egens, Rivulus Costa [W. J. E. M.] 2005:80, Fig. 11 [Neotropical Ichthyology v. 3 (no. 1); ref. 28192] Município de Camapuã, road BR-060, rio São Domingos, upper rio Verde drainage, rio Paraná basin, 19°19'26.0"S, 53°21'6.8"W, Estsdo de Mato Grosso do Sul, Brazil, elevation 532 meters. Holotype: UFRJ 5973. Paratypes: MCP 36126 (3); UFRJ 5974 (114), 5975 (3, c&s). Plus non-type material. •Valid as Rivulus egens Costa 2005 -- (Costa 2006:162 [ref. 28875] in subgenus Melanorivulus). •Valid as Melanorivulus egens (Costa 2005) -- (Costa 2011:241 [ref. 31655], Nielsen et al. 2016:87 [ref. 34407], Costa et al. 2016:270 [ref. 35405], Volcan et al. 2017:92 [ref. 35156], Volcan et al. 2018:275 [ref. 35895], Volcan et al. 2024:1499 [ref. 41484]). Current status: Valid as Melanorivulus egens (Costa 2005). Rivulidae: Rivulinae. Distribution: South America: Rio Verde drainage, Paraná River basin, Brazil. Habitat: freshwater.