The smooth helmeted iguana (''Corytophanes cristatus''), also known as the helmeted iguana, the helmeted basilisk, the elegant helmeted lizard, and several other

common names In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contras ...

, is a

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

of Basilisk and a

New World The term "New World" is used to describe the majority of lands of Earth's Western Hemisphere, particularly the Americas, and sometimes Oceania."America." ''The Oxford Companion to the English Language'' (). McArthur, Tom, ed., 1992. New York: ...

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 ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Corytophanidae Corytophanidae is a family of iguanian lizards, also called casquehead lizards or helmeted lizards, endemic to the New World. Nine species of casquehead lizards from three genera are recognized. Geographic range Corytophanids are found from Mex ...

. The species is native to southern

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 northwestern

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 ...

Taxonomic history

Etymology

The smooth helmeted iguana is named for the prominent casque, or crest on the back of its head and neck which has the appearance of a helmet.

Evolutionary history

The

family of lizards is thought to have

Euramerica Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pa ...

n and

Laurasia Laurasia () was the more northern of two large landmasses that formed part of the Pangaea supercontinent from around ( Mya), the other being Gondwana. It separated from Gondwana (beginning in the late Triassic period) during the breakup of Pa ...

n ancestral beginnings, and is believed to have moved down to the tropics after the

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 ...

period cooling, approximately 33–56 million years ago.

Geographic range and habitat

''C. cristatus'' can be found ranging from

Chiapas Chiapas, officially the Free and Sovereign State of Chiapas, is one of the states that make up the Political divisions of Mexico, 32 federal entities of Mexico. It comprises Municipalities of Chiapas, 124 municipalities and its capital and large ...

in southern Mexico to north-western

Colombia Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...

. The habitat it primarily occupies in this range is primary and secondary mesic rain-forest. It lives predominantly in trees, but also hunts on the forest floor where it uses leaf litter as a micro-habitat.

Description

The smooth helmeted iguana is a medium-sized lizard with long slim legs and very long toes. It can be grey, olive, brown, black or reddish-brown with irregular blotches. The smooth helmeted iguana can change the color of its skin as a method of

camouflage Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the b ...

. As indicated by its name, the smooth helmeted iguana has a prominent crest on its head, which tapers to a saw-tooth ridge down its back. The crest is present in both males and females of the species, though the crest is larger in males. ''C. cristatus'' is approximately in snout-to-vent length (SVL) when mature. It is a non-heliotherm species, meaning that it does not use the sun to increase its body temperature. Rather, it maintains its body temperature at around , close to the temperature of the forest floor habitat where it lives. It is very wary of predators and freezes at the approach of danger from up to away.

Behavior and ecology

Reproduction

Adult females of ''C. cristatus'' lay five to six eggs in a depression on the forest floor. It is speculated that the crest on the head may be used in excavating the nest.

Diet

''C. cristatus'' feeds on insects, spiders, worms, and other lizards. ''C. cristatus'' is an extreme "sit and wait" predator, and its foraging is brief and infrequent. Therefore, this lizard is considered to be an opportunistic feeders. It is also a specialist feeder that preys on extremely large arthropods and

cicadas The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into tw ...

when available. If it has no luck being a sit and wait predator, it will sometimes become an active predator and look for its next meal. Typically, if this is the method it chooses, it will choose prey that is slow and easy to capture.

Interactions with algae and fungi

The smooth helmeted iguana has been observed to remain motionless for extended periods of time. It is thought that this behavior has resulted in its skin being used as a novel growing substrate for a species of fungus, ''

Physarum pusillum ''Physarum pusillum'' is a species of myxomycete (true slime mould) in the polyphyletic genus ''Physarum''. Taxonomy ''Physarum pusillum'' was first described by Miles Berkeley and M.A. Curtis in 1873 as ''Didymium pusillum''. The holotype ( ...

''. This species of lizard is also the only known vertebrate observed with a cormophytic plant growing on it.

Color change

The smooth helmeted iguana, like

chameleon Chameleons or chamaeleons (Family (biology), family Chamaeleonidae) are a distinctive and highly specialized clade of Old World lizards with 200 species described as of June 2015. The members of this Family (biology), family are best known for ...

s and

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 ...

s, have the ability to change its coloration from dark to light or ''vice versa'', which aids in thermoregulation when basking in sunlight.

Conservation

The smooth helmeted iguana is common and widespread throughout its native range. There are no current conservation concerns for this species, although deforestation can be a localized threat to smooth helmeted iguana populations.