For a better understanding and another opinion of the relationship between what layman call “Iguana delicatissima” and “rhinolopha,” read James D. Lazell Jr., 1973, “The Lizard Genus Iguana in the Lesser Antilles,” Bulletin of the Museum of Comparative Zoology, Harvard University, Cambridge, Massachusetts, Volume 145, Number 1. Lazell is satisfied that there are two species, I iguana and I. delicatissima, and further that “rhinolopha” is not a valid species but rather that some iguanas just happen to have horn-like scales on their snouts. Dr. Lazell goes on in this 28-page illustrated dissertation to describe not only the structural features of these animals but also their natural history, and he makes an important point for pet keepers by remarking that he has seen wild iguanas eating birds’ eggs and carrion, but never papaya or citrus fruits.
The name iguana according to the eleventh edition of the Encyclopedia Britannica is derived from the Spanish equivalent of the Carib Indian name for these lizards, iwana. This name – iguana – was applied in 1825 to a fossil of a giant extinct herbivorous reptile, the Iguanodon. The Iguanodon, an extinct contemporary of the dinosaurs, and its modern namesake have in common a peculiar form of tooth, being round at the root and blade-like with serrated edges toward the tip. The teeth are described as pleurodont – that is, they are fastened to the inner surface rather than the top edge of the lower jaw.
This business of systematically classifying iguanas gets sticky, and with the aim of clarifying the issue you might want to refer to the informal arrangement in the next chapter. Bear in mind that this chapter is primarily about the true iguana, Iguana iguana, and in passing we will make reference to the dozen or so typical iguanas.