Stenichnus (s. str.) rhinocerosus, Song & Byeon & Park, 2024

Song, Min-Ho, Byeon, Ui-Joung & Park, Jong-Seok, 2024, A Taxonomic Study of the Genus Stenichnus Thomson (Coleoptera: Staphylinidae: Scydmaeninae) in Korea with Descriptions of Three New Species, The Coleopterists Bulletin 78 (2), pp. 141-149 : 143-145

Stenichnus (s. str.) rhinocerosus Song, Byeon, and Park, new species zoobank.org/ urn:lsid:zoobank.org:act:15139FB3-6E5B-4427-AE5E-160C34962097 ( Figs. 2A, D , 3A, D , 4A–C , 5 )

Type Material (n = 18, 9♂♂ 9♀♀). Holotype. 1♂ (genitalia dissected, card mounted, CBNUIC), “ Korea: Gangwon Prov. Jangyeol-ri, Bukpyeong-myeon, Jeongseon-gun, 24IV2020, 37°28′34.6″N 128°42′16.8″E, 415 m, Sifting, Soil & Leaf litter J.-Y. Kang, J.-W. Kim ” . Paratypes. Jeonbuk Prov. : 2♂♂ 1♀ (1♂ genitalia dissected, CBNUIC), Sohyang-ri 84, Gosan-myeon, Wanju-gun, 19 iii 2021, 36°00′36.5′′N 127°17′34.3′′E, 180 m, sifting leaf litter, soil, and moss, J.-W. Kang, J.-I. Shin; Chungbuk Prov. : 1♂ (slide mounted, CBNUIC), Songgye-ri, Hansu-myeon, Jecheon-si, 10 ix 2020, 36°52′52.9′′N 128°05′04.5′′E, 256 m, sifting leaf litter and soil, M.-H. Song, J.-W. Kim ; 1♀ (slide mounted, CBNUIC), Songgye-ri, Hansu-myeon, Jecheon-si, 09 vi 2021, 36°52′53.3′′N 128°05′13.8′′E, 292 m, sifting leaf litter and soil, M.-H. Song, J.-I. Shin ; 1♂ (genitalia dissected, card mounted, CBNUIC), Songgye-ri, Hansu-myeon, Jecheon-si, 10 ix 2020, 36°53′00.4′′N 128°05′39.1′′E, 459 m, sifting leaf litter and soil, Y.-J. Choi, U.-J. Byeon; Gangwon Prov. : 2♂♂ 3♀♀ (1♂ 1♀ card mounted, CBNUIC), 104-2, Jikjeon-ri, Sabuk-eup, Jeongseon-gun, 16 xii 2019, 37°16′15.3′′N 128°49′56.7′′E, 620 m, sifting leaf litter and soil near stream, J.-S. Park, J.-Y. Kang, J.-W. Kang, Y.-J. Choi, M.-S. Jang, U.-J. Byeon, T.-Y. Jang, J.-W. Kim ; 1♂ (genitalia dissected, CBNUIC), Odaecheon-ro, Bukpyeong-myeon, Jeongseon-gun, 21 viii 2020, 37°28′02.7′′N 128°36′57.5′′E, 400 m, sifting leaf litter, soil, and fungi, S.-H. Choi ; 2♀♀ ( CBNUIC), Odaecheon-ro, Bukpyeong-myeon, Jeongseon-gun, 21 viii 2020, 37°28′02.7′′N 128°36′57.5′′E, 400 m, sifting leaf litter and soil, J.-W. Kim ; 1♂ (genitalia dissected, CBNUIC), Mt. 84, Sukam-ri, Bukpyeon-myeon, Jeongseon-gun, 27 x 2019, 37°31′39.0′′N 128°35′ 18.0′′E, 607 m, sifting leaf litter and soil near stream, M.-S. Jang, J.-Y. Kang, U.-J. Byeon ; 1♀ ( CBNUIC), Jungdong-gil, Yeoyang-myeon, Jeongseon-gun, 19 viii 2020, 37°31′11.0′′N 128°44′45.2′′E, 473 m, sifting leaf litter and soil near stream, J.-I. Shin ; 1♀ ( CBNUIC), 210, Gujeol-ri, Yeoyang-myeon, Jeongseon-gun, 24 iv 2020, 37°31′07.1′′N 128° 44′52.9′′E, 514 m, sifting leaf litter and soil near stream, J.-Y. Kang, J.-W. Kim .

