INTRODUCTION

or even millions, of years. While studies that consider phylogenetically independent taxa are useful, they have Research on island organisms has contributed much to an often overlooked drawback: the determination of our understanding of the selective pressures that shape selective mechanisms that have shaped phenotypic phenotypic diversity (Losos & Ricklefs 2009, Schluter diversity in populations over long periods of time 2000, Wallace 1902, Whittaker & Ferm'mdez-Palacios (geological scales) is dillicult because the role that past 2007). Modern comparative studies emphasi7.e the ecological conditions play in current morphological or importance of using phylogenetically distinct taxonomic genetic divergence is unknown (Huey & Bennett 1987). units in an effort to eliminate pseudoreplication By examining multiple populations of one species that (Harvey & Pagel 1991. Hurlbert 1984). Thus, the have been recently isolated on islands which vary in majority of comparative studies of insular biota have their ecological conditions, we may reasonably assume concentrated on endemic species and multi-species that observed differences between these populations are radiations (Roughgarden 1995, Schluter 2000), which related to current conditions (Garland et al. 1991. Grant have often been isolated for hundreds of thousands. & Grant 2002, 2003, Schluter 2000, Whittaker &
Fernandez-Palacios 2007), In this study, we focused on insular populations of I Corresponding author. Email: miehael.l.logan@dnrtmouth.edu the lizard Analis lemurinus, and build upon a single,
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previous study examining the phylogeographic history of this species in the Bay Islands and Cayos Cochinos of Honduras. Klutsch et aI. (2007) supported a 'stepping stone' model of archipelago colonization whereby A. Ieml/rinus independently colonized the distant islands of Roatan and Utila after Iirst arriving in the Cayos Cochinos from the mainland. Their observations, as well as those of other authors (Kohler 2003, McCranie et aI. 2005) suggest that the population on Utila is somewhat divergent in general ecology and morphology from those in the Cayos Cochinos and on mainland Honduras, and probably represents a good species. Anolis Iemurinus in the Bay Islands thus appear to be in the midst of a radiation event. Klutsch et £II. (2007) also found. however, that populations in the Cayos Cochinos were genetically and morphologically indistinguishable from one another and from mainland populations, suggesting that they have undergone limited evolutionary ditTerentiation or that gene flow between them is ongoing. Nevertheless, these authors did not consider potential differences in habitat use, and only examined coarSe aspects of morphology.
This system offered an opportunity to examine ecological and morphological divergence among populations exposed to differing environmental conditions after a relatively recent colonization event. Due to noticeable differences in the abiotic and biotic environments among islands in the Cayos Cochinos, we hypothesized that
A. lemurinus populations would differ in aspects of morphology and habitat use not considered by Klutsch and colleagues, and that these differences would provide evidence of recent selection or phenotypic plasticity despite genetic homogeneity among populations.