Stenus jiangrixini Tang, Liu & Dong, new species

(Figs 2, 16–21)

Material examined. Holotype: ♂, glued on a card with labels as follows: “ China: Sichuan, Dayi County, Xiling Xueshan, 30°41'59''N, 103°12'10''E, mixed leaf litter, sifted, 2150 m, 29.VII.2015, Jiang, Peng, Tu & Zhou leg”. “ Holotype / Stenus jiangrixini / Tang, Liu & Dong ” [red handwritten label] (SHNU) . Paratypes: 1♀, same data as for the holotype. (SHNU).

Description. Brachypterous; head black, pronotum and elytra brown, each elytra with a small indistinct spot on median portion? abdomen dark brown. Antennae, maxillary palpi and legs yellowish brown except antennal club infuscate. Labrum reddish brown.

BL: 4.0– 4.1 mm, FL: 1.9–2.0 mm.

HW: 0.71–0.76 mm, PL: 0.57–0.59 mm, PW: 0.54–0.57 mm, EL: 0.60–0.64 mm, EW: 0.61–0.67 mm, SL: 0.42–0.44 mm. Head 1.14–1.17 times as wide as elytra, pronotum 1.03–1.05 times as long as wide, elytra 0.96–0. 98 times as long as wide;

Similar to S. cariniventris sp. n. in most aspects, but differs in the following characters: punctation of pronotum and elytra more confluent; pronotal impressions deeper and elytral impressions shallower; elytra each with a hump at elytral spot; abdominal segment IV with traces of degenerated paratergites on basal fourth; abdominal tergites with punctures smaller and sparser especially those of posterior area of each tergite.

Male. Sternite VII with posteromedian portion slightly impressed; sternite VIII (Fig. 16) emarginated at middle of posterior margin with anterior margin of the emargination straight; sternite IX (Fig. 17) with very long and strong apicolateral projections. Aedeagus (Figs. 18, 19) with apical sclerotized portion roundly projected at apex; expulsion clasps large, strongly sclerotized; parameres as long as the median lobe, each with 8–10 setae on apicointernal margins.

Female. Sternite VIII (Fig. 20) with posterior margin weakly pointed at middle; sclerotized spermatheca (Fig. 21) with very complicated bends.

Distribution. China (Sichuan).

Remarks. The new species is similar to S. cariniventris sp.n.,but differs in smaller body size, the appearance of small and prominent elytral spots, smaller and sparser punctation of abdominal tergites.

Etymology. This species is named in honor of Mr. Ri-Xin Jiang who collected some specimens of the new species.