Xanthophius unicidentatus, Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2013

Zhou, Yu-Lingzi & Zhou, Hong-Zhang, 2013, Two new species of Xanthophius Motschulsky (Coleoptera: Staphylinidae, Staphylininae, Xantholinini) from China with notes on X. filum (Kraatz), Zootaxa 3626 (3), pp. 363-380 : 370-373

2. Xanthophius unicidentatus sp. n.

( Fig. 5 A–H; Fig. 6 A–G)

Type material. Holotype: male, CHINA: Yunnan: Mengla co.: Longmen: Pinghe village, 1014 m, 07.X.2010, Zhou Yulingzi collected (IZ-CAS); Paratypes: 1 female, 2 male, same locality and collector as holotype, 945 m, 06.X.2010; Jingdong Yizu Autonomous Co.: Wenlong village, 1 female, 1268 m, 18.VII.2010, Liu Wangang collected; Zhejiang: Shunxi Co.: Qingliangfeng Reserve Zone, 1 female, 400 m, 09.VIII.2008, Zhou Yulingzi; Guangxi: Daxin Co.: Fulong: 1 male, 220 m, 20.IV.1998, Zhou Haisheng collected; Longzhou Co.: Nonggang Reserve Zone, 1 female, 330 m, 15.VI. 2000, Chen Jun collected; Hainan: Qiongzhong Li and Miao Autonomous Co., Limuling, 1 male, 600 m, 15.V.2007, Zhao Zongyi collected (IZ-CAS).

Description.

Measurement (N=3). BL= 3.52–4.27 mm, FL= 2.10–2.37 mm, HL= 0.63–0.70 mm, HW= 0.50–0.60 mm, PL= 0.71–0.77 mm, PW= 0.45–0.53 mm, EL= 0.70–0.80 mm, EW= 0.65–0.70 mm.

Body nearly cylindrical and of small size. Head distinctly dark brown; elytra brown with paler apical 1/5; pronotum, abdomen, legs and labial and maxillary palpi yellowish brown; antennae brown except for the apical 1/2 of last segment yellowish.

Head ( Fig. 6 A). Subrectangular (HL to HW ratio 1.25), tempora not distinctly widened posteriorly, posterior angles narrowly rounded. Dorsal integument without microsculpture; but with numerous medium-sized punctures, puncture intervals equal to 2–3 punctures’ diameter. Median longitudinal region impunctate; deflexed portion of tempora without any punctures. Each side of cranium with a puncture on epistoma, 3–4 punctures situated in frontal furrow, an anterolateral puncture near antennal insertion, a midlateral puncture about a distance of 2 punctures’ diameter from dorsal margin of eye, temporal puncture and occipital puncture not apparent. Frontal furrows long, but not longer than eye’ length; anteocular furrows distinct and short, with 3–4 medium sized punctures. Eye medium-sized, equal to the length of tempora (eye: tempora = 0.20: 0.40 mm). Epistoma relatively broad, slightly narrowed apically. Distance between antennal insertions (0.17 mm) being larger than that from antenna to eye (0.08 mm).

Antennae. Scape stout, thickened apically, much longer than three subsequent antennomeres combined, 0.25 mm long; antennomere II elongate, 0.08 mm long; III slightly elongate, shorter than II, 0.06 mm long; IV and V subequal in length and 0.04 mm long; last antennomere relatively long, 0.15 mm, equal to length of three preceding antennomeres combined.

Neck. Wide (0.20 mm), narrower than half the width of head.

Pronotum ( Fig. 6 B). Subrectangular, elongate (PL to PW ratio 1.55), longer and slightly narrower than head. Anterior angle well-defined and protruding laterally, lateral margins sinuate, widest at anterior 1/3 and narrowest at posterior 1/3, posterior angles broadly rounded. Dorsal integument without microsculpture, but bearing a pair of admedian rows of 9–10 punctures, a pair of lateral rows of 8–9 punctures, and also with few irregular punctures near anterior and lateral margins of pronotum.

