Phylogenetic relationships and tempo of early diversification in Anolis lizards

We examine phylogenetic relationships among anoles using mitochondrial DNA sequences from the NADH dehydrogenase subunit 2 gene (ND2) and five transfe r RNA genes representing 1,455 alignable base positions and 866 phylogeneti cally informative characters (parsimony criterion). We also present 16 morp hological characters for phylogenetic analysis. Our analyses yielded poorly -supported nodes deep in the anole tree but many well-supported nodes for m ore recent phylogenetic divergences. We test the hypothesis that the major clades of anoles form a hard polytomy and present a general statistical fra mework for testing hypotheses of simultaneous branching of lineages by usin g molecular sequence data. Our results suggest that rapid diversification e arly in the evolutionary history of anoles explains why numerous researcher s have had difficulty reconstructing well-supported dichotomous phylogeneti c trees for anoles.