Rhyncocheilus yangxiaodongi Tang, Schillhammer & Zhao, 2021

Tang, Liang, Schillhammer, Harald & Zhao, Xin, 2021, Notes on the genus Rhyncocheilus in China (Coleoptera, Staphylinidae Staphylininae) with descriptions of three new species, Zootaxa 4948 (1), pp. 99-112 : 108-111

Rhyncocheilus yangxiaodongi Tang, Schillhammer & Zhao sp. n.

( Figs 11, 12 , 28, 29 , 54–57)

Type material. Holotype. China: Yunnan: ³, glued on a card with labels as follows: “ China: Yunnan Prov. , Dian-

tan, Dadongshan, alt. 2147 m, light traps, 10.VII.2016, Yang Xiao-Dong leg.” “ Holotype / Rhyncocheilus yangxiaodongi / Tang, Schillhammer & Zhao” [red handwritten label] ( SHNU) .

Description. Measurements of male: BL: 23.0 mm, FL: 12.8 mm. HL: 3.28 mm, HW: 3.28 mm, EYL: 1.28 mm, TL: 1.39 mm, PL: 2.89 mm, PW: 2.89 mm, EL: 5.56 mm, EW: 5.56 mm. HW/HL: 1.00, TL/EYL: 1.09, PL/ PW: 1.00, EL/EW: 1.00.

Head dorsally black with clypeus and portions around antennal insertions reddish, ventral face of head black, narrowly reddish along eyes and broadly reddish along base and posterior portion of tempora, labrum reddish, mandibles reddish with inner margins darkened, palpi dark brown, antennomere 1 dark brown, antennomeres 2–6 dark brown with basal third to half reddish, antennomeres 7–10 blackish with basal margin more or less reddish, antennomere 11 reddish, pronotum black, scutellum black, elytra black with margins and posterior portions lighter; abdomen black, posterior margin of each segment narrowly reddish, styli of tergite IX black, front legs yellowish with basal two thirds of profemora blackish and protibiae slightly darkened apicad, mid and hind legs blackish with apical fourth of mesofemora and metafemora and basal fourth of mesotibiae and metatibiae yellowish.

Head ovoid, eyes markedly protruding; dorsal surface of head uneven with three tubercles between eyes, vertex strongly convex, punctation mostly dense except those of tubercles and convex vertex, punctures on the portions near eyes rugose; punctures of macrosetae in deep fossae; pubescence of head moderately dense, short, silvery to golden; surface of labrum ( Fig. 29 ) conspicuously but rather sparingly punctate and setose; antennae long and slender, antennomeres 1–5 distinctly oblong, antennomere 3 shorter than scapus, antennomere 2 shorter than antennomere 3 and longer than antennomere 4, antennomere 6 longer than wide, antennomere 7 slightly longer than wide, antennomeres 8 and 9 wider than long, antennomeres 10 as long as wide, antennomere 11 longer than penultimate, antennomeres 7–10 slightly asymmetrical, antennomeres 11 asymmetrical.

Pronotum as long as wide, widest at anterior angles, lateral margins irregularly curved, anterior margin shallowly emarginate in the middle; dorsal surface more or less uneven with irregular shallow impressions; midline impunctate in posterior half; pubescence silvery to golden, more or less indistinct.

Elytra as long as wide, lateral margins distinctly divergent posteriad and jointed posterior margin distinctly angulate, surface with shallow impressions along macrosetae, punctation very dense and fine; base, shoulders and portions along posterior margins with pubescence similar to that of head and pronotum, remaining portion with very dense, variegated, modified silvery pubescence. Scutellum with shallow depression, densely and finely punctate, pubescence blackish.

Abdominal tergites III–VI impressed mediobasally, variegated with blackish, silvery and golden pubescence, forming pairs of black tomentose patches along midline of first four visible tergites; tergite VII covered with silvery pubescence except for the anteriolateral corners; tergite VIII–X variegated with blackish, silvery and golden pubes- cence; tergite X triangular with round apex.

Male. Sternite VIII emarginate in the middle of posterior margin; aedeagus ( Figs 54, 55 ) slender, median lobe apically with small tooth on left side and median blunt tooth (pointed by arrow in Fig. 56 ) on ventral side; paramere little shorter than median lobe, apex moderately acute, inner side of apical portion densely covered with peg setae ( Fig. 57 ), subapical portion close to the peg setae area with cavity to accommodate the blunt median tooth of median lobe.

Female. Unknown.

Distribution. China (Yunnan).

Diagnosis. The new species differs from R. griseosericans , R. sommersgutteri , R. gonggashanus and R. henanensis by the body coloration, the ventral side of head darker, eyes larger, surface of pronotum relatively flat, punctation of head and pronotum finer.

Etymology. This species is named in honor of Mr. Xiao-Dong Yang who collected the single specimen of the new species.

Figures

FIGURES 7–12. Habitus. 7, 8—Rhyncocheilus griseosericans; 9, 10—R. gonggashanus; 11, 12—R. yangxiaodongi. Scale bars: 2 mm.

FIGURES 22–29. 22–24—Rhyncocheilus griseosericans; 25–27—R. gonggashanus; 28, 29—R. yangxiaodongi; 22, 25, 28— male head; 23, 26—female head; 24, 27, 29—Labrum. Scale bars: 1 mm.

FIGURES 54–57. Aedeagal characters of Rhyncocheilus yangxiaodongi. 54—aedeagus in lateral view; 55—aedeagus in ventral view; 56—apical potion of aedeagal median lobe in ventrolateral view; 57—inner side of apical parameral potion. Scale bars: 0.5 mm.