Phylogenetic Relationships and Tempo of Early Diversification in Anolis Lizards

Abstract

We examine phylogenetic relationships among anoles using mitochondrial DNA se- quences from the NADH dehydrogenase subunit 2 gene (ND2) andve transfer-RNA genes repre- senting 1,455 alignable base positions and 866 phylogenetically informative characters (parsimony criterion). We also present 16 morphological characters for phylogenetic analysis. Our analyses yielded poorly-supported nodes deep in the anole tree but many well-supported nodes for more recent phylogenetic divergences. We test the hypothesis that the major clades of anoles form a hard polytomy and present a general statistical framework for testing hypotheses of simultaneous branching of lineages by using molecular sequence data. Our results suggest that rapid diversi- �cation early in the evolutionary history of anoles explains why numerous researchers have had difculty reconstructing well-supported dichotomous phylogenetic trees for anoles. ( Anolis; mito- chondrial DNA; parametric bootstrap; permutation test; phylogeny; polytomy.)