Phylogeny of the Procyonidae (Mammalia: Carnivora): molecules, morphology and the Great American Interchange.

The Procyonidae (Mammalia: Carnivora) have played a central role in resolving the controversial systematics of the giant and red pandas, but phylogenetic relationships of species within the family itself have received much less attention. Cladistic analyses of morphological characters conducted during the last two decades have resulted in topologies that group ecologically and morphologically similar taxa together. Specifically, the highly arboreal and frugivorous kinkajou (Potos flavus) and olingos (Bassaricyon) define one clade, whereas the more terrestrial and omnivorous coatis (Nasua), raccoons (Procyon), and ringtails (Bassariscus) define another clade, with the similar-sized Nasua and Procyon joined as sister taxa in this latter group. These relationships, however, have not been tested with molecular sequence data. We examined procyonid phylogenetics based on combined data from nine nuclear and two mitochondrial gene segments totaling 6534bp. We were able to fully resolve relationships within the family with strongly supported and congruent results from maximum parsimony, maximum likelihood, minimum evolution, and Bayesian analyses. We identified three distinct lineages within the family: a (Nasua, Bassaricyon) clade, a (Bassariscus, Procyon) clade, and a Potos lineage, the last of which is sister to the other two clades. These findings, which are in strong disagreement with prior fossil and morphology-based assessments of procyonid relationships, reemphasize the morphological and ecological flexibility of these taxa. In particular, morphological similarities between unrelated genera possibly reflect convergence associated with similar lifestyles and diets rather than ancestry. Furthermore, incongruence between the molecular supermatrix and a morphological character matrix comprised mostly of dental characters [Baskin, J.A., 2004. Bassariscus and Probassariscus (Mammalia, Carnivora, Procyonidae) from the early Barstovian (Middle Miocene). J. Vert. Paleo. 24, 709-720] may be due to non-independence among atomized dental characters that does not take into account the high developmental genetic correlation of these characters. Finally, molecular divergence dating analyses using a relaxed molecular clock approach suggest that intergeneric and intrageneric splits in the Procyonidae mostly occurred in the Miocene. The inferred divergence times for intrageneric splits for several genera whose ranges are bisected by the Panamanian Isthmus is significant because they suggest diversification well precedes the Great American Interchange, which has long been considered a primary underlying mechanism for procyonid evolution.