Sclerochiton peniculatus, Assing, 2015

Assing, Volker, 2015, A revision of Sclerochiton. II. Two new species and additional records, including the first records of the genus from Vietnam (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 47 (2), pp. 1197-1208 : 1206-1207

Sclerochiton peniculatus nov.sp. ( Figs 5-14 , Map 4 )

T y p e m a t e r i a l: Holotype 3: "N-Vietnam - 6 km NW Sa Pa , 22°21'39''N, 103°47'19''E, 1810 m, pasture margin, 7.VIII.2013, V. Assing [8+2] / Holotypus 3 Sclerochiton peniculatus sp. n., det. V. Assing 2015" (cAss) . Paratypes: 333, 1♀: same data as holotype (cAss, MNHUB) ; 933, 10♀♀: same data as holotype, but leg Wunderle (cWun, cAss) ; 13, 1♀: "N-Vietnam - 7 km NW Sa Pa , 22°21'49''N, 103°46'49''E, 1840 m, stream valley, 30.VII.2013, V. Assing [3+2]" (cAss, MNHUB) ; 3♀♀: same data, but leg. Wunderle (cWun) ; 433, 3♀♀: "N-Vietnam - 7 km NW Sa Pa , 22°21'49''N, 103°46'49''E, 1850 m, stream valley, 1.VIII.2013, V. Assing [3a+2]" (cAss, MNHUB) ; 13: '"N-Vietnam - pass 8 km NW Sa Pa , 22°21'13''N, 103°46'01''E, 2030 m, forest margin, 9.VIII.2013, V. Assing [10+2]" (cAss) .

E t y m o l o g y: The specific epithet is an adjective derived from the Latin noun peniculus (brush) and alludes to the pair of clusters of long setae at the posterior margin of the male sternite VII.

D e s c r i p t i o n: Body length 3.5-4.2 mm; length of forebody 2.0- 2.2 mm. Habitus as in Fig. 5 . Coloration: body blackish; elytra with or without very indistinct reddish spot; legs yellowish; antenna yellowish with the apical 2-5 antennomeres often slightly darker.

Head ( Fig. 6 ) approximately 1.25 times as wide as long; neck approximately 0.25 times as wide as head across eyes; posterior outline of head smoothly convex, nearly semicircular in dorsal view; punctation coarse, areolate, and extremely dense, interstices reduced to narrow ridges ( Fig. 7 ); dorsal surface matt. Eyes large, nearly twice as long as distance from posterior margin of eye to posterior constriction in dorsal view, with short pubescence. Antennae 0.75-0.80 mm long. Anterior margin of labrum with distinct and narrow median incision.

Pronotum ( Fig. 6 ) small and slender, 1.12-1.18 times as long as broad and approximately 0.75 times as wide as head; punctation slightly coarser and more defined than that of head; pubescence extremely short, shout, and barely noticeable.

Elytra ( Fig. 1 ) approximately as long as, or slightly longer than, pronotum; humeral angles marked; punctation coarse, very dense, defined, not confluent; pubescence fine, short, depressed, and indistinct. Hind wings fully developed. Metatarsomere I elongate, approximately as long as the combined length of II and III.

Abdomen slightly narrower than elytra; punctation very coarse and very dense on tergites III-V ( Fig. 8 ), distinctly sparser and less coarse on tergites VI-VIII ( Fig. 9 ); microsculpture absent; posterior margin of tergite VII with palisade fringe.

3: sternite VII ( Fig. 10 ) strongly transverse, with a rather extensive and distinct impression in postero-median portion, posterior margin broadly and shallowly, but distinctly concave in the middle, on either side of this concavity with a conspicuous dense cluster of long black setae; sternite VIII ( Fig. 11 ) weakly transverse, posterior excision moderately deep and anteriorly convex (not V-shaped), near margins of this excision with a row of very short setae on either side; aedeagus ( Figs 12-14 ) approximately 0.6 mm long and of distinctive shape.

C o m p a r a t i v e n o t e s: Sclerochiton peniculatus is readily distinguished from all its congeners particularly by the distinctive shape and internal structures of the aedeagus, as well as by the shape and chaetotaxy of the male sternite VII. Based on the modifications of the male sternites VII and VIII, as well as on the general morphology of the aedeagus, the new species is most closely allied to S. schuelkei and S. barbatus . It is additionally distinguished from these species as follows:

from S. schuelkei only by the more slender and more oblong pronotum ( S. schuelkei : pronotum 1.05-1.10 times as long as broad);

from S. barbatus by smaller body size, a more slender habitus, the more slender and oblong pronotum, and the very indistinct or obsolete reddish spot on the elytra (always distinct in S. barbatus ).

For illustrations of the external and male sexual characters of other Sclerochiton species see ASSING (2011).

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: The type specimens were collected in several close localities near a pass about 8 km to the northwest of Sa Pa, North Vietnam ( Map 4 ), by sifting leaf litter, roots of herbs, and various debris at the margin of a pasture, near bushes and small trees in steep stream valley, and at the margin of a secondary deciduous forest at altitudes of 1810-2030 m. In all the localities, the species was found together with S. barbatus .

Figures

Map 4: Distributions of Sclerochiton sinuatus (white circles), S. excisus (black circles), S. rougemonti (black diamonds), S. peniculatus (black stars), and S. pectinatus (white star).

Figs 1-7: Sclerochiton pectinatus nov.sp. (1-4) and S. peniculatus nov.sp. (5-7): (1, 6) forebody; (2) male sternite VII; (3) male sternite VIII; (4) aedeagus in lateral view; (5) habitus; (7) antero-median portion of head. Scale bars: 5: 1.0 mm; 1, 6: 0.5 mm; 2-3: 0.2 mm; 4, 7: 0.1 mm.

Figs 8-14: Sclerochiton peniculatus nov.sp.: (8) median portion of tergite IV; (9) median portion of tergite VII; (10) male sternite VII; (11) male sternite VIII; (12-14) aedeagus in lateral and in ventral view. Scale bars: 10-11: 0.2 mm; 8-9, 12-14: 0.1 mm.