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Temporal range: Early Jurassic - present, 190–0  Ma
Leiocephalus personatus , a species of iguanian
Scientific classification Red Pencil Icon.png
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Clade: Toxicofera
Clade: Iguanomorpha
Sukhanov, 1961
Suborder: Iguania
Cope, 1864

Iguania is an infraorder of squamate reptiles 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, and comprise nearly 13,000 named species [ citation needed ]. However, molecular information has placed Iguania well within the Squamata as sister taxa to the Anguimorpha and closely related to snakes. [1] 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. [2] Most Iguanias are arboreal but there are several terrestrial groups. They usually have primitive fleshy, non-prehensile tongues, although the tongue is highly modified in chameleons. The group has a fossil record that extends back to the Early Jurassic (the oldest known member is Bharatagama , which lived about 190 million years ago in what is now India). [3] Today they are scattered occurring in Madagascar, the Fiji and Friendly Islands and Western Hemisphere [4]



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: [7]


Hoyalacerta sanzi

Huehuecuetzpalli mixtecus

Pristiguana brasiliensis


Mimeosaurus crassus

Priscagama gobiensis

Phrynosomimus asper








Iguanoidea  (=Pleurodonta)

Polrussia mongoliensis

Igua minuta

Isodontosaurus gracilis

Anchaurosaurus gilmorei

Zapsosaurus sceliphros

Saichangurvel davidsoni

Temujinia ellisoni

Ctenomastax parva






Polychrus gutturosus

Polychrus marmoratus

Polychrus femoralis

Afairiguana avius





Anolis electrum

Anolis occultus

Anolis heterodermus

Anolis vermiculatus














sand lizards




Chalarodon madagascariensis

Oplurus quadrimaculatus B

Oplurus quadrimaculatus A

Oplurus cyclurus











Conservation Status

As of 2020 The IUCN Red List of endangered species lists 63.3% of the species as Least concern, 6.7% Near Threatened, 8.2 vulnerable, 9.1% endangered, 3.1% critically endangered, 0.3 extinct and 9.2% data deficient. The major threats include agriculture , residential and commercial development {https://www.iucnredlist.org/}.

Related Research Articles

Lizard Suborder of reptiles

Lizards are a widespread group of squamate reptiles, with over 6,000 species, ranging across all continents except Antarctica, as well as most oceanic island chains. The group is paraphyletic as it excludes the snakes and Amphisbaenia; some lizards are more closely related to these two excluded groups than they are to other lizards. Lizards range in size from chameleons and geckos a few centimeters long to the 3 meter long Komodo dragon.

Squamata Order of reptiles

Squamata is the largest order of reptiles, comprising lizards, snakes and amphisbaenians, which are collectively known as squamates or scaled reptiles. With over 10,900 species, it is also the second-largest order of extant (living) vertebrates, after the perciform fish. Members of the order are distinguished by their skins, which bear horny scales or shields. They also possess movable quadrate bones, making it possible to move the upper jaw relative to the neurocranium. This is particularly visible in snakes, which are able to open their mouths very wide to accommodate comparatively large prey. Squamata is the most variably sized order of reptiles, ranging from the 16 mm (0.63 in) dwarf gecko to the 5.21 m (17.1 ft) green anaconda and the now-extinct mosasaurs, which reached lengths of over 14 m (46 ft).

Agamidae Family of lizards

Agamidae is a family of over 300 species of iguanian lizards indigenous to Africa, Asia, Australia, and a few in Southern Europe. Many species are commonly called dragons or dragon lizards.

Hoplocercidae Family of lizards

Hoplocercidae are a family of lizards native to the tropical forests, woodlands and savanna-like habitats of Central and South America. Alternatively they are recognized as a subfamily, Hoplocercinae. Sixteen species in three genera are described.

Iguanidae Family of lizards

The Iguanidae are a family of lizards composed of iguanas and related species. This family consists of species such as the Green Iguana, the Lesser Antillean Iguana, and marine iguana, just to name a few.

<i>Brachylophus</i> Genus of lizards

The genus Brachylophus consists of four extant iguanid species native to the islands of Fiji and a giant extinct species from Tonga in the South West Pacific. One of the extant species, B. fasciatus, is also present on Tonga, where it has apparently been introduced by humans.

<i>Conolophus</i> Genus of lizards

The Galápagos land iguanas comprise the genus Conolophus of the Galápagos Islands (Ecuador). The number of species of this variable genus has always been disputed; the most current taxonomic surveys suggest that three species exist:

<i>Ctenosaura</i> Genus of lizards

Ctenosaura is a lizard genus commonly known as spinytail iguanas or ctenosaurs. The genus is part of the large lizard family, Iguanidae and is native to Mexico and Central America. The name is derived from two Greek words: ctenos (κτενός), meaning "comb", and saura (σαύρα), meaning "lizard".

