Orsunius granulosissimus, Assing, 2015

Assing, Volker, 2015, On Orsunius III. Four new species from China and Thailand, and additional records (Coleoptera: Staphylinidae: Paederinae: Medonina), Linzer biologische Beiträge 47 (1), pp. 83-96 : 88-92

Orsunius granulosissimus nov.sp. ( Figs 12-21 )

T y p e m a t e r i a l: Holotype 3: " CHINA [16] - Yunnan, valley S Gejiu, field margin, 23°08'53''N, 103°10'58''E, 1250 m, 21. VIII.2014, V. Assing / Holotypus 3 Orsunius granulosissimus sp.n. det. V. Assing 2015" (cAss) . Paratypes: 13, 4♀♀ [partly slightly teneral]: same data as holotype (cAss) ; 2♀♀: same data, but leg. Schülke (cSch) ; 1♀: " CHINA [15] - Yunnan, valley S Gejiu, road margin, 23°08'38''N, 103°11'42''E, 1010 m, 21. VIII.2014, V. Assing " (cAss) .

E t y m o l o g y: The specific epithet is the superlative of the Latin adjective granulosus and alludes to the strongly granulose punctation of the head and pronotum.

D e s c r i p t i o n: Body length 4.6-5.4 mm; length of forebody 2.5-2.7 mm. Coloration: body dark-brown to blackish-brown; legs brown; antennae brown with the apical antennomeres gradually paler.

Head ( Figs 12-13 ) more or less distinctly wedge-shaped (dilated posteriad) and strongly transverse, approximately 1.35 times as broad as long; posterior angles rather marked; posterior margin weakly concave, nearly straight; punctation strongly granulose. Ventral aspect with coarse non-granulose punctation and without gular sutures ( Fig. 14 ). Eyes moderately large and moderately bulging, slightly shorter than postocular portion in dorsal view. Antennae 1.3-1.4 mm long; preapical antennomeres moderately transverse. Anterior margin of labrum ( Fig. 14 ) with small concave excision of somewhat variable depth in the middle. Right mandible ( Fig. 14 ) with three large molar teeth, and with or without an additional minute tooth; maxilla and labium as in Figs 15 and 21 .

Pronotum ( Figs 13, 16 ) distinctly transverse, 1.20-1.25 times as wide as long and approximately 1.1 times as broad as head; posterior angles rounded, weakly marked; punctation strongly granulose and not confluent, similar to that of head; midline with or without rudiment of a narrow impunctate band posteriorly; interstices without microsculpture. Prosternum obtusely keeled.

Elytra ( Fig. 12 ) approximately as long as pronotum, with conspicuously long and rather erect dark pubescence; punctation moderately fine and very dense; interstices without microsculpture. Hind wings present. Protarsomeres I-IV not dilated in females, very weakly dilated in males. Metatarsomere I slender and elongated, approximately as long as the combined length of II and III.

Abdomen narrower than elytra; punctation fine and dense, slightly less dense on tergites VII and VIII; interstices without distinct microreticulation; posterior margin of tergite VII with palisade fringe.

3: sternite VII ( Fig. 17 ) with very weakly concave posterior margin, otherwise unmodified; sternite VIII ( Fig. 18 ) distinctly oblong, posterior excision small, but distinct; aedeagus ( Figs 19-20 ) 0.58 mm long, ventral process of distinctive shape, apically hook-shaped in lateral view; dorsal plate weakly sclerotized and small; internal sac with a pair of straight and moderately sclerotized internal structures.

C o m p a r a t i v e n o t e s: Orsunius granulossimus is readily distinguished from all previously described Orsunius species by the strongly granulose punctation of the head and pronotum, larger body size, the erect and long pubescence of the elytra, the absence of gular sutures on the ventral aspect of the head, and the distinctive shape of the aedeagus. For characters separating it from the highly similar and evidently closely related syntopic O. confluens see the comparative notes in the following section.

In view of the pronounced differences between this and other previously described Orsunius species, it is with some hesitation that this species is attributed to Orsunius . The possibility that O. granulosissimus and O. confluens may eventually have to be moved to a separate genus cannot be ruled out. On the other hand, in view of the fact that most of the medonine genera and species of the Oriental region have not yet been subject to modern taxonomic studies, it seems appropriate to adopt a conservative approach and attribute these species to Orsunius , based on the similarities in the general morphology of the male primary and secondary sexual characters, the mouthparts, the habitus, and other external characters.

D i s t r i b u t i o n a n d n a t u r a l h i s t o r y: Thespecimenswerecollected in two adjacent localities in the southeast of Yunnan province, Southwest China, by sifting litter and other debris at a field margin and at a road margin at altitudes of 1250

and 1010 m, respectively. In the type locality the species was found together with O. confluens . The paratypes are partly teneral.

Figures

Figs 12-20: Orsunius granulosissimus nov.sp.: (12) forebody; (13) head and pronotum; (14) head and prothorax in ventral view; (15) maxilla; (16) postero-median portion of pronotum; (17) male sternite VII; (18) male sternite VIII; (19-20) aedeagus in lateral and in ventral view. Scale bars: 12: 1.0 mm; 13-14: 0.5 mm; 15-20: 0.2 mm.

Figs 21-29: Orsunius granulosissimus nov.sp. (21) and O. confluens nov.sp. (22-29): (21) labium; (22) forebody; (23) head and pronotum; (24) median portion of head; (25) postero-median portion of pronotum; (26) male sternite VII; (27-28) aedeagus in lateral and in ventral view; (29) apical portion of aedeagus in lateral view. Scale bars: 22: 1.0 mm; 23: 0.5 mm; 21, 24-29: 0.2 mm.