Historical biogeography of New World Passalidae

Aim: The fauna of Mesoamerica is extraordinarily species rich and exhibits a high degree of local, regional, and high-elevation endemism. Traditionally, this area has been seen as a transition zone between the Nearctic and Neotropical regions; in contrast, new data suggest Mesoamerica is a center of origin and taxonomic diversification. For example, the diversity of species and genera of Passalidae in Mesoamerica is concentrated in montane environments and there are many locally-endemic taxa; thus, Mesoamerica has been suggested as a center of origin and taxonomic diversification for the group. However, this hypothesis has not been formally tested.

Location: New World tropics, with an emphasis on Mesoamerica

Taxon: Coleoptera, Passalidae (tribes Passalini and Proculini)

Methods: We studied timing and geographic patterns in the taxonomic diversification of Neotropical Passalidae. We used DNA sequence data from 3 genes (CAD, Wingless, 28S) for 93 species of Passalidae, along with information from the fossil record, to generate a time-calibrated phylogeny for the group. Additionally, we performed Ancestral Area Estimation and Ancestral State Reconstruction of the altitudinal distribution niche.

Results: The divergence time analyses recovered a much older estimated timing of origin and diversification events in Passalidae than previously proposed. We recovered the origins of the New World Passalidae in the late Jurassic and the split between Passalini and Proculini during the mid-Cretaceous. Moreover, we observed congruence between timing and patterns of clade diversification and major paleogeographical events. For example, the origin and crown diversification of montane genera during the uplift and emergence of Mesoamerica from the sea.  

Main conclusions: Orogenic events throughout the Paleogene and Neogene played a major role in the diversification of New World Passalidae. Moreover, Nuclear and Southern Mesoamerica are centers of origin and taxonomic diversification for Proculini.