Phylogeny and morphological character evolution in the Idiocerus group (Hemiptera: Cicadellidae)

The higher classification of the diverse, globally-distributed arboreal leafhopper subfamily Eurymelinae ( sensu lato ) was recently revised based on a phylogenetic analysis using molecular and morphological characters. Within the largest tribe, Idiocerini, prior analysis supported recognition of an informal Idiocerus group comprising genera restricted to the Holarctic region. To resolve relationships among genera within this group, test prior generic concepts, and examine the stability of morphological characters previously used to diagnose genera, a more detailed molecular phylogenetic analysis was conducted. A dataset comprising sequences of 13 protein-coding and 2 ribosomal genes from the mitochondrial genome and 28S ribosomal RNA gene for 35 specimens, representing 23 in-group species belonging to 13 genera and 6 outgroups, was analyzed using maximum likelihood and Bayesian inference methods. The results consistently supported the monophyly of the Idiocerus group. The genera Chinaocerus Zhang & Li, 2016, Koreocerus Kwon, 1985, Nabicerus Kwon, 1985, Parocerus Vilbaste, 1980, Populicerus Dlabola, 1974 and Rhytidodus Fieber, 1872 were recovered with high support but excluding Balcanocerus Maldonado-Capriles, 1971. Two strongly supported clades were revealed within the Idiocerus group, but we refrain from proposing taxonomic changes due to the limited sample of species available for clades A–B. Alloidiocerus gen. nov. with type species Alloidiocerus leucophilus sp. nov. , and Sahlbergotettix Zachvatkin, 1953 are added to this group. Ancestral character state reconstructions based on the molecular phylogeny revealed that most morphological characters previously used to define genera show little or no homoplasy.