riograndensis, Rivulus Costa [W. J. E. M.] & Lanés [L. E. K.] 2009:92, Fig. 1 [Ichthyological Exploration of Freshwaters v. 20 (no. 1); ref. 30256] Pai João swamp, Parque Nacional da Lagoa do Peixe, 31°03'24"S, 50°49'40"W, Estado do Rio Grande do Sul, Brazil. Holotype: UFRJ 6639. Paratypes: MCP 14977 (1), 22485 (2); UFRGS 5809 (9 + 3 c&s), 6674 (2); UFRJ 6640 (4), Plus non-type mmaerial. •Valid as Atlantirivulus riograndensis (Costa & Lanés 2009) -- (Costa 2011:244 [ref. 31655], Costa 2014:19 [ref. 33307], Bertaco et al. 2016:423 [ref. 34561], Loureiro et al. 2018:11 [ref. 36240]). Current status: Valid as Atlantirivulus riograndensis (Costa & Lanés 2009). Rivulidae: Rivulinae. Distribution: Patos lagoon basin and adjacent coastal plains, Rio Grande do Sul state, southern Brazil. Habitat: freshwater.