por What is the iguana?
iguana It is a genus of reptiles that is part of the Iguanidae family. Animals belonging to this clade have a dorsal crest, made up of beak-shaped keratinized scales, which extends from the occipital region to the tail.
In addition, they have a gular sac. The male extends it to court the female or to demonstrate superiority to other males. It also contributes to the regulation of body temperature.
The iguana has a «third eye» on the top of its head, associated with the pineal gland. It is not capable of forming images, it functions as a photoreceptor unit for light and movement.
Its natural habitat is the tropical jungles and forests of South America, Central America and the Caribbean. There it is found in the treetops, where it spends most of its time foraging and resting. This genus is made up of two species, the green iguana (iguana iguana) and the Caribbean iguana (delicate iguana).
The distinction between these may be based on the fact that the green iguana has black stripes on its tail. In addition, under the eardrum it has some pearly scales. These aspects are absent in the other species.
Iguana Vulnerability
Iguana populations have been progressively decreasing in recent decades. the species iguana iguana It belongs to the list of species that make up Appendix II of CITES. It is protected and under the legal control of its import and export.
Although the green iguana is not among the group of animals with a high possibility of extinction, it is possible that it will be, if its commercialization is not controlled.
For international trade, the CITES legal framework does not provide for a specific import permit. However, each country may have legal statutes that regulate this. The purpose is that the iguana trade does not harm its conservation within the natural habitat where it is found.
On the other hand, the delicate iguana It is part of the IUCN Red List, being considered a reptile vulnerable to extinction.
threats
One of the causes that has caused the population decline of this genus is the consumption of products obtained from iguanas. Eggs and meat are an important source of protein in many communities, although they are also valued for their alleged aphrodisiac and medicinal properties.
In addition, fine items for personal use are made from the skin, such as shoes and handbags, sold at exorbitant prices.
Its sale as a pet has also influenced the vulnerability of both species. While most of these animals may come from farms, it is highly likely that wild iguanas are captured to supplement commercial requirements.
In particular, the Caribbean iguana (delicate iguana) is affected by the fragmentation of its habitat, due to logging and deforestation for the establishment of agricultural and urban spaces.
In addition, the introduction of the green iguana as an exotic species in the Lesser Antilles has affected its development in those Caribbean islands. This has generated a fierce competition for resources and food, generating the decline in at least three islands: the islands of Los Santos, San Bartolomé and the island of Tierra Baja.
iguana characteristics
Size. It can measure between 1.5 and 1.8 meters long, including the tail. However, species up to 2 meters have been found. As for the weight, it oscillates around 15 and 17 kilograms.
Eyes. The eye orbit measures, in adults, about 1.5 centimeters in diameter and 1 centimeter in height. The eyelids are thin, the upper one having less mobility than the lower one, which rises to close the eyeball. The species of this genus have, in the central and upper region of the head, on the parietal bones, a transparent scale, known as the pineal eye or third eye. It is actually a photoreceptor connected to the pineal gland, via a parietal nerve, which originates from the retina. Although it has a retina and a lens, it does not function the same as a normal eye. This is because the retina is primitive and the lens is not capable of forming images. This structure is sensitive to light and can detect movement. In this way, it works as a compass, calibrated with sunlight. It also uses it as a defense organ, since it could confuse predators, causing them to approach from above.
Ear. The iguana lacks an external pavilion, it has a differentiated transparent scale, located near the eyes. This lines a short canal, which contains a tympanic membrane.
Smell. D.They detect pheromones using the vomeronasal organ, also known as Jacobson’s organ. This accessory structure is molecularly and structurally different from the primary olfactory epithelium. It is housed in the palate, forming two pits, covered by a sensory epithelium. In iguanas, the tongue is responsible for capturing the odor particles and conducting them to the chambers of the vomeronasal organ.
Lungs. The green iguana has a pair of elongated lungs. In the young, the lung tissue reaches up to about half of the pleural sac, the remainder being made up of the pleura. One aspect that characterizes these animals is that they do not have a diaphragm. Due to this, the main responsible for respiratory movements is the intercostal musculature.
