Stenus (Hemistenus) uncinulatus Zhao & Zhou, 2006

Zhao, Cai-Yun & Zhou, Hong-Zhang, 2006, A new species of Stenus (Hemistenus) with new records and a key to Chinese species of the viridanus group (Coleoptera, Staphylinidae), Zootaxa 1304 (1), pp. 21-29 : 26-27

5. Stenus (Hemistenus) uncinulatus Zhao & Zhou , sp. n. ( Figs. 3–7 )

Type Material. Holotype: China: Sichuan: male, Emei mountain (103.5°E, 29.62°N), 29 Aug.2005, Ye­Jun Zhang collected ; Paratypes: 1 female, same data as holotype ; 1 female, 1 male, same data as holotype except Hong­Zhang Zhou collected; 1 male, same data as holotype except Cai­Yun Zhao collected.

Description. Body length 6.7 mm. Body black and glossy, antennae brown except for almost black apical part; maxillary palpi brown but first segment yellowish brown; front margin of labium yellowish brown and transparent, clypeus and labium black and both covered with golden pubescence; legs brown except basal part of tibiae and apical part of femora black. Elytra without spots but with sculpture formed by confused punctures on the disc area.

Head narrower than elytra (1.3: 1.5 mm), with an average distance between eyes 0.65 mm; area between eyes deeply depressed, with two longitudinal furrows converging anteriorly, area between furrows distinctly convex but below the level of inner margin of eyes, narrower than lateral areas outside the furrows; vertex with narrow impunctate area along middle line; punctures on head long, not round, distinctly larger than diameter of apical section of 3rd antenna on the median area, but punctures on the sides smaller and sparser; interstices larger than diameter of punctures. Antenna long, when extended posteriad reaching hind margin of pronotum by penultimate segment, apical three segments distinctly longer than wide. Paraglossa oval.

Pronotum as long as wide (1.0 mm), widest in middle, sides round anteriorly and constricted posteriorly; surface of pronotum uneven, with transverse impression just behind anterior margin, and with distinct longitudinal furrow along median line occupying 2/3 length of pronotum and gradually weakening forward and backward, impunctate in furrow; on each sides of furrow with two irregularly shallow impressions; punctures on pronotum coarse and confused, interstices mostly formed into short keels. Elytra measured along suture shorter than pronotum (1.05: 1.0 mm), wider than long (1.50: 1.45 mm). Sides inflated, widest at about posterior 1/5 and slightly constricted posteriad. Each elytron without emargination in outer part of hind margin. Surface of elytra convex, humerus with distinct depression, along suture with deep depression which gradually becomes shallower and narrower posteriorly. Punctures on elytra confused except for those on humeral area, where punctures larger than apical section of 3rd segment of antenna, and interstices smaller than diameter of a puncture; confused punctures on disc formed into vorticose sculptures. Hind wings distinctly longer than elytra.

Abdomen robust, with complete and almost parallel paratergites, paratergites very slender and without punctures; 3rd–6th abdominal tergites with shallow transverse depression near base. Punctures in depression of 3rd abdominal tergite as large as basal section of 3rd segment of antenna, and their interstices smaller than diameter of puncture; punctures in other areas of 3rd abdominal tergite smaller than basal section of 3rd segment of antenna, and their interstices larger than diameter of puncture; punctures gradually smaller and sparser towards hind segments, punctures on 7th abdominal tergite smaller than size of an inner eye­facet, interstices distinctly larger than diameter of puncture. Abdomen covered with white pubescence, which gradually becomes denser posteriad. Legs robust, 1st metatarsal segment longer than three following segments together, 4th deeply bilobed with lobes reaching middle of 5th.

Male. Mesotibiae with strong apical spurs on inner margin; metatibiae with weak spurs on inner margin near apex; median part of metasternum with distinct depression covered with dense golden hairs; 6th abdominal sternite with slight depression along longitudinal median; 7th abdominal sternite with deep depression along longitudinal median where covered with dense long yellowish hairs, posterior margin directly behind the depression with shallow broad emargination; 8th abdominal sternite with deep notch on posterior margin ( Fig. 5 ), sides of 9th abdominal sternite formed into slender teeth without denticles on their outer side, as shown in Fig. 4 . Median lobe of aedeagus longer than parameres, with distinct hook ( Fig. 3 ).

Female. Spermatheca as in Fig. 6 .

Etymology. The species epithet is derived from the Latin word uncinulatus (with small clasp).

Remarks. The new species is similar to S. scopulus in appearance, but with slender paratergites and simple spermatheca, and the aedeagus of new species with more complex structure. The new species is also similar to S. rugosipennis and S. habropus , but can be distinguished from them by a different inner structure of the aedeagus.

Figures

FIGURES 1–8. Details of Stenus pullidistortus Zhao & Zhou (1), S. scopulus Zheng (2), S. uncinulatus, sp. n. (3–7) and S. wuyimontium Puthz (8). Spermatheca (1–2, 6, 8), aedeagus (3), male sternite 9 (4), male sternite 8 (5), median hook of aedeagus (7). Scale bars 0.1mm.