Orphnebius (Deroleptus) pertortus, Assing, 2017

Assing, Volker, 2017, On the Lomechusini fauna of the East Palaearctic and Oriental regions, with a focus on the genera Orphnebius and Amaurodera (Coleoptera: Staphylinidae: Aleocharinae), Beiträge Zur Entomologie = Contributions to Entomology 67 (1), pp. 63-106 : 85-86

Orphnebius (Deroleptus) pertortus spec. nov.

urn:lsid:zoobank.org:act:D6784D78-D101-4BF6-B59F-78D0097BF255

( Figs 4, 29–31 , 79–81 )

Type material: Holotype ♀: “ India W. Bengal, Darjeeling dist. , Teesta 250 m. 10.X.78, Besuchet Löbl / Holotypus ♀ Orphnebius pertortus sp. n., det. V. Assing 2016” ( MHNG).

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

Description: Body length 3.8 mm; length of forebody 1.6 mm. Coloration ( Figs 4, 29–31 ): head dark-brown with the anterior portion dark-yellowish; pronotum dark-yellowish with pale-yellowish lateral margins; elytra yellowish with the postero-lateral portions slightly darker; abdomen yellowish with most of segments VI and VII slightly darker; legs yellowish; antennae dark-yellowish; maxillary palpi yellow.

Head ( Fig. 31 ) flattened, strongly transverse, nearly 1.5 times as broad as long, and with moderately marked posterior angles; posterior margin not distinctly concave in the middle; dorsal surface with fine, shallow, and moderately sparse punctation, median dorsal portion impunctate; interstices without microsculpture. Eyes extremely large, occupying almost all of lateral margins of head nearly to posterior margin. Antenna ( Fig. 4 ) 1.3 mm long, weakly incrassate; antennomeres IV approximately as long as broad, V–X weakly to moderately transverse and of gradually increasing width, X less than 1.5 times as broad as long, and XI approximately as long as the combined length of IX and X.

Pronotum ( Fig. 31 ) small in relation to head, of trapezoid shape, and strongly transverse, broadest at anterior angles, 1.5 times as broad as long, and 0.87 times as broad as head, moderately convex in cross-section; lateral margins straight, distinctly converging posteriad in dorsal view; punctation extremely fine and moderately sparse; pubescence depressed, short, and pale; near anterior angles with a moderately long and erect dark seta on either side; midline broadly impunctate.

Elytra ( Fig. 31 ) approximately 1.15 times as long as pronotum; anterior portion of suture with an indistinct elevation at some distance from apex of scutellum; punctation moderately sparse and fine, but much more distinct than that of pronotum; pubescence pale, depressed, much longer than that of pronotum. Hind wings present. Legs moderately long and slender; metatibia 0.85 mm long; metatarsus nearly as long as metatibia; metatarsomere I approximately as long as the combined length of II and III.

Abdomen ( Figs 29–30 ) slightly narrower than elytra; sternites III and IV with large and short, on the whole rather indistinct postero-lateral extension of triangular shape on either side; tergites III–IV each with one, tergite V with two lateral setiferous punctures on either side, tergite VI with a lateral setiferous puncture on either side and with four setiferous punctures at posterior margin; tergite VII in posterior three-fourths with very dense and coarse non-setiferous punctation, near posterior margin with ten long dark setae, posterior margin with palisade fringe; tergite VIII ( Fig. 79 ) with numerous setiferous granules in posterior portion, with a pair of clusters of gland openings anteriorly, posterior margin concave and serrate.

♀: sternite VIII ( Fig. 80 ) transverse, postero-laterally with some stout dark setae on either side, posterior margin weakly concave, nearly concave and narrowly membranous in the middle; spermatheca ( Fig. 81 ) 0.26 mm long, proximal portion of capsule of conspicuous shape, twisted.

Comparative notes: As can be inferred from the similar external characters, particularly the morphology of the head and pronotum, the similar chaetotaxy of the abdomen, as well as the shapes of tergite VIII and of the spermatheca, O. pertortus is closely allied to O. tortus ASSING, 2016 (Meghalaya) of the O. siwalikensis group. It is distinguished from this species by distinctly smaller size ( O. tortus : length of forebody 2.1 mm), much shorter antennae with distinctly transverse antennomeres V–X, shorter elytra with sparse punctation, the absence of pronounced postero-lateral extensions of the abdominal sternites III and IV, the shape of sternite VIII, and by the much shorter and differently shaped spermatheca. For illustrations of O. tortus see ASSING (2016b).

Distribution and natural history: The type locality is situated in Darjeeling District, West Bengal, North India. The holotype was collected at an altitude of 250 m.

Figures

Figs 1–30: Antenna (1–19), forebody (20, 23, 26), abdomen (21, 24, 27, 29), antero-lateral portion of abdomen in lateral-dorsal view (22, 25, 28), and abdominal segment VII (30) of Orphnebius triacuminatus (1, 20–22), O. gracilis (2, 23–25), O. protuberatus (3, 26–28), O. pertortus (4, 29–30), O. reticulipennis (5), Zyrastilbus almorensis (6), Pheidologitonetes bursata (7), Rabdotodrusilla vara (8), Amaurodera bicarinata (9), A. gilvicornis (10), A. latisulcata (11), A. brevipes (12), A. migritheca (13), A. longisetosa (14), A. calicitheca (15), Drusilla smetanai (16), D. nepalensis (17), D. lativentris (18), and Witteia tensa (19). Scale bars: 1–29: 1.0 mm; 30: 0.5 mm.

Figs 31–42:Orphnebius pertortus(31),O. migrus(32–33),O. reticulipennis(34–36),Zyrastilbusalmorensis(37–38),Pheidologitonetes bursata (39–40), and Rabdotodrusilla vara (41–42): forebody (31–32, 34, 37, 39, 41); elytra and abdomen (33); abdomen (35, 38, 40, 42); antero-lateral portion of abdomen in dorso-lateral view (36). Scale bars: 37–38: 1.0 mm; 31–36, 39–42: 0.5 mm.

Figs 62–81: Orphnebius triacuminatus (62–65), O. niger (66–70), O. gracilis (71–74), O. protuberatus (75–78), and O. pertortus (79–81): female tergite VIII (62, 71, 75, 79); posterior margin of female tergite VIII (63); female sternite VIII (64, 72, 76, 80); spermatheca (65, 74, 78, 81); male tergite VIII (66); male sternite VIII (67); median lobe of aedeagus in lateral and in ventral view (68–69); paramere (70); medio-lateral portion of female sternite VIII (73, 77). Scale bars: 62, 64, 66–67:0.5 mm; 68–72, 75–76, 79–80: 0.2 mm; 63, 65, 73–74, 77–78, 81: 0.1 mm.