Mainland colonization by island lizards.

We investigate biogeographic relationships within the lizard genusAnolisDaudin, 1802 to test the hypothesis that the mainland (Central and South American) Norops-clade species descended from a West IndianAnolisancestor. Previous hypotheses have suggested that close island relatives of mainland Norops species (the CubanAnolis sagreiand JamaicanA. grahamiseries) represent over-water dispersal from a mainland ancestor. These previous hypotheses predict that theA. sagreiandA. grahamiseries should be phylogenetically nested within a Norops clade whose ancestral geography traces to the mainland. If Norops is West Indian in origin, then West Indian species should span the deepest phylogenetic divergences within the Norops clade.Central and South America and West Indian islands.The phylogenetic relationships ofAnolislizards are reconstructed from aligned DNA sequences using both parsimony and Bayesian approaches. Hypotheses are tested in two ways: (1) by reconstructing the ancestral geographic location for the Norops clade usingBayesian approach, and (2) by testing alternative topological arrangements via Wilcoxon Signed-Ranks tests () and Shimodaira–Hasegawa tests ().Our evidence supports an origin of mainland Norops anoles from a West Indian ancestor. A West Indian ancestor to the Norops clade is statistically supported, and alternatives to the biogeographic pattern [Cuban (Jamaican, Mainland)] are statistically rejected by Shimodaira–Hasegawa tests, although not by Wilcoxon Signed-Ranks tests.Our data support the hypothesis of a West Indian origin for mainland Norops. This result contradicts previous hypotheses and suggests that island forms may be an important source for mainland biodiversity. [ABSTRACT FROM AUTHOR]