Diartiger dentatus Yin

Yin, Zi-Wei & Li, Li-Zhen, 2013, Notes on synonymy of Diartiger Sharp with Microdiartiger Sawada (Coleoptera: Staphylinidae: Pselaphinae), with description of two new species from East China, Zootaxa 3717 (3), pp. 369-376 : 370-373

Diartiger dentatus Yin and Li, new species

( Figs 1 A, 2, 4)

Type material (114 ♂♂, 40 ♀♀). Holotype: CHINA: ♂, labeled ‘ China: SW Anhui, Liu’an City, Yue’xi County, Yaoluoping N. R., 30°58′24″N, 114°03′47″E, path near Zhao Guan, under rock, colony of Lasius sp., ca. 1235 m, 20.vi.2013, Dai & Peng leg. (SNUC)’. Paratypes: CHINA: 47 ♂♂, 18 ♀♀, same label data as holotpye; 42 ♂♂, 10 ♀♀, same label data, except ‘30°59′05″N, 114°04′40″E, roadside near the resort, ca. 1055 m, 17.vi.2013 ’; 17 ♂♂, 6 ♀♀, same label data, except ‘ 16.vi.2013 ’; 3 ♂♂, same label data, except ‘30°58′53″N, 114°04′31″E, path 300 m SW resort, ca. 1060 m, 21.vi.2013 ’; 4 ♂♂, 6 ♀♀, same label data, except ‘ 22.vi.2013 ’ (all SNUC).

Description. Male. Body ( Fig. 1 A) length 2.01–2.11 mm; reddish brown. Head longer than wide, HL 0.40– 0.41 mm, HW 0.24–0.25 mm; clypeus with round anterior margin; eyes each composed of about 15 facets; antennomeres IV ( Fig. 2 A) more than twice length of III. Pronotum about same length as width, PL 0.37–0.39 mm, PW 0.39–0.41 mm. Elytra ( Fig. 2 E) wider than long, EL 0.48–0.50 mm, EW 0.72–0.78 mm; lacking microsculpture; with small tufts of setae at posterolateral margins, and bigger triangular, posteriorly-narrowed trichomes at posterolateral margins ( Fig. 2 F). Metathoracic wings fully-developed. Mesoventrite ( Fig. 2 G) with short median carina, metaventrite ( Fig. 2 G) convex, both meso- and metaventrites with dense, thick setae along midline. Profemora ( Fig. 2 B) with several long ventral setae at base, protibiae basally narrowed and then thickened in apical 3/4; mesotrochanters ( Fig. 2 C) with large ventral spine, mesofemora with sharp basoventral spine; mesotibiae with triangular projection at middle and apex; metatibiae ( Fig. 2 D) roundly expanded at basal 1/4, then largely concave along mesal margin. Abdomen ( Fig. 2 H) slightly wider than long, AL 0.76–0.81 mm, AW 0.83– 0.84 mm; composite tergite with transverse basolateral trichomes curved mesally, first pair of paratergites with linear trichomes ( Fig. 2 I). Aedeagal length 0.5 mm; median lobe pointed apically in lateral view (Figs J–L).

Female. Antennae lack obvious sexual dimorphism. Identical to male except as follows: mesofemora and mesotibiae lacking spines; abdomen relatively broader. Measurements: BL 2.10–2.15 mm, HL 0.38–0.39 mm, HW 0.26–0.27 mm, PL 0.37–0.38 mm, PW 0.38–0.40 mm, EL 0.51–0.52 mm, EW 0.78–0.79 mm, AL 0.84–0.86 mm, AW 0.86–0.88 mm.

Comparative notes. Diartiger dentatus differs from all other congeners by having antennomeres IV being more than twice the length of antennomeres III, elytra being distinctly longer than wide, dentate mesotibiae, and mesally concave metatibiae.

Distribution. East China: Anhui Province.

Biology. Adults of the new species were collected from nests of Lasius sp. nesting under stones ( Fig. 4A ). Some individuals were observed mating in a nest ( Fig. 4 B). A number of Diartiger yaoluopingensis sp. n. were collected in the same nests.

Etymology. The species name refers to the dentate mesotibiae.

Figures

FIGURE 1. Dorsal habitus of Diartiger dentatus (A) and D. yaoluopingensis (B). Scales: 0.5 mm.

FIGURE 2. Diagnostic features of Diartiger dentatus. A. Antenna. B. Fore leg. C. Mid leg. D. Hind leg. E. Left elytron. F. Elytral trichome, enlarged. G. Meso- and metaventrite. H. Left half of abdomen. I. Abdominal trichome, enlarged. J. Aedeagus, in dorsal view. K. Same, in lateral view. L. Same, in ventral view. Scales: all 0.2 mm, except F, I = 0.1 mm.

FIGURE 4. A. General habitat of Diartiger dentatus and D. yaoluopingensis. B. Diartiger dentatus and D. yaoluopingensis in a nest of Lasius sp. C. A living Diartiger dentatus.