Epitrichius Tagawa, 1941

Li, Chun-Lin, Yang, Ping-Shih & Wang, Kuo-Sheng Hsu Chuan-Chan, 2008, A review of the genus Epitrichius Tagawa, with an analysis of the internal sac armature of the male genitalia (Coleoptera: Scarabaeidae: Cetoniinae), Zootaxa 1895, pp. 10-24 : 13

Genus Epitrichius Tagawa, 1941

Epitrichius Tagawa, 1941: 18 ; Isida and Fujioka 1988: 58 (catalog); Fujioka 2001: 127 (catalog, comment). Type species: Trichius elegans Kano, 1931 by original designation.

As it is currently defined, Epitrichius includes a morphologically diverse group of species. Epitrichius can be diagnosed by the lack of cretaceous markings over the body surface, the ventral side of the metatarsomeres has a conspicuous fringe of long setae in the males and the internal sac of the male genitalia has two distinct, hook-like armatures. The paired tufts of long setae on the pygidium (usually more developed in the females than the males) is also a feature of this genus.

Some other characteristics show different degrees of variation among the species. The dorsal surface may be dully velutinous or glabrous with a shiny metallic luster. The anterior margin of the clypeus may be smooth to strongly emarginate medially. Both the head and the pronotum are moderately punctate to rugopunctate and setose. The general shape of the pronotum varies from elongate to rounded with outwardly acute basolateral angles. The elytral markings are always well defined with two or three transverse bands, or they are fragmented into spots, except in the males of E. shinshuingensis where markings are diffused marginally. The mesometasternal process is usually vestigial but is distinctly protruding in E. shinshuingensis . The interparamere extension plate varies in the degree of sclerotization from well-developed to semi-membranous.

The species of Epitrichius are distinctly sexual dimorphism compared to some other genera within the tribe Trichiini . The shape of the protibia makes it possible to distinguish the sex in all species in the genus as a unidentate protibia indicates males and a bidentate protibia indicates females. The fringe of setae at the ventral side of the metatarsomeres is found only in males, and the females have distinctly shorter and sparser setae. In males the shape of the pygidium is convex apically and is slightly elongated, while it is truncated in females. Tubercles on the pygidium occur on only females of E. cupreipes , E. bowringii and E. elegans , all of which exhibit a pair of longitudinally ridged or papillose tubercles at the apical half of the pygidium.

Remarks. Krikken (1972) divided his Trichius bifasciatus species group into three “subgroups:” T. elegans , T. bifasciatus and T. fraterculus . However, we reject the concept of delimiting groups and subgroups before a comprehensive phylogenetic analysis is conducted for the genus Epitrichius . The most important characteristics used to separate the species are the anterior margin of the clypeus, the basolateral angles of the pronotum, the pattern of the elytral markings, the development of the setae on the pygidium, the degree of sclerotization of the inter-paramere extension plate and the shape of the parameres and internal sac armature of the male genitalia.