Stiliderus aviformis, Assing, 2014

Assing, V., 2014, Seven new species and additional records of Stilicoderus and Stiliderus (Coleoptera: Staphylinidae: Paederinae), Linzer biologische Beiträge 46 (1), pp. 481-498 : 493-495

Stiliderus aviformis nov.sp. ( Figs 31-35 )

T y p e m a t e r i a l: Holotype: "NW THAILAND, road 30 km NE Mae Hong Song [sic], 500 m, 21.-23.IV.2004, leg. W. Schawaller / Holotypus Stiliderus aviformis sp. n. det. V. Assing 2013" (SMNS). Paratypes: 3, 7: same data as holotype (SMNS, cAss).

E t y m o l o g y: The specific epithet (Latin, adjective: shaped like a bird) alludes to the shape of the ventral process of the aedeagus (lateral view), which somewhat resembles the contours of a bird´s head.

D e s c r i p t i o n: Body length 5.0- 5.7 mm; length of forebody 3.1-3.4 mm. Habitus as in Fig. 31 . Coloration: body black; legs yellowish with the apices of the profemora weakly and those of the meso- and metafemora more distinctly narrowly infuscate; antennae reddish to brown, with antennomere I blackish.

Head ( Fig. 32 ) very weakly oblong, approximately 1.01-1.05 times as long as broad; lateral margins behind eyes smoothly rounded towards posterior constriction, posterior angles obsolete; punctures moderately coarse, dense, somewhat oval, and not umbilicate; interstices without microsculpture, on average slightly narrower than diameter of punctures. Eyes strongly bulging, approximately half as long as distance from posterior margin of eye to posterior constriction in dorsal view, or slightly longer. Antenna 1.9- 2.0 mm long.

Pronotum ( Fig. 32 ) approximately 1.1 times as long as broad and 0.85 times as broad as head, strongly convex in cross-section; punctation coarse, very dense, and umbilicate; at posterior margin with transverse row of very coarse punctures; midline with complete impunctate band, this band broad and elevated posteriorly, narrow in the middle, and triangularly widened anteriorly; near posterior margin with transverse impunctate band.

Elytra ( Fig. 32 ) short and strongly transverse, approximately 0.6 times as long and 1.3 times as broad as pronotum; punctation very coarse, somewhat irregular in sutural half and indistinctly seriate in lateral half; interstices without microsculpture. Hind wings present.

Abdomen short and broad, approximately 1.1 times as broad as elytra, widest at segments V and VI; punctation extremely fine and dense; pubescence very fine, short, depressed and silvery to greyish, condensed in antero-lateral portions of tergites III-V; anterior portions of tergites with distinct transverse microsculpture, posterior portions of tergites with very indistinct microsculpture at most; posterior margin of tergite VII with palisade fringe.

: sternite VII ( Fig. 33 ) strongly transverse, posterior margin broadly concave; sternite VIII ( Fig. 34 ) transverse, posterior excision U-shaped; aedeagus ( Fig. 35 ) 0.55-0.60 mm long, of similar general morphology as in S. cicatricosus , but with ventral process of different shape.

C o m p a r a t i v e n o t e s: Many species of the S. cicatrisosus group are highly similar not only in external, but also regarding their male secondary sexual characters. In external appearance, S. aviformis is highly similar to the sympatric S. cicatricosus , from which it differs by the less transverse male sternite VII, the less deep posterior excision of the male sternite VIII, and particularly by the shape of the ventral process of the aedeagus. Regarding the latter, S. aviformis is somewhat similar to S. capitalis (BERNHAUER 1928) and S. nitidipennis (BERNHAUER 1928) , both from the Philippines, but the dorsal portion of the aedeagus is of different shape in these species. The male sexual characters of S. cicatricosus are illustrated in Figs 36-38 ; for sketches of the aedeagi of other species of the S. cicatricosus group see ROUGEMONT (1986b, 1996).

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 northwestern Thailand at an altitude of 500 m. The specimens were collected together with S. crassus .

Figures

Figs 31-38: Stiliderus aviformis nov.sp. (31-35) and S. cicatricosus MOTSCHULSKY (Malaysia) (36-38): (31) habitus; (32) forebody; (33, 36) male sternite VII; (34, 37) male sternite VIII; (35, 38) aedeagus in lateral view. Scale bars: 31-32: 1.0 mm; 33-38: 0.2 mm.