Millipede assassins and allies (Heteroptera: Reduviidae: Ectrichodiinae, Tribelocephalinae): total evidence phylogeny, revised classification and evolution of sexual dimorphism

Evolution of sexual dimorphism in animals has long been of interest to scientists, but relatively few studies have reconstructed evolutionary patterns of extreme sexual dimorphism at a phylogenetic scale, especially in insects. Millipede assassin bugs (Heteroptera: Reduviidae: Ectrichodiinae; 736 spp.) and their sister taxon, Tribelocephalinae (150 spp.), exhibit sexual dimorphism that ranges from limited to extreme, a phenomenon apparently modulated by female morphology. Here, we reconstruct the first phylogeny for the subfamilies Ectrichodiinae and Tribelocephalinae with comprehensive generic representation (152 taxa in 72 genera) using morphological and molecular data (six gene regions). The combined phylogenetic results indicate that Tribelocephalinae are paraphyletic with respect to Ectrichodiinae, and that Ectrichodiinae themselves are polyphyletic. Based on these results, we synonymize Tribelocephalinae with Ectrichodiinae syn.n., describe three new tribes (Ectrichodiini trib.n., Tribelocodiini trib.n., and Abelocephalini trib.n.) and two new subtribes (Opistoplatyina subtrib.n. and Tribelocephalina subtrib.n.), and revise Tribelocephalini sensu n. Ancestral state reconstruction of sexual dimorphism reconstructed limited sexual dimorphism in the ancestor of Ectrichodiinae sensu n. with at least seven evolutionary transitions to extreme sexual dimorphism within the clade. This published work has been registered in ZooBank, This published work has been registered in ZooBank,http://zoobank.org/urn:lsid:zoobank.org:pub:C810E20F-D66A-461F-A0E6-AB1073EA3E3C.