Acanthurus nigricauda Duncker & Mohr 1929 —Blackstreak surgeonfish (Fig. 145)

Status at New Ireland. Originally described from Massau Island, St. Mathias Group as Acanthurus gahm var. nigricauda by Duncker & Mohr (1929: 75), based on ZMH H.149 (lectotype, selected by Ladiges et al., 1958: 156). Specimens observed at Kavieng fish market in 2004–2005 by Jeff Kinch during CFMDP Survey, and by Barry C. Russell during 7–28 June 2014. A specimen photographed at Lissenung Island at 3 m depth by Dean Tully in Sept. 2015; a specimen observed at Balang Island, New Hanover, 0–18 m depth, St. T21, on 6 Nov. 2006, by Gerald R. Allen.

Distribution and habitat. New Ireland: 1, 2, 4.—General distribution: East and South Africa, Madagascar and Mascarenes east to Tuamotu Islands, north to Ryukyu Islands, south to Queensland (Australia) and New Caledonia. Found in clear lagoon and seaward coral and rocky reefs around isolated coral heads; prefers sandy bottoms of bays and lagoons, 0–30 m depth. Marine.