Lobrathium (Lobrathium) bipeniculatum, Assing, 2010

Assing, Volker, 2010, On the Lathrobiina of Taiwan (Coleoptera: Staphylinidae: Paederinae), Beiträge Zur Entomologie = Contributions to Entomology 60 (2), pp. 301-361 : 334-336

Lobrathium (Lobrathium) bipeniculatum sp. n. ( Figs 118-123 )

Type material:

Holotype ♂ [teneral]: " Taiwan, Ilan Hsien , Chyr Duan, 1100 m, 18.IV.90, A. Smetana [ T8 ] / Holotypus ♂ Lobrathium bipeniculatum sp. n., det. V. Assing 2010" (cSme) . Paratypes: 2 ♂ ♂, 1 ♀ [2 ♂ ♂ teneral]: same data as holotype (cSme, cAss) .

Description:

Small species, body length 4.8-6.0 mm. Coloration: body blackish-brown to black; elytra with moderately large reddish-yellow spot of subtriangular shape near posterior margin; middle and hind legs yellowish-brown, profemora dark-brown, protibiae and -tarsi brown; antennae reddishbrown, antennomere I infuscate.

Head approximately 1.05 times as long as wide, widest across eyes; behind eyes convexly tapering posteriad in dorsal view, posterior angles practically obsolete ( Fig. 118 ); punctation very coarse and of variable density, moderately sparse to dense; interstices without microsculpture; eyes large and bulging, 0.7-0.8 times the length of postocular region from posterior margin of eyes to neck in dorsal view. Antenna moderately slender, approximately 1.8 mm long; antennomere X approximately 1.5 times as long as wide.

Pronotum slender, approximately 1.35 times as long as broad and 0.90-0.95 times as broad as head ( Fig. 118 ); punctation as coarse as that of head and moderately sparse; impunctate midline of variable width; interstices without microsculpture.

Elytra long, approximately 1.05 times as long as pronotum ( Fig. 118 ); submarginal line present; punctation coarse, dense, well-defined, and arranged in more or less irregular series.

Abdomen slightly narrower than elytra; anterior impressions of tergites I-IV with dense and coarse punctation, punctation of remainder of tergal surfaces moderately fine and moderately dense; interstices with or without shallow microsculpture, glossy; posterior margin of tergite VII with palisade fringe.

♂: posterior margin of tergite VIII indistinctly angled in the middle ( Fig. 121 ); sternite VII with shallow and small median impression without pubescence, posterior margin rather strongly concave, in the middle with small convex projection ( Fig. 120 ); sternite VIII highly distinctive, with large, oblong median impression, this impression without pubescence (except posterior portion) or peg-setae, on either side with extensive and conspicuous cluster of long black setae, posterior excision large, deep, and broadly V-shaped ( Fig. 121 ); aedeagus approximately 0.9 mm long, ventral process of very distinctive morphology, slender and furcate apically (lateral view) ( Figs 122-123 ).

♀: posterior margin of tergite VIII convexly produced in the middle; sternite VIII somewhat longer than tergite VIII, posterior margin broadly and weakly convex; segments IX-X not particularly slender; tergite IX undivided anteriorly, anterior margin emarginate in the middle; tergite X of subovoid shape, not particularly slender.

Comparative notes:

This species is distinguished from all its congeners particularly by the morphology of the ventral process of the aedeagus, as well as by the shape and chaetotaxy of the male sternites VII-VIII. From other Taiwanese Lobrathium species with a reddish elytral spot, it is additionally separated by the glossy abdomen and the combination of small size, coarse punctation of the head and pronotum, and long elytra.

Etymology:

The specific epithet is an adjective derived from the Latin noun peniculus (brush) and refers to the conspicuous chaetotaxy of the male sternite VIII.

Distribution and natural history:

The type locality is situated in Ilan Hsien, northeastern Taiwan, at an altitude of 1100 m. The material was collected at the edge of a pond by pushing CarexCarex tufts into the water. Three of the type specimens are teneral .

Figures

Figs 118-123: Lobrathium bipeniculatum sp. n.: forebody (118); male tergite VIII (119); male sternite VII (120); male sternite VIII (121); aedeagus in lateral and in ventral view (122-123). Scale bars: 118: 1.0 mm; 119-123: 0.5 mm.