Plastus (Stigmatochirus) menglaius, Li, Guo-Feng, Li, Hong-Wei, Liu, Ying-Jie & Huang, Rong-Wen, 2013

Li, Guo-Feng, Li, Hong-Wei, Liu, Ying-Jie & Huang, Rong-Wen, 2013, A new species of the subgenus Stigmatochirus of Plastus Bernhauer (Coleoptera: Staphylinidae: Osoriinae) from Yunnan, China, Zootaxa 3636 (1), pp. 190-195 : 191-194

Plastus (Stigmatochirus) menglaius sp. nov.

( Figs. 1 A–B, Figs. 2 A–E, Figs. 3 A–B, Figs. 4 A–D)

Type material. Holotype: CHINA:Yunnan Prov.: 3, Mengla County, Man dan village, alt. 650m, 21°15ʹN, 101°26ʹE, 13-14-August-2012, Li Guo-feng leg. (YFTC). Paratypes: CHINA: Yunnan Prov.: 53, 8ƤƤ, same data as the Holotype (YFTC).

Description. BL: 12–15mm. HL: 0.96mm, PL: 1.51mm, EL: 3.10mm, HW: 2.30mm, PW: 2.69mm, EW: 3.01mm. Body convex, moderately stout, almost cylindrical, surface glossy and setose (except disc of pronotum and elytra). Color black, with mandibles, antenna, femora, tibiae, tarsi, abdominal tergite 8 (only posterior margin) yellowish-brown. ( Figs. 1 A–B).

Male: Head transverse, frontal impression broadly depressed with a short longitudinal carina in the middle, basal side of clypeus with two pairs of teeth, frontal pair elongate and blunt, posterior pair small and blunt. Median sulcus broad, as long as diameter of eye, narrowed frontally. Lateral lobes broadly elevated and impunctate, anterior margin with a small and blunt lateral tubercles. Other part of the vertex covered with densely coarse punctures and long yellowish pubescence. Clypeus elongate with frontal margin subarcuate, covered with extra dense and yellowish setae.

Labrum ( Fig. 4 C) rounded frontally and laterally, covered with dense long and short setae, on the side of anterior margin with two membraneous lobes projecting and ciliate. Mandible ( Fig. 3 B) robust, punctate and setose on outer face, dorsal tooth sharp, apical tooth biforked. Inner lobe of maxilla ( Fig. 3 A) elongate, with three robust and pointed teeth at the apex, the inner margin ciliate and dentate with 7 inconspicuous denticles, outer lobe narrower, top part densely ciliate. Mentum ( Fig. 4 A) trapezoiform and sparsely setaceous. Glossa frontally truncated and ciliate, on each side with one long seta. Paraglossa ciliate and separated from glossa ( Fig. 4 D).

Antennae short, slightly geniculate, posteriorly reaching the frontal margin of elytra, 1st segment baculiform, apically emarginated, 2nd small, 3rd long and narrowed at base, beyond twice as long as 2nd, 4th to 7th moniliform, 8th to 10th slightly transverse, 11th elongate, apically rounded, about 1.5 as long as 10th, the relative length of segments from base to apex as 1.40: 0.39: 0.79: 0.43: 0.35: 0.37: 0.28: 0.30: 0.31: 0.29: 0.41. All segments covered with long setae, especially at inner side of 2nd to 4th segments.

Pronotum convex and rectangular, frontal margin sinuate, lateral side rounded, posterior margin edged and protruding in the middle, posterior angle weakly angulate, median longitudinal sulcus narrow and deep, slightly expand at posterior end, frontal margin, lateral margin and posterior margin covered with densely coarse punctures and yellowish pubescence, disc glossy and smooth without punctures.

Protibiae broadened apically, crenulate externally, with 12 to 13 prominent denticles. Elytra longer than wide (ratio 1.03), posterior margin subarcuate, laterally and frontally coarsely punctate and pubescent, disc glossy with finely sparse punctures, each elytron with a shallow sulcus paralled to suture. Wing well developed.

Abdomen cylindrical, micropunctures denser on basal half of segment 3–7, long pubescent especially denser on lateral and anterior part of each segment.

Aedeagus ( Figs. 2 A–C) with median lobe slightly bulbous at base, constricted and curved behind basal orifice, membraneous on the dorsal side and truncated at apex; parameres short, thin and pointed, with basal part deeply emarginated. Ninth tergites sclerotized and left and right plates separated, each with 13 setae of various length. Tenth tergite almost membraneous except for sclerotized apical part, posterior margin emarginate in middle, each side with 8 long setae ( Fig. 4 B). Ninth sternite composed of two plates, apical plate sclerotized except for membraneous apex, with three pairs of setae, basal plates less sclerotized, broadened in middle ( Fig. 2 E).

Female: Similar to male, but 9th sternite ( Fig. 2 D) with hemisternite less sclerotized, anterior margin weakly protruding, second gonocoxite strongly sclerotized except for membraneous apex, with four setae.

Remarks. Plastus (Stigmatochirus) menglaius is slightly similar to P. (Stigmatochirus) magnificus Wu & Zhou from Yunnan, in the shape of the head, pronotum and elytra, but can be distinguished from the latter by the following characters (see key below): pronotum with frontal margin, lateral margin and posterior margin covered with densely coarse punctures and yellowish pubescence, disc glossy and smooth without puncture; protibiae with 12 to 13 prominent denticles. Elytra with posterior margin arcuate, disc glossy with finely sparse punctures.

Etymology. The specific epithet is derived from the name of the type locality “Mengla”.

Habitat and Distribution. The new species was found in dead wood. It is at present only known from the type locality in southwest Yunnan, China.

Figures

FIGURE 1. Stigmatochirus menglaius sp. nov. A. male habitus, dorsal view. B. female habitus, dorsal view. Scale bars: 2.00 mm.

FIGURE 2. Stigmatochirus menglaius sp. nov. A. ventral view of aedeagus. B. Dorsal view of aedeagus. C. lateral view of aedeagus. D. female sternite 9. E. male sternite 9. Scale bars: 0.20 mm.

FIGURE 3. Stigmatochirus menglaius sp. nov. A. Dorsal view of left maxilla. B. Dorsal view of left mandible. Scale bars: 0.20 mm.

FIGURE 4. Stigmatochirus menglaius sp. nov. A. Mentum. B. Ventral view of male tergites 9 and 10. C. Labrum. D. Ligula and labial palpi. Scale bars: 0.20 mm.