Chydorus reticulatus Daday 1898

45. Chydorus reticulatus Daday, 1898 Localities and specimens found: 50 – 1♀; 51 – 7♀, 3♀ ov, 1♀ em, 2j. Distribution and ecology. This representative of the genus is an Oriental inhabitant (Michael & Hann 1979; Frey 1982c; Smirnov 1996; Korovchinsky 2013; Kotov et al. 2013a; 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. 2013b; 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 1982c; 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). 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 1982c; Idris 1983). Probably, in the past, Ch. reticulatus was also often mistaken for young individuals of Ch. ventricosus Daday, 1898 (Michael & Hann 1979).