Tetrabothrus punctiventris, 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 : 102

Tetrabothrus punctiventris spec. nov.

( Figs 163–166 )

Type material: Holotype ♂ [teneral]: “ Sabah, Mt. Kinabalu , 1550–1650 m, 24.IV.1987, Burckhardt-Löbl / Holotypus ♂ Tetrabothrus punctiventris sp. n., det. V. Assing 2016 ” ( MHNG).

Comment: The specific epithet (adjective) alludes to the dense and distinctive non-setiferous punctation on tergites VII and VIII.

Description: Body length 5.4 mm; length of forebody 2.2 mm. Coloration: body pale-brown, with the posterior margins of the abdominal segments yellowish; legs pale-yellowish; antennae bicoloured, with antennomeres IV–VIII dark-brown, I–III yellowish, and IX–XI dark-yellowish; maxillary palpi yellowish.

Head ( Fig. 163 ) strongly transverse, 1.3 times as broad as long, with weakly marked posterior angles, extensively impunctate in the middle; punctation in lateral dorsal portions fine and rather dense. Eyes large, approximately as long as distance from posterior margin of eye to posterior constriction of head. Antenna ( Fig. 164 ) 1.4 mm long.

Pronotum ( Fig. 163 ) 1.15 times as broad as long and 1.08 times as broad as head, somewhat flattened in postero-median portion of disc; punctation fine and rather dense, except along the impunctate midline; pubescence long and depressed to suberect.

Elytra ( Fig. 163 ) long, approximately 1.1 times as long as pronotum; punctation fine and rather dense. Hind wings fully developed. Metatarsomere as long as the combined length of metatarsomeres II and III.

Abdomen ( Fig. 165 ) narrower than elytra and with deep anterior impressions on tergites III–VI; tergites III–VI each with four setiferous punctures at posterior margins; tergite VII ( Fig. 166 ) with coarse and moderately dense non-setiferous punctation in anterior three-fourths, posterior margin with palisade fringe; tergite VIII with very dense and moderately coarse non-setiferous punctation in anterior three-fourths (much denser and less coarse than that of tergite VII), posteriorly with a pair of setiferous punctures.

♂: posterior margin of sternite VIII produced, broadly truncate in the middle; median lobe of aedeagus ( Fig. 450–451 ) 0.53 mm long, with pronounced crista apicalis; ventral process subapically angled in lateral view; paramere nearly 0.7 mm long, its apical lobe of moderate length and somewhat conical.

Comparative notes: Tetrabothrus punctiventris is distinguished from its congeners particularly by the dense and extensive non-setiferous punctation of tergites VII and VIII, the medially depressed pronotum, the coloration of the antennae, as well as by the shape of the aedeagus, above all the pronounced crista apicalis. It additionally differs from T. malaysianus , the only other species with non-setiferous punctation on tergite VII known from Borneo, by the uniformly yellowish legs, the much paler coloration of the body, and the medially truncate posterior margin of the male sternite VIII.

Distribution and natural history: The type locality is situated in northern Borneo ( Malaysia: Sabah). The slightly teneral holotype was collected at an altitude of 1550–1650 m, probably by sifting.

Figures

Figs 160–180. Tetrabothrus borneensis, holotype (160–162), T. punctiventris (163–166), T. sulawesicus (167–169), Zyras illecebrosus, paratype (170–172), Z. gibbus, holotype (173–177), and Z. quasar, holotype (178–180): forebody (160, 163, 167, 170, 173, 178); antenna (161, 164, 168, 171, 174, 179); abdomen (162, 165, 169, 172, 175, 180); tergite VIII (166); tergite III (176); tergites VII– VIII (177). Scale bars: 160–165, 167–175, 178–180: 1.0 mm; 166, 176–177: 0.5 mm.

Figs 442–458. Tetrabothrus collucatus (442–443), T. borneensis (444–449), T. punctiventris (450–451), T. sulawesicus (452–454), Zyras illecebrosus, paratype (455–456), and Z. quasar, holotype (457–458): median lobe of aedeagus in lateral and in ventral view (442–445, 450–453, 455–458); apico-ventral portion of median lobe in lateral view (446–448); male sternite VIII (449, 454). Scale bars: 0.2 mm.