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

Abstract

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, http://zoobank.org/urn:lsid:zoobank.org:pub:C810E20F-D66A-461F-A0E6-AB1073EA3E3C.

Australian millipede assassins (Heteroptera: Reduviidae): Malingeus tumidus gen. et sp. nov. and Yaramayahus rufescens gen. et sp. nov., with new generic synonyms and an updated key

“…Finally, the length and position of the strong vein‐spur at the apex of the medial cell of the hemelytral membrane might also differentiate this genus from both Colastocoris and Mendola . While it is true that many of the diagnostic characters pertain to morphologies of the pronotum, a structure that has been shown to exhibit varying degrees of sexual dimorphism (Forthman & Weirauch ), differences in the pronotum seem to correlate with the reduction of wings, and all species herein discussed are based on macropterous individuals.…”

“…Members of the nominate tribe Ectrichodiini (Ectrichodiinae), commonly known as millipede assassins, constitute the majority of the subfamily, accounting for 672 species in 120 genera (Swanson, unpublished; updated from Putshkov & Putshkov ; Putshkov & Putshkov ; Maldonado Capriles ; Forthman & Weirauch ). Its species generally are robust, often brightly coloured ground‐dwelling predators, well known for their preference for diplopod prey (Schuh & Slater ; Forthman & Weirauch ).…”

“…). However, Forthman and Weirauch () recently, in a more comprehensive analysis, demonstrated the polyphyly of Ectrichodiinae sensu stricto and the subsequent need to include the triangle‐headed bugs within Ectrichodiinae, wherein they proposed a revised classification.…”

“…Knowledge concerning the taxonomy and biodiversity of Ectrichodiini has increased in the last several decades (e.g., Dougherty , ; Carpintero & Maldonado Capriles ; Forthman & Weirauch , ). Additionally, Villiers's () and Cook's () keys still facilitate separation of most African and Asian genera, respectively.…”

Uncovering hidden biodiversity: phylogeny and taxonomy of Physoderinae (Reduviidae, Heteroptera), with emphasis on Physoderes Westwood in the Oriental and Australasian regions

“…In contrast, the physoderine fauna of Madagascar and the nearby Comoros Islands (11 genera with 29 spp. ;Villiers 1962) shows considerable morphological diversity, with some taxa resembling assassin bugs in other subfamilies, such as Tribelocephaloides Villiers, 1962 andMimoelasmodema Villiers, 1962, that superficially resemble Tribelocephalini (in the subfamily Ectrichodiinae) and Elasmodeminae, respectively (Villiers 1962;Weirauch et al 2014;Forthman & Weirauch 2017;Fig. 2).…”