Stenus longchishanicus Lv & Zhao & Zhou 2018, sp. nov.

1. Stenus longchishanicus Lv et Zhou, sp. nov.

(Figs. 1 & 2)

Type locality: China: Sichuan: Dujiangyan County.

Type material. Holotype: male, China: Sichuan: Dujiangyan County, Longchishan (30°97'N, 103°62'E), 180 m, 26.VIII.2005, Xiao-Yan Li leg. (IZ-CAS). Paratypes. 5 males, 3 females, same data as for the holotype. (IZ-CAS).

Description. BL: 3.7–4.0 mm, FL: 1.9–2.1 mm, HW: 0.83–0.86 mm, PL: 0.64–0.68 mm, PW: 0.63–0.67 mm, EL: 0.71–0.73 mm, EW: 0.82–0.84 mm, SPL: 0.53–0.54 mm.

Brachypterous; body dark brown except head black. Antennae yellowish, club slightly infuscate; maxillary palpi yellowish, segment III infuscate; legs red brown, but knees darker; clypeus black, labrum dark brown with sparse pubescent; paraglossae oval.

Head slightly broader than elytra. Frons broad with a pair of deep and broad longitudinal furrows, median portion distinctly elevated, slightly extending beyond the level of dorsal eye margins; punctures round, partly confluent, diameter of the largest punctures as large as largest cross section of antennal segment II; interstices smooth, distinctly smaller than half the diameter of punctures. Antenna slender, when reflexed distinctly extending beyond the posterior margin of pronotum.

Pronotum slightly longer than broad, disk uneven, with a broad median furrow throughout, two moderately deep impression in the middle; punctures confluent, varied in size, as large as those on frons; interstices distinctly ridge-like, narrower than half the diameter of punctures.

Elytra shorter than broad; weakly uneven, shoulders oblique, postero-lateral impression indistinct, humeral impression and long sutural impression shallow; punctuation shallow, mostly well delimited, slightly smaller than those on pronotum; interstices smooth, distinctly smaller than diameter of punctures.

Legs slender; tarsomeres IV deeply bilobed.

Abdomen cylindrical, with line-like paratergites on segments III–VI and shallow basal furrows on anterior segments, tergite VII without apical membranous fringe; punctures round, punctures of abdominal tergite III as large as those on elytra in average, gradually becoming smaller and sparser posteriorly; punctures on tergite VII slightly smaller than eye facets near dorsal eye margin. Interstices smooth, larger than diameter of punctures.

Male: sternite VIII (Figs. 1 F & 2 B) posteromedially with a semi-circular-shaped emargination; sternite IX (Figs. 1 G & 2 C) with long acute apicolaterally, posterior margin serrate; tergite IX & X (Figs. 1 H & 2 D) entire posteriorly. Aedeagus (Figs. 1 E & 2 A) almost elongate-ovoidal, acutely pointed apex; apical sclerotized area triangular, with vague longitudinal keels. Endophallus with median bands moderately long; expulsion clasps almost H-shaped, connected by the point a little behind the middle of mesial margin; copulatory tube relatively short, thickening posteriorly. Parameres extending posteriorly a little beyond the apex of median lobe, tapering apicad at apical sixth, each with 4 subapical setae and 6 basal setae on apical area margins.

Female: sternite VIII (Figs. 1 I & 2 E) entire; sternite X (Figs. 1 J & 2 F) convex at posterior margin. Gonocoxite (Figs. 1 K & 2 G). (Figs. 2 H) with distinct basal porch, the rest duct undetected.

Distribution. China (Sichuan).

Etymology. The specific name is derived from the name of the type locality of this species

Remarks. Stenus longchishanicus Lv et Zhou, sp. nov. belongs to Stenus aureolus group. The new species can be easily distinguished from other related species by the following characters: body dark brown without elytra spot, tergites III–VI with distinct paratergites and different details of other sexual characters.