Taxonomy of the coastal Thinobius Kiesenwetter (Coleoptera: Staphylinidae Oxytelinae) in Korea Author Lee, Jae-Seok 0000-0003-4502-7330 Department of Biology, Chungnam National University, Daejeon 34134, South Korea & ljs 7615 @ naver. com; https: // orcid. org / 0000 - 0003 - 4502 - 7330 ljs7615@naver.com Author Yoo, In-Seong 0000-0002-6720-6025 Division of Restoration Research, Research Center for Endangered Species, National Institute of Ecology, Yeongyang 36531, South Korea & webila @ naver. com; https: // orcid. org / 0000 - 0002 - 6720 - 6025 webila@naver.com Author Ahn, Kee-Jeong Department of Biology, Chungnam National University, Daejeon 34134, South Korea text Zootaxa 2021 2021-06-14 4985 2 261 268 journal article 5859 10.11646/zootaxa.4985.2.9 146beedf-2d3c-4ba4-944a-c6050ffde9cd 1175-5326 4943584 F799B16C-4CAE-49B0-AA18-DB0C77B4264F Genus Thinobius Kiesenwetter, 1844 Thinobius Kiesenwetter, 1844: 355 ; Herman, 1970: 395 ; 2001: 1735 . Yosiityphlus Sawada, 1971: 327 . See Herman (2001) for more synonymies and references. Diagnosis. Maxillary palpomere 4 aciculate; protrochantin exposed; epipleural ridge of elytra absent; longitudinal row of tibial spines absent; tarsal formula 2-2-2; basolateral ridges on tergites II–VII present ( Herman 1970 ). Habitats. They occur on banks of rivers, streams, ponds and other freshwater, but a few are found in intertidal mudflats or fine gravels ( Frank & Ahn 2011 ). FIGURE 1. Habitus of Korean coastal Thinobius . A. Thinobius jejuensis sp. n. , 1.04 mm; C. Thinobius koreanus sp. n. , 1.60 mm; B. Thinobius kuroshio , 1.06 mm. Key to the species of Korean coastal Thinobius 1. Antennomeres 4–6 transverse ( Fig. 2A ); metaventral carinae present ( Fig. 2F ); paramere short, lateral part of aedeagus without serrated pattern ( Fig. 3B )............................................................ Thinobius jejuensis sp. n - Antennomeres 4–6 elongate ( Figs. 4A and 6A ); metaventral carinae absent ( Figs. 4E and 6E ); paramere long, lateral part of aedeagus with serrated pattern ( Figs. 5B and 7B )............................................................ 2 2. Eye present ( Fig. 4B ); hind wings not reduced; anterior part of metaventrite with setae.......... Thinobius koreanus sp. n. - Eye absent ( Fig. 6B ); hind wings extremely reduced; anterior part of metaventrite without setae....... Thinobius kuroshio