. According to Korovchinsky et al. (2021 b), its northern populations usually live in the open sandy littoral of lakes and ponds of various trophic levels and are not generally found in the thickets of aquatic plants. However, it is also present in swamps, including among sphagnum. In Southeast Asia, A. intermedia is positioned as a littoral species, associated with vegetation (Sinev 2016). In this region, it is recorded in lakes, streams, ponds, rice fields, swamps (Idris 1983; Dang & Ho 2001; Choedchim & Maiphae 2023). We detected these chydorids in a densely plant-filled, acidified small man-made pond and in a clean mountain stream in the dry season (see Appendix 1). Thus, it is obvious that A. intermedia can inhabit a wide spectrum of habitats.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ACB5AFF0EFE03FA8BFBFF.taxon	discussion	Remarks. Globally, A. intermedia populations most likely represent a group of cryptic species in need of comprehensive revision (Van Damme et al. 2010, 2013; Sinev 2016, 2017; Korovchinsky et al. 2021 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ACB5AFF0EFB1FFB00F87B.taxon	materials_examined	Localities and specimens found: 17 – 1 ♀; 32 – 16 ♀, 1 ♀ ov, 5 ♀ em, 9 j; 33 – 4 ♀, 1 j; 35 – 3 ♀; 50 – 1 ♀, 1 ♀ em, 2 j; 51 – 2 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ACB5AFF0EFB1FFB00F87B.taxon	distribution	Distribution and ecology. Anthalona harti is distributed in the tropics and subtropics of the Eastern Hemisphere (South Europe, Africa and also Middle, Southwest, South and Southeast Asia). In Asia, this crustacean is represented by the subspecies A. harti harti (Van Damme et al. 2011; Sinev & Kotov 2012; Korovchinsky 2013; Korovchinsky et al. 2021 b; Dadykin et al. 2024 b). In the Oriental region, it is the most common member of the genus, which in many earlier sources was attributed to Alona verrucosa Sars, 1901, Biapertura verrucosa (Sars, 1901) or Biapertura pseudoverrucosa (Sars, 1901), the synonyms of modern Anthalona verrucosa (Sars, 1901), now recognized as an inhabitant only of the Neotropics (Fernando 1974; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Rane 2002, 2005, 2011; Maiphae et al. 2005, 2008; Van Damme et al. 2011; Sinev & Kotov 2012; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Ji et al. 2015; Padhye & Dumont 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015, 2020; Sinev 2016; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). From Vietnam, this chidorid is known as Biapertura pseudoverrucosa verrucosa (Sars, 1901) (Dang et al. 1980; Dang & Ho 2001) and by its present name (Korovchinsky 2013; Sinev & Korovchinsky 2013; Gusakov et al. 2014; Zhdanova 2014; Sinev & Semenyuk 2021). Anthalona harti harti inhabits various permanent and temporary water bodies, usually rich in aquatic vegetation: lakes, reservoirs, ponds, paddy fields, pools, swamps, floodplains, etc. In large bodies of water, it is associated with the littoral zone. The species can be found at the bottom, in plankton, among thickets (Idris 1983; Van Damme et al. 2011; Sinev & Korovchinsky 2013; Zhdanova 2014; Padhye & Dumont 2015; Sinev & Yusoff 2015; Sinev et al. 2015; Sinev 2016; Korovchinsky et al. 2021 b; Choedchim & Maiphae 2023). In our material, it was found only in natural lakes, in the open littoral and in the rhizosphere of floating plants (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5DFF0EFF22FF21FDC7.taxon	materials_examined	Localities and specimens found: 2 – 1 ♀ ov, 1 ♀ em; 16 – 1 ♀ ov; 25 – 17 ♀, 37 ♀ ov, 50 ♀ em, 66 j; 26 – 20 ♀, 16 ♀ ov, 19 ♀ em, 21 j; 100 – 1 ♀; 102 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5DFF0EFF22FF21FDC7.taxon	distribution	Distribution and ecology. This is a recently described rare species from Indochina, probably endemic to Southeast Asia. To date, it has only been found in Thailand, Laos and Vietnam (Sinev & Kotov 2012; Korovchinsky 2013; Kotov et al. 2013 a, b; Sinev & Korovchinsky 2013; Zhdanova 2014; Sinev 2016; Choedchim & Maiphae 2023; present study). The species lifestyle and ecology are little known. Most likely, this chydorid prefers running water bodies (rivers and streams) (Sinev & Kotov 2012; Sinev & Korovchinsky 2013; Sinev 2016), although it occurs in lakes and reservoirs too (Zhdanova 2014; Choedchim & Maiphae 2023). In our material, A. sanoamuangae was especially abundant in qualitative samples from the open and overgrown littoral of a small reservoir (Nos. 25, 26; see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5DFF0EFD06FF21FBFF.taxon	materials_examined	Localities and specimens found: 42 – 1 ♀, 1 ♀ ov.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5DFF0EFD06FF21FBFF.taxon	distribution	Distribution and ecology. As the previous congener, this is a rare member of the genus, recently described from Thailand (Tiang-nga et al. 2016). It probably also belongs to the endemics of the region. So far, A. spinifera has only been recorded in Thailand and Malaysia (Sinev 2016, 2017; Tiang-nga et al. 2016, 2020; Sinev & Yusoff 2018; Choedchim & Maiphae 2023; Sinev et al. 2023 b). This is its first find in Vietnam. The lifestyle and ecology of A. spinifera are poorly studied. Obviously, it is a macrophyte-associated species that prefers overgrown shallow biotopes. Tо date, the crustacean has been detected in lakes, swamps, rice fields and slow-flowing rivers (Sinev 2017; Tiang-nga et al. 2016, 2020; Sinev & Yusoff 2018; Choedchim & Maiphae 2023). We found two of its females in a small artificial pond, abundantly plant-filled and heavily acidified (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5CFF0EFB1EFBCFFEC3.taxon	materials_examined	Localities and specimens found: 41 – 17 ♀, 3 ♀ ov, 1 ♀ em, 2 ♂, 8 j; 42 – 5 ♀, 7 ♀ ov, 5 ♀ em, 10 j; 59 – 3 j; 92 – 1 ♀ ov, 1 ♀ em.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5CFF0EFB1EFBCFFEC3.taxon	distribution	Distribution and ecology. Biapertura affinis s. lat. is a nearly cosmopolitan group of closely related species (Sinev 1997, 2017, 2020; Van Damme et al. 2010; Chatterjee et al. 2013; Kotov et al. 2013 a; Korovchinsky et al. 2021 b). There are numerous reports of findings of B. affinis - like populations (mainly as Alona affinis (Leydig, 1860), A. cf. affinis or Biapertura affinis, B. cf. affinis) in the Oriental and surrounding areas (Chiang & Du 1979; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1998; Sanoamuang 1998; Rane 2005, 2011; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Ji et al. 2015; Sinev 2016; Lopez et al. 2017; Sharma & Sharma 2017; Gogoi et al. 2018; Sinev et al. 2020; Tiang-nga et al. 2020; Choedchim & Maiphae 2023; Dadykin et al. 2023). In Vietnam, these crustaceans were designated as Alona affinis (Shirota, 1966; Sinev & Korovchinsky 2013), Biapertura affinis vietnamica Dang, 1967 (Dang et al. 1980, 2002; Dang & Ho 2001), Alona cf. affinis (Zhdanova 2014), A. affinis var. ornata Stingelin, 1895 (Gusakov et al. 2014). Biapertura affinis is a littoral cladoceran occurring in the bottom sediments and among the vegetation thickets. Throughout the world, its populations live in a wide variety of water bodies and biotopes, in a wide range of environments (Fryer 1968; Sinev 2020; Korovchinsky et al. 2021 b). In Southeast Asia, this crustacean was recorded in floodplain and oxbow lakes, reservoirs, ponds, rice fields, marshes, peat swamps, rivers, streams (Idris 1983; Dang & Ho 2001; Sinev & Korovchinsky 2013; Zhdanova 2014; Sinev 2016; Gogoi et al. 2018; Choedchim & Maiphae 2023). In our samples, specimens corresponding to this taxon were most numerous in overgrown acidified ponds, but they were also found in a mountain river (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4DCB5CFF0EFB1EFBCFFEC3.taxon	discussion	Remarks. This chydorid has a complicated taxonomic history with many synonymized names (Van Damme et al. 2010; Kotov et al. 2013 a; Sinev 2020; Korovchinsky et al. 2021 b; WoRMS Editorial Board 2024). At the present time, it is considered that the B. affinis s. str. is a Palearctic inhabitant, with similar worldwide populations represented by a complex of sibling species. The analogous Oriental populations still need careful revision and possibly include more than one allied species (Van Damme et al. 2010, 2013; Chatterjee et al. 2013; Kotov et al. 2013 b; Sinev 2016, 2017; Lopez et al. 2017; Sinev 2020; Korovchinsky et al. 2021 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4CCB5CFF0EFE03FD47FAF3.taxon	materials_examined	Localities and specimens found: 17 – 5 ♀, 2 ♀ ov, 1 j; 45 – 1 ♀; 48 – 1 ♀ ov; 51 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4CCB5CFF0EFE03FD47FAF3.taxon	distribution	Distribution and ecology. This is a rare species originally found and described in the Northern Vietnam (Dang 1967 cited by Phan et al. 2015; Dang et al. 1980, 2002; Dang & Ho 2001). Later, it was noted in the Southern part of the country (Sinev, 2011; Sinev & Korovchinsky 2013; Phan et al. 2015; Gusakov et al. 2014). Now, C. vietnamensis has already been indicated in India, Laos, Thailand, China and South Korea (Kotov et al. 2012; Kotov et al. 2013 b; Jeong et al. 2014, 2015; Sinev et al. 2015; Sinev 