Orsunius incurvatus, 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 : 86-88

Orsunius incurvatus nov.sp. ( Figs 6-11 )

T y p e m a t e r i a l: Holotype 3: " THAILAND - Khao Yai N.P., nr. Haew Narok Falls, 19.XI.2004, leg. W. Rossi / Holotypus 3 Orsunius incurvatus sp.n. det. V. Assing 2015" (cAss). Paratype 3 [slightly teneral]: same data as holotype (cAss).

E t y m o l o g y: The specific epithet is the past participle of the Latin verb incurvare (to bend) and alludes to the curved ventral process of the aedeagus in lateral view.

D e s c r i p t i o n: Body length 4.0- 4.3 mm; length of forebody 2.0- 2.2 mm. Coloration: head blackish-brown, diffusely reddish anteriorly; pronotum reddish; elytra dark-yellowish, each with a large infuscate spot reaching lateral margins, but not suture; abdomen reddish, with the middle of tergites VI and VII indistinctly darker; legs reddish-yellow; antennae reddish.

Head ( Fig. 7 ) strongly transverse, approximately 1.25 times as broad as long; lateral margins behind eyes weakly converging in dorsal view; posterior angles marked; posterior margin only indistinctly concave, nearly straight; punctation umbilicate, dense and rather fine, slightly sparser in median dorsal portion; interstices without microsculpture. Eyes large and bulging, nearly twice as long as postocular portion in dorsal view. Antennae approximately 1.2 mm long; preapical antennomeres very weakly transverse or as long as broad. Anterior margin of labrum with U-shaped excision in the middle. Right mandible with three molar teeth.

Pronotum ( Fig. 7 ) transverse, approximately 1.2 times as wide as long and about as broad as head; posterior angles rounded, weakly marked; punctation non-umbilicate, fine and dense; midline with more or less pronounced narrow impunctate band; interstices without microsculpture.

Elytra ( Fig. 6 ) approximately 1.15 times as long as pronotum; punctation fine and dense, finer than that of pronotum; interstices without microsculpture. Hind wings present. Protarsomeres I-IV dilated. Metatarsomere I much longer than II, nearly as long as the combined length of II and III.

Abdomen narrower than elytra; punctation fine and dense; interstices without distinct microreticulation; posterior margin of tergite VII with palisade fringe.

3: sternite VII unmodified; sternite VIII ( Fig. 8 ) distinctly oblong and with small, but distinct posterior excision; aedeagus ( Figs 9-11 ) 0.68 mm long, ventral process of distinctive shape, apically very acute, subapically curved in lateral view, and very slender in ventral view.

C o m p a r a t i v e n o t e s: Orsunius incurvatus is similar to O. stimulans ASSING, 2014 from Thailand in body shape, coloration, and particularly in the shape of the aedeagus, but distinguished by distinctly larger and more bulging eyes, distinctly less densely punctate and more glossy head and pronotum, the differently shaped posterior excision of the male sternite VIII, and by the distinctly curved ventral process of the aedeagus in lateral view. For illustrations of O. stimulans see ASSING (2014).

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: The type locality is situated in Khao Yai National Park (approximately 14°17'N, 101°23'E) in Thailand. The specimens were collected by hand near water (ROSSI pers. comm.). The paratype is slightly teneral.

Figures

Figs 6-11: Orsunius incurvatus nov.sp.: (6) forebody; (7) head and pronotum; (8) male sternite VIII; (9-10) aedeagus in lateral and in ventral view; (11) ventral process of aedeagus in ventral view. Scale bars: 6-7: 0.5 mm; 8-11: 0.2 mm.