Herpetological Monographs, 18, 2004, 90–126 Ó 2004 by The Herpetologists’ League, Inc. PHYLOGENY, ECOMORPHOLOGICAL EVOLUTION, AND HISTORICAL BIOGEOGRAPHY OF THE ANOLIS CRISTATELLUS SERIES MATTHEW C. BRANDLEY 1,3,4 AND KEVIN DE QUEIROZ 2 1 Sam Noble Oklahoma Museum of Natural History and Department of Zoology, The University of Oklahoma, Norman, OK 73072, USA 2 Department of Zoology, National Museum of Natural History, Smithsonian Institution, Washington, DC 20560, USA ABSTRACT: To determine the evolutionary relationships within the Anolis cristatellus series, we employed phylogenetic analyses of previously published karyotype and allozyme data as well as newly collected morphological data and mitochondrial DNA sequences (fragments of the 12S RNA and cytochrome b genes). The relationships inferred from continuous maximum likelihood reanalyses of allozyme data were largely poorly supported. A similar analysis of the morphological data gave strong to moderate support for sister relationships of the two included distichoid species, the two trunk-crown species, the grass-bush species A. poncensis and A. pulchellus, and a clade of trunk-ground and grass-bush species. The results of maximum likelihood and Bayesian analyses of the 12S, cyt b, and combined mtDNA data sets were largely congruent, but nonetheless exhibit some differences both with one another and with those based on the morphological data. We therefore took advantage of the additive properties of likelihoods to compare alternative phylogenetic trees and determined that the tree inferred from the combined 12S and cyt b data is also the best estimate of the phylogeny for the morphological and mtDNA data sets considered together. We also performed mixed-model Bayesian analyses of the combined morphology and mtDNA data; the resultant tree was topologically identical to the combined mtDNA tree with generally high nodal support. This phylogenetic hypothesis has a basal dichotomy between the Hispan ˜ olan distichoids and the bimaculatus series, on the one hand, and the cristatellus series inhabiting the Puerto Rican Island Bank, its satellite islands, the Bahamas, and St. Croix, on the other. The trunk-crown species form a clade, while the trunk-ground and grass-bush species do not as A. gundlachi, a trunk-ground species, is nested within a clade of grass-bush species. The patterns of relationships among the trunk-ground and grass-bush species suggest that one of these ecomorphs may have been ancestral to the other and that one or both evolved convergently. In the context of our preferred phylogeny and divergence dates estimated by NPRS analyses, we propose several biogeographical hypotheses that explain the current distribution of the cristatellus series. The presence of endemic species on the islands of the Bahamas, Desecheo, Mona, Monita, and St. Croix are likely due to over-water dispersal. Vicariance resulting from Pliocene or Pleistocene changes in sea levels likely explains the occurrence of A. cristatellus (including A. ernestwilliamsi), A. pulchellus, and A. stratulus on different islands of the Puerto Rican Bank. Key words: Bayesian; Caribbean Biogeography; Ecomorphology; Frequency coding; Maximum likelihood; Mixed-model; Puerto Rico Bank; Taxonomy. ANOLIS LIZARDS of the Greater Antilles are of particular interest to evolutionary biologists because they represent a striking case study of convergent evolution and adaptive radiation (Beuttell and Losos, 1999; Losos 1990, 1992, 1994; Losos and de Queiroz, 1997; Williams 1972, 1983). Each of the islands of Cuba, Jamaica, Hispan ˜ ola, and Puerto Rico is in- habited largely by endemic species of anoles, yet the anole communities of the different islands are remarkably similar in terms of the ecomorphological adaptations of their compo- nent species. These communities consist of species with different body plans, called ecomorphs, each of which is morphologically adapted to the structural microhabitat in which it occurs. Ecomorph names correspond to their associated microhabitats: trunk-crown, trunk-ground, grass-bush, crown giant, and twig (Williams, 1983). Higher-level phyloge- netic studies based on morphology (Etheridge, 1959; Guyer and Savage, 1986; Poe, 1998; Williams, 1989) and mitochondrial DNA (Jackman et al., 1997, 1999; Losos et al., 1998) have demonstrated that, for the most part, the same set of ecomorphs (or a subset) 3 CURRENT ADDRESS: Museum of Vertebrate Zoology and Department of Integrative Biology, 3101 Valley Life Sciences Bldg, University of California, Berkeley, CA 94720, USA. 4 CORRESPONDENCE: e-mail, brandley@berkeley.edu 90