Evolutionary Relationships of the Anolis bimaculatus Group from the Northern Lesser Antilles

•Lizards in Ihe Anolis bimaculatus group from the northern Lesser Antilles have played an important role in theoretical and empirical developments in ecology, behavior, and evolution over the last four decades. Despite intense interest, the lack of a formal phylogenetic analysis for the bimaculatus group has limited comparative and historical evolutionary analyses. Here we present a phylogenetic analysis of species relationships within the bimaculatus group based on separate and combined analyses of mitochondrial DNA and previously published allozyme data. These analyses indicate that (1) the wattsi group of small anoles is a basal, well-supported monophyletic group; (2) the large anoles A. bimaculatus and A. leachi are not sister species•rather, there is a well-supported sister relationship between A. bimaculatus and A. gingivinus; (3) the A. marntoratus complex from the Guadeloupean archipelago is deeply differentiated and paraphyletic, with A. sabanus, A. lividus, and possibly A. oculatus nested within it; (4) the phylogenetic position of A. leachi is not well resolved, but a combined analysis of mtDNA and allozyme data favor placing A. leachi as the sister taxon to the {A. marmoratus, A. lividus, A. sabanus, A. oculatus) group; and (5) the phylogenetic position of A. nubilus remains uncertain pending additional data. The proposed phylogeny elucidates the evolutionary history and biogeography of the bimaculatus group and allows a reassessment of the character displacement and taxon cycle/loop hypotheses. The Caribbean radiation of Anolis lizards is one of the best known cases of adaptive radiation (reviewed in Williams, 1983; Losos, 1994; Jackman et al., 1997; Jackman et al., 1999). More than 100 of the approximate 140 species of Caribbean anoles occur on the islands of the Greater Antilles, where most research has been conducted. Nonetheless, the 20 species from the Lesser Antilles have received significant attention, including studies of locomotor behavior (Moermond, 1986), habitat use (Roughgarden et al., 1981, 1983; Losos and de Queiroz, 1997; Staats et al., 1997), size evolution (Roughgarden and Pacala, 1989; Losos, 1990), interspecific interactions (Pacala and Roughgarden, 1982; Roughgarden et al., 1984, 1987; Rummel and Roughgarden, 1985; Schall, 1992), social behavior (e.g.. Stamps, 1991; Stamps and Krishnan, 1994a, b, 1995, 1997, 1998); phenotypic and genetic differentiation (Malhotra and Thorpe, 1991a, b, 1993, 1994, 1997a, b; Schneider, 1996), and natural selection (Malhotra and Thorpe, 1991a, 1994). Traditionally, anoles of the Lesser Antilles have been classified in two distantly related groups, the roquet group in the southern Lesser Antilles (north to Martinique), allied to certain South American taxa, and the bimaculatus group in the northern Lesser Antilles (from Dominica northward, see Fig. 1), related to other West Indian anoles (Underwood, 1959; Etheridge, 1960). A number of phylogenetic hypotheses, often conflicting with each other, have been proposed for the two groups (e.g., Lazell, 1972; Yang et al., 1974; Gorman and Kim, 1976; Roughgarden et al., 1987). Given the advent of DNA sequencing and advances in analytical techniques, the time seems ripe for a new look at the phylogeny of these groups, particularly given the great breadth of information that could be interpreted in an evolutionary context once a robust hypothesis of relationships is obtained. Recently, such a hypothesis has been derived for the roquet group in the southern Lesser Antilles (D. A. Creer, K. de Queiroz, T R. Jackman, J. B. Losos, and A. Larson, unpubl. data). Here, we present a phylogeny for the bimaculatus group of the northern Lesser Antilles based on analysis of mtDNA sequence data in combination with previously published allozyme data (Gorman and Kim, 1976). MATERIALS AND METHODS We sequenced a portion of the mitochondrial cytochrome b (cyt b) gene from at least two individuals from each of 20 populations representing all species from the bimaculatus group (sensu Etheridge, 1960; Gorman and Kim, 1976), plus one individual from a Puerto Rican outgroup A. cristatellus. The only taxon missing C. J. SCHNEIDER ET AL.