Millerichthys Costa [W. J. E. M.] 1995:18 Masc. Rivulus robustus Miller & Hubbs 1974. Type by original designation (also monotypic). Preoccupied by Millerichthys Miller 1892 in fossil fishes (Miller 1892:716 [ref. 41076]) that was proposed as a replacement name for Pterichthys Agassiz 1841 (Agassiz in Miller 1841:46, Pl. 1 [ref. 41078]), also appearing as nomen nudum in Agassiz 1841 (Agassiz [ex Miller] in Murchison 1841: Transactions p. 99, footnote [ref. 41077]), preoccupied by Pterichthys Swainson 1839 in Recent fishes. Millerichthys Miller 1892 has not been used as valid since 1899, while Millerichthys Costa 1995 was used as valid more than 25 times (R. Fricke, pers. comm., May 2024), so according to ICZN Art. 23.9 reversal or precedence is applied; Millerichthys Costa 1995 is here treated as nomen protectum, and Millerichthys Miller 1892 as nomen oblitum. •Valid as Millerichthys Costa 1995 -- (Costa 1998:79 [ref. 23792], Huber 1999:40 [ref. 23834], Lazara 2001:209 [ref. 25711], Costa in Reis et al. 2003:531 [ref. 27061], Costa 2004:2 [ref. 27874], Huber 2005:15 [ref. 28394], Scharpf 2007:11 [ref. 30398], Loureiro et al. 2018:6 [ref. 36240]). Nomen Protectum. Current status: Valid as Millerichthys Costa 1995. Rivulidae: Rivulinae.