Iguanidae synonyms

Zonuridae and Anguidae assume a central position, with Agamidae and Iguanidae as two parallel families (not very different from each other) of highest development, one in the Old World, the other in America.

Xenosaurus seems to be an offshoot intermediate between the Iguanidae and the Anguidae; a degraded form of latter is perhaps Aniella of California, whilst Heloderma and Lanthanotus are also specialized and isolated offshoots.

In their general structure the Iguanidae closely resemble the Agamidae, from which they differ mainly by the pleurodont dentition.