2016, 2017; Sharma & Sharma 2017; Tiang-nga et al. 2020; Dadykin et al. 2023; Padhye et al. 2023). In addition, previous records in the regions of some other congeners (see Remarks for details) need to be revised and should be attributed at least partially to C. vietnamensis as well (Sinev 2011, 2016, 2017; Kotov et al. 2013 b; Lopez et al. 2017). Thus, the established current range of C. vietnamensis covers, as a minimum, Southern, Southeastern and part of Eastern Asia. The species lifestyle and ecology are not yet fully understood. It often occurs in rivers and streams, which, together with specific morphological adaptations, may indicate its rheophilicity (Sinev 2011; Sinev & Korovchinsky 2013; Korovchinsky et al. 2021 b). However, C. vietnamensis was also repeatedly found in different stagnant water bodies: lakes, reservoirs, rice fields, swamps, pools (Dang et al. 2002; Dang & Ho 2001; Kotov et al. 2012; Jeong et al. 2015; Phan et al. 2015; Sinev et al. 2015; Dadykin et al. 2023; Padhye et al. 2023). In our material, a few individuals of this crustacean were encountered only in vegetation-rich natural lakes, on the bottom and in the rhizosphere of floating moss (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4CCB5CFF0EFE03FD47FAF3.taxon	discussion	Remarks. Camptocercus vietnamensis is very close to C. uncinatus Smirnov, 1971, which is also present in the Оriental region. It is noted (Sinev 2011, 2016, 2017; Kotov et al. 2013 b; Lopez et al. 2017) that at least some earlier records of C. uncinatus in this area may in reality refer to C. vietnamensis. The records of C. rectirostris Schödler, 1862 (Shirota 1966; Chiang & Du 1979; Tanaka & Ohtaka 2010; Kotov et al. 2012; Korovchinsky 2013) and C. australis Sars, 1896 (Idris & Fernando 1981; Idris 1983; Korovchinsky 2013) in Southeast and East (South Korea, China) Asia are also apparently erroneous and in most (if not all) cases should be attributed to C. vietnamensis as well (Sinev 2011, 2016; Kotov et al. 2012, 2013 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4CCB5FFF0EFA13FD79FE53.taxon	materials_examined	Localities and specimens found: 15 – 1 ♀; 16 – 1 ♀, 1 ♀ em; 32 – 1 ♀; 33 – 1 ♀, 1 ♀ ov; 65 – 8 ♀, 3 ♀ ov, 1 ♀ em, 2 ♂, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4CCB5FFF0EFA13FD79FE53.taxon	distribution	Distribution and ecology. Coronella acuticostata is the current name of one of the Oriental representatives of the genus (Sinev 2016, 2017). The species is rather common in most countries of Southeast Asia, India and Southern China, where it was previously recorded under a number of synonymous names: Alona monacantha (or A. cf. monacantha) Sars, 1901, A. monacantha tridentata Stingelin, 1905, A. acuticostata var. tridentata Stingelin, 1905, Coronatella monacantha (or C. cf. monacantha) (Sars, 1901), C. monacantha tridentata (Stingelin, 1905) (Idris & Fernando 1981; Rajapaksa & Fernando 1982 a; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Van Damme et al. 2010, 2013; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Sinev et al. 2015; Sinev & Yusoff 2015; Sinev 2016; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In Vietnam, this crustacean was earlier reported as Alona monacantha (Shirota 1966; Duong et al. 2008; Dang & Ho 2001; Dang et al. 2002), A. cf. monacantha (Gusakov et al. 2014) or Coronatella cf. monacantha (Sinev & Korovchinsky 2013). Sinev (2016) classifies C. acuticostata as a littoral species associated with vegetation. So far, this chydorid has been detected in different water bodies, mainly permanent: lakes, reservoirs, ponds, mining pools, rice fields, marshes, rivers, streams, drains (Idris 1983; Sanoamuang 1998; Dang & Ho 2001; Tanaka & Ohtaka 2010; Sinev & Korovchinsky 2013; Sinev & Yusoff 2015; Sinev et al. 2015; Gogoi et al. 2018; Choedchim & Maiphae 2023). We encountered several individuals of this species in overgrown and vegetation-free biotopes of natural lakes and in a temporary roadside pool (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4CCB5FFF0EFA13FD79FE53.taxon	discussion	Remarks. The distribution of the present Coronatella (former Alona) monacantha s. str., to which C. acuticostata was previously often attributed, seems to be limited only to the Neotropical region. Asian populations of C. acuticostata still require additional, more detailed analysis (Sinev 2004; Kotov et al. 2013 b; Van Damme et al. 2010, 2013; Sinev & Yusoff 2015; Sinev et al. 2015).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4FCB5FFF0EFDF3FA07FAAB.taxon	materials_examined	Localities and specimens found: 16 – 1 ♀; 25 – 1 ♀ em; 97 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4FCB5FFF0EFDF3FA07FAAB.taxon	distribution	Distribution and ecology. Coronatella rectangula (formerly most often recognized as Alona rectangula Sars, 1862) is a very confusing taxon with a complicated taxonomic history and many synonyms (Van Damme & Dumont 2008; Van Damme et al. 2010, 2013; Sinev 2017; Korovchinsky et al. 2021 b; WoRMS Editorial Board 2024). Until recently, it was supposed that it has an almost global distribution (Kotov et al. 2013 a). According to modern concepts, the distribution of the typical form of this chydorid seems to be limited to the Palearctic and Oriental regions (Sinev 2017; Korovchinsky et al. 2021 b), although the Southeast Asian populations have some differences and require additional research (Sinev & Yusoff 2015; Sinev et al. 2015; Sinev 2016, 2017). The findings of C. rectangula - like specimens are rather common in the Oriental and adjacent areas (Chiang & Du 1979; Rajapaksa & Fernando 1982 a; Idris 1983; Michael & Sharma 1998; Sanoamuang 1998; Tanaka & Ohtaka 2010; Maiphae et al. 2005, 2008; Rane 2011; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Ji et al. 2015; Sinev & Yusoff 2015; Sinev et al. 2015; Sinev 2016; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In Vietnam, this crustacean is well known as well (Shirota 1966; Dang et al. 1980, 2002; Dang & Ho 2001; Duong et al. 2008; Gusakov et al. 2014; Zhdanova 2014). Coronatella rectangula is considered one of the most eurybiont representatives of the Aloninae. It occurs in almost all types of water bodies of any trophic level, in a wide range of environments. The species is found both in plankton and benthos. In big water bodies, it prefers littoral habitats, usually with aquatic vegetation (Van Damme et al. 2010; Sinev 2016; Korovchinsky et al. 2021 b). In our samples, the species was rare and in low concentrations.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4FCB5FFF0EFAEBFEBFF833.taxon	materials_examined	Localities and specimens found: 3 – 1 ♀ em; 25 – 1 ♀, 1 ♀ em, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4FCB5FFF0EFAEBFEBFF833.taxon	distribution	Distribution and ecology. This is a rare East Asian member of the genus, originally classified as a subspecies of Alona (now Coronatella) rectangula: A. rectangula trachystriata Chen, Zhang et Liu, 1994 (Chen et al. 1994; Van Damme et al. 2010; Sinev et al. 2024). Until now, the species has only been recorded in the Far East of Russia (Amur River basin), South Korea and China, including Hainan Island (Kotov et al. 2011, 2017; Ji et al. 2015; Sinev et al. 2015; Sinev 2016, 2017; Korovchinsky et al. 2021 b; Sinev et al. 2024). The present work is the first report of C. trachystriata specimens in Vietnam and the southernmost record of them. The species lifestyle and ecology are still weakly understood. Until now, it was found in lakes, ponds, reservoirs and river mouths (Chen et al. 1994; Kotov et al. 2011; Sinev et al. 2015, 2024; Korovchinsky et al. 2021 b). According to recent observations in one of the lakes in China (Sinev et al. 2024), C. trachystriata is obviously a bottom-dwelling species which prefers soft sediments at some distance from the shallowest coastal zone. It can also occur sporadically in plankton due to the agitation of bottom sediments by waves. During our research, several exemplars of this species were found on the open shoreline of two reservoirs on sandy and sandy-silty deposits (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB5EFF0EFF22FEC9FD0F.taxon	materials_examined	Localities and specimens found: 50 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB5EFF0EFF22FEC9FD0F.taxon	distribution	Distribution and ecology. Graptoleberis testudinaria s. lat. has an almost cosmopolitan distribution, but populations recorded around the world (and the Oriental area is not an exception) probably represent a complex of closely related, separate species (Chatterjee et al. 2013; Van Damme et al. 2013; Sinev 2016, 2017; Korovchinsky et al. 2021 b). This crustacean, although rare, is quite widely known in the Oriental region (Fernando 1974, 1980; Chiang & Du 1979; Idris & Fernando 1981; Idris 1983; Sharma & Michael 1987; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2008; Rane 2011; Chatterjee et al. 2013; Korovchinsky 2013; Ji et al. 2015; Sinev et al. 2015, 2020; Sinev 2016; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023; Dadykin et al. 2023). In Vietnam, G. testudinaria has not been recorded before. This is its first finding in