Plastus Plastus shanghaiensis Wu & Zhou

Wu, Jie & Zhou, Hong-Zhang, 2010, Taxonomic study of subgenus Plastus s. str. (Coleoptera, Staphylinidae, Osoriinae) in China, with descriptions of five new species, ZooKeys 51, pp. 17-32 : 28-29

Plastus Plastus shanghaiensis Wu & Zhou sp. n. Figs 4914

Type material.

Holotype female,Zi Ka Wei (Shanghai: Xujiahui), 4.v.1939, collector unknown (IZ-CAS).

Description.

Measurement. Body length: 9.75 mm. HL: 0.72 mm; HW: 1.42 mm; PL: 1.63 mm; PW: 2.02 mm; EL: 2.05 mm; EW: 2.14 mm.

Coloration. Head black with labrum red-brown (Fig. 9), mandibles black with inner side red-brown. Pronotum and elytra black (Fig. 4). Abdomen black with posterior margin of VII and whole VIII segment rufous. Antennae brown. Femora black, tibiae black at base and gradually become red-brown apically. Tarsi red-brown.

Structural attributes. Head (Fig. 9) transverse, twice as long as wide, sides almost parallel, slightly concave in middle; frontal impression transverse, about 2 times as wide as median length, anterior margin almost semicircular, posterior margin rounded; lateral teeth straight and blunt, ventral side medially with weakly convex subsidiary denticle, on inner side with row of 2 or 3 long setae extending onto lateral anterior margin of frontal impression; lateral impression narrowly depressed at outer base of lateral tooth, bearing 2 or 3 short setae, anterior margin of frontal angle of head weakly convex and forming small granulated tooth; median sulcus on vertex about 1.5 times as long as median length of frontal impression, gradually broadened posteriorly, but abruptly divergent at posterior 1/4, the posterior end of which is almost 2.5 times as wide as middle; clypeus short and steeply inclined, anterior margin moderately rounded, with 3-5 long setae scattered along lateral side; eye glabrous and convex, occupying about 3/5 of side of head; vertex moderately convex, gradually inclining in regions near posterior margin of frontal impression, without distinct depression on each side of median sulcus, surface almost polished and covered with fine micropunctures, along lateral and postero-lateral margin with some scattered punctures and long setae, at each side of posterior end of median sulcus with indistinct fovea bearing 2 or 3 setiferous punctures.

Antennae subgeniculate, antennomere I baculiform and apically slightly depressed to form shallow sulcus on dorsal side, antennomere II smallest, slightly transverse; antennomere III elongate about 2 times as long as II; antennomeres IV–V slightly quadrate; VI–X gradually transverse; antennomere XI elongate, apically rounded, about 1.8 times as long as X.

Mentum trapeziform (Fig. 14), frontal angle slightly rounded, anterior margin weakly depressed in middle, with indistinct median denticle, ventral surface with coarse and mutually contiguous ridges, behind which disc strongly rugose and setose.

Pronotum transverse (Fig. 4), distinctly wider than head, anterior margin slightly bisinuate, sides almost parallel, but slightly convex at anterior angle, median longitudinal sulcus deep and narrow, not distinctly broadened posteriorly, not reaching either anterior or posterior margins; lateral marginal area with 17-20 setiferous punctures, punctures on upper half not larger than on those lower half, disc polished, with fine micropuncture evenly distributed, in central with two indistinct punctures at sides of sulcus.

Protibiae externally furnished with 10 denticles, which gradually become shorter basally.

Elytra almost quadrate, epipleural line complete, setiferous punctures on lateral marginal side sparser and less distinct than those on side of pronotum.

Abdomen cylindrical, along anterior and posterior margin of III–VI segments respectively with row of setae, but VI segment with additional median row of setae, segments VII and VIII densely setose, disc of III–VI segments densely punctured, without distinct glabrous region near posterior margin, basal distinctly denser than apical, VII punctured, centrally without longitudinal glabrous region, glabrous region on VIII short and not extending to basal half.

Remarks.

Wu and Zhou (2007) misidentified this species as Plastus Plastus brachycerus (Kraatz, 1859) (tables 1, 2; figures 1-4; and locality error in Wu and Zhou 2007). Plastus (Plastus) shanghaiensis sp. n. is closely allied to Plastus Plastus brachycerus in the shape of lateral teeth and frontal impression, but can be distinguished from the latter by more depressed lateral impression at the outer base of lateral tooth, and anterior margin of frontal angle of head is furnished with a small granulate tooth.

Distribution.

Known from type locality in Shanghai.

Etymology.

The specific name ‘shanghaiensis’ is derived from the name of the type locality, Shanghai.