Karualona arcana Tiang-Nga, Sinev & Sanoamuang 2021

25. * Karualona arcana Tiang-nga, Sinev et Sanoamuang, 2021 Localities and specimens found: 32 – 1♀. 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).