Trisunius appendiculatus, Assing, 2011

Assing, V., 2011, Trisunius gen. nov. from the southern East Palaearctic and the Oriental regions (Coleoptera: Staphylinidae: Paederinae: Medonina), Linzer biologische Beiträge 43 (1), pp. 195-220 : 212-214

Trisunius appendiculatus nov.sp. ( Figs 52-56 )

T y p e m a t e r i a l: Holotype Ƌ: " China: Yunnan, Baoshan Pref., Gaoligong Shan, W Pass 35 km SE Tengchong, 2100 m, 24°50'18''N, 98°45'43''E, devast. prim. dec. forest, litter, wood, mushrooms sifted, 25.VIII.2009, leg. M. Schülke [ CH 09-06] / Holotypus Ƌ Trisunius appendiculatus sp.n. det. V. Assing 2011" (cAss). Paratype: 1Ƌ: same data as holotype (cSch).

D e s c r i p t i o n: Body length 3.0- 3.2 mm. Habitus as in Fig. 52 . Coloration: head and pronotum dark-brown; elytra blackish-brown, with the anterior and posterior margins broadly reddish-yellow; abdomen blackish, with the posterior margins of segments VII and VIII yellowish.

Head ( Fig. 53 ) 1.05-1.10 times as long as wide; punctation fine and moderately dense, in anterior half with pair of larger punctures; interstices without microsculpture and distinctly glossy. Eyes distinctly convex and distinctly more than half as long as postocular region in dorsal view. Anterior margin of labrum with two rather small teeth on either side of median incision.

Pronotum ( Fig. 53 ) 1.05-1.10 times as long as wide and approximately 0.95 times as wide as head; punctation less fine, less dense, and more distinct than that of head; midline with narrow impunctate band; interstices without microsculpture.

Elytra long and large, approximately 1.15 times as long as, and much broader than pronotum; humeral angles marked; lateral margins convex ( Fig. 53 ); punctation dense and shallow, weakly defined; interstices without microsculpture. Hind wings fully developed. Metatarsomere I approximately as long as II.

Abdomen narrower than elytra, widest at segment VI; punctation fine and moderately dense; interstices with pronounced microsculpture; posterior margin of tergite VII with palisade fringe.

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun appendix and refers to the small process at the apex of the ventral process of the aedeagus.

C o m p a r a t i v e n o t e s: This species is readily distinguished from its congeners by the conspicuous shape of the small aedeagus, from all the species known from China also by the glossy head and the coloration of the long and large elytra.

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: Trisunius appendiculatus is known only from a single locality in the Gaoligong Shan in western Yunnan, China. The two type specimens were sifted from litter in a degraded primary deciduous forest at an altitude of 2100 m in August. Trisunius ligulatus was found in the same locality.

Figures

Figs 50-56: Trisunius truncatus nov.sp. (50-51) and T. appendiculatus nov.sp. (52-56): (50, 56) aedeagus in lateral view; (51) aedeagus in ventral view; (52) habitus; (53) forebody; (54) male sternite VII; (55) male sternite VIII. Scale bars: 52: 1.0 mm; 53: 0.5 mm; 54-55: 0.2 mm; 50-51, 56: 0.1 mm. Ƌ: sternite VII in posterior median portion weakly impressed, on either side of this impression with moderately dense and not very evident cluster of long setae (Fig. 54); sternite VIII with not very deep, V-shaped excision (Fig. 55); aedeagus small, approximately 0.3 mm long; ventral process laterally compressed, of highly distinctive shape (Fig. 56).