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University of California Publications in Zoology 



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Am Co 



FIG. 48. Alternative interpretations of character transformation for homoplastic characters on a 

 minimum-step cladogram (Fig. 47B). A and B are alternative interpretations for character 23; C and D for 

 character 46. Solid squares represent transformations to the derived condition; open squares represent 

 reversals; half-solid squares represent intermediate states. 



LOWER-LEVEL ANALYSIS 



In an attempt to gain better resolution of iguanine phylogenetic relationships, I performed 

 an analysis at a lower hierarchical level (node 3), using Brachylophus and Dipsosaurus as 

 outgroups in order to determine the polarities of characters that were undeterminable at the 

 level of all iguanines. I chose node 3 for this analysis because it is the most inclusive 

 group within iguanines whose monophyly is well supported. 



The precise relationships oi Brachylophus and Dipsosaurus to the rest of the iguanines 

 are problematical. One of the minimum-step cladograms resulting from the preliminary 

 analysis has Dipsosaurus as the sister group of all other iguanines (Fig. 46A), while the 

 other has Brachylophus in this position instead (Fig. 46B). The second hypothesis might 

 at first appear to be better supported, because Dipsosaurus shares two derived characters 

 with the other iguanines (characters 25-B and 46-B,-C, or-D), while Brachylophus shares 

 only one derived character (23-B) with them. However, character 46 has four equally 

 simple alternative interpretations, and in only two of these (Fig. 48C,D) does it support a 

 sister-group relationship between Dipsosaurus and all iguanines other than Brachylophus. 



