Orphnebius (Deroleptus) tortus, 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 : 71

Orphnebius (Deroleptus) tortus spec. nov.

( Figs 62 , 88, 98–100 , 345–347 )

Type material: Holotype ♀: “ India Meghalaya, Khasi Hills 1000 m, Mawsynram–Balat 27.X.78, Besuchet-Löbl / Holotypus ♀ Orphnebius tortus sp. n., det. V. Assing 2015” ( MHNG).

Etymology: The specific epithet is the past participle of the Latin verb torquere (to twist) and alludes to the twisted proximal portion of the spermatheca.

Description: Body length 5.4 mm; length of forebody 2.3 mm. Coloration: head yellowish-brown; pronotum dark-yellowish; elytra yellowish; abdomen with segments III–IV and VIII yellowish, V–VI yellowish-brown, and VII somewhat infuscate; legs yellowish; antennae reddish-brown with the basal 4–5 antennomeres reddish; maxillary palpi pale-reddish, with the terminal palpomere yellowish.

Head ( Fig. 88 ) flattened, strongly transverse, 1.5 times as broad as long, and with moderately marked posterior angles; posterior margin concave in the middle; dorsal surface with fine, shallow, and moderately sparse punctation, median dorsal portion impunctate; interstices without microsculpture. Eyes extremely large, extending along almost all of lateral margins of head nearly to posterior margin. Antenna ( Fig. 62 ) 1.8 mm long, not incrassate; antennomeres IV–VII oblong, VIII approximately as long as broad, IX–X weakly transverse, and XI slightly longer than the combined length of IX and X.

Pronotum ( Fig. 88 ) small and strongly transverse, broadest near anterior angles, 1.5 times as broad as long, and 0.9 times as broad as head, moderately convex in cross-section; lateral margins straight, weakly converging posteriad in dorsal view; punctation very fine and moderately dense; pubescence suberect, short, and pale; near anterior angles probably with a long seta on either side (puncture visible, but setae broken off in the holotype).

Elytra ( Fig. 88 ) approximately 1.25 times as long as pronotum; along anterior half of suture with narrow and indistinct elevation; punctation moderately dense and fine, but much more distinct than that of pronotum, weakly granulose in posterior portion; pubescence pale, moderately short, and depressed. Hind wings present. Legs long and slender; metatibia 1.3 mm long; metatarsus approximately 0.9 times as long as metatibia; metatarsomere I approximately as long as the combined length of II and III.

Abdomen ( Figs 98–100 ) broader than elytra; sternite III with a large, but not very long lateral extension of triangular shape; sternite IV with long, slender but somewhat massive, dorso-ventrally flattened, weakly erect, and apically acute postero-lateral extension; paratergite IV with a smaller, spine-shaped, and apically convex posterior extension; posterior extensions of paratergites and sternite IV contiguous; tergites III–VI each with one or two lateral setiferous punctures on either side, tergite VI additionally with median pair of setiferous punctures at posterior margin; tergites III each with a small tubercle on either side; tergite VII in posterior three-fourths with very dense and coarse non-setiferous punctation, near posterior margin with twelve setiferous granules, posterior margin with palisade fringe; tergite VIII ( Fig. 345 ) with numerous setiferous granules in posterior portion, with dense short pubescence anteriorly, with a transverse series of non-setiferous teeth near posterior margin, with numerous small gland openings near anterior margin, and with a pair of extensive clusters of gland openings anteriorly, posterior margin concave; sternite VIII ( Fig. 346 ) transverse and with smoothly convex posterior margin, laterally with a cluster of stout black setae on either side.

♀: spermatheca ( Fig. 347 ) of distinctive shape, proximal portion of capsule of conspicuous shape, twisted.

Comparative notes: As can be inferred from the similar external characters, particularly the shared morphology of the head, the similar modifications of the head and the abdominal segment IV, O. tortus is undoubtedly closely allied to O. baccillatus (see the following section), from which it differs particularly by paler coloration, more slender antennae, the slightly different shapes of the posterior processes of sternite and paratergites IV, the deeper posterior excision of tergite VIII, and the shape of the spermatheca.

Distribution and natural history: The type locality is situated in the Khasi Hills, Meghalaya, Northeast India. The slightly teneral holotype was collected at an altitude of 1000 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 340–358. Orphnebius vates (340–344), O. tortus (345–347), O. baccillatus (348–350), O. carinatus (351–353), and O. dispar (354–358): median lobe of aedeagus in lateral and in ventral view (340–341, 354–355); paramere (342, 356); tergite VIII (343, 345, 348, 351, 357); male sternite VIII (344); female sternite VIII (346, 349, 352); spermatheca (347, 350, 353, 358). Scale bars: 0.2 mm.