Author's personal copy Phylogeny, biogeography, and display evolution in the tree and brush lizard genus Urosaurus (Squamata: Phrynosomatidae) Chris R. Feldman a,⇑ , Oscar Flores-Villela b , Theodore J. Papenfuss c a Department of Natural Resources and Environmental Sciences, University of Nevada, Reno, NV 89557-0186, USA b Museo de Zoología, Facultad de Ciencias, Universidad Nacional Autónoma de México, A.P. 70-399, México D.F. C.P. 04510, Mexico c Museum of Vertebrate Zoology, University of California, Berkeley, CA 94720-3160, USA article info Article history: Received 6 December 2010 Revised 29 July 2011 Accepted 4 August 2011 Available online 19 August 2011 Keywords: Urosaurus Phylogenetics Mitochondrial DNA Nuclear DNA Ancestral state reconstruction Dewlap abstract The brush and tree lizards (Urosaurus) are a small clade of phrynosomatid lizards native to western North America. Though not as well known as their diverse sister clade, the spiny lizards (Sceloporus), some Uro- saurus have nonetheless become model organisms in integrative biology. In particular, dramatic pheno- typic and behavioral differences associated with specific mating strategies have been exploited to address a range of ecological and evolutionary questions. However, only two phylogenies have been proposed for the group, one of which is pre-cladistic and both based principally on morphological characters that might not provide robust support for relationships within the group. To help provide investigators work- ing on Urosaurus with a robust phylogeny in which to frame ecological and evolutionary questions, we establish a molecular phylogeny for the group. We sampled three mitochondrial and three nuclear loci, and estimated phylogenetic relationships within Urosaurus using both maximum parsimony (MP) and Bayesian inference (BI), as well as a coalescent-based species tree approach. Finally, we used two meth- ods of ancestral state reconstruction (ASR) to gain insight into the evolution of microhabitat preference and male display signals, traits that have been the focus of studies on Urosaurus. All reconstruction meth- ods yield nearly the same ingroup topology that is concordant in most respects with the previous cladistic analysis of the group but with some significant differences; our data suggest the primary divergence in Urosaurus occurs between a clade endemic to the Pacific versant of Mexico and the lineages of Baja Cal- ifornia and the southwestern US, rather than placing Urosaurus graciosus as the basal taxon and linking the Baja and Mexican endemics. We find support for a single transition to a saxicolous lifestyle within the group, and either the independent gain or loss of arboreality. The evolution of throat color patterns (i.e. dewlaps) appears complex, with multiple color morphs likely involving orange reconstructed as ancestral to the group and to most lineages, followed by a single transition to a fixed blue-throated morph in one clade. These results should provide a useful framework for additional comparative work with Urosaurus, and establish the phylogenetic context in which Urosaurus diversity arose. Ó 2011 Elsevier Inc. All rights reserved. 1. Introduction The brush and tree lizards of the genus Urosaurus (Squamata: Phrynosomatidae) form a small group of nine species (Wiens, 1993) endemic to the arid and semiarid lands of western United States and Mexico. Species of Urosaurus can be found from south of the Isthmus of Tehuantepec in Chiapas, Mexico, to as far north as southwestern Wyoming in the US, and from central and south- ern Texas to the cape of Baja California, and even a few oceanic is- lands west of that peninsula (Fig. 1)(Mittleman, 1942; Grismer, 2002; Stebbins, 2003). Brush and tree lizards are easily distin- guished from other phyrnosomatid genera by the presence of a dis- tinctive, narrow band of enlarged keeled scales running down the dorsum, and by several other morphological synapomorphies (Mittleman, 1942; Wiens, 1993). As their common name implies, most of these lizards are highly scansorial and spend most of their time on shrubs, trees, or boulders, rather than on the ground (Smith, 1946; Stebbins, 2003). Though not as widely studied as spiny lizards (Sceloporus; Sites et al., 1992), the sister group of Urosaurus (Wiens et al., 2010), some brush and tree lizards are nonetheless becoming model organisms of integrative biology because they display extensive morphological and behavioral variation, and are easily manipulated both in captiv- ity and the field (e.g. Urosaurus graciosus and Urosaurus ornatus). Thus, some Urosaurus species, especially U. ornatus, have become the focus of a wide range of research, from studies of physiological tradeoffs (French et al., 2007), to the roles of phenotypic plasticity 1055-7903/$ - see front matter Ó 2011 Elsevier Inc. All rights reserved. doi:10.1016/j.ympev.2011.08.008 ⇑ Corresponding author. Fax: +1 775 784 4583. E-mail address: ophis@cabnr.unr.edu (C.R. Feldman). Molecular Phylogenetics and Evolution 61 (2011) 714–725 Contents lists available at SciVerse ScienceDirect Molecular Phylogenetics and Evolution journal homepage: www.elsevier.com/locate/ympev