Orphnebius (Deroleptus) gracilis, 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 : 75-77

Orphnebius (Deroleptus) gracilis spec. nov.

urn:lsid:zoobank.org:act:F52577E3-1AD2-4C33-80E9-1C129D969EFB

( Figs 2, 23–25 , 71–74 )

Type material: Holotype ♀: “ INDIA 28 Madras , Palni H. 16 km E. de Kodaikanal, 1400 m. 15-XI-72, Besuchet Löbl Mussard / Holotypus ♀ Orphnebius gracilis sp. n., det. V. Assing 2016” ( MHNG).

Etymology: The specific epithet (Latin, adjective: slender) alludes to the slender habitus and the pronounced resemblance to O. gracilior ASSING, 2016 .

Description: Body length 5.0 mm; length of forebody 2.0 mm. Coloration ( Figs 2, 23–24 ): head and pronotum blackish-brown; elytra brown with the postero-lateral portion extensively, but indistinctly darker; abdomen dark-brown with tergites II–III, the posterior margins of tergites IV–VII, and part of the paratergites pale-brown; legs yellowish; antennae with antennomeres I–V reddish, VI–XI gradually becoming darker, and IX–XI dark-brown; maxillary palpi brown with the apical palpomere yellowish. Head ( Fig. 23 ) as long as broad, broadest across eyes, tapering behind eyes, posterior angles practically obsolete; punctation moderately dense, fine, and shallow; median dorsal portion impunctate; interstices without microsculpture. Eyes large and bulging, approximately as long as distance from posterior margin of eye to posterior constriction in dorsal view. Antenna ( Fig. 2 ) 1.6 mm long and slender; antennomeres IV approximately twice and long as broad, V–VI approximately 1.5 times as long as broad, VII weakly oblong, VIII approximately as broad as long, IX–X weakly transverse, and XI slightly longer than the combined length of IX and X.

Pronotum ( Fig. 23 ) approximately as long as broad and slightly broader than head, antero-medially strongly concave; lateral margins weakly sinuate in posterior half; posterior angles moderately marked; margins finely carinate; disc with a median pair of larger punctures behind middle, otherwise extremely finely punctured.

Elytra ( Fig. 23 ) 0.92 times as long as, and much broader than pronotum; punctation distinct, dense, and somewhat granulose, slightly denser anteriorly than posteriorly. Hind wings fully developed. Legs long and slender; mesotibia weakly, metatibia distinctly curved in apical half; metatibia 1.0 mm long; metatarsomere I approximately as long as the combined length of II and III.

CONTRIBUTIONS TO ENTOMOLOGY: BEITRÄGE ZUR ENTOMOLOGIE — 67 (1) 063–106

bars: 1.0 mm.

Abdomen ( Figs 24–25 ) broader than elytra, broadest at segment IV, gradually tapering posteriad; sternite III with an acute, oblique, and moderately long postero-lateral process on either side; tergite III unmodified; tergites III– VI each with a lateral setiferous puncture on either side; tergite VI without lateral keels; tergite VII anteriorly with eleven oblong impressions separated by narrow carinae, laterally with coarse non-setiferous punctation, posteromedially with a glossy area without punctation, but with indistinct median tubercle; tergite VIII ( Fig. 71 ) of distinctive shape, posterior margin with two small close protuberances, antero-laterally with a cluster of moderately dense gland openings on either side, and laterally with a cluster of dense short setae on either side.

♂: unknown.

♀: sternite VIII ( Figs 72–73 ) transverse, laterally with a few stout setae inserting in blunt processes, posterior margin strongly projecting in the middle and apically truncate; spermatheca small in relation to body size, 0.2 mm long and shaped as in Fig. 74 .

Comparative notes: As can be inferred from the similarly slender habitus, similarly long and modified legs (metatibiae distinctly curved), similar head shape, and numerous other similarities, O. gracilis is closely allied to O. gracilior (Arunachal Pradesh) of the O. niger group, from which it differs by distinctly shorter and less slender antennae ( O. gracilior : antennae 2.1 mm long and with more oblong antennomeres), shorter metatibiae ( O. gracilior : metatibiae 1.3 mm long), a narrower head in relation to pronotum ( O. gracilior : head at least as broad as pronotum), much coarser and denser punctation of the elytra, a broader abdomen ( O. gracilior : abdomen narrower than elytra), an unmodified abdominal tergite III (with a postero-median process in O. gracilior ), the absence of lateral keels on tergite VI, the modifications of tergite VII, a tergite VIII and a female sternite VIII of completely different shape, and by the shape of the spermatheca. For illustrations of O. gracilior see ASSING (2016b).

Distribution and natural history: The type locality is situated in Madras, Tamil Nadu, Southeast India. The holotype was collected at an altitude of 1400 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 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.