INTRODUCTION 



Containing approximately 55 genera and more than 600 species, Iguanidae is one of the 

 largest families of lizards. Its members occur primarily in the New World, from southern 

 Canada to austral South America including the Galapagos Archipelago and much of the 

 West Indies. Iguanids also occur on the island of Madagascar and in the Comores 

 Archipelago in the western Indian Ocean, and on the Fiji and Tonga island groups in the 

 southwestem Pacific. 



For over 100 years, systematists have attempted to discover the pattern of 

 interrelationships among the genera in the family Iguanidae, but, because of the 

 bewildering morphological diversity within this family, the task is far from complete. 

 Nevertheless, many systematists have recognized suprageneric groups of iguanids (e.g., 

 Wagler, 1830; Dumeril and Bibron, 1837; Fitzinger, 1843; Gray, 1845; Cope, 1886, 1900; 

 Boulenger, 1890; H. M. Smith, 1946; Savage, 1958; Etheridge, 1959, 1964a). One of the 

 earliest of these suprageneric groups to be recognized consists of the genera currently 

 known informally as iguanines. This assemblage is also one of the most readily diagnosed 

 on the basis of uniquely derived features. As currently conceived, there are eight genera 

 and 31 species of iguanines (Etheridge, 1982). The iguanine genera are listed in Table 1, 

 which also gives the number of included species, their habits, and the geographic 

 distribution for each genus. 



HISTORICAL REVIEW 



The concept of an iguanine group is remarkably old, predating the publication of Darwin's 

 Origin of Species (1859). This accomplishment is even more surprising when one realizes 

 that all iguanines are native to regions far from western Europe, where systematists were 

 developing the concept of an iguanine group. These systematists undoubtedly had few 

 specimens at hand, and must have relied heavily on each others' character descriptions. 

 Although I have been unable to see all of the potentially relevant literature, I attempt to trace 

 and summarize the history of iguanine higher systematics. 



The Eighteenth Century. Although the eighteenth century was an important one for 

 biological systematics as a whole, it was not so important for iguanine systematics. A 

 convenient date to begin a historical discussion of iguanine systematics is 1758, when 

 Linnaeus published the tenth edition of his Systema Naturae, the starting point of 

 zoological nomenclature. Linnaeus himself was neither interested in nor fond of the 

 "lower" tetrapods. He placed all tetrapodous squamates in two genera, one of which 



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