The Iguanidae is a family of

lizard Lizard is the common name used for all Squamata, squamate reptiles other than snakes (and to a lesser extent amphisbaenians), encompassing over 7,000 species, ranging across all continents except Antarctica, as well as most Island#Oceanic isla ...

s composed of the

iguana ''Iguana'' (, ) is a genus of herbivorous lizards that are native to tropical areas of Mexico, Central America, South America, and the Caribbean. The genus was first described by Austrian naturalist Josephus Nicolaus Laurenti, J.N. Laurenti in ...

chuckwalla Chuckwallas are lizards found primarily in arid regions of the southwestern United States and northern Mexico. Some are found on coastal islands. The five species of chuckwallas are all placed within the genus ''Sauromalus''; they are part of th ...

s, and their prehistoric relatives, including the widespread green iguana.

Taxonomy

Iguanidae is thought to be the sister group to the collared lizards (family Crotaphytidae). This family likely first appeared in

Cenozoic The Cenozoic Era ( ; ) is Earth's current geological era, representing the last 66million years of Earth's history. It is characterized by the dominance of mammals, insects, birds and angiosperms (flowering plants). It is the latest of three g ...

, previously identified two

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 143.1 to 66 mya (unit), million years ago (Mya). It is the third and final period of the Mesozoic Era (geology), Era, as well as the longest. At around 77.1 million years, it is the ...

genera ('' Pristiguana'' and '' Pariguana'') are unlikely to belong to this family. The subfamily

Iguaninae The Iguanidae is a family of lizards composed of the iguanas, chuckwallas, and their prehistoric relatives, including the widespread green iguana. Taxonomy Iguanidae is thought to be the sister group to the Crotaphytidae, collared lizards (fam ...

, which contains all modern genera, likely originated in the earliest

Paleocene The Paleocene ( ), or Palaeocene, is a geological epoch (geology), epoch that lasted from about 66 to 56 mya (unit), million years ago (mya). It is the first epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), ...

, about 62 million years ago. The most basal extant genus, '' Dipsosaurus,'' diverged from the rest of Iguaninae during the late

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

, 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 The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

. All other modern iguana genera formed in the

Neogene The Neogene ( ,) is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period million years ago. It is the second period of th ...

period. A

phylogenetic tree A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In ...

of Iguaninae is shown here:

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 Arboreal locomotion is the locomotion of animals in trees. In habitats in which trees are present, animals have evolved to move in them. Some animals may scale trees only occasionally (scansorial), but others are exclusively arboreal. The hab ...

, living in trees, but some species tend to be more terrestrial, which means they prefer the ground. Iguanas are typically

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

s 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 Parental care is a behavioural and evolutionary strategy adopted by some animals, involving a parental investment being made to the evolutionary fitness of offspring. Patterns of parental care are widespread and highly diverse across the animal k ...

when their eggs hatch. They do, however, display nest-guarding behavior. Like all extant non-avian reptiles, they are

poikilotherm A poikilotherm () is an animal (Greek ''poikilos'' – 'various', 'spotted', and ''therme'' – 'heat') whose internal temperature varies considerably. Poikilotherms have to survive and adapt to environmental stress. One of the most important s ...

ic, and also rely on regular periods of basking under the sun to thermoregulate.

Distribution

All but one of the modern iguana genera are native to the Americas, ranging from the

deserts A desert is a landscape where little precipitation occurs and, consequently, living conditions create unique biomes and ecosystems. The lack of vegetation exposes the unprotected surface of the ground to denudation. About one-third of the l ...

of the

Southwestern United States The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural list of regions of the United States, region of the United States that includes Arizona and New Mexico, along with adjacen ...

through

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

, and the

Caribbean The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America ...

, to throughout

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

down to northernmost

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

. 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. 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. The only non-American iguana species are the members of the genus '' Brachylophus'' and the extinct '' Lapitiguana'', which are found on

Fiji Fiji, officially the Republic of Fiji, is an island country in Melanesia, part of Oceania in the South Pacific Ocean. It lies about north-northeast of New Zealand. Fiji consists of an archipelago of more than 330 islands—of which about ...

and formerly

Tonga Tonga, officially the Kingdom of Tonga, is an island country in Polynesia, part of Oceania. The country has 171 islands, of which 45 are inhabited. Its total surface area is about , scattered over in the southern Pacific Ocean. accordin ...

; 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

from the

Americas The Americas, sometimes collectively called America, are a landmass comprising the totality of North America and South America.''Webster's New World College Dictionary'', 2010 by Wiley Publishing, Inc., Cleveland, Ohio. When viewed as a sing ...

to the Fiji and Tonga.

Extant genera

Fossils

Cretaceous '' Pristiguana brasiliensis'' and '' Pariguana lancensis'' are later excluded from the family.

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. Frost and Etheridge (1989) formally recognized these informal groupings as

families Family (from ) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictability, structure, and safety as ...

. 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. 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. Townsend et al. (2011), Wiens et al. (2012) and Pyron et al. (2013), in the most comprehensive

phylogenies A phylogenetic tree or phylogeny is a graphical representation which shows the evolutionary history between a set of species or taxa during a specific time.Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA. In o ...

published to date, recognized most groups at family level, resulting in a narrower definition of Iguanidae.

