Tetrabothrus breviatus, Assing, 2016

Assing, Volker, 2016, On some Lomechusini of the Palaearctic and Oriental regions (Coleoptera: Staphylinidae: Aleocharinae), Beiträge Zur Entomologie = Contributions to Entomology 66 (1), pp. 13-111 : 97-98

Tetrabothrus breviatus spec. nov.

( Figs 472–475 )

Type material: Holotype ♂: “ China: Sichuan Prov., Baoxing, 12.VI.2014, Wenxian Shan Park, above Panda Pavilon , 1200 m, 30°22'12"N 102°48'57"E, / sift #14, mixed forest with Pinus , broadleaved trees; trunk bases, debris below small rock, J. Hájek & J. Růžička leg. / Holotypus ♂ Tetrabothrus breviatus sp. n., det. V. Assing 2015” ( NMP).

Comment: The specific epithet is the past participle of the Latin verb breviare (to shorten) and alludes to the short elytra.

Description: Body length 6.0 mm; length of forebody 2.3 mm. Coloration: head blackish-brown; pronotum and elytra dark-brown, with the humeral portions of the elytra paler; abdomen blackish-brown, with the posterior margins of segments III-VI and the apex (segments VII-X) dark-reddish; legs dark-yellowish, with the apices of the metafemora and the metatibiae brown; antennae dark-brown with blackish antennomere I; maxillary palpi yellowish-red.

Head ( Fig. 472 ) moderately transverse, 1.17 times as broad as long, small in relation to pronotum and remainder of body, extensively impunctate in the middle; punctation in lateral dorsal portions fine and moderately sparse. Eyes shorter than distance from posterior margin of eye to posterior constriction of head. Antenna 1.4 mm long.

Pronotum ( Fig. 472 ) weakly transverse, 1.06 times as broad as long and 1.15 times as broad as head, moderately convex in cross-section; punctation very fine and moderately dense in lateral portions; midline broadly impunctate; pubescence long and semi-erect.

Elytra ( Fig. 472 ) short, approximately 0.75 times as long as pronotum; punctation fine and moderately dense; pubescence long and semi-erect. Hind wings not examined, possibly reduced. Metatarsomere I slightly longer than the combined length of metatarsomeres II and III.

Abdomen ( Fig. 473 ) as broad as elytra and with rather deep anterior impressions on tergites III–VI; tergites III– VI with a lateral seta and one or two marginal setae on either side, otherwise impunctate; tergite VII with a transverse series of six setae posteriorly (but directly at posterior margin); tergite VIII with numerous setae at and near posterior margin; posterior margin of tergite VII with a weakly pronounced palisade fringe; posterior margin of tergite VIII weakly convex.

♂: median lobe of aedeagus ( Figs 474–475 ) 0.61 mm long; ventral process relatively long, weakly curved in lateral view, relatively slender in ventral view, and with long and acute apex.

Comparative notes: Tetrabothrus breviatus is distinguished from all of its congeners by the shape of the median lobe aedeagus (particularly the shape of the ventral process), from most of them also by its rather short elytra and the weakly pronounced palisade fringe at the posterior margin of tergite VII. It additionally differs from Tetrabothrus species with similarly short elytra as follows: – from T. micropterus ( Nepal) by a relatively smaller and less transverse head, much darker coloration ( T. micropterous : body yellowish-red), and by the uniformly yellowish pro- and mesofemora (apically infuscate in T. micropterus );

– from T. curtipennis ( Nepal) by the coloration ( T. curtipennis : antennae reddish; all femora yellowish with distinctly infuscate apices; metatibiae pale yellowish), a more slender body, a relatively much smaller and much less transverse head, and denser punctation of the pronotum;

– from T. brevalatus ( China: Yunnan) by a relatively smaller and less transverse head, much paler coloration of the femora ( T. brevalatus : femora dark-reddish), a distinctly more convex (cross-section) and less transverse pronotum, and slightly longer elytra;

– from T. semiapterus ( Taiwan; male unknown) by a relatively smaller and less transverse head, a broader pronotum, the darker coloration of the antennae (reddish in T. semiapterus ), darker metatibiae, and more distinct punctation of the forebody.

Distribution and natural history: The type locality is situated some 120 km to the west of Chengdu, Sichuan ( China). The holotype was sifted in a mixed forest from around trunk bases or from debris below a small rock at an altitude of 1200 m.

Figures

Figs 472–475. Tetrabothrus breviatus: forebody (472); abdomen (473); median lobe of aedeagus in lateral and in ventral view (474–475). Scale bars: 472–473: 1.0 mm; 474–475: 0.2 mm.