Rabigus triquetrus Fei & Zhou, 2021

Fei, Xu-Dong & Zhou, Hong-Zhang, 2021, Three new species of Rabigus Mulsant & Rey (Coleoptera, Staphylininae Philonthina) from China, Zootaxa 4996 (1), pp. 126-132 : 130-131

Rabigus triquetrus Fei & Zhou , sp. nov.

( Figs. 3A–G )

Type material. Holotype: ♂, China: Beijing: Haidian, the Old Summer Palace , 13.V.1997, collected by Zhou Haisheng ( IZ-CAS) . Paratypes: Beijing: 5 ♂♂, Haidian, the Old Summer Palace , 13. V.1997, collected by Zhou Haisheng ( IZ-CAS) ; 2 ♂♂, Haidian, the Old Summer Palace , 20. V.1996, collected by Hao Chenggang ( IZ-CAS) ; 8 ♂♂, Haidian, the Old Summer Palace , 55 m, 2.VIII.1993, collected by Zhou Hongzhang ( IZ-CAS) ; 5 ♂♂, the Old Summer Palace , 50 m, 30.III.1994, collected by Zhou Hongzhang ( IZ-CAS) ; 1 ♂, Haidian, Institute of Zoology , 10.IV.1996, collected by Zhou Hongzhang ( IZ-CAS) ; 1 ♂, Haidian, Anhe Bridge , 13. VI.1996, collected by Zhou Haisheng ( IZ-CAS) ; 1 ♂, Chaoyang, Datun Village , 21. V.1996, collected by Zhou Hongzhang ( IZ-CAS) ; Shanxi: 1 ♂, Guandi Mountain, Haojiagou , 1630 m, 14.VII.2004, collected by Zhao Caiyun ( IZ-CAS) ; Shanxi: 1 ♂, Guandi Mountain, Hengjian Town , 1540 m, 6.VII.2004, collected by Zhao Caiyun ( IZ-CAS) .

Description. Measurements: BL= 5.30 mm (HPL= 1.66 mm); HL= 0.77 mm, HW= 0.66 mm (HW: HL= 0.86); ELL= 0.26 mm; TL= 0.40 mm; PL= 0.88 mm, PW= 0.66 mm (PW: HW= 1.00); EL= 1.00 mm, EW= 1.11 mm; AW= 1.00 mm.

Head black, pronotum and elytra dark reddish - brown, pronotum usually slightly paler than head and elytra, elytra slightly paler around scutellum, along suture and toward apex; maxillary and labial palpi, antennae brownishyellow, antennomeres I–II more or less paler. Abdomen dark reddish - brown, shining, posterior margin of tergites III–VII slightly paler; legs brownish-yellow.

Head narrow, oval, gradually narrowing towards base, with completely obliterated hind angles, slightly narrower than pronotum. Eyes small and flat, about 0.65 times as long as tempora; dorsal surface of head with moder- ately coarse setiferous punctures and slight microsculpture of specialized short lines. Antenna fairly long, antennomeres II–III sub-equal in length, antennomeres IV–VII longer than wide, gradually becoming shorter, antennomeres VIII–X about as long as wide, antennomere XI shorter than two preceding segments combined.

Pronotum oval, elongate, 1.33 times as long as wide, slightly convex, almost parallel-sided, dorsal rows on pronotum each with 1+5 punctures, surface shiny, with slight microsculpture of specialized short lines.

Elytra 0.9 times as long as wide, 1.13 times as long and 1.68 times as wide as pronotum, slightly convex, almost parallel-sided, densely and finely punctate, pubescence fine, surface between punctures without microsculpture. Scutellum densely punctate.

Abdomen wide, very gradually narrowing towards apex; punctures on abdominal tergites similar to that on elytra, but less asperate and somewhat finer, tergites densely and finely pubescent, surface between punctures without microsculpture

Male: Sternite VIII with moderately wide, triangular medioapical emargination at the apex ( Fig. 3G ). Genital segment with styli of tergite IX simple, short and thick, densely setae apically ( Fig. 3E ). Sternite IX long and slen- der, with slightly asymmetrical basal portion, apex deeply emarginate ( Fig. 3D ). Tergite X simple, triangular, almost truncate apically, with slight emargination and with four setae at apex ( Fig. 3F ).

Aedeagus ( Figs. 3B–C ) narrow and elongate; median lobe in ventral view gradually narrowed apically, apical portion with subacute apex; apex of paramere triangular, sharply constricted at middle, with two sensory peg setae near the margin of lateral angle.

Remarks. Rabigus triquetrus Fei & Zhou , sp. nov. is quite similar to Rabigus formosus (Motschulsky, 1860) , but can be distinguished by the apical 1/4 of paramere with obviously pointed angles on each side, whereas R. formosus has rounded ones.

Female. Unknown.

Etymology. The specific epithet is derived from the Latin word triquetr - (triangle), and refers to the shape of the paramere apex.

Distribution. China (Beijing, Shanxi).

Figures

FIGURE 3. Rabigus triquetrus Fei & Zhou, sp. nov. A. Habitus; B. aedeagus, ventral view; C. aedeagus, lateral view; D. sternite IX of male; E. stylus of tergite IX of male; F. tergite X of male; G. sternite VIII of male. Scale bars: A = 1 mm, B–G = 0.2 mm.