Orsunius pravus, Assing, 2011

Assing, V., 2011, Orsunius gen. nov. from the Oriental region (Coleoptera: Staphylinidae: Paederinae: Medonina), Linzer biologische Beiträge 43 (1), pp. 221-244 : 235-236

Orsunius pravus nov.sp. ( Figs 50-56 )

T y p e m a t e r i a l: Holotype Ƌ: " Thailand - river near Ban Pong Din , 32 km ENE Chiang Mai, 27.XI.2004, leg. W. Rossi / Holotypus Ƌ Orsunius pravus sp. n. det. V. Assing 2011" (cAss).

D e s c r i p t i o n: Body length 4.2 mm. Habitus as in Fig. 50 . Coloration: head reddish-brown; pronotum reddish; elytra reddish-yellow; abdomen reddish-brown; legs and antennae reddish.

Head approximately 1.2 times as broad as long, weakly dilated posteriad ( Fig. 51 ); posterior margin weakly concave in the middle; punctation coarse and sparse ( Fig. 52 ); interstices glossy, in most of dorsal surface broader than diameter of punctures; sides of head with long black setae. Eyes large and bulging, approximately as long as postocular portion in dorsal view.

Pronotum weakly transverse, 1.06 times as wide as long and approximately 1.05 times as broad as head ( Fig. 51 ); posterior angles rounded, weakly marked; lateral margins visible only in posterior two thirds when viewed from above; punctation denser and less coarse than that of head; midline impunctate ( Fig. 53 ); lateral margins without long black setae.

Elytra approximately 1.05 times as long as pronotum ( Fig. 51 ); punctation very dense and moderately fine; interstices without microsculpture. Hind wings fully developed. Protarsomeres I-IV distinctly dilated; metatarsomere I longer than II and slightly shorter than the combined length of II and III.

Abdomen narrower than elytra; punctation extremely fine, dense on anterior tergites and slightly less dense on posterior tergites; interstices with distinct microsculpture; posterior margin of tergite VII with palisade fringe.

Ƌ: sternite VII with weakly concave posterior margin, otherwise unmodified; sternite VIII oblong, posterior margin weakly concave ( Fig. 54 ); aedeagus 0.55 mm long; ventral process large, laterally compressed, somewhat asymmetric in ventral view, and with apex of distinctive shape ( Figs 55-56 ).

E t y m o l o g y: The specific epithet (Latin, adjective: twisted) alludes to the asymmetric ventral process of the aedeagus.

C o m p a r a t i v e n o t e s: This species is characterized particularly by the morphology of the aedeagus and distinguished from most congeners also by the sparse and coarse punctation of the head, and by the weakly transverse pronotum.

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: Thetypelocalityissituatedin northwestern Thailand, where the holotype was apparently collected on a river bank.

Figures

Figs 50-56: Orsunius pravus nov.sp.: (50) habitus; (51) forebody; (52) anterior median portion of head in dorsal view; (53) median portion of pronotum; (54) male sternite VIII; (55-56) aedeagus in lateral and in ventral view. Scale bars: 50: 1.0 mm; 51: 0.5 mm; 52-56: 0.2 mm.