Orphnebius (Deroleptus) cultellatus, 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 : 68-69

Orphnebius (Deroleptus) cultellatus spec. nov.

( Figs 59 , 86, 92–94 , 325–334 )

Type material: Holotype ♂: “ Thailand – Chiang Mai, Doi Suthep 890 m, Barber F. III.86. P. Schwendinger / Holotypus ♂ Orphnebius cultellatus sp. n., det. V. Assing 2015” ( MHNG).

Paratypes: 1 ♂, 2 ♀♀: same data as holotype ( MHNG, cAss) ; 1 ♂: same data as holotype, but “ 950 m IV.86 ” ( MHNG) ; 1 ♀: “ Thailand: Chiang Mai, Rd to Wab Pang An , 50 km NE Chiang Mai, 900 m, Burckhardt-Löbl, 3.XI.85 ” ( MHNG) ; 1 ♂, 1♀: “ Laos-N ( Louangphrabang ), 11–21.v.2002, 19°35'N, 101°58'E, Thong Khan , ~ 750 m, Vít Kubáň leg. / Collection Naturhistorisches Museum Basel” ( NHMB); 1 ♀: “ Laos, Phongsaly prov., 21°21'N, 102°03'E, Ban Sano Mai, 19.–26.v.2004, ~ 1150 m, Vít Kubáň leg.” (cAss) .

Etymology: The specific epithet is an adjective derived from the Latin noun cultellus (small knife) and alludes to the knife-shaped ventral process of the aedeagus.

Description: Body length 4.3–5.3 mm; length of forebody 1.7–2.1 mm. Coloration: forebody blackish-brown to black, with the humeral and sutural portions of the elytra usually reddish to reddish-brown; abdomen bicoloured with segments III–VI bright-reddish and VII–X blackish-brown to blackish; legs: femora dark-brown to blackish-brown, tibiae mostly reddish, meso- and metatibiae rarely dark-brown to blackish-brown, tarsi reddish to dark-reddish; antennae blackish-brown to black, with the basal four antennomeres usually more or less extensively reddish to brown; maxillary palpi dark-brown to blackish with the apical palpomere yellowish.

Head ( Fig. 86 ) 1.15–1.19 times as broad as long; lateral dorsal portions with sparse and fine punctation; median dorsal portion extensively impunctate; dorsal surface without microsculpture. Eyes large and bulging, slightly to distinctly longer than the distance from posterior margin of eye to posterior constriction in dorsal view. Antenna ( Fig. 59 ) 1.3–1.5 mm long; antennomere IV oblong and flattened; antennomere V weakly oblong and somewhat flattened; antennomeres VI–X of gradually increasing width and increasingly transverse, X slightly less than 1.5 times as broad as long, and XI slightly shorter than the combined length of VIII–X.

Pronotum ( Fig. 86 ) 1.10–1.15 times as broad as long and slightly broader than head, strongly convex in crosssection; lateral margins straight and subparallel in dorsal view; disc with few scattered macropunctures and with sparse setiferous micropunctation.

Elytra ( Fig. 86 ) approximately as long as pronotum; punctation fine and sparse; pubescence long, depressed to sub-erect; interstices without microsculpture. Hind wings fully developed. Legs long and slender; metatibia 0.85–1.05 mm long; metatarsomere I of variable length, as long as the combined length of II–III, or as long as the combined length of II–IV, or of intermediate length.

Abdomen ( Figs 92–94 ) approximately as broad as (small specimens) or broader than elytra (large specimens); sternites III and IV with distinct postero-lateral processes of highly variable length, width, and shape; tergites III– VI with a lateral puncture on either side and with sparse fine punctures at posterior margins; tergite VII with dense, coarse, and circular non-setiferous punctures in anterior half and with irregular striae in posterior half, postero-median portion smooth, posterior margin with pronounced palisade fringe; tergite VIII ( Fig. 328 ) with dense and coarse non-setiferous punctation, except for a narrow smooth impunctate median band, posteriorly with a pronounced excision and anterior to this excision with a more or less pronounced median tubercle; sternite VIII ( Figs 329–331 ) sharply produced posteriorly, laterally with a comb of 3–4 setiferous tooth-shaped projections; tergite X ( Fig. 332 ) with dense and long pubescence.

♂: sternite VIII ( Fig. 329 ) without oblong folds; median lobe of aedeagus ( Figs 325–326 ) approximately 0.55 mm long; ventral process laterally compressed, somewhat knife-shaped, and sharply edged ventrally; paramere ( Fig. 327 ) 0.45 mm long, condylite with a large velum.

♀: sternite VIII ( Figs 330–331 ) in postero-median portion with a pair of oblong folds; segment IX ( Fig. 332 ) with sclerotized ventral structure of characteristic shape; spermatheca ( Figs 333–334 ) small (0.2 mm) and of simple shape.

Intraspecific variation: The specimens from Laos differ slightly from those from Thailand by the shapes of the female sternite VIII and of the spermatheca ( Figs 330–334 ), but otherwise no evidence was found suggesting that they should represent distinct species.

Comparative notes: Orphnebius cultellatus is characterized not only by the distinctive primary sexual characters, but also by the conspicuous modifications of tergite and sternite VIII.

Distribution and natural history: The species was found in two localities in North Thailand (Doi Suthep and a locality to the northeast of Chiang Mai) and two in Laos. The specimens from the type locality were collected with pitfall traps. The altitudes range from 750 to 1150 m.

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 84–101. Forebody (84–90), abdomen (91–94, 97–98), lateral portion of abdominal segments III–V/VI (95, 99, 101), and tergite VII (96, 100) of Orphnebius spp. of the subgenus Deroleptus: sexcarinatus (84), spoliatus (85, 91), cultellatus (86, 92–94), septemcuspis (87, 95–96), tortus (88, 98–100), vates (89, 97), baccillatus (90, 101). Scale bars: 84–95, 97–99, 101: 1.0 mm; 96, 100: 0.5 mm.

Figs 317–339. Orphnebius spoliatus (317–324), O. cultellatus (325–334: 331, 334: Laos), and O. septemcuspis (335–339): median lobe of aedeagus in lateral and in ventral view (317–318, 325–326, 335–336); paramere (319, 327, 337); tergite VIII (320, 328, 338); male sternite VIII (321, 329, 339); female sternite VIII (322, 330–331); female segments IX–X in ventral view (323, 332); spermatheca (324, 333–334). Scale bars: 0.2 mm.