Lathrobium obscurum Peng & Li

Peng, Zhong, Li, Li-Zhen & Zhao, Mei-Jun, 2013, Eight new apterous Lathrobium species (Coleoptera, Staphylinidae) from Sichuan, Southwest China, ZooKeys 303, pp. 1-21 : 10

Lathrobium obscurum Peng & Li sp. n. Figs 6A, 7

Type material.

(1 ♂). Holotype: ♂, labelled 'CHINA: Sichuan Prov., Shimian County, Liziping. Yele, 28°54'N, 102°13'E, 15.vii.2012 alt. 2,600 m, Dai, Peng & Yin leg.' (SNUC).

Description.

Measurements (in mm) and ratios: BL 10.17, FL 4.10, HL 1.15, HW 1.20, PL 1.55, PW 1.20, EL 0.83, AL 2.38, HL/HW 0.96, HW/PW 1.00, HL/PL 0.74, PL/PW 1.29, EL/PL 0.54.

Habitus as in Fig. 6A. Body blackish brown with paler apex, legs dark brown, antennae dark brown to brown.

Head weakly transverse; punctation coarse and moderately dense, sparser in median dorsal portion; interstices with fine microreticulation; eyes 1/4 times as long as postocular region in dorsal view.

Pronotum nearly parallel-sided; punctation somewhat sparser than that of head; impunctate midline broad; interstices without microsculpture.

Elytra 0.54 times as long as pronotum; punctation fine, shallow, and moderately dense. Hind wings completely reduced.

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

Male. Sternites III-VI unmodified; sternite VII (Fig. 7A) strongly transverse, with median impression of triangular shape posteriorly, this impression with numerous distinctly modified, short and stout black setae; posterior margin distinctly concave in the middle; sternite VIII (Fig. 7B) transverse and broadly impressed along the middle, this impression with short modified setae, posterior margin shallowly concave in the middle; sternite IX (Fig. 7D) nearly symmetric; aedeagus as in Figs 7C, 7E; ventral process long, slender and evenly curved; dorsal plate (Fig. 7F) sclerotized and with long apical portion, apically acute in dorsal view and weakly curved in lateral view; basal portion short and thin; internal sac without sclerotized spines and with membranous structures.

Female. Unknown.

Distribution and biological notes.

This species is currently known only from the type locality. The holotype was collected by sifting litter of bamboo and rhododendronfrom the floor of rhododendron forestat an altitude of 2,600 m.

Etymology.

The specific epithet (Latin, adjective: dark) alludes to the dark brown coloration of the legs.

Comparative notes.

The morphology of the aedeagus suggests that Lathrobium obscurum belongs to the Lathrobium curvatissimum group (Assing, in press a), which previously included five species from Yunnan ( Assing, in press a) and two species from Sichuan ( Assing, in press b, c), with which the new species shares the long, evenly curved ventral process, the long apical portion of the dorsal plate of the aedeagus and the absence of a distinct posterior excision of the male sternite VIII. It is distinguished from the other representatives of this group by the shape and chaetotaxy of the male sternites VII, as well as by with membranous structures in the internal sac of aedeagus.