Gabrius dentatus, Li, Liang, Schillhammer, Harald & Zhou, Hong-Zhang, 2010

Li, Liang, Schillhammer, Harald & Zhou, Hong-Zhang, 2010, Fourteen new species of the genus Gabrius Stephens, 1829 (Coleoptera: Staphylinidae: Philonthina) from China, Zootaxa 2572, pp. 1-24 : 9-11

5. Gabrius dentatus sp. n.

( Figs. 4 A–G)

Type material. Holotype: CHINA: Sichuan: ɗ, Baoxing: Guobayan, 2503 m, 4–7.VIII.2003, leg. Yu Xiaodong (IZ-CAS). Paratypes: CHINA: Sichuan: ɗ, same data as holotype, but 3340 m, 1–4.VII.2001 ( IZ- CAS); Ψ, Baoxing: Fengtongzhai, 2.IX.2005, leg. Zhang Yejun (IZ-CAS); 2 ɗɗ, Daxue Shan: Hailuogou Glacier Park, Camp 1 (29°36.00’N, 102°03.35’E), 2000 m, 27–31.V.1997, leg. M. Schülke ( CSB, NMW); ɗ, Ganzi: Luding Co., W Erlangshan Pass, 2600 m, 7 km SSE Luding (29°51’N, 102°15’E), 22.VI.1999, leg. M. Schülke ( CSB).

Description. Head and pronotum black, shining. Elytra dark brown or reddish-brown. Abdomen black, posterior margins of tergites III–VII markedly reddish-brown, tergite VIII entirely reddish-brown. Antennae dark-brown, with basal two segments reddish-brown. Mandibles dark brown. Maxillary and labial palpi and legs reddish-brown.

Body 6.20–6.36 mm long (HPL = 1.88–2.04 mm). Head of rounded quadrangular shape, 0.82–0.90 mm long, 0.63–0.71 mm wide (HW:HL = 0.80–0.82). Tempora 0.41–0.49 mm long, almost evenly rounded, sparsely and coarsely punctate; eyes moderately large, slightly protruding, 0.25 mm long, 0.50–0.60 times as long as tempora. Dorsal surface of head with scattered, large setiferous punctures along lateral sides, vertex largely impunctate; entire head with distinct and profound microsculpture of transverse waves. Antennae moderately long, 1st segment long, slightly thickened towards apex, 3rd segment almost as long as 2nd, 4th–5th segments distinctly longer than wide, 6th–8th segments almost as long as wide, 9th–10th segments slightly transverse, last segment distinctly longer than wide, obliquely truncated.

Pronotum almost parallel-sided, 0.98 mm long, 0.82 mm wide, slightly wider than head (PW:HW = 1.11– 1.25); dorsal rows each with six punctures, sublateral rows each with two punctures; entire surface with microsculpture similar to that on head.

Elytra 1.14–1.22 mm long, 1.22 mm wide, along sides 1.17–1.25 times as long as pronotum, sparsely and finely punctate, punctures separated by 3–4 times their diameter. Scutellum large, triangular, sparsely and finely punctate and pubescent.

Abdomen slightly narrowed posteriad, widest 1.06–1.14 mm, almost uniformly and densely punctate, punctures separated by 2–3 times their diameter; surface between punctures with exceedingly fine and dense microsculpture of transverse striae; tergites III–V with two basal lines, elevated area between basal lines almost impunctate.

Male. Tergite VIII subarcuate and prolonged medio-apically ( Fig. 4 E). Sternite VIII with apical margin narrowed and truncated, without emargination ( Fig. 4 F). Genital segment with styli of tergite IX simple, moderately setose apically. Sternite IX largely membranous at median portion, basal portion narrow and long, almost symmetrical, apical portion reduced into very narrow lobe with slightly emarginate apex, shifted toward left side ( Fig. 4 D). Tergite X simple, triangular, subacuate at apex ( Fig. 4 G).

Aedeagus large and robust; apical portion of median lobe abruptly narrowed anteriad into knob-like, roundly truncated apex ( Fig. 4 A); in lateral view, median lobe with a subapical tooth-like extension and apical portion slightly bent dorsad ( Fig. 4 B); paramere large, divided into two wide and long branches, face adjacent to median lobe with sensory peg setae closely arranged along latero-apical margin of each branch ( Fig. 4 C), external faces of parameral branches densely pubescent.

Female. Sternite VIII subrounded at apex, without medio-apical emargination. Genital segment with styli of tergite IX similar to that of male. Tergite X narrow, triangular, emarginate at apex.

Remarks. The new species belongs to the G. cinctiventris group; because of the pubescent parameral branches and the highly asymmetrical apical portion of the male sternite IX. Externally, the species closely resembles G. burckhardti Schillhammer, 1997 . Gabrius dentatus sp. n. differs from the latter species by darker head and pronotum, more slender build, and larger aedeagus with much broader parameral branches.

Distribution. The species is at present known only from China (Sichuan).

Etymology. The specific epithet is derived from the Latin word dentatus (having tooth), and refers to the sharp subapical tooth-like extension of the median lobe of aedeagus in lateral view.

Figures

FIGURE 4. Gabrius dentatus sp. n. A, aedeagus, ventral view; B, median lobe of aedeagus (paramere removed), lateral view; C, underside of paramere; D, sternite IX of male; E, tergite VIII of male; F, sternite VIII of male; G, tergite X of male; Scale bars 0.5 mm.