Taxonomy And Phylogeny Of The Genus Rybaxis(Coleoptera: Staphylinidae: Pselaphinae) Of China

Members of the ant-loving beetle Rybaxis(Coleoptera: Staphylinidae: Pselaphinae:Brachtglutini)are predatory beetles with small sizes,a high species richness,and a wide distribution.They feed on tiny invertebrates such as springtails,and are commonly found in decaying logs and forestry leaf litter.Rybaxis may play an ensscial role in food web and ecological equilibrium.The first record of Rybaxis was in 1817.Thereafter,a total of 84 species of this genus have been reported worldwide.Members are mainly distributed in Australian,Oriental,Nearctic and Afrotropical Regions.Yet,before this study no species has benn reported from China.Based on an examination of over 200 specimens collected from various provinces,the taxonomic knowledge of Rybaxis of China is summarized.The results are as the followings:1.Eighteen new species are recognized: Rybaxis aculeus sp.nov.(Xizang),R antennalis sp.nov.(Yunnan),R.cornus sp.nov.(Yunnan),R.diaoluomontis sp.nov.(Hainan),R.femoralis sp.nov.(Yunnan),R.grandiceps sp.nov.(Sichuan,Xizang),R.hani sp.nov.(Yunnan),R.hujiayaoi sp.nov.(Yunnan),R.lebuensis sp.nov.(Xizang),R.nyingchiensis sp.nov.(Xizang),R.longus sp.nov.(Xizang),R.nabanhensis sp.nov.(Yunnan),R.quadrilobus sp.nov.(Sichuan),R.robusta sp.nov.(Xizang),R.simplex sp.nov.(Xizang),R.tangliangi sp.nov.(Yunnan),R.trifoveatus sp.nov.(Yunnan),R.trochantails sp.nov.(Yunnan,Xizang),and a new country record is provided for R.lamellifer L(?)bl,1973(from Beijing).All species treated in this paper are diagnosed and described in detail.Illustrations of the major diagnostic characters,and a habitus picture for each species are given.2.A key to the Chinese species of Rybaxis is presented.3.Based on the morphological characteristics of the subtribe Brachyglutina,a morphological phylogenetic tree of Brachyglutina is established using TNT and Winclada softwares,and the phylogeny of Brachyglutina is analyzed.4.The distribution of Rybaxis in China is mapped,and their geographical distribution is analyzed.5.A list of the world species of Rybaxis is included.