Fur. Iguana skin has two layers, the epidermis (outer) and the dermis (inner). In the epidermis there are blood vessels and nerves that nourish the dermis. In addition, it is made up of keratinous scales. Each is attached to the other through a flexible area, which allows the body to bend and move freely. This animal regularly sheds its skin. This occurs because a new dermal integument forms under the old one. When this process is complete, the old layer falls off.
tips. All members of this species have pointed dorsal ridges, which arise from the occipital region and extend to the tail. They have a gular sac, located below the throat. Some ridges are also found in this fold, which vary in number, depending on the stage of development. In the juvenile stage, it has around 210 dorsal ridges and in adults they can have up to 358.
Coloration. These reptiles have a coloration that ranges from gray to green, in light and dark tones. Some species have dark stripes on the tail, where they form a kind of rings. These colors could vary for various reasons, such as adaptation to changes in temperature, the heat period and as an expression of stress or illness. The colors of its skin give it the perfect camouflage to hide among the foliage of the trees where it lives.
femoral pores. Within the glands found in the skin are the femoral pores, located in a row on the ventral area of the thighs. Males have these larger structures than females. In heat, the pores enlarge and become more noticeable. They secrete a chemical substance with a very particular odor, used by the male to attract the female and mark her territory.
Taxonomy and species of the iguana
Kingdom: Animal.
Subkingdom: Bilateria.
phylum: chordate.
Subphylum: Vertebrate.
Superclass: Tetrapoda.
Class: Reptile.
Order: Squamata.
Suborder: iguania.
Family: Iguanidae.
Gender: iguana (Laurenti, 1768).
Species
This genus is divided into two species:
delicate iguana or the Caribbean
This species is native to the Lesser Antilles. Its coloration can vary between the different populations of the island. However, the predominant color is gray, with green spots in the lower region. On the head it has large scales, of an ivory tone.
In males, the gular sac is pink and there are blue scales around the eyes. They are bigger than the females, thus, their body measures approximately 40 centimeters and the tail 80 centimeters.
iguana iguana or green
The green iguana is a large herbivorous species native to South America and Central America. It can reach a length of 2 meters, including the tail. The weight can be around 10 kilograms.
Regarding coloration, newborns can be bright green or a little browner, especially those that inhabit xerophytic regions. Additionally, they have an aquamarine stripe on their forelimbs and dark eyelids.
The young are light green and the adults are dark green. They could turn an orange color during the reproductive period. The gular sac is green and the tail has black bands.
Habitat and distribution of the iguana
Iguanas are distributed in the humid jungle regions of South America, Central America, North America and the Caribbean. the species iguana iguana spans a wide geographic area. Specimens can be found from the southern part of Brazil and Paraguay to the Caribbean islands and the northern part of Mexico.
In the United States, it is an exotic species found in wild populations in Hawaii, Florida, and in Texas, in the Rio Grande Valley.
The Caribbean islands where he lives are Cozumel, Roatán, Utila, Corn islands, Guanaja, San Andrés, Providencia, Trinidad, Aruba, Tobago and other islands of the Lesser Antilles. The iguana iguana it has been introduced to Barbuda, Antigua, British Virgin Islands, Bahamas.
The delicate iguana It is endemic to the Lesser Antilles, where it occurs in scrub, mangrove swamps, and forests on Saint Martin, Anguilla, Saint Eustatius, Guadeloupe, Antigua, Martinique, and Dominica.
Habitat
The iguana is an arboreal animal, which descends to the ground mainly to nest. It spends most of its time high up in the trees, in regions of thick vegetation.
An example of these ecosystems are the humid tropical forests, mangroves, grasslands, forests and riverbanks, which do not exceed 1,000 m asl In these, the annual temperature is between 27 and 28 °C, with a humidity greater than 70%. .
It could also live in other habitats, such as dry forest, savannas, gallery forests, even on xeric islands, with shrub-type vegetation.
As reptiles, they are cold-blooded animals. For this reason, the iguana climbs to the highest branches to receive the sun’s rays and warm its body. Then, it dedicates itself to looking for its food, made up of leaves, shoots and fruits, which it obtains without having to go down to the ground.
iguana reproduction
female reproductive system
Ovaries. It has two, located in the abdominal cavity. Each contains a series of follicles, developed to different degrees, covered by a thin mesovarium. It has two oviducts, characterized by an irregular internal surface and by having a developed infundibulum. Each one ends independently in the cloaca.
male reproductive system
hemipenes. It is a bilobed penis that the iguana can keep, inverted and voluntarily, in the internal part of the cloaca. It is elongated and structured with erectile muscle tissue. It is located in the ventral area of the base of the tail. The spermatic cord is located in the…