gahm, Chaetodon Gmelin [J. F.] 1789:1268 [Caroli a Linné ... Systema Naturae per regna tria naturae v. 1 (pt 3); ref. 18139] No locality stated (Red Sea). No types known. Authorship according to Fricke 2008:55 [ref. 30182]. Based on unnamed variation (Arabic name Gahhm) of Chaetodon nigrofuscus Forsskål in Niebuhr, 1775 of Forsskål in Niebuhr, 1775:64, xiii [ref. 1351] (see Fricke 2008:55 [ref. 30182]); made available as Chaetodon gahm by Gmelin 1789:1268 [ref. 18139]. Spelled gahm by many early authors; spelling gahhm is here retained due to prevailing usage. •Synonym of Acanthurus nigricans (Linnaeus 1758) -- (Dor 1984:254 [ref. 29757]). •Valid as Acanthurus gahhm (Forsskål 1775) -- (Randall 1956:207 [ref. 12221], Kishimoto in Masuda et al. 1984:232 [ref. 6441], Randall 1988:56 [ref. 14257], Goren & Dor 1994:68 [ref. 25356], Myers 1999:270 [ref. 23965], Kuiter & Debelius 2001:45 [ref. 26232], Manilo & Bogorodsky 2003:S120 [ref. 27377], Randall 2005:579 [ref. 28239], DiBattista et al. 2015:22 [ref. 35706], Carpenter et al. 2017:41 [ref. 35143], Bogorodsky & Randall 2018:[17] 255 [ref. 36492], Golani & Fricke 2018:166 [ref. 36273], Zajonz et al. 2019:98 [ref. 36871]). •Valid as Acanthurus gahhm (Gmelin 1789) -- (Fricke 2008:55 [ref. 30182], Randall 2022:223 [ref. 40150]). Current status: Valid as Acanthurus gahhm (Gmelin 1789). Acanthuridae. Distribution: Red Sea; northwestern Indian Ocean: Gulf of Aden, Socotra (Yemen). Habitat: marine.