Historical classification

Family Iguanidae *Informal grouping anoloids: anoles, leiosaurs, ''Polychrus'' *Informal grouping basiliscines: casquehead lizards *Informal grouping crotaphytines: collared and leopard lizards *Informal grouping iguanines: marine, Fijian, Galapagos land, spinytail, rock, desert, green, and chuckwalla iguanas *Informal grouping morunasaurs: wood lizards, clubtails *Informal grouping oplurines: Madagascan iguanids *Informal grouping sceloporines: earless, spiny, tree, side-blotched and horned lizards *Informal grouping tropidurines: curly-tailed lizards, South American swifts, neotropical ground lizards

Frost et al. (1989) classification of iguanas

Family Corytophanidae
Family Crotaphytidae
Family Hoplocercidae
Family Iguanidae *Genus '' Amblyrhynchus'' – marine iguana *Genus '' Brachylophus'' – Fijian/Tongan iguanas *Genus '' Cachryx'' – spinytail iguanas *Genus '' Conolophus'' – Galápagos land iguanas *Genus '' Ctenosaura'' – spinytail iguanas *Genus '' Cyclura'' – West Indian rock iguanas *Genus '' Dipsosaurus'' – desert iguana *Genus ''

Iguana ''Iguana'' (, ) is a genus of herbivorous lizards that are native to tropical areas of Mexico, Central America, South America, and the Caribbean. The genus was first described by Austrian naturalist Josephus Nicolaus Laurenti, J.N. Laurenti in ...

'' – green and Lesser Antillean iguanas *Genus '' Sauromalus'' – chuckwallas *Genus '' Armandisaurus'' (extinct chuckwalla) *Genus '' Lapitiguana'' (extinct giant Fijian iguana) *Genus '' Pumilia'' (extinct Palm Springs iguana) *Genus '' Pristiguana'' (Cretaceous Brazilian iguana) Family Opluridae
Family Phrynosomatidae
Family Polychridae
Family Tropiduridae

Macey et al. (1997) classification of Iguanidae

Family Iguanidae *Subfamily Corytophaninae: casquehead lizards *Subfamily Crotaphytinae: collared and leopard lizards *Subfamily Hoplocercinae: wood lizards, clubtails *Subfamily

: marine, Fijian, Galapagos land, spinytail, rock, desert, green, and chuckwalla iguanas *Subfamily Oplurinae: Madagascan iguanids *Subfamily Phrynosomatinae: earless, spiny, tree, side-blotched and horned lizards *Subfamily Polychrotinae: anoles, leiosaurs, '' Polychrus'' *Subfamily Tropidurinae: curly-tailed lizards, neotropical ground lizards, South American swifts

Schulte et al. (2003) classification of Iguanidae

Here families and subfamilies are proposed as clade names, but may be recognized under the traditional Linnean nomenclature. Iguanidae * Corytophaninae: casquehead lizards * Crotaphytinae: collared and leopard lizards * Hoplocercinae: wood lizards, clubtails *

: marine, Fijian, Galapagos land, spinytail, rock, desert, green, and chuckwalla iguanas * Oplurinae: Madagascan iguanids * Phrynosomatinae: earless, spiny, tree, side-blotched and horned lizards * Polychrotinae: anoles, leiosaurs, '' Polychrus'' :*subclade of Polychrotinae '' Anolis'': anoles :*subclade of Polychrotinae Leiosaurini: leiosaurs ::*subclade of Leiosaurini Leiosaurae: ::*subclade of Leiosaurini Anisolepae: :*subclade of Polychrotinae '' Polychrus'' : * Tropidurinae: curly-tailed lizards, neotropical ground lizards, South American swifts :*subclade of Tropidurinae '' Leiocephalus'': curly-tailed lizards :*subclade of Tropidurinae Liolaemini: South American swifts :*subclade of Tropidurinae Tropidurini: neotropical ground lizards :

Townsend et al. (2011), Wiens et al. (2012) and Pyron et al. (2013) classification of Iguanidae

*Family Corytophanidae *Family Crotaphytidae *Family

Dactyloidae Dactyloidae are a family of lizards commonly known as anoles (singular anole ) and native to warmer parts of the Americas, ranging from southeastern United States to Paraguay. Instead of treating it as a family, some authorities prefer to treat ...

*Family Hoplocercidae *Family Iguanidae *Family Leiocephalidae *Family

Leiosauridae Leiosauridae is a Family (biology), family of iguanian lizards containing six genera and 34 species. The family is Endemism, endemic to Central America and South America. Taxonomy A 2022 phylogenetic study found the Leiosauridae to be the sist ...

*Family

Liolaemidae Liolaemidae are a family of iguanian lizards. They were traditionally included in the family Iguanidae as subfamily Liolaeminae, which some more recent authors prefer to delimit in a more restricted way. This family is only found within South Ame ...

*Family Opluridae *Family

Phrynosomatidae The Phrynosomatidae are a diverse family of lizards, sometimes classified as a subfamily (Phrynosomatinae), found from Panama to the extreme south of Canada. Many members of the group are adapted to life in hot, sandy deserts, although the spiny ...

*Family Polychrotidae *Family

Tropiduridae The Tropiduridae are a family of iguanid lizards."Tropiduridae". The Reptile Database. www.reptile-database.org. The family is sometimes considered a subfamily, Tropidurinae. The subfamily is native to South America, including the islands of Tri ...

References

External links

Family Iguanidae
{{Authority control Taxa named by Nicolaus Michael Oppel Lizard families Extant Late Cretaceous first appearances