Phylogenomics-based click-beetle classification tackles multiple origins of phenotypic modifications

Click beetles (Elateridae) have garnered scientific interest due to their
diversity, bioluminescence, and ontogenetic modifications. However, their
classification is still poorly resolved. Here, we explore the internal
relationships by analyzing 46 tribes and ~4,200 orthologs. We classify
elaterids into 17 subfamilies and 52 tribes. We propose new ranks for
Protelaterinae stat. nov., Thylacosternini stat.
nov. (Lissominae), Semiotina stat.
nov. (Dendrometrini), and Aplastini stat.
nov. (Elaterinae). We resurrect Drapetini stat.
nov. (Lissominae), Pachyderini stat.
nov. (Agrypninae), and Corymbitina stat.
nov. (Dendrometrini). and synonymize Pomachiliini syn.
nov., and Synaptini syn. nov. to Agriotini and
Quasimusini syn. nov. to Negastriini. Hypnoidinae
retains its subfamily rank, regardless of its documented affinities to
Dendrometrinae. Our research provides a phylogenomic framework for
understanding the evolution of morphological disparity. The non-clicking
forms have evolved repeatedly in separate groups since the early evolution
of click beetles. Cebrionini, Pleonomini, and Plastocerini represent
soil-dwelling click beetles living in seasonally arid areas. They exhibit
high sexual dimorphism, but either both sexes are winged (Pleonomini,
Plastocerini), or females have slightly shortened elytra (some
Cebrionini). Omalisinae and Drilini (Agrypninae) have neotenic females
with a modified thoracic morphology, vestigial to absent elytra, and
always absent wings. Aplastine females resemble Omalisinae but share
biological traits with Cebrionini. We propose that genomic data suggest
different relationships among clicking and non-clicking elaterids than
earlier morphology-based hypotheses, which suggested the placement of some
modified click beetles in Dascilloidea and Cantharoidea, respectively,
within a cantharoid clade of Elateroidea. Future research should
investigate the molecular background of ontogenetic modifications,
concentrating on potential differences between slightly modified groups
from seasonally arid regions (e.g., Cebrio spp.) and
predators with highly modified neotenic females
(e.g., Omalisus spp. and Drilus spp.).