Priochirus (Eutriacanthus) pulchellus, Wu & Zhou, 2007

Wu, Jie & Zhou, Hong-zhang, 2007, Taxonomy Of The Subgenus Eutriacanthus Jakobson, Of The Genus Priochirus Sharp, From Southern China, With The Description Of Two New Species From Guangxi And Yunnan (Coleoptera: Staphylinidae: Osoriinae), Raffles Bulletin of Zoology 55 (2), pp. 267-276 : 269-271

Priochirus (Eutriacanthus) pulchellus , new species

( Figs. 3–7 )

Material examined. – Holotype: male, China, Xishuangbanna , Damenglong, 650 m, 18 Apr.1958, Leyi Deng coll. ( IOZ-CAS).

Paratypes: 2 females, same data as holotype ( IOZ-CAS) ; 1 male, 2 females, China, Xishuangbanna , Damenglong, 650 m, 16 Apr.1958, Shuyong Wang coll. ( IOZ-CAS) ; 1 male, China, Xishuangbanna , Damenglong, 650 m, 16 Apr.1958, Xuwu Meng coll. ( ZRC) ; 1 female, China, Xishuangbanna , Damenglong, 650 m, 16 Apr.1958, Yiran Zhang coll. ( ZRC) .

Description. – Body moderately depressed. Antennae reddish-brown; head dark red and shiny with anterior margin reddish; pronotum and elytra dark red; femorae and tibiae reddish, tarsi slightly yellowish; abdomen dark red with 8th segment red.

Head transverse ( Fig. 3 ), parallel-sided, frontal angle weakly convex behind lateral teeth; frontal impression about twice as wide as median length, posterior margin medially protruding backwards; median tooth triangularly projecting and sharply pointed, distinctly longer than two lateral teeth, base slightly convex along central disc of frontal impression; lateral teeth short and pointed, weakly divergent anteriorly, but with their apex slightly curved inwards, lateral face with 4 or 5 setae turning upward, medial face with row of long setae extending onto anterior margin; median sulcus deep, scarcely connected with frontal impression, gradually broadened backwards, posterior end distinctly wider than middle width of median longitudinal sulcus on pronotum; vertex smooth, along lateral and postero-lateral margin with some scattered punctures and setae, posterior margin near to posterior end of sulcus with indistinct fovea bearing 2 or 3 setae; clypeus short and declivous anteriorly, anterior margin almost truncate. Eyes glabrous and distinctly convex, longitudinal diameter distinctly longer than 1/2 length of head.

Mandible moderately protruding, anterior half moderately bent, with row of setae along lateral margin, dorsal tooth long and pointed, gradually curved inwards, medial side of first ventral tooth slightly convex at apex ( Fig. 7 ). Mentum trapeziform and setose, anterior margin truncate with pointed tooth in middle, lateral margin convex, with two distinct transverse, evenly convex ridges ( Fig. 4 ).

Antennae short, posteriorly reaching base of pronotum; 1st segment baculiform, emarginate at apex; 2nd segment smallest and quadrate; 3rd segment elongate and narrowed at base, about 1.5 times as long as 2nd; 4–10th transverse; 11th slightly elongate, apically rounded, about twice as long as 10th.

Pronotum wider than long, anterior margin weakly bisinuate, sides parallel, posterior margin slightly protruding backwards in middle; surface smooth with sparse micropunctures; median longitudinal sulcus deep, widest in middle, not reaching both anterior and posterior margins; disc on each side of sulcus with distinct puncture; along marginal area with some scattered, coarse, setiferous punctures, especially denser at posterior angle; lateral line complete, but vanishing before reaching protruding part of posterior margin. Mesoscutellum not very elongate, slightly heartshaped, smooth and shiny.

Protibiae laterally with 9–11 denticles, which become gradually shorter basally, dorsal side with indistinct spine close behind apical spur, which is moderately thicker than other erect dorsal setae. Middle and hind tibiae densely setose.

Elytra slightly longer than wide, humeri rounded, almost parallel-sided, combined posterior margins shallowly emarginate; surface glabrous with dense micropunctuations; moderately dense setae of various lengths along base and laterally.

Abdomen cylindrical, broadened posteriorly and widest at 7th segment; all segments, except 8th, narrowed at base; surface with moderately dense setae, mostly long and erect, relatively denser laterally; punctures small, denser in basal half of tergites, gradually becoming sparser posteriorly.

Male: Aedeagus almost membraneous with basal orifice rounded and slightly convex lateral outline; median lobe slightly bulbous at base, strongly curved behind basal orifice, posterior part stick-shaped, weakly sclerotized dorsally, slightly contracted apically; parameres thin and short, apically pointed, dorsally protruding, but not connected with each other ( Figs. 5, 6 ).

Measurements. – Body length: 6.5–7.0 mm. HL: 0.42 mm; HW: 0.92 mm; PL: 0.93 mm; PW: 1.32mm; EL: 1.35 mm; EW: 1.28 mm (n = 3).

Etymology. – The species name is derived from the Latin word “ pulcher ” (meaning “beautiful”) to indicate its beautiful body coloration.

Remarks. – This new species is similar to P. (E.) tridens (Motschulsky, 1857), but may be distinguished from the latter by red body coloration and two distinct punctures on each side of the sulcus on pronotum. This new species is also similar to P. (E.) bipunctatus ( Fauvel, 1895) , but differs in distinctly smaller body size, incomplete lateral line on posterior margin of pronotum and the sharper median tooth on anterior margin of frontal impression.

Distribution. – China (Yunnan).

Figures

Figs. 3–7. Priochirus (Eutriacanthus) pulchellus, new species: 3, head and pronotum, dorsal view; 4, mentum; 5, aedeagus, dorsal view; 6, aedeagus, lateral view; 7, left mandible. Scale bars: (Fig. 3) = 1.00 mm; (Figs. 4–7) = 0.25 mm.