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 Thinobius kuroshio ( Sawada, 1971 ) ( Figs. 1C , 6–7 ) Yosiityphlus kuroshio Sawada, 1971: 327 . Thinobius kuroshio : Gusarov & Makranczy, 2004: 3 ; Frank & Ahn, 2011: 32 . Redescription. Length 1.02–1.32 mm . Body flattened, surface pubescent; light brown. Head . Slightly elongate and slightly narrower than pronotum; widest at about half of head; arrow shaped; clypeus slightly trapezoidal, anterolateral margin rounded; eye absent; temple well developed, gular suture fused and broadly divergent at anterior and posterior part; neck well developed, seta absent and reticulate sculptures distinct ( Figs. 6B–C ); antenna slender, moderately elongate and pubescent, antennomere 1 longest, 1–2 and 9–11 elongate, 3–8 slightly elongate ( Fig. 6A ). Mouthparts . Labrum transverse, lateral margin rounded, anterior margin slightly emarginate; epipharynx slightly developed; mandible triangle, apex bifid, with one blunt subapical tooth, prostheca and molar tooth well developed; maxillary palpus with four palpomeres, palpomere 1 transverse and small, 2 slightly dilated to apex; 3 largest, 2–3 with many setae; apical margin of 3 more than 2.0 times as wide as basal part of palpomere 4; labial palpus with three elongate palpomeres, palpomere 1 with one long and one short setae and two pores, 2 with one long seta and one pore, 3 with few short sensilla at apex; antero-middle part of hypopharynx with two blunted macro spines; mentum subquadrate with one pairs of long macrosetae and many setae. Thorax . Pronotum transverse, width 0.19–0.23 mm , surface pubescent with seven pairs of long macro setae; apex of prosternal process sharp and elevated; prosternum with one pair of long setae and few setae ( Fig. 6D ); scutellum an inverted triangle, middle of anterior margin emarginate, posterior part weakly reticulate with few setae and diamond shaped impression, impression about 1.7 times as wide as long; elytra elongate and pubescent, posterior margin with membranous lobe; hind wing extremely reduced; mesoventrite with one pair of long setae; mesoventral process slightly extended and pointed at apex; metaventral carina absent; metaventrite reticulate, anterior part without setae ( Fig. 6E ); all tibiae with one long macroseta in middle. Abdomen . Posterior margin of tergite VII with fringe of setae; posterior margin of sternite VIII convex. Secondary sexual characteristics . Male tergite IX with ventral struts, struts shorter than remainder, female tergite IX without ventral strut; male sternite IX present and female genital appendages present; female with one ring structure ( Fig. 6F ). Genitalia . Aedeagus oval ( Fig. 7A ) with serrated pattern in lateral aspect ( Fig. 7B ); paramere long and slender; spermatheca as in Fig. 7C . FIGURE 6. Thinobius kuroshio . A: antenna; B: head, dorsal aspect; C: head, ventral aspect; D: prosternum, ventral aspect; E: meso- and metaventrite, ventral aspect; F: ring structure with female genital appendage. Scales = 0.1 mm. Circles in B, C, and E show magnification of sculptures. FIGURE 7. Thinobius kuroshio . A: aedeagus, ventral aspect; B: aedeagus, lateral aspect; C: spermatheca. Scales = 0.1 mm. Materials examined. KOREA : Gyeongbuk Prov. : 3 exx., Gyeongju-si, Gampo-eup, Najeong-beach, N35°46'56" E129°29'27" , 21 VI 2018 , KJ Ahn , pebble beach in mid-tide, flotation; 16 exx., same data as former except for ‘ Najeong-ri , Najeong-beach , N35°46′56.79″ E129°29′30.95″ 0 m, 13 VII 2018 , IS Yoo , JS Lee , JG Jung , 10–80 cm deep under gravels in mid-high tide, flotation’; 6 exx., Jeju Prov. : Seogwipo-si , Daejeong-eup , Sangmori , N33°11′55.6″ E126°16′30.7″ 2 m , 20 IX 2018 , IS Yoo , JS Lee , WJ Jeong , 30–50 cm deep under fine gravels on gravel beach, flotation; 3 exx., same data as former except for ‘ N33°12'22.21" E126°17'25.76" , 21 IX 2018 , IS Yoo , JS Lee , WJ Jeong , in gravels covered with seaweed, flotation’ Distribution. Korea , Japan .