Phylogenomics of Phengodidae (Coleoptera: Elateroidea): towards a natural classification of a bioluminescent and paedomorphic beetle lineage, with recognition of a new subfamily

Phengodidae (Coleoptera: Elateroidea), commonly known as glowworm beetles, are a small family of bioluminescent and paedomorphic beetles. There are few phylogenetic studies of Phengodidae, and these are mostly discordant, especially when comparing morphology-based and molecular-based phylogenetic hypotheses. Here, we used the anchored hybrid enrichment approach to undertake the first phylogenomic analysis of Phengodidae (≤358 loci and 39 taxa) and evaluate the higher-level classification of the group. In agreement with previous molecular studies, we recovered Phengodidae as sister to Rhagophthalmidae, and the Old World Cydistinae as sister to all New World Phengodidae. In contrast to previous hypotheses, both Phengodinae and Mastinocerinae were each recovered as monophyletic. Cenophengus was found to be sister to Mastinocerinae, in contrast to some previous hypotheses that placed it as sister to all New World Phengodidae. Considering its morphological divergence, we here establish Cenophenginae subfam. nov. Despite the largest and most comprehensive sampling of Phengodidae in any molecular-based study to date, we had only limited success in revealing the relationships among genera within the most species-rich subfamily, Mastinocerinae. Further studies should focus on the phylogeny and classification of this taxonomically neglected subfamily, on the phylogenetic placement of enigmatic Penicillophorinae, and on seeking morphological support for the main clades of Phengodidae.