Phylogeny and Taxonomy of Paxillus MacLeay and Passipassalus Reyes-Castillo and Fonseca (Coleoptera: Passalidae: Passalini), with the Description of New Species

The first phylogenetic analysis of the genera Passipassalus and Paxillus is presented. We studied all species of these two genera, including Passipassalus nukak sp. nov., Paxillus amati sp. nov., Paxillus inca sp. nov., Paxillus martinezi sp. nov., and Paxillus akatanga sp. nov. A morphological matrix with 40 characters was analyzed employing maximum parsimony. Nine species from other genera of Passalini (Ameripassalus, Passalus, Spasalus, and Ptichopus) were included. A single most-parsimonious tree was found with three polytomies caused by collapsing zero-length branches. Two species of Paxillus were grouped with Passipassalus buhrnheimi Fonseca and Reyes-Castillo (Passipassalus macrocerus (Reyes-Castillo and Fonseca) n. comb. and Passipassalus corniculatus (Fonseca, Gouveia and Fernandez) n. comb.). The remaining species of Paxillus constitute a monophyletic group divided in two clades that we called the Leachi and Forsteri species groups. The transfer of two species from Paxillus to Passipassalus makes mandatory the redescription and redelimitation of these two genera. Likewise, reviewing the morphological characters, we found that the lacinia, a traditional character employed to delimit Paxillus, is bidentate in all species of Forsteri group. Our results suggest an early separation of the ancestors of Paxillus and Passipassalus within Passalini, and agree with observations by other authors about the paleoendemism of Paxillus in the Greater Antilles.