Renius cornutus, a new genus and species of Chilocorini from Tibet, China (Coleoptera, Coccinellidae)

Abstract A new monotypic genus of Chilocorini, Renius Li & Wang, gen. n., with a new species R. cornutus Li et Wang, sp. n. is described from Tibet, China. All diagnostic features are illustrated. The relationships with other genera of Chilocorini are discussed and a key to Chinese genera of Chilocorini is provided.

The tribe is also diverse in China being represented with nine genera and 39 species (Pang et al. 2004;Ren et al. 2009;Hu et al. 2013;Li et al. 2015a;2015b). During our study of the Chinese Chilocorini, a particular species from Tibet was found, recorded twice during collecting trips in 2009 and 2011, respectively. This new species is similar to members of Orcus Mulsant, 1850 in body shape and coloration. However, some characters make it hard to group it to any extant genus of Chilocorini.
Therefore, a new genus, Renius gen. n. is established for the only so far known species, Renius cornutus Li et Wang sp. n., which is also described here. Additionally, a key is provided to the genera of Chilocorini known in China and the diagnostic features of the new genus and species are illustrated. Lastly, the relationships between Renius and the other genera of Chilocorini are discussed.

Materials and methods
Specimens examined in this study were collected in Tibet, China. Type specimens designated in the present paper are deposited at the Department of Entomology, South China Agriculture University (SCAU), Guangzhou.
All the morphological photographs were taken by Zeiss AxioCam HRc digital camera mounted on a Zeiss Stereo Discovery V20 stereomicroscope or Zeiss Imager Z2m microscope. A number of serial images were combined in Zerene Stacker in order to obtain an entirely focused image, and photographs were cleaned up and laid out in plates in Adobe Photoshop CS 8.0. Morphological terms of Coccinellidae follow Ślipiński (2007) and Ślipiński and Tomaszewska (2010). 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, including eyes; 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.
Etymology. The generic name is dedicated to the memory of the well-known Chinese entomologist, Ren Shunxiang, who devoted most of his life to the study of Coccinellidae and biological control. Gender masculine. Body roundish, moderately convex. Head bluish black, mouthparts yellow, only clypeal portion covered with short, greyish pubescence. Pronotum, scutellum and elytra bluish black (Fig. 1a-d). Underside bluish black except legs yellow, abdomen brownish black, sparsely covered with short, grayish pubescence.
Male genitalia: penis slender, penis capsule with long outer arm and short inner one, apex of penis acute, screw-shaped from apical 1/11 to apical 2/11 (Fig. 2d-e). Tegmen stout, penis guide narrow at base, widest at basal 1/3 then gradually converging to blunt tip, symmetrical in ventral view; widest at base gradually converging to blunt apex in lateral view. Parameres stout, slightly shorter than penis guide, densely covered with short setae at inner surfaces and a distal end in lateral view (Fig. 2f-g).
Distribution. Motuo County, Tibet, China. Etymology. The species name is derived from Latin cornutus and refers to middle of clypeus with a horn-like projection in the male.

Discussion
Although Renius share ten antennomeres of the antenna and similar shapes of the tibiae with Exochomus, it does not have the terminal antennomere embedded in the penultimate one, and it lacks apical spurs on mid and hind tibiae. Initially, the specimens were thought as a member of Orcus Mulsant. Both genera share many characters, like: roundish body; basal margin of pronotum with border line; elytral margin strongly reflexed; elytral epipleuron broadened; penultimate labial palpomere stout; shape of abdominal postcoxal lines etc. (Łączyński and Tomaszewska 2009). Therefore, it appears likely having a close relationship with Orcus Mulsant. However, the shape of spermatheca, mesoventrite, and meso-metaventral junction of Renius resemble those of Chilocorus Leach. According to morphology, Renius should have a closer relationship with Orcus rather than with Chilocorus. However, the molecular phylogenetic analysis of Chilocorini reveal Renius and (Chilocorus + Phaenochilus + Anisorcus) to be a sister group (Li et al., in prep.).
Renius differs from all other genera of Chilocorini in having unique characters, such as clypeus with median projection and subtriangular large sclerite between coxites of female ovipositor. These characters, together with an antenna composed of ten antennomeres with antennomeres 3-5 gradually shortening, define this new genus.