Silusa mandibulata, 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 : 295-297

Silusa mandibulata nov.sp. ( Figs 13-17 )

T y p e m a t e r i a l: Holotype: " China: Shaanxi, Daba Shan, NW pass 25 km NW Zhenping , 32°01'N / 109°19'E, 2150 m, 11.VII.2001, A. Smetana [C99] / Holotypus Silusa mandibulata sp. n. det. V. Assing 2010" (cAss).

D e s c r i p t i o n: Body length 3.4 mm. Habitus as in Fig. 13 . Coloration: head blackish; pronotum reddish-brown; elytra red, with the postero-lateral portion of the elytra indistinctly and diffusely infuscate; abdomen blackish, with segments III-IV darkbrown and the apex reddish; legs reddish with the femora slightly darker; antennae reddish-brown, with the basal three antennomeres reddish.

Head ( Fig. 14 ) weakly transverse; punctation dense, rather coarse, and defined, somewhat sparser in anterior dorsal portion; interstices without distinct microsculpture. Eyes moderately large and weakly convex, slightly longer than postocular portion in dorsal view. Antennae stout and approximately 0.9 mm long; antennomere IV weakly transverse; V-X gradually increasing in width; preapical antennomeres nearly twice as wide as long.

Pronotum ( Fig. 14 ) approximately 1.4 times as wide as long and 1.4 times as wide as head; maximal width slightly before the middle; lateral margins not sinuate in posterior half, posterior angles obtusely marked; near posterior margin with weakly pronounced, short transverse impression without conspicuously coarse punctures; punctation of remainder of dorsal surface defined and slightly finer than that of head; pubescence long, fine, and suberect; interstices without distinct microsculpture.

Elytra ( Fig. 14 ) approximately as long as pronotum; posterior margin moderately sinuate near postero-lateral angle; punctation coarse and very dense; interstices without microsculpture and glossy. Hind wings present. Metatarsomere I somewhat longer than II.

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

: tergite VII at posterior margin with small median tubercle; posterior margin of tergite VIII with three pronounced tooth-like processes on either side ( Fig. 15 ); sternite VIII moderately transverse, posterior margin convexly produced in the middle ( Fig. 16 ); median lobe of aedeagus 0.38 mm long, with apical internal structures of distinctive shape ( Fig. 17 ).

: unknown.

E t y m o l o g y: The name (Latin, adjective) refers to the shape of the apical internal structures of the aedeagus, which somewhat resemble mandibles.

C o m p a r a t i v e n o t e s: This species is readily distinguished from all other Silusa species known from China by the shape of the male tergite VIII and particularly by the characteristic shape of the apical internal structures of the aedeagus. 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 in the literature, 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: Thetypelocalityissituatedin the Daba Shan, Shaanxi province, at an altitude of 2150 m.

Figures

Figs 13-19: Silusa mandibulata nov.sp. (13-17) and Oroekklina excaecata (ASSING) (18-19): (13) habitus; (14) forebody; (15) male tergite VIII; (16) male sternite VIII; (17-18) median lobe of aedeagus in lateral view; (19) median lobe of aedeagus in ventral view. Scale bars: 13: 1.0 mm; 14: 0.5 mm; 15-16: 0.2 mm; 17-19: 0.1 mm.