Iguana is a genus of lizard native to tropical areas of Central and South America and the Caribbean first described by Austrian naturalist Josephus Nicolaus Laurenti in his book Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena in 1768. The genus iguana includes two species: the Green Iguana and the Lesser Antillean Iguana.
The word "Iguana" is derived from a Spanish form of the original Taino name for the species "Iwana".
The two species of lizard within the genus Iguana possesses a dewlap, a row of spines running down their back to their tail, and a third eye on their head. This eye is known as the Parietal eye, which looks just like a pale scale on the top of their head. Behind their neck are small scales which resemble spikes, known as tuberculate scales. They also have a large round scale on their cheek known as a subtympanic shield.
Iguanas have excellent vision and can see long distances, shapes, shadows, color and movement. An iguana uses its eyes to navigate through winding threes trees and confusing forests, as well as finding food. They also use visual signals to communicate with members of the same species.
An iguana's ear is known as the tympanum. It is the iguana's ear drum and is located right above the subtympanic shield and behind the eye. This is a very thin, delicate part of the iguana, and crucial to its hearing.