A new species of the genus Phaenochilus Weise from China (Coleoptera, Coccinellidae, Chilocorini)

Abstract A new species Phaenochilus albomarginalis Li & Wang, sp. n. is described. The only other species recorded from China is Phaenochilus metasternalis Miyatake, 1970 and it is described here for comparison. Diagnoses, detailed descriptions, illustrations, and distributions are provided.


Introduction
Chilocorini is a medium-sized tribe in the Coccinellidae which was placed in the superfamily Coccinelloidea by recent molecular phylogenetic research on Cucujoidea (Robertson et al. 2015). It consists of 26 genera and about 280 species (Łączyński and Tomaszewska 2012). Chilocorini have been shown to be a monophyletic group by some phylogeny works, but the generic relationships within this tribe are ambiguous (Giorgi et al. 2009;Magro et al. 2010;Seago et al. 2011).

Phaenochilus
Weise is a small genus of the tribe Chilocorini, the species of which mainly feed on scale insects and a few species of whitefly nymphs. The genus Phaenochilus was proposed by Weise (1895). Korschefsky (1932) designated Phaenochilus punctifrons as the type species. Giorgi and Vandenberg (2012) revised the genus and described a new species. So far, there are nine species known, distributed mainly in Southeast Asia, China, India and Japan (Giorgi and Vandenberg 2012). Except for P. metasternalis, which is widely distributed in China and Southeast Asia, the other species of Phaenochilus have more restricted distributions.
The genus was unknown from China until Miyatake (1970) described P. metasternalis. Pang and Mao (1979), Cao et al. (1992), and Ren et al. (2009) redescribed this species, but no new species from China have been added to this genus in recent decades.
In this paper, a second species of Phaenochilus from China is described and compared with P. metasternalis.

Material and methods
Type specimens of the new species are deposited at the Department of Entomology, South China Agriculture University, Guangzhou, China (SCAU).
External morphological characters were observed with a dissecting stereoscope (SteREO Discovery V20). The following measurements were made with an ocular micrometer:

TL
total length, length from apical margin of clypeus to apex of elytra; TW total width, width across both elytra at widest point; TH height measured across the highest point of the elytra; HW head width in frontal view; PL pronotal length, from middle of anterior margin to base of pronotum; PW pronotal width at widest point; EL elytral length, from the apex of the elytra to the base including the scutellum; EW elytral width, equal TW.
Male and female genitalia were dissected, cleared in 10% NaOH by boiling for several minutes, and examined with an Olympus BX51 microscope. Genitalic morphological character photographs were generated with digital cameras (AxioCam HRc and Coolsnap-Procf & CRI Micro*Color), attached to the microscopes using AxioVision Rel. 4.8 and Image-Pro Plus 6.0 to capture images from both cameras, and photographs were cleaned up and laid out in plates in Adobe Photoshop CS 8.0.
Male genitalia: penis slender and long, penis capsule with short outer arm and long inner arm, apex of penis with small protuberance and membranous appendage ( Fig. 2d-e). Tegmen stout, penis guide gradually broadened to basal 2/5, subparallel to apical 1/5 thereafter, then gradually converging apically to blunt tip in ventral view; only one lateral margin slightly emarginate at basal 3/5 (Fig. 2c). Parameres slightly shorter than penis guide with dense, long setae at inner sides and apices with group of long setae in lateral view (Fig. 2b).
Male genitalia: penis slender and long, outer arm of penis capsule slightly longer than inner arm, apex of penis with a small protuberances and membranous appendage inside (Fig. 3e-f ). Tegmen stout, penis guide knife-like in ventral view (Fig. 3h). Parameres as long as penis guide with dense short setae at inner sides and apices with patches of short setae visible in lateral view (Fig. 3g).