Provisional checklist of freshwater fish diversity and distribution in Perak, Malaysia, and some latest taxonomic concerns Author Ng, Casey Keat Chuan Author Lim, Teow Yeong Author Ahmad, Amirrudin Author Khaironizam, Md Zain text Zootaxa 2019 2019-03-18 4567 3 515 545 journal article 28342 10.11646/zootaxa.4567.3.5 45397b0e-2315-410d-9640-3e8eb26fd613 1175-5326 2599047 08F8D9C4-EF4F-4D61-90B2-3C7B5E09A2A5 Macrognathus maculatus (Cuvier 1832) Mastacembelus perakensis : Herre & Myers 1937 : 74 (Bukit Merah reservoir). Macrognathus maculatus : Ahmad et al ., 2014: 21 (Sungkai Wildlife Reserve); Ahmad & Zakaria-Ismail, 2014 : 415 (Sg. Ketir; Sg. Tiang); Shafiq et al., 2014 : 826 (Sg. Ara); Authors' data (Jalong; Lata Ulu Chepor). Remarks. Mastacembelus perakensis was first described by Herre & Myers (1937) as they observed their material was different from its closest congener M. maculatus (without vs. with preopercular spine). Subsequently, Sufi (1956) reported that the presence of a preopercular spine may be variable in some Mastacembelids and the spine can be pungent or hidden beneath the skin. Thereon Sufi (1956) treated M. perakensis as a doubtful species but he/ she did not examine the holotype . The holotype was eventually examined and confirmed to possess a preopercular spine by Roberts (1989) and it was synonymized with M. maculatus . We note that Kottelat (2013) lists M. perakensis as a valid species although no reference is provided. We therefore follow Roberts (1989) by treating M. perakensis as a junior synonym of M. maculatus .