Lathrobium xui Peng and Li

Peng, Zhong, Li, Li-Zhen & Zhao, Mei-Jun, 2014, Seventeen new species and additional records of Lathrobium (Coleoptera, Staphylinidae) from mainland China, Zootaxa 3780 (1), pp. 1-35 : 23-24

Lathrobium xui Peng and Li , new species

( Figs 13 C, 16)

Type material. (3 ♂♂). HOLOTYPE: ♂, labelled ‘ CHINA: Chongqing City, Chengkou County, Huangangou, 31°51'N, 109°07'E, 22–23.iv.2008 alt. 2,040 m, Wang Xu leg.’ ( SNUC). PARATYPES: 2 ♂♂, same label data as holotype ( SNUC).

Description. Measurements (in mm) and ratios: BL 7.50–8.39, FL 3.39–4.03, HL 0.96–0.98, HW 0.93–0.99, AnL 1.95–2.01, PL 1.26–1.30, PW 1.06–1.07, EL 0.78–0.83, AL 1.46–1.48, HL/HW 0.99–1.03, HW/PW 0.88– 0.92, HL/PL 0.75–0.76, PL/PW 1.19–1.21, EL/PL 0.62–0.64.

Habitus as in Fig. 13 C. Body brown with paler apex, legs and antennae brown to light brown.

Head approximately as long as broad; punctation moderately coarse and dense, much sparser in median dorsal portion; interstices with very shallow microreticulation. Eyes 0.37–0.45 times as long as postocular region in dorsal view and composed of approximately 50 ommatidia.

Pronotum with weakly convex lateral margins in dorsal view; punctation sparser than that of head; impunctate midline narrow; interstices without microreticulation and glossy.

Elytra moderately short; punctation dense and shallow. Hind wings completely reduced.

Abdomen with fine and dense punctation, that of tergite VII slightly sparser than that of anterior tergites; interstices with very shallow microsculpture; posterior margin of tergite VII without palisade fringe.

Male. Posterior margin of tergite VIII weakly convex; sternites III–IV unmodified; sternite VII ( Fig. 16 A) with distinct median impression posteriorly, this impression with numerous distinctly modified stout black setae, posterior margin distinctly concave in the middle; sternite VIII ( Fig. 16 B) distinctly tapering posteriorly, with oblong and extensive median impression posteriorly, this impression without setae along the middle, on either side of middle with numerous strongly modified, stout black setae, posterior excision broadly V-shaped; aedeagus as in Figs 16 C, D, strongly modified, asymmetric and somewhat twisted, with lamelliform ventral process; internal sac with long and apically bifid sclerotized spine.

Female. Unknown.

Comparative notes. As can be inferred from the similarly derived male sexual characters, particularly the general morphology of the aedeagus and the presence of a long sclerotized spine in the internal sac, L. xui undoubtedly belongs to the L. fissispinosum group ( Assing, 2013a), which was previously represented in the Qinling Shan, the Daba Shan and adjacent mountain ranges by eleven species. It is distinguished from all the species of this group by the very shallow microreticulation of the head, by the chaetotaxy of the male sternites VII and VIII (with more numerous modified setae), and by the morphology of the aedeagus (a long and apically bifid sclerotized spine in internal sac). The male sternite VII is most similar to that of L. fissispinosum Assing, 2013 , from which L. xui additionally differs by the shape of the ventral process of the aedeagus. For illustrations of the species of the L. fissispinosum group see Assing (2013a) and Peng et al. (2013b).

Distribution and biological notes. The type locality is situated in the Daba Shan to the east of Chenkou, northern Chongqing. The specimens were collected at an altitude of 2,040 m, partly together with L. trifidum .

Etymology. The species is named after Wang Xu, who collected some of the type specimens.

Figures

FIGURE 13. Habitus of Lathrobium spp., A — L. sanqingense; B — L. badagongense; C — L. xui. Scale bars: 1.0 mm.

FIGURE 16. Lathrobium xui. A — male sternite VII; B — male sternite VIII; C — aedeagus in ventral view; D — aedeagus in lateral view. Scale bars: 0.5 mm.