Chydorus idrisi Sinev, 2014

42. Chydorus idrisi Sinev, 2014

Localities and specimens found: 50 – 21♀, 10♀ ov, 19j; 51 – 6♀, 2♀ ov, 4j; 60 – 1♀ em.

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.

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.