A Molecular Phylogeny of the Petaluridae (Odonata: Anisoptera): A 160-Million-Year-Old Story of Drift and Extinction

Petaluridae (Odonata: Anisoptera) are a relict dragonfly family of eleven species that are notable among odonates (dragonflies and damselflies) for their exclusive use of fen and bog habitats, their burrowing behavior as nymphs, large body size as adults, and extended lifespans. Using an anchored hybrid enrichment dataset of over 900 loci we reconstructed a maximum likelihood phylogeny to evaluate their evolutionary history. We investigate intrafamilial relationships through the comparison of gene tree likelihoods for alternate topologies for each gene (deltaGLS) and quartet scores. To estimate the age of origin of the genera within this family, we used a set of well-vetted fossils and a relaxed molecular clock model in a divergence time estimation analysis. We estimate that Petaluridae originated in the early Cretaceous and confirm the monophyly of a Gondwanan and a Laurasian clade within the family. Our relaxed molecular clock analysis estimated that these clades separated approximately 160 mya. Species ages range from 6 (Uropetala) to 120 million years (Phenes). The intergeneric relationships in the Laurasian clade were well resolved and supported by high gene and quartet concordance factors. Our biogeographical analyses focusing on a set of key regions suggests that divergence within Petaluridae is largely correlated with continental drift, the exposure of land bridges, and the development of mountain ranges. Our results support the hypothesis that species lineages within Petaluridae have persisted for tens of millions of years. Specialization tends to lead to extinction on long time scales; Petaluridae appear to be an exception to this evolutionary norm.