Orphnebius (Deroleptus) ulcerosus, 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 : 75

Orphnebius (Deroleptus) ulcerosus spec. nov.

( Figs 68 , 105, 115–116 , 365–369 )

Type material: Holotype ♂: “ Borneo, Sabah, Tibow , 45 km NE of Sapulut, 600–900 m, 7–15 Apr 2000, Bolm lgt. / Holotypus ♂ Orphnebius ulcerosus sp. n., det. V. Assing 2015” ( NHMB).

Etymology: The specific epithet (Latin, adjective: with ulcers) alludes to the tubercles and other elevations on the elytra.

Description: Body length 5.2 mm; length of forebody 2.2 mm. Coloration: head blackish; pronotum and elytra blackish-brown, with the elytral suture dark-reddish; abdomen reddish-brown with the antero-median portions of tergites III–VI dark-brown; legs pale-brown; antennae dark-brown with antennomeres II–III and apex of XI reddish and antennomere I brown; maxillary palpi reddish with the apical palpomere yellowish.

Head ( Fig. 105 ) strongly transverse, 1.37 times as broad as long; punctation in lateral portions sparse, shallow, and fine; median and posterior dorsal portions extensively impunctate; interstices without microsculpture. Eyes enormous and bulging, nearly reaching posterior margin of head. Antenna ( Fig. 68 ) 1.4 mm long and weakly incrassate; antennomere IV approximately as long as broad; antennomeres V–X weakly transverse, gradually and very weakly increasing in width; X less than 1.5 times as broad as long; XI barely as long as the combined length of IX and X.

Pronotum ( Fig. 105 ) 1.3 times as broad as long and as broad as head, moderately convex in cross-section, of subrectangular shape; lateral margins straight in dorsal view; posterior angles moderately marked; behind middle with two circular impressions separated by a narrow carina; disc with scattered punctation.

Elytra ( Fig. 106 ) 1.13 times as long as, and much broader than pronotum; each elytron with a small median tubercle, with an oblique elevation near postero-sutural angle, and with an extensive, moderately deep impression externally limited by an oblong elevation in posterior half; punctation fine and sparse; interstices with pronounced microsculpture composed of obliquely transverse meshes; pubescence short and indistinct. Hind wings present. Legs of moderate length and moderately slender; metatibia 1.15 mm long and distinctly curved; metatarsus little more than 0.8 times as long as metatibia; metatarsomere I nearly as long as the combined length of II–IV.

Abdomen broad, much broader than elytra; sternites III–V not distinctly modified, only lateral portion of sternite weakly elevated; paratergites IV each with an anterior tubercle; setiferous punctation of tergites III– VII as in O. biimpressus ; anterior and lateral portions of tergites III–VI with distinct microreticulation; tergite V with a pronounced and extensive median impression; tergite VI with a pair of distinct lateral tubercles at posterior margin and with additional smaller granules between these tubercles; tergite VII with non-setiferous punctation, posterior margin with palisade fringe; tergite VIII ( Fig. 368 ) transverse, anteriorly with a pair of extensive clusters of numerous gland openings, posterior margin distinctly serrate and broadly excised; sternite VIII ( Fig. 369 ) strongly transverse, laterally with a cluster of several very stout setae inserting in sclerotized projections, posterior margin nearly truncate in the middle.

♂: median lobe of aedeagus ( Figs 365–366 ) 0.55 mm long; paramere as in Fig. 367 .

♀: unknown.

Comparative notes and comment: Based on the similar morphology of the antennae and the head, the shared median impression(s) on the pronotum, the similarly shaped pronotum, the shared presence of microsculpture and of a lateral elevation on the elytra, the shared presence of microsculpture in the anterior portions of tergites III–VI, the shared presence of a pair of tubercles at the posterior margin of tergite VI, the similar shapes of tergite and sternite VIII, as well as the presence of a distinct anterior pair of clusters of numerous gland openings on tergite VIII, O. ulcerosus is very closely allied to O. biimpressus , from which it differs by larger body size, the pair of impressions on the pronotum, the modifications and more pronounced microsculpture of the elytra, a much broader abdomen, the presence of an anterior tubercle on paratergites IV, the absence of lateral tubercles on tergites IV–VI, the more widely separated lateral tubercles and the additional smaller tubercles at the posterior margin of tergite VI, the weakly concave posterior margins of tergites IV and V, and the deep median impression of tergite V.

Distribution and natural history: The type locality is situated in Sabah, North Borneo, Malaysia, at an altitude between 600 and 900 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 102–118. Forebody (102–108), abdomen (109–110, 112–113, 115), lateral portion of abdominal segments III–V/ VII (111, 117–118), and tergites VII(–VIII) (114, 116) of Orphnebius spp. of the subgenus Deroleptus: carinatus (102, 117), laticeps (103, 112), biimpressus (104, 108, 113–114), ulcerosus (105, 115–116), dispar (106, 110–111), falagrioides (107, 118), baccillatus (109). Scale bars: 102–110, 112–113, 115, 117–118: 1.0 mm; 111, 114, 116: 0.5 mm

Figs 359–378. Orphnebius laticeps (359–361), O. biimpressus (362–364), O. ulcerosus (365–369), O. falagrioides (370–372), and Drusilla bifida (373–378): tergite VIII (359, 362, 368, 370, 374); female sternite VIII (360, 363, 371); spermatheca (361, 364, 372); median lobe of aedeagus in lateral and in ventral view (365–366, 376–377); paramere (367); male sternite VIII (369, 375); posteromedian portion or head (373); apex of ventral process of aedeagus (378). Scale bars: 359–372, 374–377: 0.2 mm; 373, 378: 0.1 mm.