Lathrobium conexum Assing & Peng

Assing, Volker, Peng, Zhong & Zhao, Mei-Jun, 2013, On the Lathrobium fauna of the Emei Shan, Sichuan, China (Coleoptera, Staphylinidae, Paederinae), ZooKeys 277, pp. 47-67 : 55-56

Lathrobium conexum Assing & Peng sp. n. Figs 2C511

Type material.

Holotype ♂: 'CHINA: Sichuan Prov., Emeishan City, Mt. Emeishan, 29°33'N, 103°23'E, 27.vii.2012, alt. 1,100 m, Dai, Peng & Yin leg. / Holotypus ♂ Lathrobium conexum sp. n., det. Assing & Peng 2012' (SNUC). Paratypes: 2♂♂, 2♀♀: same data as holotype (SNUC).

Etymology.

The specific epithet (Latin, adjective: connected) refers to the merged ventral process and dorsal plate of the aedeagus and emphasizes the hypothesized close relationship of Lathrobium conexum to Lathrobium iunctum and Lathrobium coniunctum .

Description.

Body length 8.8-10.0 mm; length of forebody: 4.1-4.5 mm. Habitus as in Fig. 2C. Head noticeably transverse, 1.05-1.10 times as broad as long. Other external characters as in Lathrobium iunctum .

Male. Sternite VII (Fig. 5D) distinctly transverse and with relatively small, subelliptic, and shallow posterior impression in asymmetric position, this impression with defined and extensive cluster of numerous distinctly modified, short and stout black setae; posterior margin weakly convex. Sternite VIII (Fig. 5E) weakly transverse, with small and shallow impression in asymmetric position posteriorly, this impression with few short black setae; posterior excision shallow and in distinctly asymmetric position. Sternite IX as in Fig. 5F. Aedeagus (Figs 5G, H) approximately 1.4 mm long (from base to apex of dorsal plate) and distinctly asymmetric; ventral process and dorsal plate fused; basal portion of aedeagus small; internal sac with weakly sclerotized basal sclerite.

Female. Sternite VIII (Fig. 5B) oblong, its posterior margin strongly convex. Tergite IX with short and undivided median portion and with moderately long postero-lateral proce sses; tergite X approximately 2.3 times as long as tergite IX in the middle (Fig. 5C).

Comparative notes.

As can be inferred from the similarly derived morphology of the aedeagus (ventral process and dorsal plate fused and distinctly asymmetric; small basal portion; internal sac with weakly sclerotized basal sclerite), the similar modifications of the male sternite VII (posterior impression in asymmetric position and with cluster of distinctly modified setae), the similar female secondary sexual characters, and the practically identical external characters, Lathrobium conexum is closely allied to Lathrobium iunctum and Lathrobium coniunctum . The similar modifications of the male sternite VIII would suggest that it may be most closely related to the latter.

Distribution and natural history.

This species is currently known only from the type locality. The specimens were collected by sifting leaf litter and humus from the floor of hardwood forest with Kalopanax at an altitude of 1,100 m (Fig. 11).