Preliminary analysis of phylogenetic relationships among Galapagos Island lizards of the genus Tropidurus

Abstract Albumin evolution in six species of Galapagos iguanid lizards of the genus Tropidurus was measured using the quantitative immunological technique of micro-complement fixation. We propose a phylogeny for these species based upon their albumin differentiation. Our data suggest several colonizations from the South American mainland are needed to account for current species diversity on the Galapagos Islands. The standard calibration for the albumin molecular clock yields divergence estimates for Galapagos Tropidurus that are similar to those previously reported for the iguanas in the Galapagos and are not in conflict with recent understanding of the geological history of these islands.