tristis, Acanthurus Randall [J. E.] 1993:4, Figs. 1-3 [The J.L.B Smith Institute of Ichthyology Special Publication No. 54; ref. 21092] Lively Rocks, Trincomalee, east coast of Sri Lanka, depth 10-12 meters. Holotype: BPBM 18802. Paratypes or non-types: BPBM 35043 (1), 34752 (1); ROM 39948 (1), 40376 (1); SMF 17869 (1). Tickell names published in synonymy by Day 1888:788 [ref. 1082] were not made available before 1961 (see Eschmeyer 1990:647 [ref. 20647]) (contra Myers 1951:26 [ref. 13464]) and therefore cannot date to Tickell in Day 1888. In the case of Acanthurus tristis Tickell, Day is unclear if he treats it as valid, but he calls it a "form" which is infrasubspecific. Therefore, the species dates to Randall's use of tristis as above. We regard Randall's "neotype" to be the holotype of the species [Art. 71.1 of the Code]; his additional specimens can be regarded as either paratypes or non-types. •Synonym of Acanthurus pyroferus Kittlitz 1834 -- (Randall 1956:197 [ref. 12221]). •Valid as Acanthurus tristis Randall 1993 -- (Myers 1999:271 [ref. 23965] as trisits, Kuiter & Debelius 2001:34 [ref. 26232] with author and date as Tickell 1888, Randall 2001:3665 [ref. 26301], Randall et al. 2001:115 [ref. 25316], Allen & Adrim 2003:63 [ref. 26830], Hobbs et al. 2008:10 [ref. 39350], Allen & Erdmann 2012:1026 [ref. 31980], Psomadakis et al. 2020:560 [ref. 37272], Randall 2022:230 [ref. 40150]). Current status: Valid as Acanthurus tristis Randall 1993. Acanthuridae. Distribution: Indian Ocean: Maldives, Sri Lanka, Myanmar, Andaman Sea, Christmas Island (Australia), western Sumatra, Java and Bali (Indonesia). Habitat: marine.