Toxicofera Proposed clade of scaled reptiles

Toxicofera is a proposed clade of scaled reptiles (squamates) that includes the Serpentes (snakes), Anguimorpha and Iguania. Toxicofera contains about 4,600 species, of extant Squamata. It encompasses all venomous reptile species, as well as numerous related non-venomous species. There is little morphological evidence to support this grouping, however it has been recovered by all molecular analyses as of 2012.

<i>Iguana</i> Reptile genus of herbivorous lizards

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 in 1768 by Austrian naturalist Josephus Nicolaus Laurenti in his book Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena. There are two species in the genus; the green iguana, which is widespread throughout its range and a popular pet, and the Lesser Antillean iguana, which is native to the Lesser Antilles; genetic analysis indicates that the green iguana may comprise a species complex of multiple species, some of which have been recently described, but the Reptile Database considers all of these as subspecies of the green iguana.

Scleroglossa Evolutionary group of lizards

Scleroglossa is a clade of lizards that includes geckos, autarchoglossans, and amphisbaenians. Scleroglossa is supported by phylogenetic analyses that use morphological features. According to most morphological analyses, Scleroglossa is the sister group of the clade Iguania, which includes iguanas, chameleons, agamids, and New World lizards. Together, Scleroglossa and Iguania make up crown group Squamata, the smallest evolutionary grouping to include all living lizards and snakes.

Pleurodonta Clade of lizards

Pleurodonta is one of the two subdivisions of Iguania, the other being Acrodonta. Pleurodonta includes all families previously split from Iguanidae sensu lato, whereas Acrodonta includes Agamidae and Chamaeleonidae. The name Pleurodonta was first used by paleontologist and herpetologist Edward Drinker Cope in 1864, although he used it in a different sense than it is used today. Because of this difference, the name Iguanoidea has been proposed as a replacement for Pleurodonta in phylogenetic nomenclature.

<i>Huehuecuetzpalli</i> Extinct genus of lizards

Huehuecuetzpalli mixtecus is an extinct lizard from the Early Cretaceous Tlayúa Formation in Tepexi de Rodríguez, Central Mexico. Although it is not the oldest known lizard, Huehuecuetzpalli may be the most basal member of Squamata, making it an important taxon in understanding the origins of squamates. It may or may not be a basal member of Iguania, a large clade of lizards that traditionally includes the iguanas and their close relatives, chameleons, and agamids: if it is an iguanian, H. mixtecus represents the earliest major offshoot of the squamate evolutionary tree.

Polychrotidae Family of lizards

The Polychrotidae family of iguanian lizards contains the living genus Polychrus and the extinct genus Afairiguana. The family Polychrotidae was once thought to encompass all anoles, including those in the genus Anolis. Studies of the evolutionary relationships of anoles based on molecular information has shown that Polychrus is not closely related to Anolis, but instead closer to Hoplocercidae. It is therefore not part of Dactyloidae and instead is treated as the family, Polychrotidae.

Gobiguania is an extinct clade of iguanian lizards from the Late Cretaceous. All known gobiguanians are endemic to the Gobi Desert of Mongolia. Gobiguania was given a phylogenetic definition by Jack Conrad and Mark Norell in 2007 as all taxa more closely related to Anchaurosaurus gilmorei than to Iguana iguana, Crotaphytus collaris, or Agama agama. According to Conrad and Norell's phylogenetic analysis, Gobiguania includes Anchaurosaurus as well as several other Late Cretaceous lizards such as Ctenomastax, Temujinia, Saichangurvel, and Zapsosaurus. A phylogenetic analysis published in 2012 indicated that three other lizard genera — Igua, Isodontosaurus, and Polrussia, all from Mongolia and all from the Late Cretaceous — are also gobiguanians. Below is a cladogram from the analysis:

Chamaeleontiformes Clade of lizards

Chamaeleontiformes is a hypothesized clade of iguanian lizards defined as all taxa sharing a more recent common ancestor with Chamaeleo chamaeleon than with Hoplocercus spinosus, Polychrus marmoratus, or Iguana iguana. It was named by paleontologist Jack Conrad in 2008 to describe a clade recovered in his phylogenetic analysis that included the extinct genus Isodontosaurus, the extinct family Priscagamidae, and the living clade Acrodonta, which includes agamids and chameleons. It is a stem-based taxon and one of two major clades within Iguania, the other being Pleurodonta. Below is a cladogram from Daza et al. (2012) showing this phylogeny:

