Trisunius rastratus, Assing, 2014

Assing, V., 2014, A revision of Trisunius IV. Two new species and additional records from China (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 46 (1), pp. 443-448 : 446-448

Trisunius rastratus nov.sp. ( Figs 8-14 )

T y p e m a t e r i a l Holotype: " China: W-Hubei Daba Shan crk. valley 8 km NW Muyuping, 31°29'N / 110°22'E 1550-1650 m, 18.VII.2001, A. Smetana [C115b] / Holotypus Trisunius rastratus sp.n. det. V. Assing 2013 " (cAss).

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun rastrum (hoe, pick) and alludes to the shape of the ventral process of the aedeagus.

D e s c r i p t i o n: Body length 4.1 mm; length of forebody 2.3 mm. Habitus as in Fig. 8 . Coloration: body pale-reddish; legs yellowish; antennae reddish.

Head ( Fig. 9 ) weakly oblong, 1.03 times as long as broad; lateral margins behind eyes weakly convex in dorsal view; dorsal surface matt; punctation extremely fine and dense, barely noticeable in the pronounced microreticulation even at a magnification of 100 x ( Fig. 10 ). Eyes weakly convex, not distinctly protruding from lateral contours of head, and small, approximately one-fourth as long as postocular region in dorsal view. Antenna 1.35 mm long.

Pronotum ( Fig. 9 ) 1.14 times as long as broad and 0.90 times as broad as head; lateral margins very weakly converging posteriad in dorsal view; punctation and microsculpture similar to those of head ( Fig. 11 ); surface matt; midline with extremely fine furrow posteriorly.

Elytra ( Fig. 8 ) short, 0.7 times as long as pronotum; punctation fine and dense; interstices without microreticulation. Hind wings completely reduced. Metatarsomere I approximately as long as II.

Abdomen approximately 1.2 times as broad as elytra; punctation very fine and very dense; interstices with distinct microreticulation, matt; posterior margin of tergite VII with narrow and incomplete rudiment of a palisade fringe.

: sternite VII ( Fig. 12 ) strongly transverse, with distinct median impression without pubescence, on either side of this impression with cluster of dense black setae, posterior margin distinctly concave in the middle; sternite VIII ( Fig. 13 ) distinctly transverse and with median impression without pubescence, posterior excision conspicuously deep and narrow, reaching beyond middle of sternite; aedeagus 0.59 mm long, with ventral process of highly distinctive shape in lateral view.

C o m p a r a t i v e n o t e s:UsingthekeytospeciesinASSING (2011), T. rastratus would key out at couplet 4, together with T. discrepans . It is readily distinguished from this (and other) species by the pronounced microsculpture and matt appearance of the head and pronotum, the practically invisible punctation of the head and pronotum, the small eyes, the distinctive shapes and chaetotaxy of the male sternites VII and VIII, as well as by the conspicuous shape of the aedeagus.

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 west of Hubei province, China, at an altitude of 1550-1650 m. The apparently slightly teneral holotype was sifted from deep humus between rocks in a mixed forest (SMETANA pers. comm.).

Figures

Figs 8-14: Trisunius rastratus nov.sp.: (8) habitus; (9) forebody; (10) median dorsal portion of head; (11) median portion of pronotum; (12) male sternite VII; (13) male sternite VIII; (14) aedeagus in lateral view. Scale bars: 8: 1.0 mm; 9: 0.5 mm; 12-14: 0.2 mm; 10-11: 0.1 mm.