the country. Graptoleberis testudinaria is a highly specialized phytophilic chydorid, adapted to crawling on submerged substrates. It lives in a wide variety of water bodies, mainly in thickets of aquatic plants (Fryer 1968; Smirnov 1971; Korovchinsky et al. 2021 b). The only female in our material was encountered in the root system of a water hyacinth (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB5EFF0EFD4EFB0FFBB7.taxon	materials_examined	Localities and specimens found: 32 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB5EFF0EFD4EFB0FFBB7.taxon	distribution	Distribution and ecology. Karualona arcana is a recently discovered and described very rare chydorid from Southeast Asia, presumably an endemic to this region. Up to now, it had only been recorded in Thailand (Tiang-nga et al. 2021; Choedchim & Maiphae 2023). This is the first registration of the species outside of this country. In Thailand, K. arcana was found in a single locality, a rice field (Tiang-nga et al. 2021; Choedchim & Maiphae 2023). Our only female was collected in the open littoral of a natural lake (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB5EFF0EFBD6FB24F93F.taxon	materials_examined	Localities and specimens found: 50 – 11 ♀, 5 ♀ ov, 9 ♀ em, 12 j; 51 – 3 ♀, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB5EFF0EFBD6FB24F93F.taxon	distribution	Distribution and ecology. This is another lately discovered member of the genus Karualona from Southeast Asia, which was previously identified in the region usually as K. karua (King, 1853) or K. cf. karua (Sinev & Semenyuk 2023). Karualona fatimae was described in Vietnam and is still known here only from Cat Tien National Park (Dong Nai Province), including before its description as K. karua (Sinev & Korovchinsky 2013; Sinev & Semenyuk 2021, 2023). We also found K. fatimae only in this territory. According to Sinev & Semenyuk (2023), previous references of K. karua in Chinese Hainan Island and some locations in Thailand and Malaysia (Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Tiang-nga et al. 2020) belong to K. fatimae as well. Dadykin et al. (2024 b) report the presence of K. fatimae in Central Asia (Tajikistan), where it was previously listed as Alonella karua King, 1853. In general, the currently known distribution of K. fatimae covers Sri Lanka, Central and Southeast Asia, South China and probably India (Sinev & Semenyuk 2023; Dadykin et al. 2024 b). Karualona fatimae is characterized as a phytophilous cladoceran. It inhabits slow-flowing rivers, lakes, reservoirs, ponds, rice fields, swamps and some temporary water bodies (Sinev & Semenyuk 2023). In our material, this species was detected in a permanent forest lake, in the rhizosphere of floating plants (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB41FF0EF95EFDB6FEC3.taxon	materials_examined	Localities and specimens found: 50 – 2 ♀, 1 j; 51 – 10 ♀, 3 ♀ ov, 1 ♀ em, 3 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC4ECB41FF0EF95EFDB6FEC3.taxon	distribution	Distribution and ecology. This is a rare species, one more endemic to Southeast Asia. Currently, K. serrulata is known in Thailand, Laos, Vietnam and Indonesia (Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Van Damme et al. 2013; Sinev 2016, 2017; Choedchim & Maiphae 2023). In Thailand, Laos and Vietnam, it was first listed as Karualona sp. (Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Van Damme et al. 2013). The location in the work of Sinev & Korovchinsky (2013), Bau Sau Lake in Cat Tien National Park (Dong Nai Province), is so far the only known habitat of this species in Vietnam. We found K. serrulata in the same lake among the roots of water hyacinth and Salvinia, together with the above noted congener K. fatimae (see Appendix 1). As many other small chydorids, K. serrulata is obviously a littoral, phytophilous species. To date, it has been recorded in swamps and in a shallow, vegetation-rich lake (Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Van Damme et al. 2013; present study).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB41FF0EFE03FCBEFC03.taxon	materials_examined	Localities and specimens found: 15 – 1 ♀; 16 – 1 ♀ ov, 1 ♀ em; 61 – 1 ♀; 65 – 1 ♀, 1 ♀ ov, 1 ♀ em, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB41FF0EFE03FCBEFC03.taxon	distribution	Distribution and ecology. Kurzia brevilabris is a representative of the Oriental fauna. The species is rather common in the region (Rajapaksa & Fernando 1986 b; Hudec 2000; Sharma & Sharma 2012, 2017; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Sinev et al. 2015; Sinev 2016; Sinev & Yusoff 2018; Tiang-Nga et al. 2020; Choedchim & Maiphae 2023). It is noted that some previous mentions of K. longirostris (Daday, 1898) in the region (e. g., by Idris (1983) for Malaysia) in fact also refer to K. brevilabris (Sinev 2016). In Vietnam, finds of K. brevilabris are not yet numerous (Sinev & Korovchinsky 2013; Sinev & Semenyuk 2021; present study). Kurzia brevilabris is mainly confined to shallow biotopes with rich aquatic vegetation. It occurs in various permanent and temporary water bodies: lakes, reservoirs, ponds, rice fields, swamps, floodplains, flooded forest areas, streams (Idris 1983; Sinev & Korovchinsky 2013; Gusakov et al. 2014; Sinev et al. 2015; Sinev 2016; Gogoi et al. 2018; Sinev & Yusoff 2018; Sinev & Semenyuk 2021; Choedchim & Maiphae 2023). We found the species in two lakes and a temporary roadside pool (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB41FF0EFC43FE3BF93F.taxon	materials_examined	Localities and specimens found: 72 – 3 ♀, 1 ♀ ov, 1 j; 75 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB41FF0EFC43FE3BF93F.taxon	distribution	Distribution and ecology. Kurzia longirostris is distributed in the tropical and subtropical regions of Australia, Asia, Africa and South America (Rajapaksa & Fernando 1986 b; Kotov et al. 2012, 2013 a, 2013 b; Lopez et al. 2017). In South and Southeast Asia, it is more common than K. brevilabris, and in East Asia, K. longirostris penetrates as far as South Korea (Rajapaksa & Fernando 1986 b; Michael & Sharma 1988; Sanoamuang 1998; Hudec 2000; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Rane 2011; Kotov et al. 2012, 2013 b; Chatterjee et al. 2013; Korovchinsky 2013; Ji et al. 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Sinev 2016; Lopez et al. 2017; Sharma & Sharma 2017; Tiang-Nga et al. 2020; Choedchim & Maiphae 2023; Dadykin et al. 2023). Sinev (2016) notes that some previous records of K. longirostris in Southeast Asia actually belong to K. brevilabris. In Vietnam, K. longirostris is well-known and widespread (Dang et al. 1980, 2002; Dang & Ho 2001; Sinev & Korovchinsky 2013; Gusakov et al. 2014; Phan et al. 2015). Kurzia longirostris is a phytophilous littoral chydorid, dwelling among bottom sediments and aquatic plants. It is found in a wide variety of water bodies and habitats, from lakes, reservoirs, rivers and streams to small temporary pools (Sanoamuang 1998; Tanaka & Ohtaka 2010; Sinev & Korovchinsky 2013; Phan et al. 2015; Sinev & Yusoff 2015; Sinev et al. 2015; Sinev 2016; Lopez et al. 2017; Gogoi et al. 2018; Korovchinsky et al. 2021 b; Choedchim & Maiphae 2023). During our research, several individuals of this species were found in a stagnant section of a forest stream (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB40FF0EF95FFB42FD0F.taxon	materials_examined	Localities and specimens found: 30 – 1 ♀; 46 – 1 ♀; 50 – 17 ♀, 1 ♀ ov, 3 ♀ em, 5 j; 51 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB40FF0EF95FFB42FD0F.taxon	distribution	Distribution and ecology. Leberis punctatus (formerly Alona punctata Daday, 1898) is a comparatively rare member of the genus recently redescribed in detail (Neretina & Sinev 2016). The species is generally distributed in the Afrotropical and Oriental biogeographic realms but is also recorded in southern Spain (Korovchinsky et al. 2021 b). In the Oriental area, Leberis punctatus has so far been known only in Sri Lanka, India and Thailand (Padhye & Dumont 2015; Neretina & Sinev 2016; Sinev 2016; Sharma & Sharma 2017; Korovchinsky et al. 2021 b). The present study is the first direct reference of this species in Vietnam. The record of L. diaphanus (King, 1853) in our previous report on the meiofauna of Vietnam (Gusakov et al. 2014) should also be attributed to L. punctatus (as we established after re-examination of the material). In turn, L. diaphanus is also known in Vietnam (Sinev & Korovchinsky 2013; Phan et al. 2015; Sinev & Semenyuk 2021). The lifestyle and ecology of L. punctatus are weakly studied. Most likely, this chydorid is a typical littoral inhabitant associated with vegetation (Sinev 2016; Korovchinsky et al. 2021 b). The species occurs in different types of water bodies (Neretina & Sinev 2016). We found it in two natural vegetation-rich lakes, on the bottom and in the roots of floating plants. Among the roots of water hyacinth, this crustacean was the most numerous (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC51CB40FF0EF95FFB42FD0F.taxon	discussion	Remarks. In South and Southeast Asia, L. punctatus is occurring together with another very similar, more common relative: L. diaphanus (Neretina & Sinev 2016; Sinev 2016). It cannot be ruled out that some previous indications of L. diaphanus in the region actually refer to L. punctatus, which confirms our example of an initially erroneous report that the former species was found in Vietnamese material instead of the latter (see note above). Thus, L. punctatus is likely to be more widespread in the Oriental region than currently believed.