Korean species of Hydrosmecta Thomson (Coleoptera: Staphylinidae: Aleocharinae) with descriptions of two new species Author Lee, Seung-Gyu Biodiversity Education Division, National Institute of Biological Resources, Incheon 22689, South Korea. Author Ahn, Kee-Jeong Department of Biology, Chungnam National University, Daejeon 34134, South Korea. & Corresponding author. text Zootaxa 2024 2024-01-12 5399 3 265 274 http://dx.doi.org/10.11646/zootaxa.5399.3.5 journal article 10.11646/zootaxa.5399.3.5 1175-5326 10516844 5BEEF684-5E7D-4C2D-B71B-70A994C8FD79 Hydrosmecta beolgokensis Lee & Ahn , sp. nov. ( Figs. 1A , 2A–H ) Description. Length about 1.7–2.0 mm. Body surface fairly glossy and densely pubescent, with fine microsculpture. Body reddish brown to dark brown; antennae, elytra and legs slightly paler. Head . Quadrate, about as wide as long, widest across eyes, about as wide as pronotum; eye large and distinctly prominent, about 1.3–1.4 times as long as temple; gular sutures moderately separated, more or less diverged basally; infraorbital carina absent; cervical carina absent. Antennomeres 1–3 distinctly elongate, 2 distinctly longer than 3, 4 shortest, 4–10 slightly elongate, 11 longest, slightly shorter than preceding two combined. Mouthparts . Labrum distinctly transverse, slightly emarginate in anterior margin, with ε-sensillum and 6 macrosetae on each side of midline; epipharynx with several sensilla, including 2 lateral sensory rows on each side of midline; α-sensillum setaceous, less than 2.0 times as long as ε-sensillum; β- and γ-sensilla very short. Mandibles asymmetrical, elongate, decurved and pointed apically, approximately 1.8 times as long as basal width, internal margin slightly serrulate; right one with pointed internal tooth; prostheca developed, composited three portions. Galea and lacinia of maxilla long and slender; lacinia composited seven spines in distal comb region, two isolated spines present; last spine of distal comb region and isolated spines close together; maxillary palpus elongate and pubescent; palpomere 1 smallest, 2 about 2.3–2.5 times longer than wide, 3 slightly longer than 2, about 2.5–2.7 times as long as wide, 4 digitiform, filamentous sensilla reaching to basal half. Labium with ligula elongate and parallel-sided, divided into 2 lobes in apical half; prementum with two medial setae moderately separated, 2.0–3.0 times width of setal pore; two basal pores moderately separated, about 2.0–3.0 times width of basal pore; median pseudopores absent, several lateral pseudopores, 1 setal pore and 2 real pores present on each side of midline; labial palpus elongate, with many setulae; palpomere 1 largest, about 1.8 times as long as wide, with γ-setula close to b-seta, 2 shortest, about 1.5 times as long as wide, 3 parallel-sided and about as long as 1, about 4.0 times as long as wide. Mentum trapezoidal, anterior margin slightly emarginate; v-seta very short. Thorax . Pronotum slightly transverse, 1.2–1.3 times as wide as long, widest in apical third, pubescence directed anteriorly in median region; hypomeron fully visible in lateral view. Metanotal scutum with 1 long seta and about 2–3 short setae on each side of midline. Mesoventral process pointed at apex, shorter than isthmus; metaventral process not developed; length ratio of mesoventral process and isthmus 7:11. Elytra slightly longer and wider than pronotum; elytron approximately 1.8 times as long as wide, pubescence directed posteriorly and postero-laterally; postero-lateral margin straight; hind wings fully developed, flabellum composed of about 5–6 long setose lobes. Legs slender and long, with pubescence and macrosetae; middle and hind tibia with different length of 2 spurs at apex; tarsal formula 4-5-5, length ratio of tarsomeres 18:19:21:40 (front tarsus); 21:22:22:21:36 (middle tarsus); 32:28:28:27:42 (hind tarsus); 1 empodial seta present, shorter than claw. Abdomen . Surface glossy, with imbricate microsculpture; macrochaetal arrangement of tergites II–VI 01-12-12-12-12; male tergite VIII ( Fig. 2A ) with 4 macrosetae on each side of midline, posterior margin subtruncate; male sternite VIII ( Fig. 2B ) with 8 macrosetae on each side of midline, posterior margin broadly rounded, with minute crenulation in median region, with long marginal setae; posterior margin of female tergite VIII ( Fig. 2C ) similar to male; female sternite VIII ( Fig. 2D ) with 6 macrosetae on each side of midline, posterior margin similar to male, with long marginal setae, minute setae present in median region. Aedeagus . Median lobe ( Fig. 2E–F ) narrowly ovate, narrowed apically and pointed at apex in ventral view; apical process more or less subtriangular, broader subapically and pointed at apex in lateral view. Apical lobe of paramere ( Fig. 2G ) more or less semicircular, with four setae; b-seta longest, the other setae short, subequal in length. Spermatheca . S-shaped; bursa large and dilated apically, with elongate umbilicus; duct recurved ( Fig. 2H ). Type material. Holotype , labeled as follows: ‘ KOREA : Chungnam Prov. , Nosan-si , Beolgokmyeon , Daedeokri , N36°11'25.2" E127°16'30.8" 161 m , 4 VI 2012 , SG Lee , YG Ban , under stones near stream’ . Paratypes , 5 exx., same data as holotype. FIGURE 1. Habitus. A: Hydrosmecta beolgokensis sp. nov. ; B: H . koreana sp. nov. ; C: H . sogamensis . Distribution. Korea (South). Remarks. This species is very similar to H . sogamensis but can be distinguished by the proportionally shorter elytra compared to the pronotum and the sharper, more triangular apex of the median lobe in lateral view. All specimens were collected under stones near a stream. Etymology. Named after the type locality Beolgok-myeon, where all specimens were collected.