Phylogenetic approach redefines Plistonax (Coleoptera, Cerambycidae, Lamiinae) with new combinations and a new genus of flat-faced long-horned beetles

Plistonax is a Neotropical genus of Acanthoderini flat-faced long-horned beetles with nine species. Since it was established without clear diagnostic characteristics, the subsequent classification of species in it was unstable. This work aims to clarify the taxonomic limits of Plistonax employing a phylogenetic analysis based on morphological data. A matrix was developed including 26 species and 37 characters. Two types of analyses were implemented: parsimony and Bayesian inference. The analyses show that Plistonax is a polyphyletic group, with Plistonax insolitus recovered singly, and the other eight species of the genus were recovered in a clade together with three species of other genera: Acanthoderes (Acanthoderes) ariasi, Melzerus difficilis, and Aegomorphus signatifrons. Based on these results, we redefine Plistonax to include 11 species and propose three new combinations: Plistonax ariasicomb. nov., Plistonax difficiliscomb. nov., and Plistonax signatifronscomb. nov.Melzerus, a monotypic genus, is now a junior synonym of Plistonax. We also provide a redescription for Plistonax and some of its species, propose a new genus Miguelmonneusgen. nov., and redescribe Miguelmonneus insolituscomb. nov. An identification key is given for Plistonax and the geographical records of its species are listed and updated.