Stenus pectorifossatus Tang

Tang, Liang & Yun-Long, Zhao, 2008, Three new Stenus species of the indubius group (Coleoptera, Staphylinidae) from China, Zootaxa 1741, pp. 51-58 : 55-56

Stenus pectorifossatus Tang , sp. nov.

( Figs. 2 , 9–13 )

Type material. Holotype: CHINA: Sichuan Prov.: ɗ, Luding County, Hailuogou, alt. 2200–2300m, 27–28- VII-2006, HU Jia-Yao & TANG Liang leg. ( SHNU) Paratypes: CHINA: Sichuan Prov.: ɗ, 4ΨΨ, same data as for the holotype ( SHNU); ɗ, Ψ, Hailuoguo, river valley ca. 1 km above camp 1, alt. 2100 m, 28 – 31.V.1997, A. Pütz leg. (cPut, cPüt)

Description. BL: 4.0– 4.2 mm; FL: 2.1–2.3 mm.

Proportional measurements of holotype: HW: 51.0, PL: 42.5, PW: 38.5, EL: 43.0, EW: 46.0, SL: 31.0; relative length of segments from base to apex as 7.5: 6.0: 13.0: 7.0: 7.0: 4.5: 5.0: 3.5: 4.0: 4.0: 5.5; hind tarsi 0.66 times as long as hind tibiae.

Brachypterous, blackish brown, moderately glossy, head and abdomen coarsely and very densely, pronotum and elytra coarsely and very rugosely punctate; pubescence short, recumbent. Antennae entirely light brown. Maxillary palpi and legs light brown. Clypeus blackish, labrum reddish brown, densely pubescent.

In most respects S. pectorifossatus is very similar to S. zhuxiaoyui , but different in the following characters: diameter of large puncture on head about as wide as apical cross section of 2nd antennal segment; pronotum with median longitudinal furrow and impressions deep; elytra with suture relatively less strongly convex and punctation very rugose and confluent; interstices on abdominal tergites distinctly smaller than half diameter of punctures, posteriomedial punctation of tergites 4–6 very dense, punctures arranged slightly divergent posteriad, distinct microsculpture only on tergite 10.

Male. 8th sternite ( Fig. 9 ) with triangular emargination at middle of posterior margin; 9th sternite ( Fig. 10 ) with very long apicolateral projections, posterior margin slightly serrate. Aedeagus ( Fig. 11 ) with median lobe narrowest at 2/3 its length from apex, and widest at 1/5 from apex, and then narrowed apicad into an obtuse sclerotized apex; expulsion hooks ( Fig. 12 ) large, internal sac as in Fig. 11 ; parameres extending distinctly beyond apex of median lobe, slender and bisinuate, slightly swollen at the beginning of their apical fourth and then narrowed toward apex, with about 15 subapical setae.

Female. Abdomen broader than in male; 8th sternite entire; sclerotized spermatheca as in Fig. 13 .

Remarks. See remarks for S. zhuxiaoyui .

Distribution. China (Sichuan Province).

Etymology. The specific name is a combination of the Latin words “ pectus ” and “ fossa ”, and refers to its pronotum with deep median longitudinal furrow.

Figures

FIGURES 1 – 3. Adult habitus. 1 — Stenus zhuxiaoyui sp. nov.; 2 — S. pectorifossatus sp. nov.; 3 — S. erlangshanus sp. nov. Scale = 1 mm.

FIGURES 9 – 13. Details of Stenus pectorifossatus sp. nov. 9 — male 8 th sternite; 10 — male 9 th sternite; 11 — aedeagus in ventral view; 12 — expulsion hooks of aedeagus; 13 — spermatheca. Scale = 0.25 mm.