Trisunius truncatus, 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 : 211-212

Trisunius truncatus nov.sp. ( Figs 46-51 )

T y p e m a t e r i a l: Holotype Ƌ: " China (Yunnan) Nujiang Lisu Aut. Pref., Nu Shan , 7 km NNW Coajian, 2420 m, 25°43'29''N, 99°07'57''E (second. pine forest with shrubs, litter, moss sifted) 11.VI.2007 D.W. Wrase [30] / Holotypus Ƌ Trisunius truncatus sp.n. det. V. Assing 2011" (cAss) . Paratypes: 11 exs.: same data as holotype (cSch, cAss) ; 16 exs.: " China: Yunnan [CH07- 30], Nujiang Lisu Aut. Pref., Nu Shan , 7 km NNW Coajian, 25°43'29''N, 99°07'57''E, 2420 m, second. pine forest with shrubs, litter, bark sifted, 11.VI.2007, M. Schülke " (cSch, cAss); 5 exs.: same data, but "leg. A. Pütz " (cPüt, cAss); 2 exs.: " China: Yunnan, Lincang Pref., Laobie Shan, Wei Bo Shan pass, 24°08'16''N, 99°42'53''E, 2375 m, creek valley, devastated second. decid. forest, litter & moss sifted, 8.IX.2009, leg. M. Schülke [CH09-35]" (cSch, cAss); 1♀: " China: Yunnan [CH07-20], Nujiang Lisu Aut. Pref., creek valley 3 km SE Gongshan, 1450-1500 m, 27°43'02''N, 98°41'27''E, litter, moss, sifted, 5.VI.2007, leg. A. Pütz " (cPüt) .

D e s c r i p t i o n: Body length 2.8-3.5 mm. Habitus as in Fig. 46 . Coloration: head, pronotum, and abdomen blackish-brown to blackish; elytra blackish-brown to blackish, with the posterior margin and usually also the posterior sutural portion yellowish; legs and antennae reddish.

Head ( Fig. 47 ) weakly oblong, approximately 1.05 times as long as wide; punctation fine and dense, barely noticeable in the pronounced microsculpture. Eyes somewhat more than half as long as postocular region in dorsal view. Anterior margin of labrum with two distinct teeth on either side of median incision.

Pronotum ( Fig. 47 ) 1.05-1.10 times as long as wide and approximately 0.95 times as wide as head; punctation less fine and more distinct than that of head; midline with narrow impunctate band; interstices without distinct microsculpture.

Elytra approximately as long as pronotum; humeral angles marked ( Fig. 47 ); punctation dense and shallow, less distinct than that of pronotum; interstices without microsculpture. Hind wings fully developed. Metatarsomere I approximately as long as II.

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

Ƌ: sternite VII in posterior median portion weakly impressed, on either side of this impression with moderately evident and not very extensive cluster of long setae ( Fig. 48 ); sternite VIII with moderately deep and rather narrow V-shaped excision, midline without pubescence ( Fig. 49 ); aedeagus small, little more than 0.30 mm long; ventral process short, apically truncate, apical margin concave in ventral view ( Figs 50-51 ).

E t y m o l o g y: The specific epithet (Latin, adjective) refers to the short ventral process of the aedeagus.

C o m p a r a t i v e n o t e s: This species is characterized particularly by the small and conspicuously shaped aedeagus, as well as by the coloration of the moderately long elytra, and the strongly microsculptured and finely punctate head.

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 truncatus is known only from three localities in the Nu Shan, the Laobie Shan, and the Gaoligong Shan in the west of the Chinese province Yunnan. The specimens were collected from forest litter at altitudes of 1450-2420 m in June and September. Syntopic species are T. ligulatus and T. iaculatus .

Figures

Figs 41-49: Trisunius schuelkei nov.sp. (41-45) and T. truncatus nov.sp. (46-49): (41, 46) habitus; (42, 47) forebody; (43, 48) male sternite VII; (44, 49) male sternite VIII; (45) aedeagus in lateral view. Scale bars: 41, 46: 1.0 mm; 42, 47: 0.5 mm; 43-44, 48-49: 0.2 mm; 45: 0.1 mm.

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).