Sclerochiton pectinatus, 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 : 1203-1206

Sclerochiton pectinatus nov.sp. ( Figs 1-4 , Map 4 )

T y p e m a t e r i a l: Holotype 3: " Laos: Vientiane prov.: Vientiane, 22.vi.2008; 160 m, 17°57.597'N 102°36.518'E / A. Solodovnikov & J. Pedersen leg., Bank of river Mekong ; in decaying debris; ZMUC collection / Holotypus 3 Sclerochiton pectinatus sp. n., det. V. Assing 2012" ( ZMUC) . Paratypes: 2♀♀: same data as holotype ( ZMUC, cAss) .

E t y m o l o g y: The specific epithet (Latin, adjective: with a comb) alludes to the arrangement of the internal spines of the aedeagus.

D e s c r i p t i o n: Body length 2.9-3.3 mm; length of forebody 1.6-1.7 mm. Coloration variable: body uniformly reddish or elytra with indistinct and weakly delimited, slightly darker area posteriorly; legs yellowish; antennae yellowish, gradually darkened apically. (Note that the holotype is distinctly darker, with the body blackish-brown, the pronotum dark-brown, the elytra brown, and the appendages dark-brown, apparently a result of post-mortem darkening.)

Head ( Fig. 1 ) strongly transverse, approximately 1.35-1.40 times as wide as long; neck slender, approximately 0.25 times as wide as head across eyes; posterior margin straight; punctation coarse, areolate, and extremely dense, interstices reduced to narrow ridges; dorsal surface matt. Eyes large, practically reaching posterior margin, with short pubescence. Antennae approximately 0.55 mm long. Anterior margin of labrum feebly concave in the middle.

Pronotum ( Fig. 1 ) approximately as long as broad or weakly oblong 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 pronotum; humeral angles marked; punctation similar to that of head, partly confluent; pubescence fine, short, depressed, and indistinct. Hind wings present. Metatarsomere I elongate, approximately as long as the combined length of II and III.

Abdomen distinctly narrower than elytra; punctation rather coarse and very dense on tergites III-V, distinctly sparser on tergites VI-VIII; tergites III-V matt, tergites VI-VIII glossy; posterior margin of tergite VII with palisade fringe.

3: sternite VII ( Fig. 2 ) with long pubescence, posteriorly weakly concave in the middle; posterior excision of sternite VIII of moderate depth and V-shaped ( Fig. 3 ); aedeagus ( Fig. 4 ) 0.37 mm long and of distinctive shape, with comb-like series of internal spines.

C o m p a r a t i v e n o t e s: Using the key in ASSING (2011), S. pectinatus would key out at couplet 4, together with S. rougemonti . It is distinguished from this species by paler coloration and by the male sexual characters, particularly the shape and chaetotaxy of the male sternite VII and the morphology of the aedeagus (shape of the ventral process and the comb-like arrangement of internal spines).

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 locality is situated near Vientiane, Laos, very close to the border with Thailand ( Map 4 ). The specimens were collected from debris at the bank of Mekong river at an altitude of 160 m.

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.