Phylogeny and Systematics of Wood-Degrading Neotropical Bess Beetles (Coleoptera: Passalidae: Passalinae)

Passalidae (Coleoptera: Scarabaeoidea) are saproxylophagous beetles that live and feed inside decaying wood. Passalid diversity and biogeography are relatively well-established at the tribal-level, particularly in the New World. However, a robust phylogenetic framework to test the current taxonomic status of the generic groups in the family is lacking. In the New World, Passalidae is represented by the tribes Passalini and Proculini. To test the monophyly of Proculini and Passalini and reconstruct relationships among the New World genera, we used DNA sequences from three genes along with data from 57 morphological characters. Our taxon sampling included 25 of the 26 genera of New World Passalidae across their entire geographic range (The United States of America to Argentina). We recovered Proculini and Passalini as reciprocally monophyletic sister groups. The genus Passalus was rendered polyphyletic by the other four genera of Passalini included in our analyses. The genera of Proculini were mostly monophyletic, except for Odontotaenius, Petrejoides, Popilius, Pseudacanthus, and Vindex. Based on our phylogenetic results and analyses of morphological data, we suggest transferring three species from Petrejoides to Chondrocephalus (Chondrocephalus guatemalae [Reyes-Castillo & Schuster, 1983] comb.n., Chondrocephalus pokomchii [Schuster, 1981] comb.n., and Chondrocephalus reyesi [Schuster, 1988] comb.n.), and one species, Pseudoarrox caldasi Reyes-Castillo & Pardo-Locarno, 1995 comb.n., back from Petrejoides to Pseudoarrox. The genus Passalus and the non-monophyletic genera of Proculini require extensive systematic revision.