Iguana iguana (Laurenti 1768) [extant] is a charter member of the Iguania, one of the two recognized lizards families. This herbivorous lizard was derived from a sister to Euposaurus and they were derived from a sister to Liushusaurus.
Distinct from Liushusaurus, the skull of Iguana has a taller naris on a shorter rostrum. The upper temporal fenestra is further exposed on the occipital plane. The orbit is more nearly circular. The pineal foramen is absent or coincident with the frontal/parietal suture. The frontal-parietal suture is straight and wider than the frontal-nasal suture. The postfrontals are tiny ‘droplets’ at the tips of the frontals.
The cervicals are more robust and fewer number. The caudals have elongated neural spines and chevrons. No gastralia are present.
The scapula and coracoid are more deeply fenestrated.
The pubis and ischium are separated by a large thyroid fenestra. The ilium rises posteriorly.