Taxonomy and phylogeny of the genus Gastrocentrum Gorham (Coleoptera, Cleridae, Tillinae), with the description of five new species

The genus Gastrocentrum Gorham, 1876 is revised to include nine species. Five new species are described in this genus: G. magnumsp. nov. (NE India), G. regularesp. nov. (Cameron Highlands, Malaysia), G. xiaodongisp. nov. (Gyirong, Xizang, China), G. zayuensesp. nov. (Zayü, Xizang, China), and G. gaoligongensesp. nov. (Fugong, Yunnan, China). Gastrocentrum nitidum Schenkling, 1916 is transferred to the genus Tillus as a new combination. All the species in this genus are described (except G. brevicolle), and a key is provided for their identification. Illustrations of male genitalia, female reproductive organs, and other important structures are provided. An interspecific phylogeny-estimate of Gastrocentrum is presented based on morphological data, with two main clades recognized: a clade containing G. unicolor and G. laterimaculatum, and a clade containing the remaining six species (the latter a polytomy consisting of G. magnumsp. nov., G. dux, and G. regularesp. nov., and a well-supported sub-clade representing the remaining species). Additionally, the taxonomic and phylogenetic importance of female reproductive organs is discussed.