Thinobius kuroshio ( Sawada, 1971 )

Lee, Jae-Seok, Yoo, In-Seong & Ahn, Kee-Jeong, 2021, Taxonomy of the coastal Thinobius Kiesenwetter (Coleoptera: Staphylinidae Oxytelinae) in Korea, Zootaxa 4985 (2), pp. 261-268 : 266-268

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 .

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.

Figures

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.

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.