Orphnebius (Deroleptus) triapicalis, 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 : 65-66

Orphnebius (Deroleptus) triapicalis spec. nov.

( Figs 55, 71, 76 , 307–310 )

Type material: Holotype ♂: “P.R. China, Sichuan, Emei Shan , N29°33'56", E103°21'24", 26.V. 2011, 1829 m, sift06, V. Grebennikov / Holotypus ♂ Orphnebius triapicalis sp. n., det. V. Assing 2015” ( CAS).

Etymology: The specific epithet (adjective) alludes to the tricuspidate posterior margin of the abdominal tergite VIII.

Description: Body length 5.0 mm; length of forebody 2.2 mm. Coloration: head and pronotum blackishbrown; elytra blackish-brown, with the sutural and anterior portion diffusely paler brown; abdomen with tergites III–VI reddish with the antero-median portions indistinctly darker, tergites VII–VIII dark-brown; legs dark brown (femora slightly darker than tibiae) with dark-reddish tarsi; antennae brown with reddish-brown antennomeres I and II; maxillary palpi reddish with the apical palpomere yellowish.

Head ( Fig. 71 ) approximately as long as broad, tapering posteriorly behind eyes; lateral dorsal portions with moderately dense and fine punctation; median dorsal portion only with scattered fine punctures; interstices without microsculpture. Eyes large, slightly shorter than the distance from posterior margin of eye to posterior constriction in dorsal view. Antenna ( Fig. 55 ) 1.6 mm long and rather massive; antennomere IV weakly oblong; antennomeres V–X of conical shape, weakly transverse, and of gradually, but weakly increasing width; X less than 1.5 times as broad as long; XI nearly as long as the combined length of IX and X.

Pronotum ( Fig. 71 ) 1.04 times as broad as long and 1.27 times as broad as head, strongly convex in crosssection; lateral margins nearly straight and subparallel in dorsal view; midline and posterior portion extensively impunctate, on either side of the impunctate median band with a series of denser punctures; lateral and anterior portions with very fine and sparse punctation.

Elytra ( Fig. 71 ) 0.83 times as long and 1.6 times as broad as pronotum; punctation fine and sparse. Hind wings present. Metatarsomere I slightly shorter than the combined length of II–IV.

Abdomen ( Fig. 76 ) narrower than elytra; tergites III–V each with a lateral setiferous puncture on either side and with four setiferous punctures at posterior margin; tergite VI with 2–3 seriate lateral punctures on either side and with four punctures near posterior margin; tergite VII with coarse sculpture mostly composed of dense longitudinal rugae, posterior margin with pronounced palisade fringe; tergite VIII ( Fig. 310 ) with coarsely granulose setiferous punctation and with tricuspidate posterior margin.

♂: sternite VIII slightly longer than tergite VIII, its posterior margin convex; median lobe of aedeagus ( Figs 307–308 ) 0.5 mm long and slender; paramere 0.5 mm long, slender, shaped as in Fig. 309 .

Comparative notes: Based on the similar external (habitus, punctation, tricuspidate posterior margin of tergite VIII) and male sexual characters (shapes of median lobe of aedeagus and of paramere), this species is undoubtedly closely allied to O. tricuspis ASSING, 2009 (male unknown), O. tridentatus ASSING, 2015 , both from Yunnan, and O. nanlingensis PACE, 2004 (Fujian, Guangdong). It is distinguished from them as follows: – from O. tricuspis by paler coloration and bicoloured elytra ( O. tricuspis : forebody uniformly black; femora blackish-brown), a more robust body (O. tricuspis: width of pronotum 0.65 mm, width of elytra 1.0 mm; O. triapicalis : width of pronotum 0.75 mm, width of elytra 1.25 mm), nearly straight metatibiae ( O. tricuspis : metatibiae distinctly curved), the absence of sublateral keels in the posterior portion of tergite VI, and the coarser and denser granules on tergite VIII;

– from O. tridentatus by the coloration ( O. tridentatus : forebody and legs paler; tergite VI blackish-brown, except for the yellowish anterior margin), distinctly more massive antennae, a more convex (cross-section) and less transverse pronotum ( O. tridentatus : pronotum 1.12 times as broad as long), the sculpture of tergite VII ( O. tridentatus : predominantly composed of oblong puncture-like impressions), the longer median projection at the posterior margin of tergite VIII, and the much larger aedeagus ( O. tridentatus : median lobe of aedeagus 0.38 mm long);

– from O. nanlingensis by larger body size, reddish tergites III–VI ( O. nanlingensis : abdomen nearly uniformly dark-brown), much less transverse antennomeres VI–X, less transverse head and pronotum, the longer median process at the posterior margin of tergite VIII, and a much larger and more slender median lobe of the aedeagus ( O. nanlingensis : median lobe of aedeagus 0.38 mm long).

For illustrations of O. tricuspis , O. tridentatus , and O. nanlingensis see ASSING (2006c, 2009, 2015a).

Distribution and natural history: The type locality is situated in southwestern Yunnan, Southwest China. The holotype was collected on the wing.

Figures

Figs 54–83. Antenna (54–69), forebody (70–73), abdomen (74–76), abdominal segments III–V (77, 81), lateral portion of abdominal segments III–V (78, 82), tergites VI–VII (79, 83), and hind leg (80) of Orphnebius spp. of the subgenus Deroleptus: discrepans (54, 73, 75), triapicalis (55, 71, 76), gracilior (56, 72, 77–80), sexcarinatus (57, 81–83), spoliatus (58), cultellatus (59), septemcuspis (60), vates (61), tortus (62), baccillatus (63), carinatus (64), dispar (65), laticeps (66), biimpressus (67), ulcerosus (68), falagrioides (69), siamensis (70, 74). Scale bars: 70–83: 1.0 mm; 54–69: 0.5 mm.

Figs 296–316. Orphnebius niger (296–298), O. siamensis (299–303), O. discrepans (304–306), O. triapicalis (307–310), O. gracilior (311–313), and O.sexcarinatus (314–316): tergite VIII (296, 302, 310, 311, 314); female sternite VIII (297, 312, 315); spermatheca (298, 313, 316); median lobe of aedeagus in lateral and in ventral view (299–300, 304–305, 307–308); paramere (301, 306, 309); male sternite VIII (303). Scale bars: 0.2 mm.