Priochirus (Eutriacanthus) tonkinensis Bernhauer, 1903

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 : 273-274

Priochirus (Eutriacanthus) tonkinensis Bernhauer, 1903

( Figs. 12–15 )

Priochirus tonkiensis Bernhauer, 1903: 137 , 148 (type locality: Tonkin); Bernhauer and Schubert, 1910: 16 (subgenus of Triacanthus ; Scheerpeltz, 1933: 1003 (subgenus of Triacanthochirus ); Greenslade, 1971: 138 (subgenus of Eutriacanthus ); Herman, 2001: 1140.

Material examined. – 5 males, 8 females, China, Guangxi, Napo, Nonghua , 960 m, 14 Apr.1998, Haisheng Zhou coll. ( IOZ-CAS) ; 10 males, 9 females, China, Yunnan, Xishuangbanna, Menglun , 560 m, 9 Feb.2004, Jie Wu coll. ( IOZ-CAS) ; 3 males, 4 females, Tonkin, Hao-Binh, A. de Cooman coll. ( IOZ-CAS) .

Redescription. – Body moderately depressed. Antennae black-brown; femorae and tibiae slightly red-black, tarsi red-brown; other body parts black.

Head transverse ( Fig. 12 ), parallel-sided, frontal angle weakly convex behind lateral teeth; frontal impression about twice as wide as median length, posterior margin obliquely convergent backwards forming a sharp angle; median tooth distinctly projecting and pointed, distinctly longer than 2 lateral teeth, base weakly convex along central disc of frontal impression; lateral teeth bluntly projecting, apex slightly curved inwards, lateral face with 5 or 7 setae turning upward, medial face with row of long setae extending onto anterior margin; median sulcus deep, not anteriorly connected with frontal impression, gradually broadened backwards, posterior end almost as wide as middle width of median longitudinal sulcus on pronotum; vertex smooth, sometimes with one or two distinct punctures, along lateral and postero-lateral margin with some scattered punctures and setae, posterior margin near to posterior end of sulcus with distinct fovea bearing 3 or 4 setae; clypeus short and steep, anterior margin truncate. Eyes glabrous and distinctly convex, longitudinal diameter about 1/2 length of head.

Mandible similar to that of P. (E.) pulchellus , but medial face of first ventral tooth more convex. Mentum trapeziform and setose, median tooth on anterior margin small and pointed, lateral margin convex, ventral surface with 2 distinct transverse ridges ( Fig. 15 ).

Antennae short, almost reaching base of pronotum posteriorly; 1st segment baculiform, emarginate at apical margin; 2nd segment smallest and transverse; 3rd segment elongate and narrowed at base, about 1.5 times as long as 2nd; 4th segment quadrate; 5–10th segments gradually transverse; 11 th segment slightly elongate, apically rounded, about 1.5 times as long as 10th.

Pronotum distinctly wider than long, anterior margin distinctly 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 big puncture; along marginal area with some scattered, coarse, setiferous punctures, especially denser at anterior and posterior angles; lateral line complete on posterior margin of pronotum and reaching basal line. Mesoscutellum tongue-shaped and shiny, surface sometimes with a few punctures.

Protibiae laterally with 12–15 denticles, which becoming gradually shorter basally, on dorsal side with distinct spine closely behind apical spur. Middle and hind tibiae densely setose.

Elytra almost quadrate, humeri rounded, almost parallelsided, combined posterior margins shallowly emarginate; surface shiny with sparse micropunctions; moderately dense setiferous punctures along base and sides.

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, denser laterally than in middle; punctures small, especially denser in basal half of tergites and gradually becoming sparser posteriorly.

Male: Aedeagus with median lobe bulbous at base, weakly curved behind basal orifice, posterior part weakly sclerotized dorsally, broadened in middle and gradually contracted apically; parameres apically rounded, dorsally protruding, but not connected with each other ( Figs. 13, 14 ).

Measurements. – Body length: 9.0–11.0 mm. HL: 0.59 mm; HW: 1.18 mm; PL: 1.05 mm; PW: 1.41 mm; EL: 1.43 mm; EW: 1.45 mm (n = 3).

Remarks. – In body size and shape of the teeth of head, this species is similar to P. (E.) tridens Motschulsky, 1857. But it may be distinguished from the latter by the black abdominal apex, more transverse frontal impression and pronotum disc, which has a big puncture on each side of sulcus.

Distribution. – China (Guangxi, Yunnan, Taiwan) and Vietnam.

Figures

Figs. 12-15. Priochirus (Eutriacanthus) tonkinensis Bernhauer, 1903: 12, head and pronotum, dorsal view; 13, aedeagus, dorsal view; 14, aedeagus, lateral view; 15, mentum. Scale bars: (Fig. 12) = 1.00 mm; (Figs. 13–15) = 0.25 mm.