MATERIALS AND METHODS 



SPECIMENS 



The great majority of the specimens examined in this study were partially intact, complete 

 skeletons that had been prepared by hand or with dermestid beetles. Many skulls prepared 

 by the above methods and some disarticulated skeletons were also examined. Additionally, 

 I have studied radiographs of wet specimens and some whole wet specimens. 

 Observations were made with the naked eye or with the aid of a binocular dissecting 

 microscope. Drawings were made using the camera lucida on a Wild binocular dissecting 

 microscope, from tracings of photographs and radiographs, and freehand. The specimens 

 examined are listed in Appendix I. 



PHYLOGENETIC ANALYSIS 



I have used the phylogenetic method elaborated by Hennig (1966), and subsequently by 

 many others, to study the relationships of iguanine lizards. Reviews of this method can be 

 found in Eldredge and Cracraft (1980) and Wiley (1981). Hennig's method was 

 formulated specifically for the purpose of evaluating the monophyletic status of groups of 

 organisms, and he stressed that only synapomorphies, shared features that have arisen 

 within a group, logically provide evidence for the existence of its monophyletic subgroups 

 (clades). The assessment of relative apomorphy (polarity) is thus crucial to phylogenetic 

 analysis. I have used the method of outgroup comparison (Watrous and Wheeler, 1981; 

 Farris, 1982; Maddison et al., 1984) for determining character polarity. Although early 

 fossil iguanids might be used as outgroups, I have avoided this practice until their 

 relationships to extant forms are better understood. When ontogenetic transformations are 

 adequately known, I have used the transformations themselves as characters (de Queiroz, 

 1985). 



Outgroups used in this study were the members of four suprageneric groups of 

 iguanids thought to be outside of the iguanine clade (Etheridge and de Queiroz, 1988): 

 basiliscines, crotaphytines, morunasaurs, and oplurines. Maddison et al. (1984) have 

 shown that the precise pattern of relationships among the ingroup and various outgroups 

 has a profound influence on the assessment of plesiomorphy and apomorphy. 

 Unfortunately, relationships among the major groups of iguanids are poorly understood at 

 present (Etheridge and de Queiroz, 1988). Therefore, I selected my four outgroups as 

 much for convenience as for any notion that they were closely related to iguanines. Each of 



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