violaceus, Rivulus Costa [W. J. E. M.] 1991:331, Figs. 2 C-D [Revista Brasileira de Biologia v. 51 (no. 2); ref. 20644] Rio das Mortes, lower Rio Araguaia-Rio Tocantins, Mato Grosso, Brazil. Holotype: MNRJ 11672. Paratypes: MNRJ 11672 (5). •Valid as Rivulus violaceus Costa 1991 -- (Costa 1995:219 [ref. 21883]). •Status uncertain -- (Huber 1992:443 [ref. 20639], Lazara 2001:286 [ref. 25711], Costa 2003:41 [ref. 26966], Costa in Reis et al. 2003:540 [ref. 27061], Costa 2003:2 [ref. 27635], Costa 2006:162, 163 [ref. 28875] in subgenus Melanorivulus). •Valid as Melanorivulus violaceus (Costa 1991) -- (Costa 2011:241 [ref. 31655], Costa et al. 2016:270 [ref. 35405]). Current status: Valid as Melanorivulus violaceus (Costa 1991). Rivulidae: Rivulinae. Distribution: Upper das Mortes River drainage, Araguaia River basin, Brazil. Habitat: freshwater.