Discovery of the male of Lobrathium rotundiceps (Koch), and a new species of Lobrathium from Jiangxi, East China (Coleoptera, Staphylinidae, Paederinae)

Abstract The male of Lobrathium rotundiceps (Koch, 1939) from Zhejiang and L. luoxiaoense sp. n. from Jiangxi are described and illustrated.


Introduction
Lobrathium rotundiceps was described by Koch (1939) as Lathrobium rotundiceps based on a single female collected from "Tienmuschan N.W. China", but never recorded again since. Assing (2012) revised, redescribed, and illustrated the female holotype. The male sexual characters, however, which are of great significance for taxonomy of Lobrathium species, were unknown. Recently, additional specimens of Lobrathium rotundiceps, among them males, were collected in Zhejiang, or found in the collections of Shanghai Normal University.
In July 2013, two colleagues sifted two specimens of an undescribed Lobrathium in Jiangxi.

Material and methods
The specimens treated in this study are deposited in the following public collections: The Insect Collection of Shanghai Normal University, Shanghai, P. R. China (SNUC); Naturhistorisches Museum Basel, Switzerland (NHMB).
The labels of type specimens are cited in their original spelling. A slash (/) is used to separate different labels.
All measurements are in millimeters. The following abbreviations are used: BLlength of the body from the anterior margin of the mandibles (in resting position) to the abdominal apex; HL-length of the head from the anterior margin of the frons to the posterior margin of the head; HW-maximum width of the head; PL-length of the pronotum along the midline; PW-maximum width of the pronotum; EL-length of the elytra from the anterior margin to the posterior elytral margin along suture; EWmaximum width of the elytra; AL-length of the aedeagus from the apex of the ventral process to the base of the aedeagal capsule.

Taxonomy
Lobrathium rotundiceps (Koch, 1939) (Koch), det. V. Assing 2012" (NHMB). Koch (1939) described Lathrobium rotundiceps Koch from a single female, from "Tienmuschan N.W. China". Zheng (1988) included Lobrathium rotundiceps (Koch) in his key to species based on the original description. Recently, Assing (2012) redescribed the species based on the holotype, and pointed out that the type locality specified in the description ("Tienmuschan N.W. China") was in "northeastern (not northwestern) China". Sternite VII (Fig. 2D) strongly transverse and without impression, posterior margin broadly concave; sternite VIII ( Fig. 2E) weakly transverse, with long and pronounced postero-median impression, this impression with numerous modified, stout and short black setae, posterior margin weakly concave in middle, near this concavity Comparative notes. Lobrathium rotundiceps shares a bifid ventral process with L. digitatum Assing 2010 and L. bidigitatum Assing 2010 from Taiwan, but differs from them in many respects, particularly by much larger body size, the different shape and chaetotaxy of the male sternite VIII, and by the shape of the aedeagus.
Habitat and distribution. The specimens were sifted from debris and moss in moist habitats. Tianmu Shan is a mountain with high biodiversity in Lin'an City in northwestern Zhejiang province in eastern China, its altitude ranging from 300 to 1506 m (Wu and Pan 2001). Longwang Shan is one peak of the Tiammu Shan range and situated about 5 km northwards of the West Tianmu Shan. Description. Body length 7.56-7.67 mm, length of fore body 3.50-3.73 mm. Habitus as in Fig. 3A. Coloration: body black, elytra with blue hue, and anterior portion of posterior half with yellowish spot not reaching posterior and lateral margins; legs dark brownish with paler tarsi; antennae dark reddish.
Head distinctly transverse (HL/HW = 0.90-0.91); posterior angles marked; punctation coarse and dense, sparser in median dorsal portion, interstices without microsculpture. Eyes large, more than half as long as distance from posterior margin of eye to neck. Antenna slender, 2.06-2.11 mm long.
Abdomen slightly broader than elytra; punctation fine and dense; posterior margin of tergite VII with palisade fringe; posterior margin of tergite VIII weakly convex, without appreciable sexual dimorphism.
Male. Sternite VII (Fig. 3D) with deep and very narrow and shallow median impression with pubescence, posterior margin broadly concave, weakly convex in middle; sternite VIII ( Fig. 3E) weakly transverse, with deep and pronounced postero-median impression, this impression with numerous (about 60) modified, stout and short black setae, posterior excision relatively small, near posterior excision with long dark setae; aedeagus (Figs 3B, C) 1.42 mm long, ventral process long and broad, apically convex in ventral view.
Female. Posterior margin of tergite VIII weakly convex in middle; posteriorly margin of sternite VIII broadly convex.
Etymology. The specific epithet (adjective) is derived from the Luoxiao Shan range where the type locality is situated.
Comparative notes. This species is highly similar to L. anatitum Li & Li (2013) in external (habitus, position of the elytral spots) and male sexual characters (modifications of the male sternites VII and VIII; shape of the ventral process of the aedeagus). The new species differs from L. anatitum by the narrower median impression of the male sternite VII, by the less extensive median cluster of modified setae and the smaller posterior excision of the male sternite VIII, as well as by the shape of the ventral process of the aedeagus (apex more acute in ventral view). For illustrations of L. anatitum see Li et al. (2013).
Habitat and distribution. The specimens were sifted from moss on stones in two streams, Jiangxi, East China.