Evolutionary relationships among eight species of South American phyllotine rodents (Rodentia: Muridae) based on allozymic data

Rodents of the tribe Phyllotini represents one of the main radiations of South American Sigmodontini. Phylogenetic relationships among species of this highly diversified group are poorly known. In this paper we analyse evolutionary relationships among eight phyllotine species belonging to the genera Calomys , Graomys , Phyllotis and Eligmodontia , on the basis of allozymic polymorphisms. Most of the differences among species were in allele frequencies and not of allele class. Neighbour-joining and maximum likelihood methods place P. xanthopygus in the same group as E. typus and G. griseoflavus , in agreement with results obtained by several authors on the basis of morphological characters. Parsimony analysis of 0–9 coded data suggest that the genus Calomys is paraphyletic, but with a low bootstrap support. In the tree based on genetic distance data, the genus also appears as paraphyletic. The maximum likelihood method yields a tree where Calomys is monophyletic, but this phylogeny is supported by only two out of 78 alleles analysed. Calomys hummelincki and C. venustus occupy a basal position among Calomys species. Calomys musculinus and C. lepidus are the most closely related species of the genus, with C. laucha as sister to them. These relationships are strongly supported by bootstrap percentages.