Uquiasaurus is an extinct genus of iguanian lizards represented by the type species Uquiasaurus heptanodonta from the Late Pliocene of Argentina. Uquiasaurus was first described in 2012 on the basis of isolated snout and jaw bones within the Uquía Formation, the namesake of the genus. These bones were preserved in a midden of predatory bird pellets and are part of a microvertebrate assemblage that includes the bones of rodents, marsupials, frogs, birds, and other lizards, one of the few to document the mixing of North and South American faunas during the Great American Interchange. Phylogenetic analysis indicates that Uquiasaurus is part of a clade of iguanians that includes the living families Liolaemidae, Leiocephalidae, and Tropiduridae. Below is a cladogram from Daza et al. (2012) showing its phylogenetic relationships:

Saichangurvel is an extinct genus of iguanian lizards from the Late Cretaceous of Mongolia. It is a member of a clade called Gobiguania, an exclusively Late Cretaceous group of iguanian lizards that was likely endemic to the Gobi Desert. The type species, Saichangurvel davidsoni, was named by paleontologists Jack Conrad and Mark Norell of the American Museum of Natural History in 2007. It is known from a single nearly complete and fully articulated skeleton called IGM 3/858, which was found eroding from a block of sandstone during a thunderstorm at a fossil locality called Ukhaa Tolgod. IGM 3/858 comes from the Djadochta Formation, which is between 75 and 71 million years in age. Just as it is today, the Gobi was a desert during the Cretaceous. IGM 3/858 may have died in a collapsing sand dune, the rapid burial preserving its skeleton in pristine condition.

Anchaurosaurus is an extinct genus of iguanian lizard from the Late Cretaceous of Inner Mongolia, China. It belongs to an extinct clade of iguanians called Gobiguania that was endemic to the Gobi Desert during the Late Cretaceous. The type species, Anchaurosaurus gilmorei, was named in 1995 on the basis of a well-preserved skull and incomplete skeleton from the Djadochta Formation. Compared to other iguanians, Anchaurosaurus has a relatively elongated skull, large eye sockets, and higher tooth crowns. Phylogenetic analysis indicates that among gobiguanians, Anchaurosaurus is most closely related to Zapsosaurus from Mongolia. Below is a cladogram from Daza et al. (2012) showing the phylogenetic relationships of Anchaurosaurus:

Acrodonta (lizard) Subclade of lizards

Acrodonta are a subclade of iguanian squamates consisting almost entirely of Old World taxa. Extant representation include the families Chamaeleonidae (chameleons) and Agamidae, with at least over 500 species described. A fossil genus, Gueragama, was found in Brazil, making it the only known American representative of the group.


  1. Vidal, N.; Hedges, S. B. (2005). "The phylogeny of squamate reptiles (lizards, snakes, and amphisbaenians) inferred from nine nuclear protein-coding genes" (PDF). Comptes Rendus Biologies. 328 (10–11): 1000–1008. doi:10.1016/j.crvi.2005.10.001. PMID   16286089. Archived from the original (PDF) on 2011-07-26.
  2. Daza, J., Abdala, V., Arias, J., García-López, D., & Ortiz, P. (2012). Cladistic Analysis of Iguania and a Fossil Lizard from the Late Pliocene of Northwestern Argentina. Journal of Herpetology, 46(1), 104-119. Retrieved May 12, 2020, from www.jstor.org/stable/41515023
  3. Evans, Susan E.; Prasad, G. V. R.; Manhas, B. K. (2002). "Fossil lizards from the Jurassic Kota Formation of India". Journal of Vertebrate Paleontology. 22 (2): 299. doi:10.1671/0272-4634(2002)022[0299:FLFTJK]2.0.CO;2.
  4. Moody, S. (1985). Charles L. Camp and His 1923 Classification of Lizards: An Early Cladist? Systematic Zoology, 34(2), 216-222. doi:10.2307/2413329
  5. Wiens, J.J., C. R. Hutter, D. G. Mulcahy, B. P. Noonan, T. M. Townsend, J. W. Sites Jr., T. W. Reeder. (2012) Resolving the phylogeny of lizards and snakes (Squamata) with extensive sampling of genes and species. Archived 2018-08-05 at the Wayback Machine Biology Letters
  6. Schulte II, J. A., J. P. Valladares, and A. Larson. (2003) [Phylogenetic relationships within Iguanidae inferred using molecular and morphological data and a phylogenetic taxonomy of iguanian lizards.] Herpetologica 59: 399-419
  7. Daza, J. D.; Abdala, V.; Arias, J. S.; García-López, D.; Ortiz, P. (2012). "Cladistic Analysis of Iguania and a Fossil Lizard from the Late Pliocene of Northwestern Argentina". Journal of Herpetology. 46: 104–119. doi:10.1670/10-112. S2CID   85405843.