120 University of California Publications in Zoology 



The consistency indices (Kluge and Farris, 1969) for eacli of the characters on each of the 

 two minimum-step cladograms are given in Table 7. The C-index is a measure of the 

 deviation of a character from a perfect fit (C-index of 1.00) to a given cladogram. 

 Synapomorphies for the various nodes of the cladograms are given below by the number of 

 the character and the letter of the character state as designated in the list of systematic 

 characters. Convergent characters are underlined; characters involving reversal are marked 

 with an asterisk. Because only characters whose derived states are shared by two or more 

 of the basic taxa were used in this analysis, any character interpreted as a synapomorphy of 

 a basic taxon necessarily exhibits homoplasy. 



Figure 46A: Node 1: 18-B*, 25-B*; Node 2: 23-B*; Node 3: 48-B, 66-B, 77-B; 

 Node 4: 46-B *. 46-C or-D*; Node 5: 37-B, 52-53-A; Node 6: 5-B, 7-B, 8-B, 17-B or-C, 

 21-B, 36-B or-C . 40-B, 45-B, 46-B or-A*, 50-B . 83-B; Node 7: 19-B, 28-B or-C, 39-B; 

 Amblyrhynchus: 18-A *. 46-A*, 54-B . 68-B . 69-B . 70-B : Brachylophus: 25-A*, 36-B . 

 62-B : Conolophus: 51-B : Ctenosaura: none; Cyclura: none; Dipsosaurus: 13-C . 46-B . 

 50-B . 51-B (last two characters are redundant); Iguana: 18-A *. 62-B ; Sauromalus: 13-B . 

 23-A*, 54-B . 68-B . 69-B . 70-B . 



The synapomorphies of the second cladogram (Fig. 46B) are identical to those of the 

 first (Fig. 46A), with the following exceptions: Node 1: 18-B*, 23-B*; Node 2: 25-B, 

 46-B,-C, or-D*; Node 4: 46-C or-D*; Brachylophus: 36-B . 62-B ; Ctenosaura: 46-A*. 



Six of the homoplastic characters on the first minimum-step cladogram (Fig. 46A) can 

 be interpreted in more than one way, each involving the same number of phylogenetic 

 transformations. These alternative interpretations are diagrammed in Figure 47. Character 

 25-B can be interpreted as convergent synapomorphies of Dipsosaurus on the one hand and 

 of all other iguanines except Brachylophus (node 3) on the other hand (Fig. 47A). 

 Alternatively, it can be interpreted as a synapomorphy of all iguanines that has reversed in 

 Brachylophus (Fig. 47B). Characters 54-B, 68-B, 69-B, and 70-B can be interpreted as 

 convergent synapomorphies of Amblyrhynchus on the one hand and of Sauromalus on the 

 other (Fig. 47C). Alternatively, these characters can be interpreted as synapomorphies of 

 the Galapagos iguanas plus Sauromalus (node 5) that have reversed in Conolophus (Fig. 

 47D). Two alternative interpretations of character 46 are diagrammed in Figure 47E and F. 

 Both interpretations require five phylogenetic transformations. 



Alternative interpretations of homoplastic characters on the second minimum-step 

 cladogram (Fig. 46B) are identical to those on the first (Fig. 46A), with the following 

 exceptions: Character 25-B has only one possible minimum-step interpretation; it is a 

 synapomorphy of all iguanines except Brachylophus (node 2). Character 23-B can either 

 be interpreted as convergent synapomorphies of Brachylophus on the one hand and the taxa 

 united above node 3 (Fig. 48A) on the other hand, or it can be interpreted as a 

 synapomorphy of all iguanines that has subsequently reversed in Dipsosaurus (Fig. 48B). 

 The same alternative interpretations of character 46 are available for the second minimum- 

 step cladogram as for the first, but two additional alternatives exist (Fig. 48C,D). 



Of the six subterminal nodes on each of the two minimum-step cladograms resulting 

 from the preliminary analysis, three (nodes 3, 6, and 7) are well supported. That is, these 



