A new cryptic species of the pineapple fish genus Monocentris (Family Monocentridae) from the western Pacific Ocean, with redescription of M. japonica (Houttuyn, 1782) Author Su, Yo Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan Author Lin, Hsiu-Chin Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung, Taiwan & Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung, Taiwan Author Ho, Hsuan-Ching National Museum of Marine Biology & Aquarium, Pingtung, Taiwan & Institute of Marine Biology, National Dong Hwa University, Hualien, Taiwan & Australian Museum, Sydney, Australia & Department and Graduate Institution of Aquaculture, National Kaohsiung University of Science and Technology, Kaohsiung, Taiwan * Corresponding author: ogcoho @ gmail. com text Zootaxa 2022 2022-09-23 5189 1 180 203 journal article 153861 10.11646/zootaxa.5189.1.18 b98985de-9682-4522-b07e-9f89ad1af9b2 1175-5326 7119443 E9169964-DF96-45B5-913A-338DEA6B69F2 Monocentris Bloch & Schneider, 1801 Monocentris Bloch & Schneider, 1801:100 ( Type species: Monocentris carinata Bloch & Schneider 1801 ). Lepisacanthus Lacepède, 1801:320 ( Type species: Lepisacanthus japonicus Lacepède 1801 ). Ericius Tilesius, 1809:243 ( Type species: Monocentris carinata Bloch & Schneider 1801 ). Two genera are recognized in the family Monocentridae . Monocentris differs from Cleidopus De Vis, 1882 , in having a broad (deep) suborbital space (> 8.2 % SL); a large mouth with upper jaw straight; relatively long snout, subequal to eye diameter; a black light organ at tip of lower jaw; toothless vomer; and relatively smaller maximum size (usually less than 15 cm SL), whereas Cleidopus has a very narrow suborbital space with lower margin of eye almost adjacent the upper jaw (2.9–3.2 % SL); small with S-shaped upper jaw; snout clearly shorter than eye diameter; an orange light organ on each side of lower jaw under eye; vomer with teeth; and a relatively larger maximum size (up to 26 cm ). According to Paxton (1999) , the lateral line is absent in monocentrids, however, our specimens possess a small canal through each scale in a row where a lateral line is commonly found in beryciform fishes (LLS in Fig. 1 ). Thus, we recognized this row of scales as lateral-line scales. Previously, the genus has comprised two species: M. japonica in the Indo-West Pacific and M. reedi in the southeastern Pacific. A third species similar to M. japonica is described below.