Three new species of the genus Lathrobium Gravenhorst (Coleoptera, Staphylinidae, Paederinae) from the Jiulongshan Natural Reserve, East China

Abstract Three new species of the genus Lathrobium Gravenhorst from Jiulongshan Natural Reserve, Zhejiang, East China, Lathrobium jiulongshanense sp. n., Lathrobium sheni sp. n. and Lathrobium zhaotiexiongi sp. n. are described and illustrated. A key to the Lathrobium species from Zhejiang Province is provided.


Introduction
Up to today, eight species have been recorded from Zhejiang Province: L. imadatei Watanabe & Luo, 1992 and L. tamurai Watanabe & Luo, 1992 from Wuyanling Natural Reserve, L. cooteri  from the Lin-long Shan Mountain, L. rougemonti L. tianmushanense Watanabe, 1999 from the West Tianmushan Mountain, and L. lingae Peng, Li & Zhao, 2012, L. longwangshanense Peng, Li & Zhao, 2012and L. uncum Peng, Li & Zhao, 2012 from the Longwangshan Mountain. Jiulongshan is a Natural Reserve located in southwestern Zhejiang, and no Lathrobium species have been reported from there.
In 2006, our colleagues made a collecting trip to the Jiulongshan Natural Reserve (at. 28°21'N, 118°53'E), and obtained a large number of Lathrobium specimens. Three species were recognized and all of them are new to science. In addition, some specimens collected recently in Zhuji City (approximately 29°43'N, 119°59'E) were provided by Mr. Tie-Xiong Zhao, all of them are belonging to one of the new species mentioned above.
A map (Fig. 5) showing the distribution of Lathrobium in Zhejiang and a key is provided.

Material and methods
All specimens were collected from the leaf litter of the forest floor by sifting. The following abbreviations are used in the text, with all measurements in millimeters: BL body length: length of body from the labral anterior margin to the anal apex; HL head length: length of head from the clypeal anterior margin to the posterior margin of the head; HW head width: maximum width of head; PL pronotum length: length of pronotum along midline; PW pronotum width: maximum width of pronotum; EL elytra length: length of elytra from the apex of the scutellum to the elytral posterior margin.
The type materials is deposited in the Insect Collection of Shanghai Normal University (SNUC).   Habitus as in Fig. 1A. Body brown with paler apex, legs brown, antennae brown to reddish brown.
Pronotum with lateral margins weakly convex in dorsal view; punctation sparser than that of head; impunctate midline narrow; interstices without microsculpture.
Elytra with punctation denser than that of pronotum and well-defined; hind wings reduced.
Abdomen with dense punctation; interstices with shallow microsculpture.  Distribution. East China (Zhejiang: Jiulongshan Natural Reserve). Etymology. The species is named after its type locality.
Remarks. The new species is distinguished from all its congeners in the following points: male sternites IV-VI with several peg-like setae at the posterior margin; male sternite VIII with the different length of setae surrounding the asymmetric and relatively deep emargination. Habitus as in Fig. 1B. General appearance similar to L. jiulongshanense, except for the lighter coloration of the legs, the much smaller body size, and the sparser punctation on head and pronotum.
Distribution. East China (Zhejiang: Jiulongshan Natural Reserve). Etymology. The species is named after Shan-Jia Shen, collector of the type specimens.
Remarks. This species resembles L. tamurai Watanabe, 1992, which too was described from Zhejiang Province, in having an aedeagus with a short and apically hookshaped ventral process. It resembles L. yinae Watanabe, 1997 from Yunnan in having the posterior margin of the male sternite VII weakly concave and two rows of dense setae on male sternite VIII. The new species can be readily distinguished from these species by two rows of dense setae on the male sternite VIII and by the much shorter ventral process of the aedeagus. In L. tamurai, the male sternite VIII has short darkish setae. In L. yinae, the ventral process of the aedeagus is elongate.  Habitus as in Fig. 1C. Generally similar to L. jiulongshanense, except for the lighter coloration of the legs, the somewhat larger body size, and the moderately sparse punctation on head and pronotum. Male. Sternite V (Fig. 4C) with dense short darkish setae in posterior concavity; sternite VI (Fig. 4D) similar to sternite V, but with slightly shorter setae in median concavity; sternite VII ( Fig. 4G) with different length of setae surrounding the distinctly asymmetric emargination in posterior portion; sternite VIII ( Fig. 4F) with different length of setae in large impression and shallow posterior emargination; sternite IX ( Fig. 4H) almost asymmetric; aedeagus (Fig. 4I, 4J) with short ventral process and dorsal sclerite. Female. Posterior margin of tergite VIII (Fig. 4A) slightly convex; sternite VIII ( Fig. 4B) longer than that of male, posterior margin distinctly pointed in the middle; tergite IX ( Fig. 4C) narrowly separated from X (Fig. 4C) and with moderately slender lateral processes.
Etymology. The species is named after Tie-Xiong Zhao, collector of the type series, a 12-year-old boy who is most enthusiastic about collecting beetles.
Remarks. From other Lathrobium species of the Jiulongshan N. R., L. zhaotiexiongi is readily separated by the male sternite VII having setae of variable length surrounding the posterior emargination and the male sternite VIII having setae of variable length in the postero-median impression.