Silusa excisa, Assing, 2011

Assing, V., 2011, Six new species and additional records of Aleocharinae from China (Coleoptera: Staphylinidae: Aleocharinae), Linzer biologische Beiträge 43 (1), pp. 291-310 : 294-295

Silusa excisa nov.sp. ( Figs 7-12 )

T y p e m a t e r i a l: Holotype: " China: Sichuan, Qingcheng Shan , 65 km NW Chengdu, 103.33 E, 30.53 N, 18. V./ 3.-4.VI.1997, 8 km W Taiping, 800-1000 m, leg. A. Pütz / Holotypus Silusa excisa sp. n. det. V. Assing 2010" (cPüt) . Paratypes: 3: same data as holotype (cPüt, cAss) ; 1: " China: Sichuan (17), Qingcheng Shan, NW Chengdu , 650-700 m, 30.53.57 N, 103.32.23 E, 3./ 4.06.1997, M. Schülke / Silusa bodemeyeri (E.), det. R. Pace 1999" (cSch) .

D e s c r i p t i o n: Body length 3.0- 3.5 mm. Habitus as in Fig. 7 . Coloration: head blackish-brown to blackish; pronotum and elytra yellowish-red to dark-reddish, with the postero-lateral portion of the elytra extensively infuscate; abdomen with segments III-V or III-VI dark-reddish and the remainder infuscate, except for the yellowish to reddish posterior margins of the segments; legs reddish with the femora somewhat darker; antennae reddish-brown, with the basal three antennomeres reddish.

Head ( Fig. 8 ) weakly transverse; punctation dense, moderately fine, and defined, somewhat sparser in median and in anterior dorsal portion; interstices without distinct microsculpture. Eyes large and convex, longer than postocular portion in dorsal view. Antennae approximately 0.8 mm long; antennomere IV approximately as long as wide; V-X gradually increasing in width; preapical antennomeres approximately twice as wide as long.

Pronotum ( Fig. 8 ) approximately 1.5 times as wide as long and 1.4 times as wide as head; maximal width in the middle; lateral margins very weakly sinuate in posterior half, posterior angles almost rectangularly marked; near posterior margin with long transverse impression with numerous coarse punctures; punctation of remainder of dorsal surface fine, much finer than that of head, and dense; pubescence long, fine, and suberect; interstices without distinct microsculpture.

Elytra ( Fig. 8 ) long and broad, approximately 1.15 times as long as pronotum; posterior margin strongly sinuate near postero-lateral angle; punctation coarse and very dense. Hind wings fully developed. Metatarsomere I approximately as long as II.

Abdomen anteriorly with moderately sparse, posteriorly with very sparse punctation; interstices glossy; posterior margin of tergite VII with palisade fringe.

: tergite VII posteriorly with small median tubercle; posterior margin of tergite VIII in the middle excised, on either side of this excision serrulate ( Fig. 9 ); sternite VIII strongly transverse, posterior margin strongly produced in the middle ( Fig. 10 ); median lobe of aedeagus 0.41 mm long, with apical internal structures of distinctive shape ( Fig. 11 ).

: posterior margin of tergite VIII weakly convex; posterior margin of sternite VIII weakly produced in the middle; spermathecal capsule with very long and slender proximal portion ( Fig. 12 ).

E t y m o l o g y: The name (Latin, adjective) refers to the characteristic shape of the posterior margin of the male tergite VIII.

C o m p a r a t i v e n o t e s: Tenspeciesof Silusa are currently known from China ( SMETANA 2004, PACE 2004a), the vast majority of which were described or recorded from there by PACE (1998a, 2004a). Silusa excisa is distinguished from them particularly by the male primary and secondary sexual characters, as well as by the shape of the spermatheca. For illustrations of the genitalia of most previously described species see PACE (1998a, 2004a). Silusa aliena BERNHAUER 1916 , of which no illustrations of the genitalia are available, has the head and the pronotum distinctly microsculptured ( BERNHAUER 1916).

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: The type specimens were collected in two localities to the northwest of Chengdu (Sichuan) at altitudes of 650-1000 m.

Figures

Figs 7-12: Silusa excisa nov.sp.: (7) habitus; (8) forebody; (9) male tergite VIII; (10) male sternite VIII; (11) median lobe of aedeagus in lateral view; (12) spermatheca. Scale bars: 7: 1.0 mm; 8: 0.5 mm; 9-10: 0.2 mm; 11-12: 0.1 mm.