Cynodonichthys Meek [S. E.] 1904:101 Masc. Cynodonichthys tenuis Meek 1904. Type by original designation (also monotypic). Huber 2012 [ref. 32947] regards some taxa as synonyms of Rivulus based on a reappraisal of Rivulus with a morphological and molecular analysis. •Synonym of Rivulus Poey 1860, but a valid subgenus Cynodonichthys -- (Lazara 2001:269 [ref. 25711], Costa 2006:139 [ref. 28875], Huber 2012:17 [ref. 32947], Vermeulen 2013:42 [ref. 33089]). •Synonym of Rivulus Poey 1860 -- (Parenti 1981:481 [ref. 7066], Costa 1990:85 [ref. 16650], Costa 1991:328 [ref. 20644], Costa 1998:77 [ref. 23792], Costa in Reis et al. 2003:534 [ref. 27061], Gomes 2023:4 [ref. 40174]). •Valid as Cynodonichthys Meek 1904 -- (Costa 2011:241 [ref. 31655], Loureiro et al. 2018:6 [ref. 36240]). Current status: Valid as Cynodonichthys Meek 1904. Rivulidae: Rivulinae.