Stenus latipectus Tang & Puthz

Tang, Liang, Li, Li-Zhen & Puthz, Volker, 2010, Five new Stenus species of the cephalotes group (Coleoptera, Staphylinidae) from China with a key to Chinese species of the group, Zootaxa 2335, pp. 29-39 : 35-37

Stenus latipectus Tang & Puthz , sp. nov.

( Figs.4 , 21–25 )

Type material. Holotype: CHINA: Sichuan Prov.: 3, Tianquan County, Labahe, alt. 2000 m, 30.VII.2006, HU Jia-Yao & TANG Liang leg. ( SHNU). Paratypes: CHINA: Sichuan Prov.: 2ƤƤ, same data as for the holotype (Ƥ in SHNU, Ƥ in cPut); 33, same data but alt. 2400–2600 m, 31.VII.2006, HU Jia-Yao & TANG Liang leg. (23 in SHNU, 3 in cPut).

Description. BL: 2.5–3.5 mm; FL: 1.3–1.5 mm.

Proportional measurements of holotype: HW: 42.0, PL: 33.0, PW: 33.0, EL: 34.0, EW: 39.0, SL: 26.0.

Brachypterous, moderately glossy, head black, pronotum and abdomen dark brown, elytra brown; head, pronotum and elytra coarsely and densely punctate, abdominal punctation dense, moderately fine anteriorly to fine posteriorly; pubescence short, recumbent. Antennae reddish yellow, club infuscate. Maxillary palpi and legs reddish yellow. Clypeus blackish brown, labrum reddish brown with reddish yellow along the anterior margin, densely pubescent.

Head 1.08 times as wide as elytra; clypeofrontal area densely punctate and pubescent; basiantennal tubercles small; interocular area with deep longitudinal furrows, median portion convex and very narrowly impunctate along midline, distinctly elevated above the level of inner eye margins; punctures very dense and mostly distinctly delimited, diameter of punctures about as wide as basal cross section of 2nd antennal segment, interstices indistinctly microsculptured, much smaller than half diameter of punctures, interstices along midline a little larger. Antennae when reflexed extending a little before posterior margin of pronotum; 3rd to 8th segments much narrower than 2nd; 9th to 11th gradually broadened, forming loose club; relative length of segments from base to apex as 7.0: 5.5: 9.0: 5.5: 4.5: 3.5: 3.5: 2.5: 3.5: 4.0: 5.0. Paraglossae oval.

Pronotum as long as wide, 0.85 times as wide as elytra, widest at a little before middle and constricted at base; disk uneven, with deep and broad median longitudinal furrow, two impressions in anterior half and two impressions in posterior half; punctures slightly rugose and confluent, in size similar to those on head, interstices indistinctly microsculptured, smaller than half diameter of punctures.

Elytra 0.87 times as long as wide, distinctly constricted at base, lateral margins gently divergent posteriad; posterior conjoint margins roundly and distinctly emarginate at middle; disk uneven with distinct humeral impression, distinct postero-lateral impression and distinct suture impression; punctation about as coarse as on pronotum, but slightly less dense, interstices mostly smooth and often nearly as large as half diameter of punctures.

Legs elongate, hind tarsi 0.84 times as long as hind tibiae, 4th tarsomeres distinctly bilobed.

Abdomen cylindrical; without paratergites except for the trace on basal half of 3rd segment; 7th tergite with apical narrow membranous fringe; punctures round to elliptic, gradually becoming smaller posteriad, reticulation of interstices indistinct, distinct only on 8th to 10th tergites.

Male. Sixth sternite ( Fig. 21 ) with slight emargination at middle of posterior margin; 7th sternite ( Fig. 21 ) impressed at posteromedian part with shallow emargination along the posterior margin of the impression; 8th sternite ( Fig. 21 ) with triangular emargination at middle of posterior margin; 9th sternite ( Fig. 22 ) with very long apicolateral projections, posterior margin serrate, broadly and shallowly projected at middle. Aedeagus ( Fig. 23 ) with median lobe subparallel and in apical 1/9 acutely narrowed into acuate sclerotized apex with longitudinal keel at middle; expulsion hooks ( Fig. 24 ) large, internal sac as in Fig. 23 ; parameres extending beyond apex of median lobe, slightly folded at apical portion, each with 2 groups of subapical setae (4-3) on inner side.

Female. Abdomen broader than in male; 8th sternite with posterior margin roundly pointed at middle; sclerotized spermatheca with lunate infundibulum as in Fig. 25 .

Remarks. This new species is similar to S. gonggashanus sp. nov. and S. tianquanensis sp. nov., but can be distinguished by the characters listed in the key.

Distribution. China (Sichuan Province).

Etymology. The species name is a combination of the Latin words “ latus ” and “ pectus ”, and refers to its broad pronotum.

Figures

FIGURES 1 – 5. Stenus cephalotes group, habitus. 1 — S. substrictus sp. nov.; 2 — S. breviculus sp. nov.; 3 — S. gonggashanus sp. nov.; 4 — S. latipectus sp. nov.; 5 — S. tianquanensis sp. nov. Scale bars 1 mm.

FIGURES 21 – 25. Details of Stenus latipectus sp. nov. 21 — male 6 th – 8 th sternites; 22 — male 9 th sternite; 23 — aedeagus in ventral view; 24 — expulsion clasp of aedeagus; 25 — spermatheca. Scale bars 0.25 mm.