Stenus zhuxiaoyui Tang

Tang, Liang & Yun-Long, Zhao, 2008, Three new Stenus species of the indubius group (Coleoptera, Staphylinidae) from China, Zootaxa 1741, pp. 51-58 : 52-53

Stenus zhuxiaoyui Tang , sp. nov.

( Figs.1 , 4–8 )

Type material. Holotype: CHINA: Sichuan Prov.: ɗ, Luding County, Hailuogou, alt. 3000m, 21– 26.VII.2006, HU Jia-Yao & TANG Liang leg. ( SHNU) Paratypes: CHINA: Sichuan Prov.: 35ɗɗ, 26ΨΨ, same data as for the holotype ( SHNU); 2ɗɗ, 2ΨΨ, Gongga Shan, above camp 3, alt. 3050 m, 22.VII.1994, A.

Smetana leg. (cPut, cSch, cSme); ɗ, ibidem, alt. 3300–3350 m, 23.VIII.1994, A. Smetana leg. (cPut, cSch, cSme); 3ΨΨ, Hailuoguo, above camp 3, alt. 3000 m, 6.VII.1996, A. Smetana et al. leg. (cPut, cSch, cSme); ɗ, 2ΨΨ, ibidem, alt. 3350 m, 6.VII.1996, A. Smetana et al. leg. (cPut, cSch, cSme); Ψ, ibidem, lake above camp 2, alt. 2750 m, 4.VII.1998, A. Smetana et al. leg. (cPut, cSch, cSme); 2ɗɗ, Ψ, ibidem, camp 3, alt. 3000–3100 m, 29.V.1997, M. Schülke leg. (cPut, cSch, cSme)

Description. BL: 3.0– 3.7 mm; FL: 1.5–2.0 mm.

Proportional measurements of holotype: HW: 47.0, PL: 35.5, PW: 34.5, EL: 40.0, EW: 41.5, SL: 30.5.

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

Head 1.13 times as wide as elytra; clypeofrontal area densely punctate and pubescent; basiantennal tubercles small; interocular area with deep longitudinal furrows, median portion convex, slightly extending beyond the level of inner eye margins; punctures round, partly confluent, slightly larger and sparser on median area than those near inner margins of eyes, diameter of large puncture about as wide as medial cross section of 2nd antennal segment, interstices much smaller than half diameter of punctures. Antennae when reflexed extending a little before posterior margin of pronotum; 3rd to 7th segments much narrower than 2nd; 8th to 11th gradually broadened, forming loose club; relative length of segments from base to apex as 7.0: 5.5: 10.0: 6.5: 6.0: 4.5: 4.5: 3.0: 4.0: 4.5: 5.5. Paraglossa oval.

Pronotum 1.03 times as long as wide, 0.83 times as wide as elytra, widest at a little before middle and constricted at base; disk uneven, with distinct median longitudinal furrow, two impressions in anterior half, transverse impression in about middle, and two impressions in posterior half; punctures rugose and confluent, of same size as those on head, interstices much smaller than half diameter of punctures.

Elytra 0.96 times as long as wide, distinctly constricted at base, lateral margins, with slight concavity at about half, gently divergent posteriad, posterior conjoint margins roundly and distinctly emarginate at middle; disk uneven with deep longitudinal humeral impression, distinct postero-lateral impression and long and deep sutural impression, suture strongly convex; punctation rugose and slightly confluent, punctures a little larger than those on pronotum, interstices much smaller than half diameter of punctures.

Legs elongate, hind tarsi 0.81 times as long as hind tibiae, 4th tarsomeres distinctly bilobed.

Abdomen cylindrical; distinct paratergites absent, but rudimentary lateral border present, tergites and sternites distinctly separated at about posterior sixth; 7th tergite with narrow apical membranous fringe; punctures on abdominal 3–8th tergites round to elliptic, gradually becoming smaller posteriad, interstices smaller than half diameter of punctures, faint microsculpture on tergite 7, distinct microsculpture on tergites 8–10.

Male. Seventh sternite ( Fig. 4 ) with slight emargination at middle of posterior margin; 8th sternite ( Fig. 4 ) with triangular emargination at middle of posterior margin; 9th sternite ( Fig. 5 ) with very long apicolateral projections, posterior margin serrate. Aedeagus ( Fig. 6 ) with median lobe gradually narrowed apicad into an obtuse sclerotized apex; expulsion hooks ( Fig. 7 ) very large, internal sac as in Fig. 6 ; parameres extending distinctly beyond apex of median lobe, almost straight, swollen at the beginning of their apical third, which are distinctly narrowed toward apex, with numerous long subapical setae.

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

Remarks. This new species is very similar to S. pectorifossatus sp. nov. and S. elangshanus sp. nov., but it may be distinguished by the characters listed in key. All three new species are similar to Stenus unzemontis , but can be distinguished from it by longer elytra and different sexual characters.

Distribution. China (Sichuan Province).

Etymology. This species is named in honor of Mr. Zhu Xiao-Yu, who helped us a lot during the collection trip.

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 4 – 8. Details of Stenus zhuxiaoyui sp. nov. 4 — male 7 – 8 th sternites; 5 — male 9 th sternite; 6 — aedeagus in ventral view; 7 — expulsion hooks of aedeagus; 8 — spermatheca. Scale = 0.25 mm.