Rugilus (Rugilus) bibarbatus, Assing, 2014

Assing, V., 2014, A revision of Palaearctic and Oriental Rugilus. IV. Three new species from Nepal and additional records (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 46 (1), pp. 449-459 : 451-453

Rugilus (Rugilus) bibarbatus nov.sp.

( Figs 1-7 )

Type material: Holotype: " NEPAL, Prov. Karnali, distr. Jumla, Gothichaur, Wald , 2850 m NN, 82°18,1'E, 29°12,1'N, 13.VI.1997, BF, leg. A. Weigel / Holotypus Rugilus bibarbatus sp.n., det. V. Assing 2013" ( NME) . Paratypes: 1: " NEPAL Prov. Seti Distr. Bajura, 19- 16 km SW Simikot, Kuwadi Khola , env. Chauchaur HF , 3500- 2900 m NN 06.07.2001, riverbank leg. A. Kopetz " ( NME) ; 1: " NEPAL, Prov. Karnali, Distr. Jumla, 10 km E Churta , 3500 m NN, 05./ 06.V.1995, leg. M. Hartmann, Gesiebe" ( cAss) .

Etymology: The specific epithet is an adjective composed of the Latin prefix bi- (two) and an adjective derived from the Latin noun barba (beard). It alludes to the two clusters of long black setae on either side of the posterior excision of the male sternite VII.

Description: Body length 5.6-6.2 mm; length of forebody 3.2-3.4 mm. Habitus as in Fig. 1 . Coloration: body blackish; elytra with or without slight bronze hue; legs dark-brown to blackish-brown; antennae dark-reddish, with antennomere I infuscate.

Head ( Fig. 2 ) approximately as broad as long, broadest across eyes; margins behind eyes smoothly curving towards posterior constriction in dorsal view, posterior angles weakly marked; punctation coarse, umbilicate, largely longitudinally confluent, and very dense; interstices reduced to very narrow ridges; surface almost matt. Eyes large and moderately convex, approximately 0.7-0.8 times as long as distance from posterior margin of eyes to posterior constriction. Anterior margin of labrum with two pronounced, basally fused teeth on either side of the narrow median incision.

Pronotum ( Fig. 2 ) approximately 1.15 times as long as broad and approximately 0.8 times as wide as head; midline without impunctate, glossy band; punctation similar to that of head, but somewhat less defined.

Elytra ( Fig. 2 ) long, approximately 1.1 times as long as, and much broader than, pronotum; punctation dense, distinctly finer than that of head and pronotum; interstices glossy. Hind wings fully developed. Metatarsomere I approximately as long as the combined length of II and III, or nearly so.

Abdomen 0.90-0.95 times as broad as elytra; tergites III-VI with shallow impressions anteriorly, these impressions with coarse and dense punctation; punctation of remaining tergal surfaces fine and dense; interstices without distinct microsculpture on tergites III-VI and weakly pronounced microsculpture on tergite VII; posterior margin of tergite VII with palisade fringe.

: sternite VII ( Fig. 3 ) strongly transverse, posterior margin with broad, distinct, and transversely trapezoid excision in the middle, on either side of this excision with a distinct tuft of long black setae; sternite VIII ( Figs 4-5 ) approximately 1.15 times as broad as long, posterior excision somewhat V-shaped and of rather variable depth, 0.23- 0.30 times as deep as length of sternite; aedeagus ( Figs 6-7 ) small in relation to body size, 0.63-0.66 mm long; ventral process of distinctive shape.

Comparative notes: Based on the similar external and male sexual characters, R. bibarbatus is most closely related to R. morvani (ROUGEMONT 1987) from the Dhaulagiri range, from which it differs by the different shape and chaetotaxy of the male sternite VII ( R. morvani : with shallower posterior excision, on either side of this excision without tufts of long setae), by the slightly broader posterior excision of the male sternite VIII, and by the differently shaped ventral process of the aedeagus (apical portion shorter and more strongly curved in lateral view). For a schematic drawing of the aedeagus of R. morvani see ROUGEMONT (1987).

Distribution and natural history: The species was found in three localities in Karnali and Seti provinces, West Nepal. The type specimens were collected by sifting, by hand, and with pitfall traps in forests and on a river bank at altitudes of 2850-3500 m.

Figures

Figs 1-7: Rugilus bibarbatus nov.sp.: (1) habitus; (2) forebody; (3) male sternite VII; (4-5) male sternite VIII (4: Churta env.; 5: Simikot env.); (6-7) aedeagus in lateral view (6: Churta env.; 7: Simikot env.). Scale bars: 1-2: 1.0 mm; 3-5: 0.5 mm; 6-7: 0.2 mm.