Elytra ( Fig. 6 C). Subrectangular (EL to EW ratio 1.08), slightly shorter and wider than pronotum. Humeri well developed, lateral margins divergent posteriorly, hind margin rounded. Dorsal integument bearing 4–5 rows of punctures on each side, interspaces between rows of ca. two punctures’ diameter; deflexed portion of each elytron with 2–3 rows of denser punctures.

Legs. First four segments of protarsi stout but not dilated, and those of meso- and metatarsi not slender. Last segment slightly shorter than the length of II–IV combined, respectively.

Abdomen. Cylindrical, broadest at segment VII. Tergites III–VII slightly shiny, each segment without any microsculpture, and also distributed with small, sparse punctures, interspaces between punctures about 4–5 punctures’ diameter. Each tergite without a basal impression near anterior margin. All abdominal sternites shiny, with microstriae and punctures as those on tergites.

Male ( Fig. 5 A–G; Fig. 6 D–F). Abdominal segment VIII entirely covered with punctures, posterior margin of tergite slightly rounded, and that of sternite subtruncate ( Fig. 5 A, B). Tergite IX symmetrical, connected mediobasally. Sternite IX asymmetrical, with subparalleled lateral margins, very narrow base, and rounded apex ( Fig. 5 D). Tergite X symmetrical, broadest at apical 1/4, sharply narrowed at apical 1/5, with narrow and subtruncate base, and concaved posterior margin ( Fig. 5 C). Aedeagus small ( Fig. 5 E; Fig. 6 D–F), basal bulb subspherical, 0.42 mm long. Parameres symmetrical, not attached to basal bulb, distinctly elongate, 0.30 mm long, and extended to dorsal side ( Fig. 5 F), with a small denticle in inner side. Internal sac as in Fig. 5 G, bearing numerous, dark brown, hard processes on apical and middle parts, basal part light brown.

Distribution. China (Yunnan, Guangxi, Zhejiang, Hainan).

Etymology. The specific epithet is derived from the combination of Latin words “ unicus ” (single) and “ dentatus ” (with denticle) and refers to the single denticle in the inner side of each paramere.

Remarks. This new species can be distinguished from its congeners by the following characters: elytra brown with paler apical 1/5, tempora not distinctly widened posteriorly, anteocular furrows short, paramere with a small denticle in inner side, and internal sac as illustrated ( Fig. 5 G), bearing numerous, dark brown, hard processes on apical and middle parts. Some conspecific variations were found: 1) female specimens from the type locality had head of same length, but wider, and more dilated posteriorly (HL to HW ratio 1.18); pronotum slightly sinuate; abdominal puncture intervals of ca. 3 punctures’ diameter; 2) specimen from Zhejiang: anteocular furrow slightly longer, abdominal puncture intervals of 2–3 punctures’ diameter; 3) specimen from Hainan: head and pronotum longer, eye smaller, abdominal puncture intervals of 2–3 punctures’ diameter; 4) male specimen from Guangxi: head distinctly dilated posteriorly; pronotum shorter, with distinctly sinuate lateral margin, a pair of admedian row of 11–12 punctures, abdominal puncture intervals of 2–3 punctures’ diameter; in female, abdominal puncture intervals of 2–3 punctures’ diameter. This species is similar externally to X. filum (Kraatz) , but can be distinguished by the following characters combination: puncture intervals on head equal to 2–3 punctures’ diameter, interspaces between abdominal punctures about 4–5 punctures’ diameter, and paramere with a small denticle in inner side.

Figures

FIGURE 5. Xanthophius unicidentatus sp. n.: A. male tergite VIII; B. male sternite VIII; C. male tergite X; D. male sternite IX; E. aedeagus, ventral view; F. right paramere, dorsal view; G. endophallus at rest, ventral view; H. female genital segment. Scale bars 0.15 mm.

FIGURE 6. Xanthophius unicidentatus sp. n.: A. head; B. pronotum; C. elytra; D. aedeagus, dorsal view; E. aedeagus, ventral view; F. parameres and endophallus at rest together, ventral view; G. female genital segment. Scale bars 0.30 mm.