美洲鬣蜥属属

美洲鬣蜥属的学名是源自它们的泰诺语名字“伊瓦纳”。

解剖及生理

美洲鬣蜥属有喉袋，沿背部至尾巴有一列棘刺。它们的头上有顶眼，仿佛较淡色的鳞片。颈后有细小及凸起的鳞片，两颊有很大及圆形的鳞片。

美洲鬣蜥属有锐利的视觉，可以分辨远处的形状、阴影、颜色及运动。它们会在森林中以视觉来搜索及觅食。同种间也会以视觉讯号来沟通。它们会将橙色、黄色、粉红色或蓝色等看为食物。美洲鬣蜥属的鼓膜位于两侧眼睛之下及大圆鳞片之上，很难察觉。

美洲鬣蜥属绿色的身体可以帮助它们藏身，免被大型的掠食者发现。

下属物种

本属包括以下物种：

小安德烈斯岛鬣蜥 Iguana delicatissima Laurenti, 1768

• Iguana europaea Hoffstetter, 1942
• 美洲鬣蜥 Iguana iguana (Linnaeus, 1758)
• Iguana iguana x Iguana delicatissima

暗黑鬣蜥 Iguana melanoderma Breuil et al., 2020，现接受名为美洲鬣蜥 Iguana iguana

Iguana rhinolopha Wiegmann, 1834

保育状况

本属所有种均被列为《濒危野生动植物种国际贸易公约》附录二的物种，被限制出口及贸易。

Iguana (, Spanish: [iˈɣwana]) 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 J.N. Laurenti in 1768. Two species are placed 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 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.

The word "iguana" is derived from the original Taino name for the species, iwana.

In addition to the two species in the genus Iguana, several other related genera in the same family have common names of the species including the word "iguana".

The species is a popular quarry for pets, and non-native animals have been widely introduced beyond its native area, into Ishigaki Island, the Florida Peninsula, Hawaii, Singapore, Thailand, Taiwan, and including numerous islands with native Iguana populations in the Lesser Antilles.

Anatomy and physiology

Iguanas are large lizards that can range from 1.2 to 2.0 m (4 to 6.5 ft) in length, including their tails. They possess a dewlap and a row of elongated scales running from the midline of their necks down to their tails. Iguanas have varying types of scales covering different areas of their body; for example, some large, round tuberculate scales are scattered around the lateral region of the neck among smaller, overlapping scales. The scales on the dorsal trunk of their bodies are also thicker and more tightly packed than those on the ventral sides. These scales may be a variety of colors and are not always visible from close distances. They have a large, round scale on their cheeks known as a subtympanic shield.

Iguanas have keen vision and can see shapes, shadows, colors, and movement at long distances. Their visual acuity enables them to navigate through crowded forests and to locate food. They employ visual signals to communicate with other members of the same species.

Phylogeny

A phylogeny based on nuclear protein-coding genes, reviewed by Vidal and Hedges (2009), suggested that the subclade Iguania is in a group with snakes and anguimorphs (lizards). These groups share an oral gland capable of secreting toxins (a derived trait). The phylogeny based on whole mitochondrial genomes, though, as proposed by Rest et al. (2003), places the green iguana as the closest relative of the mole skink (Plestiodon egregius). Lepidosaurs are reptiles with overlapping scales, and within this group both iguanians and tuataras (Sphenodon) project their tongues to seize prey items instead of using their jaws, which is called tongue prehension. Iguanians are the only lineage within the Squamata that display this trait, meaning that it was gained independently in both iguanians and tuataras. Iguanians are also the only squamates that primarily use their sight to identify and track prey rather than chemoreception or scent, and employ an ambush technique of catching prey instead of active searching.

As food

Iguanas have historically featured in the culinary traditions of Mexico and Central America. Iguana meat is also consumed in parts of the Dominican Republic and United States (such as Puerto Rico).

Iguana eggs are consumed in some parts of Latin America, such as Nicaragua and Colombia.

Ecology

As large herbivores, iguanas are important members of the ecosystems they live in, especially on islands where they often are the largest native terrestrial species. Given their life history characteristics their impact on other species is high. By eating leaves and flowers they promote plant growth and flowering, and by eating fruits and seeds they aid in seed dispersal and germination. The large number of eggs that female iguanas lay provides high amounts of protein for predators that either target the eggs while these are incubating, or that feed on baby iguanas once they emerge. Also, the nests that female iguanas dig (including the tunnels) create complex underground systems with looser soil that other species can utilize; a recent study found that females of the Lesser Antillean iguana can lay their clutches at a depth of 1.65 m (5.5 ft) underground.