thacbaensis, Mastacembelus Nguyen [H. D.], Nguyen [V. H.] & Ngo [S. V.] in Nguyen 2006:633, Fig. 4 [Freshwater fishes of Vietnam v. 3; ref. 29809] Thac Ba Lake, Yen Binh district, Yen Bai Province, Vietnam, about 21°52'N, 104°56'E. Holotype: lost. Original types: RIA1 (lost) [ex NCNTTS I Inst., Bac Ninh.], (5, lost). In text with two authors. Neotype ZMB 35101 designated by Endruweit 2024:109 [ref. 41040] from Lower Lo River, Yen Bai Province, Vietnam, invalid see Britz & Kottelat 2025:671 [ref. 42629]. •Questionably a synonym of Mastacembelus undulatus (McClelland 1843) -- (Kottelat 2013:313 [ref. 32989]). •Synonym of Mastacembelus undulatus (McClelland 1843) -- (Endruweit 2024:109 [ref. 41040]). •Valid as Mastacembelus thacbaensis Nguyen, Nguyen & Ngo 2006 -- (Vu et al. 2019:150 [ref. 37811], Britz & Kottelat 2025:671 [ref. 42629]). Current status: Valid as Mastacembelus thacbaensis Nguyen, Nguyen & Ngo 2006. Mastacembelidae. Distribution: Southeast Asia: Vietnam, southern China and northeastern Laos. Habitat: freshwater.