Iguanids Temporal range:
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Iguania
Clade:	Pleurodonta
Family:	Iguanidae Oppel, 1811
Genera
Amblyrhynchus Brachylophus Cachryx Conolophus Ctenosaura Cyclura Dipsosaurus Iguana Sauromalus

The Iguanidae is a family of lizards composed of the iguanas, chuckwallas, and their prehistoric relatives,^[1] including the widespread green iguana.

Taxonomy

Iguanidae is thought to be the sister group to the collared lizards (family Crotaphytidae); the two groups likely diverged during the Late Cretaceous, as that is when Pristiguana and Pariguana, the two earliest fossil genera, are known from. The subfamily Iguaninae, which contains all modern genera, likely originated in the earliest Paleocene, at about 62 million years ago. The most basal extant genus, Dipsosaurus, diverged from the rest of Iguaninae during the late Eocene, about 38 million years ago, with Brachylophus following a few million years later at about 35 million years ago, presumably after its dispersal event to the Pacific. All other modern iguana genera formed in the Neogene period.^[2]

A phylogenetic tree of Iguaninae is shown here:^[2]

Description

Iguanas and iguana-type species are diverse in terms of size, appearance, and habitat. They typically flourish in tropical, warm climates, such as regions of South America and islands in the Caribbean and in the Pacific. Iguanas typically possess dorsal spines across their back, a dewlap on the neck, sharp claws, a long whip-like tail, and a stocky, squat build. Most iguanas are arboreal, living in trees, but some species tend to be more terrestrial, which means they prefer the ground. Iguanas are typically herbivores and their diets vary based on what plant life is available within their habitat. Iguanas across many species remain oviparious, and exhibit little to no parental care when their eggs hatch. They do, however, display nest-guarding behavior. Like all extant non-avian reptiles, they are poikilothermic, and also rely on regular periods of basking under the sun to thermoregulate.^[3]

Distribution

All but one of modern iguana genera are native to the Americas, ranging from the deserts of the Southwestern United States through Mexico, Central America, and the Caribbean, to throughout South America down to northernmost Argentina. Some iguanas like I. iguana have spread from their native regions of Central and South America into many Pacific Islands, and even to Fiji, Japan, and Hawai'i, due to the exotic pet trade and illegal introductions into the ecosystems.^[4] Other iguanas, like the Galapagos pink iguana (C. marthae) are endemic only to specific regions on the Galapagos islands. The Grand Cayman blue iguana, C. lewisi, is endemic only to the Grand Cayman island, limited to a small wildlife reserve.^[3] The only non-American iguana species are the members of the genus Brachylophus and the extinct Lapitiguana, which are found on Fiji and formerly Tonga; their distribution is thought to be the result of the longest overwater dispersal event ever recorded for a vertebrate species, with them rafting over 8000 km across the Pacific from the Americas to the Fiji and Tonga.^[5]

Extant genera

Image	Genus	Species
	Amblyrhynchus Bell, 1825 – marine iguana	marine iguana (Amblyrhynchus cristatus)
	Brachylophus Cuvier, 1829 – Fijian/Tongan iguanas	Brachylophus fasciatus — Lau banded iguana Brachylophus vitiensis — Fiji crested iguana Brachylophus bulabula — Fiji banded iguana Brachylophus gau — Gau iguana
	Cachryx Cope, 1866 – spinytail iguanas	Campeche spiny-tailed iguana, Cachryx alfredschmidti (Kohler, 1995) Yucatán spinytail iguana, Cachryx defensor (Cope, 1866)
	Conolophus Fitzinger, 1843 – Galápagos land iguanas	Barrington land iguana, Conolophus pallidus Galápagos land iguana, Conolophus subcristatus Galápagos pink land iguana, Conolophus marthae
	Ctenosaura Wiegmann, 1828 – spinytail iguanas	Ctenosaura acanthura (Shaw, 1802) Ctenosaura alfredschmidti Köhler, 1995 Ctenosaura bakeri Stejneger, 1901 Ctenosaura clarki Bailey, 1928 Ctenosaura conspicuosa Dickerson, 1919 Ctenosaura defensor (Cope, 1866) Ctenosaura flavidorsalis Köhler & Klemmer, 1994 Ctenosaura hemilopha (Cope, 1863) Ctenosaura macrolopha Smith, 1972 Ctenosaura melanosterna Buckley & Axtell, 1997 Ctenosaura nolascensis Smith, 1972 Ctenosaura oaxacana Köhler & Hasbun, 2001 Ctenosaura oedirhina De Queiroz, 1987 Ctenosaura palearis Stejneger, 1899 Ctenosaura pectinata (Wiegmann, 1834) Ctenosaura quinquecarinata (Gray, 1842) Ctenosaura similis (Gray, 1831)
	Cyclura – West Indian rock iguanas	Turks and Caicos rock iguana, Cyclura carinata Bartsch's iguana, Cyclura carinata bartschi Jamaican iguana, Cyclura collei Rhinoceros iguana, Cyclura cornuta Northern Bahamian rock iguana, Cyclura cychlura Andros Island iguana, Cyclura cychlura cychlura Exuma Island iguana, Cyclura cychlura figginsi Allen Cays iguana, Cyclura cychlura inornata Grand Cayman blue iguana, Cyclura lewisi Cuban iguana, Cyclura nubila Lesser Caymans iguana, Cyclura nubila caymanensis Anegada ground iguana, Cyclura pinguis Ricord's iguana, Cyclura ricordii San Salvador iguana, Cyclura rileyi White Cay iguana, Cyclura rileyi cristata Acklins iguana, Cyclura rileyi nuchalis Mona ground iguana, Cyclura stejnegeri
	Dipsosaurus Hallowell, 1854	desert iguana (Dipsosaurus dorsalis) Catalina desert iguana (Dipsosaurus catalinensis)
	Iguana Laurenti, 1768 – green and Lesser Antillean iguanas	Lesser Antillean iguana, I. delicatissima Green iguana, I. iguana
	Sauromalus Dumeril, 1856 – chuckwallas	Sauromalus ater Sauromalus australis Sauromalus hispidus Sauromalus klauberi Sauromalus slevini Sauromalus varius

Fossils

Image	Genus	Species
	Armandisaurus Norell & de Queiroz, 1991	† Armandisaurus explorator
	Lapitiguana Pregill & Worthy, 2003	† Lapitiguana impensa
	Pumilia Norell 1989	† Pumilia novaceki
	Pristiguana Estes & Price 1973	† Pristiguana brasiliensis
	Pariguana Longrich et al., 2012	† Pariguana lancensis

Classification

Several classification schemes have been used to define the structure of this family. The "historical" classification recognized all New World iguanians, plus Brachylophus and the Madagascar oplurines, as informal groups and not as formal subfamilies.^[6]

Frost and Etheridge (1989) formally recognized these informal groupings as families.^[7][8]

Macey et al. (1997), in their analysis of molecular data for iguanian lizards recovered a monophyletic Iguanidae and formally recognized the eight families proposed by Frost and Etheridge (1989) as subfamilies of Iguanidae.^[9]

Schulte et al. (2003) reanalyzed the morphological data of Frost and Etheridge in combination with molecular data for all major groups of Iguanidae and recovered a monophyletic Iguanidae, but the subfamilies Polychrotinae and Tropidurinae were not monophyletic.^[10]

Townsend et al. (2011), Wiens et al. (2012) and Pyron et al. (2013), in the most comprehensive phylogenies published to date, recognized most groups at family level, resulting in a narrower definition of Iguanidae.^[11][12][13]

References

External links

• Family Iguanidae