Meeting Abstract

P1.136  Jan. 4  Morphological Systematics of South American Foxes JOHNSON, Frances R; San Diego State University franjohnson03@yahoo.com

The extant South American foxes are an assemblage of three endemic genera and eight species, forming one of the most speciose and least known canid groups worldwide. Of these eight canids, six belong to the genus Pseudalopex, plus Cerdocyon thous (the crab-eating fox) and Atelocynus microtis (the small-eared dog). Reconstruction of the evolutionary history of these canids has been historically problematic. A paucity of fossil evidence outside South America suggests rapid radiation of the group upon dispersal across the Panamanian land bridge into South America approximately three MA. Prior morphological study has not used current rigorous phylogenetic systematics to explore species level relationships among these foxes and recent molecular systematics show conflicting results of varying statistical support. Newer phylogenetic techniques that allow data partitioning may yield more accurate results as varying systems (i.e. dental, osteological, pelage) likely evolve along different evolutionary paths. Unweighted parsimony and partitioned Bayesian analyses were performed analyzing more than 100 morphological characters for the eight South American fox species plus five extant outgroup species. Atelocynus and Cerdocyon form a clade sister to the monophyletic Pseudalopex foxes. P. vetulus, the hoary fox, is basal to the other Pseudalopex foxes, a finding that supports reassignment of the hoary fox to Lycalopex. P. sechurae and P. fulvipes are basal to the remaining species and may be sister taxa. P. griseus, P. culpaeus and P. gymnocercus are most closely related to one another, a result consistent with their overlapping geographic ranges and other evidence suggesting hybridization. The implications of this morphology-based phylogeny allow biogeographical and ecological interpretations not yet formally discussed.