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC50CB40FF0EFD4FFDABF98B.taxon	materials_examined	Localities and specimens found: 15 – 1 ♀; 16 – 1 ♀ ov; 26 – 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC50CB40FF0EFD4FFDABF98B.taxon	distribution	Distribution and ecology. Leydigia australis is a representative of the genus from Australia, which has also been recorded in some countries of Southeast and South Asia, namely Thailand, Cambodia, Sri Lanka, India (Fernando 1974, 1980; Maiphae et al. 2008; Tanaka & Ohtaka 2010; Rane 2011; Choedchim et al. 2017; Choedchim & Maiphae 2023). However, some of these detections are questionable and most likely relate to other species (see details in Remarks below) (Chatterjee et al. 2013; Kotov et al. 2013 b; Sharma & Sharma 2017). In Vietnam, L. australis was first discovered in the course of present studies of the meiobenthos (Gusakov et al. 2014). The lifestyle and ecology of the species have not been studied in depth. Obviously, like other members of the genus, L. australis belongs to the typical bottom-dwelling chydorids (Kotov 2006). The crustacean was recorded in the benthos of the open and overgrown littoral of lakes, in dams and other lentic water bodies (Fernando 1974, 1980; Choedchim et al. 2017; Choedchim & Maiphae 2023). In our material, single individuals were found on the bottom of shallow, moderately vegetated areas of a natural lake and in the littoral of a small reservoir (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC50CB40FF0EFD4FFDABF98B.taxon	discussion	Remarks. The status of the Oriental populations of L. australis needs further study. According to the main external features, the individuals we found in Vietnam correspond to the diagnosis of this species given in the latest revision of the genus (Kotov 2009). A little later, Kotov et al. (2013 b) assigned L. australis to a species group whose Southeast Asian populations are possibly separate species requiring formal description. Chatterjee et al. (2013) noted that the Indian records of L. australis known at that time most likely refer to L. ciliata (Gauthier, 1939). Described from Sri Lanka, subspecies L. australis ceylonica (Daday, 1898) (Smirnov 1971) is now positioned as the valid species L. ceylonica (Daday, 1898) (Chatterjee et al. 2013; Kotov et al. 2013 a; WoRMS Editorial Board 2024). According to Chatterjee et al. (2013), a specimen from Cambodia listed by Tanaka & Ohtaka (2010) as L. australis also belongs to L. ceylonica.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC50CB43FF0EF9CBFD6CFC9F.taxon	materials_examined	Localities and specimens found: 49 – 1 ♀; 100 – 2 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC50CB43FF0EF9CBFD6CFC9F.taxon	distribution	Distribution and ecology. This representative of the genus is more widespread than the previous one. It is well known in tropical and subtropical areas of Africa and Asia and is also found, but less frequently, in Australia (Smirnov & Timms 1983; Kotov 2009; Sinev, 2017; Korovchinsky et al. 2021 b). In Africa and Australia, the southern limit of its distribution reaches areas with a moderate climate (Smirnov & Timms 1983; Kotov 2009). In turn, in East Asia, the species penetrates as far north as South Korea (Jeong et al. 2014). Leydigia ciliata is common in the countries of the Oriental realm (Chiang & Du 1979; Swar & Fernando 1979; Michael & Sharma 1988; Rane 2002; Maiphae et al. 2008; Tanaka & Ohtaka 2010; Sinev & Sanoamuang 2011; Kotov et al. 2013 b; Chatterjee et al. 2013; Ji et al. 2015; Padhye & Dumont 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015, 2020; Sinev 2016; Sharma & Sharma 2017; Choedchim & Maiphae 2023; Dadykin et al. 2023; Padhye et al. 2023). In Vietnam, L. ciliata is not very widespread but perhaps it was noted here earlier under other name (see details in Remarks) (Sinev & Korovchinsky 2013; Sinev & Semenyuk 2021). Leydigia ciliata is a benthic species, apparently preferring silty and silty-clay deposits (Sinev 2016; Korovchinsky et al. 2021 b). The species is most common in lakes and ponds but is also found in rice fields, peat swamps, channels, rivers, streams and other water bodies (Kotov et al. 2003; Kotov 2009; Sinev & Korovchinsky 2013; Sinev & Yusoff 2015; Sinev et al. 2015; Sinev 2016; Choedchim & Maiphae 2023; Dadykin et al. 2023). In our samples, this crustacean was rare and few. It was detected in a floodplain lake and in the riparian zone of a branch of the Mekong Delta (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC50CB43FF0EF9CBFD6CFC9F.taxon	discussion	Remarks. It should be noted that reports of finds in Vietnam of L. acanthocercoides (Fischer, 1854) (e. g., by Shirota (1966), Dang et al. (1980, 2002), Dang & Ho (2001), Phan et al. (2015 )), a northern member of the genus (Kotov 2009; Korovchinsky et al. 2021 b), are very likely erroneous and should also be attributed to L. ciliata (Sinev & Korovchinsky 2013). The same is obviously true of the records of L. acanthocercoides in China and India (Chatterjee et al. 2013; Dadykin et al. 2023). The Indian records of L. australis and L. hardingi Kurz, 1875 most likely refer to L. ciliata too (Chatterjee et al. 2013). Kotov et al. (2012, 2013 b) pointed out that the Oriental populations of L. ciliata need additional verification, as Sinev & Sanoamuang (2011) found some differences between the males from Asia and those from Africa (the region of the original description of the species). In Korovchinsky’s (2013) review, L. ciliata is presented as a complex of species.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC53CB43FF0EFC3FFA17FA3B.taxon	materials_examined	Localities and specimens found: 50 – 4 ♀, 1 ♀ em, 2 j; 51 – 4 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC53CB43FF0EFC3FFA17FA3B.taxon	distribution	Distribution and ecology. This is a relatively rare species recently described from Thailand (Van Damme & Sinev 2013). It is also known in India, Cambodia, Laos, Myanmar and Vietnam, where it was listed in some sources as Leydigiopsis sp. or L. curvirostris Sars, 1901 before being described (Sanoamuang 1998; Sharma & Sharma 2007, 2012, 2017; Maiphae et al. 2008; Tanaka & Ohtaka 2010; Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Van Damme & Sinev 2013; Sinev 2016). Representatives of the genus Leydigiopsis are considered to be true benthic cladocerans (Kotov 2006). The lifestyle and ecology of L. pulchra are still poorly understood. The species was recorded in eutrophic habitats rich in living and dead organic matter: swamps, forest ponds and small lakes (Sanoamuang 1998; Sinev & Korovchinsky 2013; Van Damme & Sinev 2013; Sinev 2016). We found it only in the samples from the root system of floating macrophytes (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC53CB43FF0EFC3FFA17FA3B.taxon	discussion	Remarks. Van Damme & Sinev (2013) pointed out a possible hidden speciation within Asian populations of L. pulchra, which is reflected in the differences the authors found between individuals from Thailand and Vietnam.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC53CB42FF0EFA5BFF7AFE2F.taxon	materials_examined	Localities and specimens found: 25 – 2 ♀ em; 26 – 1 ♀, 1 ♀ ov.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC53CB42FF0EFA5BFF7AFE2F.taxon	distribution	Distribution and ecology. Magnaspina siamensis (formerly Alona siamensis Sinev et Sanoamuang, 2007) is a rare species described from Thailand, an endemic to the Oriental region (Sinev & Sanoamuang 2007; Sinev 2016). Currently, the species is also known from Malaysia, Laos, India and South Vietnam (Korovchinsky 2013; Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Sinev 2016; Sousa & Padhye 2020). In Vietnam, Magnaspina siamensis was first recorded as Alonella dentifera Sars, 1901 by Shirota (1966) (see Remarks below for details). The lifestyle and ecology of Magnaspina siamensis are little studied. To date, this chydorid has been discovered mainly in small, vegetated water bodies, namely swamps, rice fields, ponds, ditches, floodplains (Sinev & Sanoamuang 2007; Sinev & Korovchinsky 2013; Sousa & Padhye 2020; Choedchim & Maiphae 2023). In our material, a few individuals of this species were found in the open and overgrown littoral of a small reservoir (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC53CB42FF0EFA5BFF7AFE2F.taxon	discussion	Remarks. It should be noted that probably all records of Alonella dentifera - like populations (later known as Alona or Coronatella dentifera (Sars, 1901 )) from the Oriental region (e. g., by Shirota (1966), Idris & Fernando (1981), Idris (1983), Maiphae et al. (2005, 2008), etc.) are in fact Magnaspina siamensis too (Sinev & Sanoamuang 2007; Van Damme et al. 2010; Chartejee et al. 2013; Kotov et al. 2013 b; Van Damme & Sinev 2013; Sousa et al. 2016 b; Choedchim & Maiphae 2023). The recent species M. dentifera (Sars, 1901), the “ successor ” of Alonella dentifera, originally described from Brazil, is now considered an inhabitant of the Neotropics only (Sousa et al. 2016 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC52CB42FF0EFE6FFB65FB93.taxon	materials_examined	Localities and specimens found: 77 – 4 ♀, 6 ♀ ov, 4 ♀ em, 8 j; 79 – 1 ♀, 1 ♀ ov, 3 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC52CB42FF0EFE6FFB65FB93.taxon	distribution	Distribution and ecology. According to the present views, N. eximius (formerly known as Alona eximia Kiser, 1948) is distributed generally in Southeast Asia and China (Idris 1983; Sanoamuang 1998; Kotov & Sanoamuang 2004 a; Van Damme et al. 2003, 2013; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Korovchinsky 2013; Kotov et al. 2013 b; Ji et al. 2015; Sinev 2016; Tiang-nga et al. 2020; Dadykin et al. 2023). At the same time, it is known that the species penetrates north, up to the Trans-Baikal and Primorsky territories of Russian Asia (Korovchinsky et al. 2021 b). In Vietnam, this crustacean is common and widespread (Dang & Ho 2001; Dang et al. 2002; Sinev 2011, 2012; Sinev & Korovchinsky 2013; Gusakov et al. 2014; Phan et al. 2015; Sinev et al. 2017). Nicsmirnovius eximius is considered a bottom-dwelling rheophilic species, preferring the littoral of lotic water bodies (streams, rivers, waterfalls, dams, channels) in zones with moderate current (Van Damme et al. 2003; Sinev 2016; Korovchinsky et al. 2021 b). Sometimes it occurs in stagnant basins too: ponds, lakes, reservoirs, rice fields, floodplains, swamps (Idris 1983; Dang & Ho 2001; Kotov & Sanoamuang 2004 a; Tanaka & Ohtaka 2010; Tiang-nga et al. 2020; Dadykin et al. 2023). According to Sinev et al. (2017), in rivers and streams the species can be most abundant in thickets of macrophytes and among well-washed rocks, but it is rare in the layer of bottom sediments. We found a population of N. eximius in Vietnam only in one of the forest streams (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC52CB45FF0EFB33FF6AFD0F.taxon	materials_examined	Localities and specimens found: 50 – 12 ♀, 11 ♀ ov, 11 ♀ em, 8 j; 51 – 3 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC52CB45FF0EFB33FF6AFD0F.taxon	distribution	Distribution and ecology. Notoalona globulosa s. lat. is a very small chydorid with a morphological variability not yet fully studied and an intricate taxonomic history (Rajapaksa & Fernando 1987 a; Van Damme et al. 2010, 2013; Neretina et al. 2017, 2019). According to the latest views, this crustacean is distributed in tropical Asia and Australia (Neretina et al. 2017, 2019). In Asia, the taxon is evidently represented by the subspecies N. globulosa globulosa (Rajapaksa & Fernando 1987 a; Van Damme et al. 2013; Sinev 2016), although this issue requires further research (see Remarks below) (Neretina et al. 2019). Notoalona globulosa is documented in almost the entire Oriental area (Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Rane 2011; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Ji et al. 2015; Padhye & Dumont 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Lopez et al. 2017; Sharma & Hatimuria 2017; Sharma & Sharma 2017; Yatigammana & Cumming 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023) and from many sources it was also indicated in the region under various synonymous names, primarily as Alona globulosa Daday, 1898, Indialona globulosa (Daday, 1898) or Alonella globulosa (Daday, 1898) (Chiang & Du 1979; Fernando 1980; Rajapaksa & Fernando 1982 a, 1987 a; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Chatterjee et al. 2013; Korovchinsky 2013; Ji et al. 2015). In Vietnam, the finds of Notoalona globulosa are rare. So far, it has been registered only in the southern part of the country (Sinev & Korovchinsky 2013; present study). Alonella globulosa and Indialona globulosa insulcata (Stingelin, 1905) (= Alonella sculpta var. insulcata Stingelin, 1904), reported for South Vietnam by Shirota (1966) and Smirnov (1971) respectively, should probably also be attributed to Notoalona globulosa (Rajapaksa & Fernando 1987 a). Notoalona globulosa most likely belongs to the littoral species associated with aquatic vegetation (Sinev 2016; Neretina et al. 2019). It is recorded in a wide variety of water bodies: lakes and ponds of different types, reservoirs, swamps, rice fields, ditches, channels, rivers (Idris & Fernando 1981; Sanoamuang 1998; Sinev & Korovchinsky 2013; Padhye & Dumont 2015; Sinev & Yusoff 2015; Sinev 2016; Yatigammana & Cumming 2017; Gogoi et al. 2018; Choedchim & Maiphae 2023). Rajapaksa & Fernando (1982 a) classified this crustacean as eurytopic. At the same time, according to Neretina et al. (2019), its ecology still needs to be clarified. We found N. globulosa only in samples from the rhizosphere of floating plants (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC52CB45FF0EFB33FF6AFD0F.taxon	discussion	Remarks. As recent reviews show, the morphology, distribution and ecology of representatives of Notoalona, and in particular N. globulosa, still need additional research (Van Damme et al. 2013; Neretina et al. 2017, 2019). The species N. globulosa was repeatedly transferred from genus to genus and was indicated in the literature under various names (species, subspecies, morphological forms), as can be seen from its rich synonymy (Smirnov 1971; Rajapaksa & Fernando 1987 a; Van Damme et al. 2010, 2013; Neretina et al. 2017, 2019). The specimens we found in Vietnam correspond in external morphology to the subspecies N. globulosa globulosa according to the main characteristics (Rajapaksa & Fernando 1987 a; Van Damme et al. 2013; Sinev 2016). Therefore, for now, we present them in this checklist as follows. Meanwhile, Neretina et al. (2019) doubted the convenience of distinguishing two subspecies of N. globulosa — Asian N. globulosa globulosa and Australian N. globulosa australiensis Rajapaksa et Fernando, 1987 — and pointed out the need for additional research on these populations, including the use of genetic methods.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC55CB45FF0EFD4FFEB9FA97.taxon	materials_examined	Localities and specimens found: 50 – 6 ♀, 4 ♀ ov, 1 ♀ em, 10 j; 51 – 30 ♀, 6 ♀ ov, 5 ♀ em, 23 j; 59 – 1 ♀; 60 – 1 ♀ ov.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC55CB45FF0EFD4FFEB9FA97.taxon	distribution	Distribution and ecology. This is a rare member of the genus, not long ago described from Thailand (Van Damme et al. 2013), which until recently was considered the only known habitat of the species (Sinev 2016; Neretina et al. 2017). However, the newest analysis of African and Madagascar populations of the related species N. globulosa (indicated under various synonyms in the listed territories) has shown that some of them apparently belong to N. pseudomacronyx (Neretina et al. 2019). Additionally, the latest authors noted that N. globulosa, reported by Fernando (1974) from Sri Lanka, is actually N. pseudomacronyx too. The present checklist is the first indication of N. pseudomacronyx in Vietnam. The species lifestyle and ecology are unstudied. So far, N. pseudomacronyx was known only from shallow, vegetation-rich swampy localities, including temporary ones (Van Damme et al. 2013; Sinev 2016; Neretina et al. 2017, 2019; Choedchim & Maiphae 2023). In similar habitats, it was also encountered in Vietnam: in a periodically drying, heavily vegetated forest lake and in the root system of floating macrophytes in a floodplain lake (see Appendix 1). The crustacean was most abundant among the roots, where it was found mixed with the sibling species N. globulosa.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC55CB45FF0EFA37FD67F833.taxon	materials_examined	Localities and specimens found: 50 – 2 ♀, 1 ♀ ov, 3 j; 51 – 3 ♀, 1 ♀ ov, 1 ♀ em, 1 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC55CB45FF0EFA37FD67F833.taxon	distribution	Distribution and ecology. Oxyurella singalensis is distributed in the Afrotropical, Oriental and Australian biogeographic regions (Kotov et al. 2013 a; Sinev 2017; Lopez et al. 2017). This is one of the most common Oriental species of chydorids (Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Pascual et al. 2014; Ji et al. 