Thinobius jejuensis Lee & Ahn, 2021

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 : 263-264

Thinobius jejuensis Lee & Ahn sp. n.

( Figs. 1A , 2–3 )

Description. Length 1.04–1.30 mm. Body flattened, surface pubescent; dark brown. Head. Almost as long as wide and slightly narrower than pronotum; widest across eyes; clypeus trapezoidal; eye moderate in size and rounded in lateral aspect, with large eye facets and interfacetal setae; temple well developed, about 0.8 times as long as eye length in dorsal view; gular suture fused and broadly divergent in anterior and posterior part; neck well developed, distinctly transversely reticulate sculptures with some short setae ( Figs. 2B–C ); antenna slender, moderately elongate, and pubescent, antennomere 1 longest, 4 and 6 shortest, 1–2 and 7–11 elongate, 3 and 5 slightly elongate, 4 and 6 transverse ( Fig. 2A ). Mouthparts. Labrum transverse, semicircula; 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 dense setae; apical margin of 3 about 3.0 times as wide as basal margin of 4; labial palpus with three elongate palpus, apex of palpomere 1 with two long setae and one pore, apex of 2 with one pore, 3 with few short sensilla at apex; mentum quadrate with one pair of long macrosetae and many setae. Thorax. Pronotum transverse, width 0.24–0.27 mm, widest about anterior third, surface pubescent; prosternum with few setae ( Fig. 2D ); scutellum an inverted triangle, anterior margin of scutellum emarginate, posterior part reticulate with many setae ( Fig. 2E ); elytron elongate and pubescent, posterior margin with membranous lobe; hind wing present; mesoventral process slightly extended and blunted at apex; metaventral carinae incomplete; metaventrite with two pairs of long macrosetae and dense setae ( Fig. 2F ); all tibiae with one long macroseta in middle. Abdomen. Posterior margin of tergite VII with fringe of setae; postero-lateral margin of tergite VIII slightly convex. Secondary sexual characteristics. Male sternite VIII emarginate, female with linear form; male tergite IX with ventral structs, struts as long as remainder, female tergite IX without ventral struts. Male sternite IX elongate, female sternite IX pentagon. Genitalia. Aedeagus oval ( Figs. 3A–B ); paramere short; spermatheca as in Fig. 3C .

Type material. Holotype, 1 ♂, labeled as follows: KOREA: Jeju Prov., Seogwipo-si, Haye-dong , N33°13'54.45" E126°22'19.81" 2 m, 19 X 2014, KJ Ahn, IS Yoo, JS Lee, 10-20 cm deep under/in gravels on seashore. ‘ Holotype, Thinobius jejuensis Lee and Ahn, Desig. Jae-Seok Lee and Kee-Jeong Ahn 2021 ’ ‘ Deposited in the Chungnam National University Insect Collection, Korea’ . Paratypes, 3 exx., labeled as same as Holotype (1 on slide; 1 on CNUIC voucher); 30 exx., same data as former except for ‘ N33°13'54.20" E126°22'18.49" 2 m, 05 VIII 2020, JS Lee, JY Park, YJ Kim, flotation’. 24 exx., same data as former except for ‘Yeraehaean-Ro, N33.232254, E126.371442, 19 X 2020, KJ Ahn, Under pebbles/gravels by flotation’ .

Distribution. Korea (Jeju island).

Remarks. This species is similar to T. marinus , but can distinguished by the length of temple and the shape of antennomeres. Temple is shorter than the diameter of eye in T. jejuensis Lee & Ahn , sp. n. ( Fig. 2B ), but longer than the diameter of eye in T. marinus ( Cameron, 1917) . In addition, antennomeres 5 and 7–8 are elongate in the new species ( Fig. 2A ), but 4–8 are transverse in T. marinus . All specimens were collected on Jeju-do island, Korea

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 2. Thinobius jejuensis sp. n. A: antenna; B: head, dorsal aspect; C: head, ventral aspect; D: prosternum, ventral aspect; E: scutellum, dorsal aspect; F: meso- and metaventrite, ventral aspect. Scales = 0.1 mm. Circle in B shows magnification of sculptures.

FIGURE 3. Thinobius jejuensis sp. n. A: aedeagus, ventral aspect; B: aedeagus, lateral aspect; C: spermatheca with sternite IX, dorsal aspect. Scales = 0.1 mm.