Ephemeroporus barroisi

53. Ephemeroporus barroisi (Richard, 1894) Localities and specimens found: 18 – 1♀; 46 –1j; 49 – 1♀; 50 – 18♀, 6j; 51 – 5♀, 2♀ ov, 6j. 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 1982b; Alonso 1987; Smirnov 1996; Kotov et al. 2011, 2013a; 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. 2021b). In the Oriental area, E. barroisi is well known and widespread (Fernando 1974; Chiang & Du 1979; Idris & Fernando 1981; Rajapaksa & Fernando 1982a; 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. 2013b; 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. 2021b). 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. 2021b; 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). 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 1982b; Idris 1983; Alonso 1987; Yalim & Çiplak 2010; Kotov et al. 2011, 2012, 2013b; 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 1982b; Smirnov 1996; Chatterjee et al. 2013; Kotov et al. 2013b; Elmoor-Loureiro 2014; Sinev & Yusoff 2016; Korovchinsky et al. 2021b).