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Sinev 2016; Lopez et al. 2017; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). It is also well known and widespread in Vietnam (Dang et al. 1980, 2002; Dang & Ho 2001; Sinev & Korovchinsky 2013). Oxyurella singalensis is a littoral species associated with vegetation. It dwells in bottom sediments and among aquatic vegetation in a wide variety of water bodies, primarily in stagnant ones, but it is also found in moderately flowing habitats (Idris 1983; Sanoamuang 1998; Dang & Ho 2001; Pascual et al. 2014; Sinev et al. 2015; Sinev 2016; Lopez et al. 2017; Choedchim & Maiphae 2023). In our material, the species was rare and was detected only in the rhizosphere of floating plants (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFF6AFD6DFCB3.taxon	materials_examined	Localities and specimens found: 50 – 3 ♀, 1 ♀ ov, 1 j; 51 – 11 ♀, 1 ♀ ov, 2 ♀ em, 2 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFF6AFD6DFCB3.taxon	distribution	Distribution and ecology. Alonella excisa s. lat. is one of the most known members of the genus distributed almost worldwide (Smirnov 1996; Kotov et al. 2013 a; Korovchinsky et al. 2021 b). This taxon is evidently represented by a complex of related species that require further investigation, including in the Asian region (Smirnov 1996; Kotov et al. 2013 b; Neretina et al. 2021). In the Oriental area, A. excisa - like individuals are noted relatively often (Chiang & Du 1979; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Ji et al. 2015; Sinev et al. 2015, 2020; Lopez et al. 2017; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Dadykin et al. 2023). In Vietnam, these crustaceans were mainly designated as A. excisa excisa (Fischer, 1854) (Dang et al. 1980, 2002; Dang & Ho 2001; Duong et al. 2008; Sinev & Semenyuk 2021). Alonella excisa s. lat. is an eurybiontic chydorid found in plankton, benthos and among aquatic vegetation of various types of water bodies, in big ones mainly in the littoral zone (Idris 1983; Duong et al. 2008; Lopez et al. 2017; Korovchinsky et al. 2021 b). In our material, these crustaceans were encountered only in samples from the root system of floating macrophytes (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFCD2FA84FAAB.taxon	materials_examined	Localities and specimens found: 50 – 1 ♀, 1 ♀ ov, 1 j; 51 – 2 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFCD2FA84FAAB.taxon	distribution	Distribution and ecology. This is a very rare member of the genus Chydorus, probably endemic to the Oriental region. Most of the species’detection sites are located in India (Frey 1987; Smirnov 1996; Chatterjee et al. 2013; Sharma & Hatimuria 2017; Gogoi et al. 2018). Not so long ago, it was also discovered in South Vietnam (Cat Tien National Park, Dong Nai province) (Sinev & Korovchinsky 2013). In the same area, Ch. angustirostris was found in the course of our research. Apart from the named countries, this species is not yet known anywhere else. The lifestyle and ecology of Ch. angustirostris have not been studied. So far, it has been found in a number of permanent and temporary water bodies (floodplain and oxbow lakes, wetlands, forest ponds and pools), including in plankton samples (Frey 1987; Sinev & Korovchinsky 2013; Sharma & Hatimuria 2017; Gogoi et al. 2018). We detected several specimens in a floodplain lake, in the rhizosphere of floating plants (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFAEAFE3CF833.taxon	materials_examined	Localities and specimens found: 50 – 21 ♀, 10 ♀ ov, 19 j; 51 – 6 ♀, 2 ♀ ov, 4 j; 60 – 1 ♀ em.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFAEAFE3CF833.taxon	distribution	Distribution and ecology. Chydorus idrisi is an Oriental species. It was described from Vietnam (Sinev 2014), and today it is also known from Thailand, Malaysia and Hainan Island (China) (Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Tiang-nga et al. 2020). This species was found in the open and vegetated littoral of permanent lakes and reservoirs, as well as in various small and temporary water bodies: rivers, streams, ditches, rice fields, ponds, roadside pools (Sinev 2014; Sinev & Yusoff 2015, 2018; Sinev et al. 2015). In our material, Ch. idrisi was recorded in a temporary forest lake and in a floodplain lake among the roots of floating macrophytes (see Appendix 1). It was especially abundant in the roots of water hyacinth.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC57CB47FF0EFAEAFE3CF833.taxon	discussion	Remarks. Prior to its description, Ch. idrisi was apparently confused with other closely related members of the genus, primarily with Ch. pubescens Sars, 1901, Ch. ventricosus Daday, 1898 and Ch. eurynotus Sars, 1901 (Sinev 2014; Ji et al. 2015; Sinev & Yusoff 2015). For example, Ch. cf. pubescens recorded by Idris (1983) in Malaysia is in fact Ch. idrisi (Sinev 2014; Sinev & Yusoff 2015). Thus, the actual distribution of Ch. idrisi is obviously wider than is currently known.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB46FF0EFF22FEF7FC89.taxon	materials_examined	Localities and specimens found: 50 – 2 ♀, 2 ♀ ov; 51 – 12 ♀, 11 ♀ ov, 3 ♀ em, 11 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB46FF0EFF22FEF7FC89.taxon	distribution	Distribution and ecology. Chydorus parvus is generally known from the Afrotropical and Oriental regions (Smirnov 1996; Kotov et al. 2013 a). In the latter, it is one of the most common representatives of the genus. In some sources, it was previously indicated here under synonymous names, Ch. sphaericus var. parvus Daday, 1898 and Ch. robustus Stingelin, 1905 (Swar & Fernando 1979; Rajapaksa & Fernando 1982 a; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Sinev & Yusoff 2015; Lopez et al. 2017; Sharma & Sharma 2017; Choedchim & Maiphae 2023). There is also evidence of finds of this species in Central China (Ji et al. 2015) and the Australian biogeographic realm (Maiphae et al. 2008). Prior to the present study, Ch. parvus had not been recorded in Vietnam. The lifestyle and ecology of Ch. parvus are not yet fully understood. The species was recorded in a wide spectrum of water bodies: lakes, ponds, reservoirs, channals, rivers, streams, floodplains, rice fields, swamps, pools, etc. (Idris 1983; Sanoamuang 1998; Sinev & Yusoff 2015; Choedchim & Maiphae 2023). Some authors present it as a eurytopic species, occurring in almost all types of habitats (Rajapaksa & Fernando 1982 a; Idris 1983). According to Sinev & Yusoff (2015), this chydorid is more abundant on submerged macrophytes. We found Ch. parvus only among the roots of floating macrophytes (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB46FF0EFF22FEF7FC89.taxon	discussion	Remarks. Kotov et al. (2013 b) note that the status of Ch. parvus populations found outside the Oriental area should be revised.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB46FF0EFC35FA17F9E1.taxon	materials_examined	Localities and specimens found: 50 – 7 ♀, 1 ♀ ov; 51 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB46FF0EFC35FA17F9E1.taxon	distribution	Distribution and ecology. Chydorus pubescens is considered circumtropical (Smirnov 1996; Maiphae et al. 2008; Kotov et al. 2013 a), but there are doubts about this (see Remarks for details) (Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Van Damme et al. 2013). In the Oriental region, to date, Ch. pubescens has been recorded in several countries (Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In Vietnam, so far, it has only been discovered in the south, in Cat Tien National Park (Dong Nai province) (Sinev & Korovchinsky 2013; present study). The lifestyle and ecology of the species are little studied. It was found in different lentic and lotic water bodies: rivers, streams, natural and man-made lakes, marshes, ponds, pools, peat swamps, etc. (Sanoamuang 1998; Maiphae et al. 2005; Sinev & Korovchinsky 2013; Choedchim & Maiphae 2023). Probably, Ch. pubescens is associated with aquatic vegetation (Tiang-nga et al. 2020). In our material, several individuals of this species were found only in the rhizosphere of floating plants (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB46FF0EFC35FA17F9E1.taxon	discussion	Remarks. Chydorus pubescens was originally described in Brazil (Sars, 1901). Populations of this species found outside the Neotropics, and in particular in the Oriental area, may in fact represent other closely related species and still remain to be reviewed (Chatterjee et al. 2013; Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Van Damme et al. 2013). For instance, Ch. cf. pubescens, recorded by Idris & Fernando (1981) and Idris (1983) from Malaysia, actually refers to a recently described new member of the genus in the region, Ch. idrisi (Sinev 2014).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB49FF0EF92DFD53FE53.taxon	materials_examined	Localities and specimens found: 50 – 1 ♀; 51 – 7 ♀, 3 ♀ ov, 1 ♀ em, 2 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB49FF0EF92DFD53FE53.taxon	distribution	Distribution and ecology. This representative of the genus is an Oriental inhabitant (Michael & Hann 1979; Frey 1982 c; Smirnov 1996; Korovchinsky 2013; Kotov et al. 2013 a; Sharma & Sharma 2017). It is known throughout the region, but in places it is rare and few in number (Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Kotov et al. 2013 b; Ji et al. 2015; Sinev & Yusoff 2015, 2018; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In Vietnam, Ch. reticulatus is recorded only in one of the southern provinces (Sinev & Korovchinsky 2013; Sinev & Semenyuk 2021; present study). The biology and ecology of the species are little studied. As many congeners, Ch. reticulatus seems to be linked to a littoral zone with diverse aquatic vegetation (Sinev & Yusoff 2018). Currently, this species is known from various permanent and temporary water bodies: floodplain and oxbow lakes, ricefields, swamps, ponds, pools, rivers, ditches (Frey 1982 c; Idris 1983; Sanoamuang 1998; Sinev & Korovchinsky 2013; Gogoi et al. 2018; Sinev & Semenyuk 2021; Choedchim & Maiphae 2023). We detected several of its specimens only among the roots of floating macrophytes in a floodplain lake (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC56CB49FF0EF92DFD53FE53.taxon	discussion	Remarks: In some old literary sources, Ch. reticulatus was indicated under synonymous names Ch. sphaericus var. parvus Daday, 1898 and Ch. eurynotus reticulatus Smirnov, 1971 (Smirnov 1971; Michael & Hann 1979; Frey 1982 c; Idris 1983). Probably, in the past, Ch. reticulatus was also often mistaken for young individuals of Ch. ventricosus Daday, 1898 (Michael & Hann 1979).