Chydorus angustirostris Frey 1987

41. Chydorus angustirostris Frey, 1987 Localities and specimens found: 50 – 1♀, 1♀ ov, 1j; 51 – 2♀. 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).