undulatus, Macrognathus McClelland [J.] 1843:398, Pl. 22 (fig. 1) [Calcutta Journal of Natural History v. 4 (no. 4) (for 1844); ref. 2927] Day River, Red River delta, Hoa Lu district, Ninh Binh Province, Vietnam [Chusan Island, China]. Neotype: ANSP 210057-5080. Neotype designated by Endruweit 2024:109 [ref. 41040]. •Synonym of Mastacembelus armatus (Lacepède 1800) -- (Zheng 1989:371 [ref. 21202], Menon 1999:303 [ref. 24904]). •See Kottelat 2001:63 [ref. 25482]. •Valid as Mastacembelus undulatus (McClelland 1843) -- (Britz 2007:257 [ref. 29343], Kottelat 2013:313 [ref. 32989], Endruweit 2024:109 [ref. 41040]). Current status: Valid as Mastacembelus undulatus (McClelland 1843). Mastacembelidae. Distribution: Southeast Asia: Red River and Pearl River basins, southern China and Vietnam. Habitat: freshwater.