Three new species of Lathrobium Gravenhorst (Coleoptera, Staphylinidae, Paederinae) from Sichuan, Southwest China

Abstract Three new species of the genus Lathrobium Gravenhorst, 1802 from Sichuan Province, Southwest China are described and illustrated: Lathrobium acutissimum sp. n., Lathrobium hailuogouense sp. n. and Lathrobium labahense sp. n. A checklist of Chinese Lathrobium is provided.

In 2006, Hu and Tang made a collecting trip to the Hailuogou and the Labahe natural reserves and collected a number of Lathrobium specimens. Among them, three new species are recognized and reported herein and a checklist of Chinese Lathrobium is provided.

Material and methods
All specimens were collected from the leaf litter of in broad-leaved forests by sifting. The following abbreviations are used in the text, with all measurements in millimeters: body length (BL): length of body from the labral anterior margin to the anal apex; forebody length (FL): length of the clypeal anterior margin to the elytral apex; head length (HL): length of head from the clypeal anterior margin to the posterior margin of the head; head width (HW): maximum width of head; pronotum length (PL): length of pronotum along midline; pronotum width (PW): maximum width of pronotum; elytra length (EL): length of elytra from the apex of the scutellum to the elytral posterior margin.
The type material is deposited in the Insect Collection of Shanghai Normal University, Shanghai, China. (SNUC).
Elytra with punctation denser than that of pronotum and well defined; hind wings reduced.
Male. Sternite VII ( Fig  Distribution. Southwest China: Sichuan. Etymology. The specific epithet (Latin, adjective: sharp) alludes to the apical margin of the male sternite IX.
Remarks. It resembles Lathrobium lijiangense Watanabe & Xiao, 1997 from Yunnan in having a similar shape of the male sternite VII. The new species can be readily distinguished from these species by the male sternite VIII with a triangular emargination at the apical margin and by the aedeagus with a much longer ventral process. In L. lijiangense, the male sternite VIII has a semi-elliptical emargination at the apical margin and the ventral process of the aedeagus is short.  Habitus as in Fig. 1B. General appearance similar to L. acutissimum, except for somewhat smaller body size and sparser punctation on head and pronotum.
Distribution. Southwest China: Sichuan. Etymology. The specific epithet of this new species is derived from the type locality "Hailuogou".
Remarks. The new species resembles Lathrobium zhangi Watanabe & Xiao, 1997 from Yunnan in having the posterior margin of the male sternite VII weakly concave and a similar shape of the male sternite VIII. The new species can be readily distinguished from these species by the broad ventral process of the aedeagus in lateral view. In L. zhangi, the ventral process of the aedeagus is much narrower in lateral view. Habitus as in Fig. 1C. Generally similar to L. acutissimum except for lighter coloration of legs, smaller body size, and somewhat sparser punctation on head and pronotum.
Female. Posterior margin of tergite VIII (Fig. 4F) weakly convex; sternite VIII ( Fig. 4G) much longer than that of male, posterior margin strongly convex; tergite IX ( Fig. 4H) not separated from tergite X (Fig. 4H). Distribution. Southwest China: Sichuan. Etymology. The specific epithet of this new species is derived from the type locality "Labahe".
Remarks. Lathrobium labahense resembles L. watanabei Schülke, 2002 in having a similar shape of the male sternite VIII, but can be readily separated by the aedeagus with a much longer ventral process.

A checklist of Chinese Lathrobium
The checklist is presented in Table 1. The species are arranged alphabetically, and all of them belong to the nominate subgenus. For synonymies see Smetana (2004). Lathrobium nomurai Nakane, 1955 was listed for the China in Smetana (2004). However, this species is apterous and was originally described from Tsuruoka-Do Cave, Kyushu, Japan. Since it is most unlikely that it could be also found in China, we exclude L. nomurai from the list.
The literature references are abbreviated as follows: