Stenichnus (s. str.) satus, 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 : 147-149

Stenichnus (s. str.) satus Song, Byeon, and Park, new species zoobank.org/ urn:lsid:zoobank.org:act:D3F3BD30-4A50-4792-8417-1288F19C001C ( Figs. 2C, F , 3C, F , 4G–I , 5 )

Type Material (n = 22, 11♂♂ 11♀♀). Holotype.

1♂ (genitalia dissected, card mounted, CBNUIC),

“ Korea: Gangwon Prov. Sangan-ri, Anheung-myeon, Hoengseong-gun , 28.IV.2022, 37°23’49.2”N 128°14’31.4”E, 978 m, sifting soil & leaf litter, J.-I. Shin, M.-H. Song ”. Paratypes . Chungbuk Prov.: 1♂ (genitalia dissected and mounted in Euparal on plastic card, CBNUIC), Yangbangsan-gil, Danyangeup , Danyang-gun , 21 iv 2020, 36°58′14.2′′N 128°22′57.6′′E, 585 m, sifting soil and leaf litter, Y.-J. Choi, U.-J. Byeon; 1♀ (point mounted, CBNUIC), Yangbangsan-gil, Danyang-gun, 21 v 2021, 36°58′14.2′′N 128°22′57.6′′E, 585 m, sifting soil and leaf litter, T.- Y. Jang; 1♂ ( CBNUIC), Dangdong-ri, Daegang-myeon, Danyang-gun, 19 iii 2021, 36°55′39.0′′N 128°22′30.0′′E, 360 m, sifting soil and leaf litter, J.-W. Seo, Y.-J. Choi; 1♂ (slide mounted, CBNUIC), Jagwangsa, Mt. Worak , 1560- 35, Mireuksonggye-ro, Hansu-myeon, Jecheon-si, 9 vi 2021, 36°52′53.3′′N 128°05′13.8′′E, 292 m, sifting soil and leaf litter, J.-I. Shin, M.-H. Song; 1♀ ( CBNUIC), Songgye-ri, Hansu-myeon, Jecheon-si, 10 ix 2020, 36°53′00.4′′N 128°05′39.1′′E, 459 m, sifting soil and leaf litter, Y.-J. Choi, U.-J. Byeon ; Gangwon Prov.: 3♂♂ (1♂ genitalia dissected, card mounted, CBNUIC), Anheung-ri, Anheung-myeon, Hoengseong-gun , 22 iv 2022, 37°24′07.9′′N 128°10′05.7′′E, 549 m, sifting soil and leaf litter, J.-I. Shin, J.-W. Kang, J.-W. Seo; 1♂ 3♀♀ (1♂ genitalia dissected, card mounted; 1♀ card mounted, CBNUIC), Sangan-ri, Anheung-myeon, Hoengseong-gun, 18 iv 2022, 37°24′09.8′′N 128°13′19.4′′E, 711 m, sifting soil and leaf litter, J.-I. Shin, M.-H. Song, Y.-J. Choi; 1♂ 1♀ (1♂ genitalia dissected, card mounted, CBNUIC), Sangan-ri, Anheung-myeon, Hoengseong-gun, 28 iv 2022, 37°23′33.6′′N 128°13′58.0′′E, 928 m, sifting soil and leaf litter, J.-I. Shin, M.-H. Song; 1♂ 1♀ (1♂ genitalia dissected, CBNUIC), Sangan-ri, Anheung-myeon, Hoengseong-gun, 15 iv 2022, 37°24′56.6′′N 128°13′52.7′′E, 633 m, sifting soil and leaf litter, J.-I. Shin, J.-W. Kang, M.-H. Song, U.-J. Byeon; 1♀ ( CBNUIC), Sangan-ri,Anheung-myeon, Hoengseong-gun, 28 iv 2022, 37°23′45.4′′N 128°13′37.8′′E, 813 m, sifting soil and leaf litter, J.-I. Shin, M.-H. Song; 1♀ ( CBNUIC), 429, Anheung-ri, Anheung-myeon, Hoengseong-gun, 19 iv 2022, 37°23′10.4′′N 128°10′11.6′′E, 552 m, sifting soil and leaf litter, J.-I. Shin, M.-H. Song, Y.-J. Choi; 1♀ ( CBNUIC), Sangan-ri, Anheung-myeon, Hoengseong-gun, 25 iv 2022, 37°23′40.4′′N 128°11′48.6′′E, 632 m, sifting soil and leaf litter, J.-I. Shin, U.-J. Byeon, M.-H. Song; 1♂ (slide mounted, CBNUIC), Saphyo-ri, Dunnae-myeon, Hongseong-gun, 18 ii 2020, 37°32′13.9′′N 128°17′37.3′′E, 840 m, bring, iced soil and leaf litter, J.-S. Park, U.-J. Byeon, J.-W. Kim; 1♀ (slide mounted, CBNUIC), Saphyo-ri, Dunnae-myeon, Hongseong-gun, 18 ii 2020, 37°32′13.9′′N 128°17′37.3′′E, 840 m, bring, iced soil and leaf litter, J.-S. Park, M.-S. Jang .