Diagnosis. External characters of this species are very similar to those of Stenichnus zhejiangensis Wang and Li and Stenichnus minipollens Jałoszyński , but it can be distinguished from S. zhejiangensis by the smaller body (body length of S. zhejiangensis : 1.67–1.84 mm), median lobe not concave in the middle (for aedeagus of S. zhejiangensis see Wang and Li 2016: figs. 3A, B) and from S. minipollens by having the distal part of the profemur serrated ( S. minipollens distal part of profemur not serrated), median lobe not concave in anterior third, and two darkly elongate and separate structures of the endophallus (for aedeagus of S. minipollens see Jałoszyński 2004: figs. 6D–F).

Description. Male. BL 1.52–1.56 mm (5 specimens measured), slightly stout, reddish-brown with yellowish setae; legs and maxillary palpi light brown ( Fig. 2A ).

Head wider than long, HL 0.24–0.25 mm, HW 0.32–0.33 mm; clypeus broadly expanded; frons strongly convex between eyes; vertex weakly convex; eyes large and strongly protruding; tempora slightly shorter than eyes, moderately convergent posteriad; punctures on vertex and frons fine and sparse; setae sparse, long, and suberect; antenna slender, AnL 0.71 mm, antennomeres 1–2 approximately 1.7 times longer than wide, 3–5 longer than wide, 6 about as long as wide, 7–10 wider than long, 11 about 2.5 times as long as 10 and subconical.

Pronotum as long as wide, broadest near anterior third, PL 0.38–0.39 mm, PW 0.39–0.41 mm, anterior margin slightly rounded, narrowest near posterior third, base with irregularly transverse row of numerous small pits and sparse, long setae, and with fine punctures.

Elytra oval, widest near anterior third, EL 0.89– 0.91 mm, EW 0.68–0.72 mm, EI 1.26–1.30, with indistinct humeral calli, each elytron with one distinct and one indistinct fovea, punctures on elytra distinct, with various diameters, anterior half with denser punctation than posterior one, setae long and dense, suberect to erect; hind wings present, as long as elytra.

Legs moderately long and slender; profemur with strongly expanded subapical dorsal margin, dorsal apex of clavate part serrate ( Fig. 3A ).

Aedeagus dark and stout, AeL 0.32 mm, apex of dorsal wall rounded; median lobe with T-shaped meso-dorsal projection, ventral projection well developed with rounded apex; endophallus with denticulate surface, showing two darkly elongate structures; parameres not reaching apex of median lobe, each paramere with three apical setae ( Figs. 4A–C ).

Female. BL 1.47–1.59 mm (5 specimens measured), HL 0.23 mm, HW 0.31 mm, AnL 0.68 mm, PL 0.37 mm, PW 0.41 mm, EL 0.88 mm, EW 0.67 mm, EI 1.31. Body slightly smaller than in male ( Fig. 2D ); profemur slightly less clavate than in male ( Fig. 3D ); hind wing present .

Etymology. The specific epithet “ rhinocerosus ” is a Latin adjective meaning “of a rhinoceros”. This species is named after shape of the aedeagus, which resembles a rhinoceros.

Distribution. South Korea ( Fig. 5 ).

Habitat. Specimens of S. rhinocerosus were collected by sifting leaf litter and soil in a mixed forest.

Figures

Fig. 2. Habitus of Stenichnus spp. A–C) Male, D–F) Female. A, D) S. rhinocerosus, new species, B, E) S. bukpyeongensis, new species, C, F) S. satus, new species.

Fig. 3. Profemora of Stenichnus spp. A–C) Male, D–G) Female. A, D) S. rhinocerosus, new species, B, E) S. bukpyeongensis, new species, C, F) S. satus, new species.

Fig. 4. Aedeagi of Stenichnus spp. A, D, G) Dorsal, B, E, H) Ventral, C, F, I) Lateral. A–C) S. rhinocerosus, new species, D–F) S. bukpyeongensis, new species, G–I) S. satus, new species.

Fig. 5. Collection localities for Stenichnus in South Korea.