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC59CB49FF0EFC43FE76F8D7.taxon	materials_examined	Localities and specimens found: 96 – 1 ♀; 98 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC59CB49FF0EFC43FE76F8D7.taxon	distribution	Distribution and ecology. Chydorus sphaericus s. lat. is one of the most known members of the chydorids, representing a cosmopolitan complex of closely related species with an intricate taxonomic history, many synonyms and, as previously thought, subspecies (Smirnov 1971, 1996; Belyaeva & Taylor 2009; Kotov et al. 2013 a, 2016; Karabanov et al. 2022; WoRMS Editorial Board 2024). Chydorus sphaericus - like populations are well known in the Oriental and adjacent territories (Chiang & Du 1979; Michael & Sharma 1988; Maiphae et al. 2008; Chatterjee et al. 2013; Korovchinsky 2013; Ji et al. 2015; Sinev et al. 2020), including Vietnam, where these crustaceans were often indicated as the subspecies Ch. sphaericus sphaericus (Müller, 1776) (Shirota 1966; Dang et al. 1980, 2002; Dang & Ho 2001; Phan et al. 2015). Chydorus sphaericus is considered to be a wide eurybiont, living in water bodies and habitats of different kinds (Fryer 1968). In addition to the open and vegetated littoral areas, it is often found in the open pelagic zone (in plankton). In the latter case, the crustacean can attach to various floating substrates, such as algae and detritus (Smirnov 1971, 1996; Korovchinsky et al. 2021 b). In our material, two Ch. sphaericus - like females were found in a mountain river in winter, during the period of moderate current, low water and, in comparison with lowland areas, low temperature (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC59CB49FF0EFC43FE76F8D7.taxon	discussion	Remarks. Despite the long history of this taxon, the Ch. sphaericus group of species still remains incompletely investigated. Recent studies, including molecular-genetic, have revealed that the “ typical ” form, Ch. sphaericus s. str., is found mainly in the western and central Palearctic (together with other related forms), not counting cases of anthropogenic or other introductions outside this region. In turn, in other parts of the world the Ch. sphaericus - like populations are obviously represented by sibling species, some of which have already been examined and described whereas others remain to be studied in detail (Belyaeva & Taylor 2009; Klimovsky & Kotov 2015; Kotov et al., 2016; Karabanov et al. 2022). It has not yet been precisely established which specific forms of the Ch. sphaericus group inhabit Southeast Asia.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB48FF0EFF22FF68FCFB.taxon	materials_examined	Localities and specimens found: 17 – 2 ♀; 26 – 2 ♀, 1 ♀ ov, 1 ♀ em, 6 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB48FF0EFF22FF68FCFB.taxon	distribution	Distribution and ecology. According to the latest ideas, Ch. ventricosus s. str. is distributed only in the Oriental biogeographic realm (Rajapaksa & Fernando 1986 a; Kotov et al. 2013 b; Sinev & Korovchinsky 2013; Sinev et al. 2015). This is a well-known but in patches uncommon member of the genus in the region (Chiang & Du 1979; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Tanaka & Ohtaka 2010; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Ji et al. 2015; Sinev et al. 2015; Lopez et al. 2017; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). In Vietnam, the species has so far been recorded in several locations in the central and southern provinces (Sinev & Korovchinsky 2013; present study). Chydorus ventricosus is a littoral species occurring in a wide range of water bodies and habitats, generally nonrunning (Idris 1983; Rajapaksa & Fernando 1986 a; Michael & Sharma 1988; Sanoamuang 1998; Van Damme et al. 2013; Sinev et al. 2015; Choedchim & Maiphae 2023). We found some of its individuals in the coastal area of a natural lake and reservoir (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB48FF0EFF22FF68FCFB.taxon	discussion	Remarks. Outside the Oriental area, the Ch. ventricosus - like populations should be revised as they most likely belong to other close relatives, including those not-yet-described (Rajapaksa & Fernando 1986 a; Chatterjee et al. 2013; Kotov et al. 2013 b; Van Damme et al. 2013). In addition, in the past, Ch. ventricosus was apparently often confused with other sibling species (e. g., Ch. reticulatus, Ch. sphaericus, Ch. pubescens, etc.) (Michael & Hann 1979; Frey 1982 c; Rajapaksa & Fernando 1986 a). Thus, the actual distribution of the species still needs to be clarified.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB48FF0EFC1AFB2BF9F7.taxon	materials_examined	Localities and specimens found: 50 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB48FF0EFC1AFB2BF9F7.taxon	distribution	Distribution and ecology. Dadaya macrops (formerly Alona macrops Daday, 1898) inhabits in the tropics and subtropics around the world (Rajapaksa & Fernando 1982 b; Kotov et al. 2013 a; Smirnov 1996). It is common in the Oriental region (Fernando 1980; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Rane 2011; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Ji et al. 2015; Sinev & Yusoff 2015, 2018; Lopez et al. 2017; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023) and well known in Vietnam (Shirota 1966; Dang et al. 1980, 2002; Dang & Ho 2001; Sinev & Korovchinsky 2013; Sinev & Semenyuk 2021). The lifestyle and ecology of D. macrops are not completely understood. There are few detailed descriptions of its habitats. It is considered that the species is hyponeustonic, adapted to life under the surface layer of water (Fryer 1956; Rajapaksa & Fernando 1982 b; Smirnov 1996). Probably, this crustacean is mainly associated with shallow, stagnant water bodies with abundant vegetation (rice fields, ponds, lakes, floodplains, swamps, etc.) although it is found in other types of water bodies too (Idris & Fernando 1981; Idris 1983; Sanoamuang 1998; Sinev & Korovchinsky 2013; Sinev & Yusoff 2015; Gogoi et al. 2018; Choedchim & Maiphae 2023). Our only female was encountered in a floodplain lake in the rhizosphere of water hyacinth (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB48FF0EFC1AFB2BF9F7.taxon	discussion	Remarks. Today, D. macrops is the only representative of the genus. Van Damme et al. (2010, 2013) noted that more than one species may be present in the tropics, and this chydorid still needs to be revised.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB4BFF0EF916FC81FE0B.taxon	materials_examined	Localities and specimens found: 25 – 45 ♀, 10 ♀ ov, 5 ♀ em, 65 j; 26 – 108 ♀, 30 ♀ ov, 1 ♀ em, 169 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB4BFF0EF916FC81FE0B.taxon	distribution	Distribution and ecology. This species of Disparalona was recently described from the Amur River basin in Russia (Kotov & Sinev 2011). To date, it has also been recorded in South Korea, China (including Hainan Island) and northeastern Thailand (Kotov et al. 2012; Sinev et al. 2015, 2020; Neretina et al. 2018; Korovchinsky et al. 2021 b; Dadykin et al. 2023). This is the first mention of the species in Vietnam and it is currently the southernmost known point of the species distribution. Based on the data obtained until now, D. ikarus is obviously a benthic littoral crustacean, encountered both in open and vegetated areas. The species was mainly registered in rivers, reservoirs and lakes and less often in ponds, streams and ditches (Kotov & Sinev 2011; Kotov et al. 2012; Jeong et al. 2015; Sinev et al. 2015; Korovchinsky et al. 2021 b). In our material, D. ikarus was found only once, but in large numbers, in the open and covered with water hyacinth sandy littoral of a small reservoir (see Appendix 1)	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC58CB4BFF0EF916FC81FE0B.taxon	discussion	Remarks. Prior to its description, D. ikarus has been identified mistakenly as D. rostrata (Koch, 1841) in some cases (Ji et al. 2015; Dadykin et al. 2023). It is possible that a number of previous indications of D. rostrata in Vietnam (Dang et al. 1980, 2002; Dang & Ho 2001) also actually refer to D. ikarus. Disparalona rostrata s. str. is now recognized as Palaerctic only (Neretina et al. 2018).