Diagnosis. External characters of this species are very similar to those of S. bukpyeongensis , but it can be distinguished by the larger eyes in males (eye size in S. bukpyeongensis : 0.076 mm), base of pronotum with unevenly distributed pits ( S. bukpyeongensis with four), aedeagus twice as long as wide ( S. bukpyeongensis 1.6 times as long as wide), and median lobe in lateral view widest at base and sharply pointed apically ( S. bukpyeongensis rounded, Fig. 4I ).

Description. Male. BL 1.35–1.38 mm (5 specimens measured), strongly elongate and slender, reddish-brown with yellowish setae, legs and maxillary palpi light brown ( Fig. 2C ).

Head slightly wider than long, HL 0.20–0.22 mm, HW 0.26–0.28 mm; clypeus broadly expanded; frons between eyes strongly convex; vertex weakly convex; eyes large and strongly protruding, diameter 0.095 mm; tempora shorter than eye, strongly convergent posteriad; punctures on vertex and frons fine and sparse; setae sparse, long, suberect; antenna slender, AnL 0.63–0.66 mm, antennomeres 1–2 approximately 1.7 times longer than wide, 3–6 longer than wide, 7 about as long as wide, 8–10 wider than long, 11 about twice as long as 10 and subconical.

Pronotum as long as wide, widest near anterior third, PL 0.37–0.38 mm, PW 0.34–0.37 mm, anterior margin slightly rounded, narrowest near posterior third, base with ten pits unevenly distributed, setae sparse, long, punctures fine.

Elytra oval, widest near middle, EL 0.86–0.89 mm, EW 0.52–0.54 mm, EI 1.64, humeral calli reduced; each elytron with one distinct and one indistinct fovea; punctures distinct, punctation of anterior half denser than posterior one, with long, suberect, moderately dense setae; hind wing absent.

Legs moderately long and slender; dorsal clavate margin of profemur moderately expanded and weakly convex ( Fig. 3C ).

Aedeagus elongate, teardrop-shaped, AeL 0.34 mm; median lobe bearing meso-ventral projection surrounded by triangular structure; endophallus with weakly sclerotized and denticulate structure; parameres slender, not reaching apex of median lobe, each paramere with three apical setae ( Figs. 4G–I ).

Female. BL 1.29–1.31 mm (5 specimens measured), HL 0.21 mm, HW 0.26 mm, AnL 0.59 mm, PL 0.38 mm, PW 0.34 mm, EL 0.75 mm, EW 0.54 mm, EI 1.39. Body slightly smaller than in male; eyes about 0.015 mm smaller than in males; elytra distinctly shorter than in male ( Fig. 2F ); hind wing absent.

Etymology. The specific epithet “ satus ” is a Latin noun meaning “seed”. This species is named after the shape of the aedeagus, which resembles a seed.

Distribution. South Korea ( Fig. 5 ).

Habitat. Specimens of S. satus 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.