New data on the Paederus biacutus species group from mainland China (Coleoptera, Staphylinidae, Paederinae)

Abstract Paederus jianyueae Peng & Li, sp. n. (Zhejiang: Qingliangfeng) is described and illustrated. Additional records of P. biacutus Li, Zhou & Solodovnikov, 2014 and P. parvidenticulatus Li, Zhou & Solodovnikov, 2014 are reported.


Introduction
The Paederus fauna of China previously comprised 36 species, some of which were assigned to subgenera and some are listed as incertae sedis (Smetana 2004;Li et al. 2013Li et al. , 2014. Five species, all of them brachypterous and more or less locally endemic, were placed in the Paederus biacutus species group: P. biacutus Li & al., 2014 (Fujian), P. parvidenticulatus Li & al., 2014 (Guizhou), P. sinisterobliquus Li & al., 2014 (Hubei), P. symmetricus Li & al., 2014 (Guizhou, Guangxi), and P. volutobliquus Li & al., 2014 (Guangdong). This group can be easily distinguished from other groups or subgenera of Paederus Fabricius, 1775 by the special color pattern (black head, elytra and abdomen; brownish red pronotum; elytra with weakly or distinctly metallic hue), four regularly arranged protrusions on the anterior margin of the labrum, the trapeziform elytra with weakly pronounced humeral angles, the notched posterior margin of the male sternite IX, the strongly sclerotized and more or less symmetrical aedeagus with a hooked or straight apex of the dorsal plate, and a pair of distinct round or triangular posterior excisions of the female sternite VIII.
A study of Paederus material from mainland China yielded some new records and a new species of the P. biacutus group.

Material and methods
The morphological studies were conducted using an Olympus CX31 microscope. The images were prepared using a Canon EOS 70D (with an MP-E 65 macrolens) and Canon G12 camera. The line drawings were created using Adobe Illustrator CS3 software.
The following abbreviations are used in the text, with all measurements in millimeters: Body length (BL): length of body from the anterior margin of the labrum to the apex of the abdomen.  Comment. A comparison of the original description of P. biacutus and the additional material from the type locality and its vicinity revealed some differences in the sexual characters. According to the original description and illustration, the female sternite VIII is transverse (oblong in the additional material, Fig. 2F) and the internal sac of the aedeagus has two sclerotized spines (three spines in the additional material, Fig. 2K). The previously known distribution of P. biacutus included the Chinese province of Fujian (Li et al. 2013). The above record from Jiangxi represents a new province records. Comment. An examination of the above material from the type localities of P. symmetricus and P. parvidenticulatus revealed that they are conspecific. A paper formally proposing the respective synonymy is being prepared by Xiao-Yan Li (pers. comm.).  Habitus as in Fig. 7. Coloration: head, pronotum and abdomen black; elytra black with faint blueish hue; legs and antennae dark-yellowish, apices of femora and tibiae not infuscate. Head transverse; shape without apparent sexual dimorphism; widest across eyes; punctation moderately coarse and very sparse; interstices glossy. Eyes distinctly convex, 0.6-0.8 times as long as postocular region in dorsal view. All antennomeres oblong.

Paederus jianyueae
Pronotum nearly globulous, strongly convex in cross-section; punctation similar to that of head, very sparse.  Elytra trapeziform; punctation coarse, moderately defined, and dense. Hind wings completely reduced. Metatarsomere I as long as combined length of metatarsomeres II and III.
Distribution and natural history. The species was found in two geographically close localities: Qingliangfeng, western Zhejiang and the Huang Shan, southeastern Anhui. The specimens were sifted from leaf litter and moss in coniferous forests at altitudes of 1500-1700 m.
Etymology. The species is named after Jian-Yue Qiu, who lent extensive support to our research.  Comparative notes. Paederus jianyueae belongs to the P. biacutus group, as can be inferred both from the sexual characters and from the external morphology (special color pattern, four protrusions on anterior margin of labrum, morphology of the aedeagus, shape of the male sternite IX and the female sternite VIII). This new species is distinguished from other species of this group by the shape of female sternite VIII and the morphology of the aedeagus (more slender dorsal plate of the median lobe; slender parameres; three distinctive sclerotized spines in the internal sac). Based on the similar morphology of the aedeagus, P. jianyueae may be most closely related to P. biacutus Li, Zhou & Solodovnikov, 2013.