Phylogeny and biogeography of the prionine genus Callipogon Audinet-Serville (Coleoptera: Cerambycidae) with special emphasis on the origin and conservation of its unique Palearctic member, Callipogon relictus Semenov

The genus Callipogon Audinet-Serville is a small group (~23 species described) of longhorn beetles in the subfamily Prioninae whose distribution is restricted mostly to the Neotropical region. Callipogon relictus Semenov serves as the unique exception, inhabiting the East Asian subregion of the Palearctic. This disjunction in distribution suggests that the genus may be a relict of an ancient prionine lineage with much wider distribution. To gain further insight into phylogeny and biogeography of Callipogon, we reconstructed the first molecular phylogeny of the genus using multilocus DNA sequence data. Both Bayesian and maximum likelihood inferences confirmed the sister relationship between the Palearctic and Neotropical lineages of Callipogon sensu stricto, despite the genus appearing to be a polyphyletic group. Furthermore, our biogeographic analysis under the dispersal-extinction-cladogenesis model suggested that the ancestral lineage of Callipogon originated in Mesoamerica during the Paleocene and dispersed into the Eastern Palearctic region across the Bering Land Bridge in the late Eocene. The divergence between the Palearctic and Neotropical lineages appeared to be the result of vicariance events following the demise of boreotropical forest across the Bering Land Bridge during the terminal Eocene event around 34 MYA. Lastly, considering the threatened status of Callipogon relictus, we used species distribution modeling to predict the future distribution of the species based on comprehensive climatic data. We found that the distribution of this relictual species is likely to shrink drastically in the next 50 years, highlighting the urgent need for more systematic conservation plans.