Orphnebius dilatatus, 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 : 51-52

publication ID

https://doi.org/ 10.21248/contrib.entomol.66.1.13-111



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scientific name

Orphnebius dilatatus

sp. nov.

Orphnebius dilatatus View in CoL spec. nov.

( Figs 15 View Figs 1–26 , 28, 36 View Figs 27–39 , 229–232 View Figs 216–235 )

Type material: Holotype ♂: “ Laos, Phongsaly prov., 21°21'N 102°03'E, Ban Sano Mai , 19.–26.v.2004, ~ 1150 m, Vít Kubáň leg. / Holotypus ♂ Orphnebius dilatatus sp. n., det. V. Assing 2015” ( NHMB). GoogleMaps

Paratypes: 1 ♂, 1 ♀: same data as holotype ( NHMB, cAss) GoogleMaps ; 2 ♂♂: “ Laos-N ( Louangphrabang ), 11–21.v.2002, 19°35'N, 101°58'E, Thong Khan , ~ 750 m, Vít Kubáň leg.” ( NHMB, cAss) GoogleMaps .

Etymology: The specific epithet (Latin, adjective) alludes to the medially distinctly dilated condylite of the paramere.

Description: Body size very variable; body length 3.3–5.0 mm; length of forebody 1.3–2.0 mm. Coloration: forebody black; abdomen red; legs with blackish-brown femora, brown tibiae, and reddish tarsi; antennae blackish with antennomeres II–IV at least partly dark-reddish; maxillary palpi brown to dark-brown with the apical palpomere yellowish.

Head ( Fig. 28 View Figs 27–39 ) conspicuously large, strongly wedgeshaped, broadest posteriorly, 1.5–1.6 times as broad as long; anterior margin of clypeus very broad and convexly produced in the middle; punctation extremely fine and sparse. Eyes moderately large and distinctly bulging, situated in posterior portion of head. Antenna ( Fig. 15 View Figs 1–26 ) 1.2–1.7 mm long; antennomere I conspicuously elongate, approximately as long as combined length of antennomeres II–IV; antennomeres III–IV distinctly, V–X weakly flattened; IV–X transverse and of gradually increasing width; X approximately 1.5 times as broad as long; XI nearly as long as combined length of VIII–X.

Pronotum ( Fig. 28 View Figs 27–39 ) 1.52–1.59 times as broad as long and 0.82–0.95 times as broad as head, smaller and narrower in relation to head in larger than in smaller specimens, moderately convex in cross-section; lateral and posterior margins together nearly forming a semi-circle, posterior angles completely obsolete; disc with a median pair of punctures, otherwise impunctate; lateral margins anteriorly with three long, erect, stout black setae.

Elytra ( Fig. 28 View Figs 27–39 ) approximately 0.8 times as long as pronotum; punctation sparse and fine. Hind wings fully developed. Metatarsomere I approximately as long as the combined length of II and III.

Abdomen ( Fig. 36 View Figs 27–39 ): tergites III–VI with a lateral setiferous puncture on either side, VI with four additional punctures at posterior margin; tergite VII primarily with dense longitudinal striae and additional oblong non-setiferous punctures in posterior two-thirds, near posterior margin with some setiferous punctures, posterior margin with palisade fringe; tergite VIII with two transverse series of long black setae posteriorly, posterior margin convex, in the middle truncate; sternite VIII with broadly convex posterior margin.

♂: segments IX–X distinctly modified (of the O. hauseri type), with dense and long pubescence; median lobe of aedeagus ( Figs 229–230 View Figs 216–235 ) 0.60–0.83 mm long, strongly sclerotized, and of very distinctive shape; ventral process strongly curved in lateral view, apically concave in ventral view; paramere ( Fig. 231 View Figs 216–235 ) of highly distinctive shape: paramerite and condylite very slender, condylite strongly dilated in the middle.

♀: segments IX–X distinctly modified (of the O. hauseri type), with dense and long pubescence; spermathecal capsule ( Fig. 232 View Figs 216–235 ) with long and slender distal portion and with coiled proximal portion.

Intraspecific variation: This species is subject to pronounced intraspecific variation of body size. Other variable characters (shape and relative size of the head, length of the antennae, size of the aedeagus, etc.) are related to body size.

Comparative notes: Based on the modifications of the abdominal segments IX–X and on the general morphology, O. dilatatus belongs to the O. hauseri group. As can be inferred from the similarly modified head and pronotum, it is closely allied to O. breviceps CAMERON, 1940 ( Thailand; body length 2.5–2.8 mm), O. semivorax PACE, 2000 ( Thailand; male unknown; 2.3 mm), and O. incertus PACE, 2004 ( Thailand; male unknown; 3.5 mm). It is distinguished from all of them by larger body size and (except O. semivorax ) different coloration of the forebody.

Distribution and natural history: The specimens were collected in two localities in Phongsaly and Louangphrabang provinces, North Laos, at altitudes of approximately 750 and 1500 m. In the type locality they were found together with O. cultellatus and O. serratus , and in the locality in Louangphrabang together with O. extensus , O. serratus , O. latitibialis , O. bicuspis , O. retunsus , O. cultellatus , and O. carinatus .


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