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4BFF0EFE4BFE47FB07.taxon	materials_examined	Localities and specimens found: 30 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4BFF0EFE4BFE47FB07.taxon	distribution	Distribution and ecology. It is assumed that D. crassa is distributed throughout the world in warm latitudes, up to the south of temperate regions, but its worldwide populations still need to be revised (Smirnov 1996; Kotov et al. 2013 a, 2013 b; Błędzki & Rybak 2016; Korovchinsky et al. 2021 b). The species is widely known in the Oriental region (Fernando 1974, 1980; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Rane 2002, 2005, 2011; Maiphae et al. 2005, 2008; Chatterjee et al. 2013; Korovchinsky 2013; Van Damme et al. 2013; Ji et al. 2015; Sinev & Yusoff 2015, 2018; Choedchim et al. 2017; Lopez et al. 2017; Sharma & Sharma 2017; Tiang-nga et al. 2020; Choedchim & Maiphae 2023; Dadykin et al. 2023). In Vietnam, it is registered throughout the country (Dang et al. 1980, 2002; Dang & Ho 2001; Sinev & Korovchinsky 2013; Gusakov et al. 2014). Dunhevedia crassa is a littoral species which occurs, as a rule, in the sites with well developed vegetation in a variety of water bodies (mostly lentic), both permanent and temporary. It can tolerate a fairly high level of salinity (up to 25.9 ‰) (Idris 1983; Smirnov 1996; Dang & Ho 2001; Sinev & Korovchinsky 2013; Błędzki & Rybak 2016; Korovchinsky et al. 2021 b; Choedchim & Maiphae 2023). We found the only female of the species in a small lake located very close to the sea (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4BFF0EFE4BFE47FB07.taxon	discussion	Remarks. This species was originally described from Australia. On other continents, D. crassa may represent a group of similar species that so far require careful comparative analysis (Smirnov 1996; Kotov et al. 2013 b; Korovchinsky et al. 2021 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4BFF0EFB47FD99F88F.taxon	materials_examined	Localities and specimens found: 50 – 1 ♀; 81 – 1 ♀, 1 ♀ em, 3 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4BFF0EFB47FD99F88F.taxon	distribution	Distribution and ecology. Dunhevedia serrata is distributed in the Ethiopian, Oriental and Australasian (New Guinea) regions (Rajapaksa & Fernando 1987 b; Smirnov 1996; Smirnov & De Meester 1996; Kotov et al. 2013 a). In the Oriental area, it is relatively common (Fernando 1974, 1980; Idris & Fernando 1981; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Rane 2011; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Sinev & Yusoff 2015, 2018; Lopez et al. 2017; Sharma & Sharma 2017; Tiang-nga et al. 2020; Padhye et al. 2023; Choedchim & Maiphae 2023), but there are still few records of this species in Vietnam (Sinev & Korovchinsky 2013; Gusakov et al. 2014; present study). The lifestyle and ecology of this species are poorly studied. They are probably similar to those of the previous congener. Dunhevedia serrata is known mainly from permanent and temporary stagnant water bodies, including those vegetation-rich: lakes, reservoirs, floodplains, rice fields, ponds, swamps, mining pools, ditches (Idris 1983; Sinev & Korovchinsky 2013; Sinev & Yusoff 2015; Choedchim & Maiphae 2023). In our samples, several D. serrata specimens were found in a stagnant section of a forest stream and among the roots of water hyacinth in a floodplain lake (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4AFF0EF8CFFE47FBDB.taxon	materials_examined	Localities and specimens found: 18 – 1 ♀; 46 – 1 j; 49 – 1 ♀; 50 – 18 ♀, 6 j; 51 – 5 ♀, 2 ♀ ov, 6 j.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4AFF0EF8CFFE47FBDB.taxon	distribution	Distribution and ecology. Ephemeroporus barroisi s. lat. (formerly Pleuroxus barroisi Richard, 1894 or Chydorus barroisi (Richard, 1894 )) is a complex of closely related species distributed in tropical and subtropical zones around the world (Frey 1982 b; Alonso 1987; Smirnov 1996; Kotov et al. 2011, 2013 a; Van Damme et al. 2013). In turn, the “ typical ” form of the species, E. barroisi s. str., according to recent ideas, lives chiefly in the warm regions of Asia, as well as, most likely, Africa and Australia (Sinev & Yusoff 2016; Korovchinsky et al. 2021 b). In the Oriental area, E. barroisi is well known and widespread (Fernando 1974; Chiang & Du 1979; Idris & Fernando 1981; Rajapaksa & Fernando 1982 a; Idris 1983; Michael & Sharma 1988; Sanoamuang 1998; Rane 2002, 2005, 2011; Maiphae et al. 2005, 2008; Tanaka & Ohtaka 2010; Meksuwan et al. 2012; Chatterjee et al. 2013; Korovchinsky 2013; Kotov et al. 2013 b; Van Damme et al. 2013; Pascual et al. 2014; Ji et al. 2015; Sinev & Yusoff 2015, 2018; Sinev et al. 2015; Choedchim et al. 2017; Lopez et al. 2017; Sharma & Sharma 2017; Gogoi et al. 2018; Tiang-nga et al. 2020; Choedchim & Maiphae 2023). Vietnam is no exception. Here, in some sources, this crustacean was previously noted as the subspecies Chydorus (or Ephemeroporus) barroisi barroisi (Richard, 1894) (Shirota 1966; Dang et al. 1980, 2002; Dang & Ho 2001; Sinev & Korovchinsky 2013; Zhdanova 2014; Phan et al. 2015; Sinev & Semenyuk 2021). The lifestyle and ecology of this species are not fully understood (Korovchinsky et al. 2021 b). Apparently, E. barroisi is a eurybiontic species (Sinev & Yusoff 2016) but still prefers habitats rich in aquatic vegetation. It was recorded in a wide spectrum of water bodies: large and small, stagnant and flowing, permanent and temporary (Idris & Fernando 1981; Idris 1983; Sanoamuang 1998; Tanaka & Ohtaka 2010; Van Damme et al. 2013; Pascual et al. 2014; Ji et al. 2015; Sinev et al. 2015; Sinev & Yusoff 2016, 2018; Lopez et al. 2017; Korovchinsky et al. 2021 b; Choedchim & Maiphae 2023). The species is also not rare in plankton (Fernando 1980; Idris & Fernando 1981; Boonsom 1984; Maiphae et al. 2005; Zhdanova 2014; Phan et al. 2015). In our material, E. barroisi was more abundant in the rhizosphere of floating macrophytes (see Appendix 1).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5BCB4AFF0EF8CFFE47FBDB.taxon	discussion	Remarks. Together with E. barroisi s. str., in the Asian region, there are several closely related members of the genus, probably including those not yet described (Frey 1982 b; Idris 1983; Alonso 1987; Yalim & Çiplak 2010; Kotov et al. 2011, 2012, 2013 b; Chatterjee et al. 2013; Van Damme et al. 2013; Sinev & Yusoff 2015; Lopez et al. 2017). Most E. barroisi - like populations in the rest of the world also need to be thoroughly re-examined (Frey 1982 b; Smirnov 1996; Chatterjee et al. 2013; Kotov et al. 2013 b; Elmoor-Loureiro 2014; Sinev & Yusoff 2016; Korovchinsky et al. 2021 b).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5DCB4CFF0EF9AFFD9EFE0B.taxon	description	(Fig. 6 A – C)	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5DCB4CFF0EF9AFFD9EFE0B.taxon	materials_examined	Localities and specimens found: 92 – 1 ♀.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5DCB4CFF0EF9AFFD9EFE0B.taxon	distribution	Distribution and ecology. Paralona pigra (formerly most commonly known as Chydorus piger Sars, 1862) is today the only member of the genus. It is recorded from the temperate and northern regions of Eurasia, North and South America, Africa and New Guinea (Dumont & Smirnov 1996; Smirnov 1996; Korovchinsky et al. 2021 b). There are no reports of findings of this chydorid within the Oriental biogeographic area, taking into account all available synonyms (Kotov et al. 2013 a; Błędzki & Rybak 2016; WoRMS Editorial Board 2024). It therefore appears to be the first record of the species not only in Vietnam, but in the entire region. Paralona pigra is considered a benthic species. It primarily occurs in oligotrophic and mesotrophic lakes and ponds on sandy and silty sediments. The species is also found in groundwater (Fryer 1968; Smirnov 1996; Kotov 2006; Korovchinsky et al. 2021 b). The only female from our material was discovered in a low-flow section of a mountain river in December at a water temperature of approximately 16 ° C (see Appendix 1), which is quite consistent with habitat conditions for the species at more northern latitudes.	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
961D87E9AC5DCB4CFF0EF9AFFD9EFE0B.taxon	discussion	Remarks. Paralona pigra is not yet a fully studied taxon and needs revision. Because its specimens from different parts of the world have notable morphological differences, this crustacean may in fact represent a complex of related species (Dumont & Smirnov 1996; Smirnov 1996; Korovchinsky et al. 2021 b). For example, some populations of the species are characterized by the presence of a spine (or several spines) in the posterior-ventral corners of the valves, whereas others do not have such spines (Smirnov 1996). Our Vietnamese female has a distinct spine on each valve (Fig. 6 A, C).	en	Gusakov, Vladimir A., Dien, Tran Duc, Tran, Hoan Quoc, Thanh, Nguyen Thi Hai, Huan, Phan Trong, Ha, Vo Thi, Dinh, Cu Nguyen (2025): An annotated checklist of the main representatives of meiobenthos from inland water bodies of Central and Southern Vietnam. III. Water fleas (Cladocera). Zootaxa 5613 (3): 401-455, DOI: 10.11646/zootaxa.5613.3.1, URL: https://doi.org/10.11646/zootaxa.5613.3.1
