Iguania is an infraorder of squamatereptiles that includes iguanas, chameleons, agamids, and New World lizards like anoles and phrynosomatids. Using morphological features as a guide to evolutionary relationships, the Iguania are believed to form the sister group to the remainder of the Squamata,[1] which comprise nearly 11,000 named species, roughly 2000 of which are iguanians. However, molecular information has placed Iguania well within the Squamata as sister taxa to the Anguimorpha and closely related to snakes.[2] The order has been under debate and revisions after being classified by Charles Lewis Camp in 1923 due to difficulties finding adequate synapomorphic morphological characteristics.[3] Most iguanians are arboreal but there are several terrestrial groups. They usually have primitive fleshy, non-prehensile tongues, although the tongue is highly modified in chameleons.[citation needed] Today they are scattered occurring in Madagascar, the Fiji and Friendly Islands and Western Hemisphere.[4]
Classification
The Iguania currently include these extant families:[5][6]
Below is a cladogram from the phylogenetic analysis of Daza et al. (2012) (a morphological analysis), showing the interrelationships of extinct and living iguanians:[3]
The extinct Arretosauridae (Paleogene iguanians from Central Asia) are alternatively classified in either the Acrodonta with other Old World iguanians, or in Pleurodonta as a sister group to the Crotaphytidae.[7][8]
^Gauthier, Jacques A.; Kearney, Maureen; Maisano, Jessica Anderson; Rieppel, Olivier; Behlke, Adam D. B. (April 2012). "Assembling the Squamate Tree of Life: Perspectives from the Phenotype and the Fossil Record". Bulletin of the Peabody Museum of Natural History. 53 (1): 3–308. doi:10.3374/014.053.0101. S2CID86355757.
^Schulte, James A.; Valladares, John Pablo; Larson, Allan (2003). "Phylogenetic Relationships within Iguanidae Inferred Using Molecular and Morphological Data and a Phylogenetic Taxonomy of Iguanian Lizards". Herpetologica. 59 (3): 399–419. doi:10.1655/02-48. JSTOR3893615. S2CID56054202.
Frost, Darrel R.; Etheridge, Richard (1989). A Phylogenetic Analysis and Taxonomy of Iguanian Lizards (Reptilia: Squamata). University of Kansas. ISBN978-0-89338-033-5.
