Phylogenomic Analyses of the Tenthredinoidea Support the Familial Rank of Athaliidae (Insecta, Tenthredinoidea)

Abstract

The systematic status of the genus <i>Athalia</i> and related genera is a perennial controversy in sawfly taxonomy. Several authors have hypothesized that the placement of <i>Athalia</i> within the Tenthredinidae is artificial, but no studies have focused on this topic. If the hypothesis that <i>Athalia</i> does not belong to Tenthredinidae can be supported, the taxonomic framework of Tenthredinoidea needs revision. We present a comprehensive phylogenomic study of Tenthredinoidae, focusing on the positions of <i>Athalia</i> and related genera by sampling 80 representatives mainly of the Tenthredinoidea, including Heptamelinae and Blasticotomidae. Our phylogenetic reconstructions based on nuclear genes and mitochondrial (mt) sequences support <i>Athalia</i> and related genera as a distinct clade sister to Tenthredinidae + (Cimbicidae + Diprionidae). A comparison of symphytan mitochondrial genomes reveals an innovative gene rearrangement pattern in Athaliidae, in which <i>Dentathalia</i> demonstrates a more ancestral pattern than <i>Athalia</i> and <i>Hypsathalia</i>. The lineage specificity of mt rRNA secondary structures also provides sufficient support to consider Athaliidae as a separate family. In summary, the phylogeny and genomic structural changes unanimously support the taxonomic treatment of Athaliidae as a family and the re-establishment of <i>Dentathalia</i> as a valid genus.