Orphnebius retunsus, 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 : 60

Orphnebius retunsus spec. nov.

( Figs 12 , 45 , 279–282 )

Type material: Holotype ♂: “ Laos-N ( Louangphrabang ), 11–21.v.2002, 19°35'N, 101°58'E, Thong Khan , ~ 750 m, Vít Kubáň leg. / Holotypus ♂ Orphnebius retunsus sp. n., det. V. Assing 2015” ( NHMB).

Etymology: The specific epithet (Latin, adjective: blunt) alludes to the dorsally flattened paratergites.

Description: Body length 3.3 mm; length of forebody 1.6 mm. Coloration: head blackish-brown (except for the reddish clypeus and the mouthparts), remainder of body reddish; legs and maxillary palpi yellowish; antennae reddish.

Head ( Fig. 45 ) strongly transverse, 1.4 times as broad as long; posterior angles completely obsolete; punctation of lateral portions extremely fine, barely visible, and very sparse; median and posterior dorsal portions extensively impunctate; interstices without microsculpture. Eyes extremely large, occupying all of lateral margins of head, and strongly bulging. Antenna ( Fig. 12 ) 1.0 mm long, strongly incrassate; antennomere IV strongly transverse, approximately twice as broad as long; antennomeres V–X even more transverse, nearly three times as broad as long (disc-shaped) and gradually increasing in width; XI nearly as long as the combined length of VIII–X.

Pronotum ( Fig. 45 ) strongly transverse, approximately 1.4 times as broad as long and as broad as head, moderately convex in cross-section; posterior angles moderately marked; disc with a median pair of punctures, otherwise practically impunctate.

Elytra ( Fig. 45 ) nearly as long as pronotum; suture distinctly gaping posteriorly; punctation moderately sparse and very fine; pubescence very fine and pale, barely visible. Hind wings fully developed. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen: segments III–VI with relatively broad (with distinct dorsal surface) and weakly elevated paratergites; tergites III–VI each with a lateral setiferous puncture on either side; tergite VI additionally with four setiferous punctures at posterior margin; tergite VII anteriorly with dense and coarse striae, posteriorly with oblong non-setiferous punctation, and with a transverse row of indistinct oblong setiferous tubercles near posterior margin, posterior margin with palisade fringe; posterior margin of tergite VIII ( Fig. 282 ) broadly convex, in the middle truncate; sternite VIII with convex posterior margin.

♂: hemi-tergites IX and tergite X with extremely dense and long pubescence; median lobe of aedeagus ( Figs 279–280 ) 0.53 mm long; ventral process long and apically acute in ventral view; internal sac without strongly sclerotized structures; paramere ( Fig. 281 ) nearly as long as median lobe; paramerite and condylite of subequal length, somewhat wedge-shaped, and apically acute.

♀: unknown.

Comparative notes: Based on the modifications of the abdominal tergites IX and X, as well as the shapes and chaetotaxy of tergite and sternite VIII, O. retunsus belongs to the O. hauseri group. It is distinguished from the species of the O. hauseri subgroup by the different coloration, enormous eyes, strongly transverse antennomeres IV–X, the broad (not sharp) and less strongly elevated paramerites of the abdominal segments III–VI, and by the absence of strongly sclerotized structures in the internal sac of the aedeagus. Since the species does not belong to the O. dilatatus and O. serratus subgroups either, it probably represents a subgroup of its own.

Distribution and natural history: The type locality and the circumstances of collection are identical to those of O. bicuspis .

Figures

Figs 1–26. Antenna (1–21) and forebody (22–26) of Orphnebius spp. of the O. hauseri group: spinans (1, 23), cernens (2, 24), lunatus (3, 25), bakeri (4, 26), breviceps (5), extensus (6), serratus (7), integer (8), bicuspis, Laos (9), bicuspis, NE India (10), fusicollis (11), retunsus (12), fodens (13), opticus (14), dilatatus (15), fuscapicalis (16), grandicollis (17, 22), reductus (18), biformis, male (19), biformis, female (20), effeminatus (21). Scale bars: 22–26: 1.0 mm; 1–21: 0.5 mm.

Figs 40–53. Forebody (40–50), abdomen (51), and antenna (52–53) of Orphnebius spp. of the O. hauseri group (40–49) and of the subgenus Deroleptus (50–53): opticus (40), effeminatus (41), biformis, male (42), biformis, female (43), bicuspis, NE India (44), retunsus (45), fusicollis (46–47), fodens (48), reductus (49), niger (50–52), siamensis (53). Scale bars: 1.0 mm.

Figs 277–295. Orphnebius biformis (277–278), O. retunsus (279–282), O. fodens (283–286), O. effeminatus (287–292), and O. multimpressus (293–295): median lobe of aedeagus in lateral and in ventral view (277–280, 283–284, 287–288, 293–294); paramere (281, 285, 289, 295); tergite VIII (282, 286, 290); median portion of tergite VIII (291); male tergites IX-X (292). Scale bars: 0.2 mm.