Erymus wufengensis Zhou & Zhou

Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2014, Taxonomy of the genus Erymus Bordoni (Coleoptera: Staphylinidae, Staphylininae, Xantholinini) in China with descriptions of two new species, Zootaxa 3814 (4), pp. 521-536 : 527-529

2. Erymus wufengensis Zhou & Zhou , sp. n.

( Fig. 1 B; 4A–F)

Type material. Holotype: male, CHINA: Hubei: Wufeng autonomous co. (E 110.6683, N 30.1898), IV–VIII.2011, Zhou Lei collector ( IZ-CAS).

Description. Measurements. BL= 4.04 mm, FL= 2.30 mm, HL= 0.68 mm, HW= 0.49 mm, PL= 0.77 mm, PW= 0.49 mm, EL= 0.76 mm, EW= 0.68 mm.

Body nearly cylindrical, small-sized. Head, pronotum and mesoscutellum black. Antennae, elytra, abdomen, maxillary and labial palpi dark brown; basal two antennomeres reddish brown. Legs yellowish brown.

Head ( Fig. 1 B). Subrectangular (HL to HW ratio 1.4), tempora parentheses-like, not dilated posteriorly, posterior angles rounded. Dorsal integument extensively bearing micropunctures, without any microsculpture, median longitudinal region (of the width ≈ 0.15 mm) smooth, without punctures, other surface (posterior half of head and temporal region) with deep and large punctures, distance between punctures about the diameter of two punctures; deflexed portion of tempora with 2–3 rows of punctures. Each side of cranium with anterolateral puncture near antennal insertion, midlateral puncture adjacent to dorsal margin of eye. Frontal furrows deep and long, fused with two paired tiny punctures, distinctly overpassing line connecting midth of each eye. Anteocular furrows indistinct. Eyes large, nearly half length of tempora (eye: tempora = 0.19: 0.39 mm), distinctly protruding laterad. Epistoma relatively broad, slightly narrowed forward. Distance between antennal insertions 0.17 mm, longer than distance from antenna to eye (0.10 mm).

Antennae. Scape stout, thickened apically, slightly longer than length of three subsequent antennomeres combined, 0.24 mm; antennomere II elongate, 0.10 mm; III subspherical, small, much shorter than II, 0.05 mm; IV and V slightly wider than III, subequal in length of 0.06 mm; last antennomere medium in length, 0.12 mm, subequal to length of two preceding antennomeres combined.

Neck. Medium width (0.19 mm), slightly wider than 1/3 of head width.

Pronotum ( Fig. 1 B). Subrectangular, distinctly elongate (PL to PW ratio 1.6), as wide as head, but longer. Widened anteriad, lateral margins quite sinuate, anterior angles obviously expanded outwards, posterior angles broadly rounded, with widest at anterior 1/4 and narrowest at posterior 1/4. Dorsal surface extensively bearing micropunctures, without any microsculpture. Each side bearing a paired admedian row of 9–10 small punctures, a paired lateral row of 5–6 punctures, and also with a few irregular punctures distributed near anterior margin.

Mesoscutellum. Glossy, extensively covered with shallow microstriae, and with a pair of small punctures at apical 1/3.

Elytra ( Fig. 1 B). Subrectangular, slightly elongate (EL to EW ratio 1.1), the same length of pronotum, but distinctly wider. Humeri well-developed, lateral margins slightly dilated outwards, hind margin distinctly rounded. Integument glossy, flattened, without microsculpture, each side with 2–3 rows of small punctures along median suture, a row along midwidth, and also with 1–2 rows of tiny punctures.

Abdomen. Cylindrical, broadest at segment VI. Tergites III–VII glossy, each segment covered with transverse microstriae, also with small scattered punctures, interspaces between punctures approximately the diameter of 2–3 punctures, and punctures slightly denser on tergites VI and VII. Each tergite with a shallow basal impression near anterior margin; surface between two basal transverse carinae glossy, also covered with microstriae, and rarely with tiny punctures. All abdominal sternites glossy, with microstriae and punctures as those on tergites.

Male ( Fig. 4 A–F). Abdominal segment VIII entirely covered with setiferous punctures, posterior margin of both tergite and sternite subtruncated ( Fig. 4 A, B). Tergite IX symmetrical, connected mediobasally. Sternite IX asymmetrical, lateral margins parallel and substraight, with linear-shaped base and rounded apex ( Fig. 4 C). Tergite X symmetrical and pentagonal, with pointed base and straight apex ( Fig. 4 D). Aedeagus pear-shaped, anterior portion missing, apical margin subtruncated ( Fig. 4 E–F), bulbus small, 0.27 mm long. Parameres symmetrical, not slender, thicken basally, 0.25 mm long. Internal sac entirely membranous and variably shaped, without any visible sclerotized structures.

Distribution. China (Hubei).

Etymology. The specific epithet is derived from the Chinese name (Pin-yin) of the type locality, Wufeng.

Remarks. This new species is distinguished from its congeners by the combination of the following characters: body color nearly black, interspaces between punctures of head close, number of admedian row of pronotum, male sternite IX and aedeagus. In this species the shape of the parameres is similar to that in E. dalianus Bordoni, 2006 , but it can be distinguished from the latter by stouter parameres, the male sternite IX and a longer aedeagus.

Figures

FIGURE 1. Forebody: A. Erymus gilvus sp. n.; B. E. wufengensis sp. n.; C. E. dalianus Bordoni. Scale bars 0.30 mm.

FIGURE 4. Erymus wufengensis sp. n.: A. male tergite VIII; B. male sternite VIII; C. male sternite IX; D. male tergite X; E. aedeagus, dorsal view; F. aedeagus, ventral view. Scale bars 0.15 mm.