Classification of Iguana

• Phylum :- Chordata (Dorsal tubular nerve cord, notochord and gill-slits present.)
• Group :- Craniata (Definite head, Cranium with brain present.)
• Sub phylum :- Vertebrata (Vertebral column present.)
• Division :- Gnathostomata (Jaws and paired appendages present.)
• Super Class :- Tetrapoda (Paired limbs, lungs, cornified skin and bony skeleton.)
• Class :- Reptilia (Scaly vertebrates. Right and left aortic arches present. Single condyle. Pulmonary respiration. Embryo with amnion and allantois.)
• Sub Class :- Diapsida (Skull with two temporal openings separated by post-orbital and squamosal.)
• Order :- Squamata (Lizards and snakes with horny epidermal scales or shields. Quadrate bone movable. Vertebrae procoelous. Anal opening transverse.. Vertebrae amphicentrous.)
• Sub-order :- Iguania (Lizards. Body slender, limbs 4. Pterygoid in contact with quadrate. Eyelids movable.)
• Family :- Iguanidae (Limbs normal. Teeth homodont.)
• Genus :- Iguana

Geographical distribution

Iguana is found in tropical countries. It is distributed in Mexico, West Indies, Southern and Central America.

Habit and habitat

Iguana is adapted for active running and climbing. It feeds on leaves, fruits, some insects and small vertebrates. It lives on trees.

General Characteristics of Iguana

• Lizard measures about 2 metres having head short neck, compressed trunk and elongated tail.
• General colour of upper part is a mixture of green and black and underpart pale greenish or whitish.
• Back contains lance-like spines along mid-dorsal line extending upto tail. Mid-line spines are also present along lower jaw flap of skin.
• Head contains wide mouth, small eyes, nostrils and opening of external ear. Teeth are acrodont like and fixed to the sides of the jaw. Eyelids complete. Tongue is fleshy and non-protractile. (5) (6) (7)
• Forelimbs and hind limbs are normal. Digits are clawed.
• Both sexes have femoral pores.
• In tropics Iguana is used as food by man.

Ecological Importance

They play a vital role in maintaining the balance and health of the ecosystems they inhabit. Their ecological importance lies in their interactions with plants, animals, and the environment, which contribute to biodiversity and ecological stability.

1. Herbivory and Plant Dynamics

• They are primarily herbivorous, feeding on leaves, flowers, and fruits. This makes them key players in shaping plant communities by influencing vegetation growth and structure.
• Their selective feeding habits can regulate the population of certain plant species, preventing overgrowth and promoting biodiversity.

2. Seed Dispersal

• By consuming fruits and defecating seeds at different locations, iguanas contribute to seed dispersal. This facilitates the regeneration and spread of plant species, promoting forest growth and ecosystem resilience.

3. Nutrient Cycling

• They contribute to nutrient cycling through their droppings, which enrich the soil with organic matter and nutrients. This process supports plant growth and enhances soil fertility in their habitats.

4. Food Web Dynamics

• As both prey and consumers, iguanas are integral to the food web. They serve as a food source for predators such as snakes, birds of prey, and large mammals, supporting the survival of these species.
• By preying on plants and certain insects (in some species), they maintain ecological balance and prevent overpopulation of specific groups.

5. Habitat Maintenance

• They often create burrows or use natural crevices, which can provide shelter for other animals such as insects, amphibians, and small reptiles. This activity increases habitat complexity and supports biodiversity.

6. Indicators of Ecosystem Health

• The presence and health of iguana populations can indicate the condition of their ecosystems. A decline in their numbers may signal habitat destruction, pollution, or climate change impacts, prompting conservation efforts.

7. Pollination Assistance

• While feeding on flowers or nectar, some iguana species inadvertently assist in pollination. This behavior supports the reproductive success of certain plant species in their ecosystems.

8. Cultural and Ecotourism Value

• They are often a focus of local culture and ecotourism. Their conservation raises awareness about the importance of protecting habitats and biodiversity, indirectly supporting broader ecological preservation.

Conservation Implications

• Habitat loss, hunting, and invasive species threaten iguana populations. Protecting iguanas helps safeguard the ecosystems they inhabit, as their ecological roles are interconnected with other species and processes.

By contributing to plant growth, nutrient cycling, food web dynamics, and biodiversity, iguanas are essential for maintaining the health and balance of tropical and subtropical ecosystems. Their conservation is critical for preserving these ecological benefits.

Special Features

They are unique and fascinating reptiles known for their distinctive physical and behavioral characteristics that help them adapt to their environments. Here are some special features of iguanas:

1. Body Structure

• Large Size: Iguanas are among the largest lizards, with some species, like the green iguana (Iguana iguana), reaching lengths of up to 6 feet, including their tail.
• Long Tail: Their tails are often longer than their body and serve multiple purposes, such as balance, swimming, and defense. They can use their tails to deliver powerful whips to deter predators.

2. Coloration and Camouflage

• They exhibit various colors, including green, blue, orange, and even red, depending on the species. These colors provide camouflage in their natural habitats, such as forests and rocky areas.
• Some species can change color slightly, which may help with thermoregulation or communication.

3. Parietal Eye (“Third Eye”)

• They possess a parietal eye on the top of their heads. This sensory organ can detect changes in light and movement, helping them detect predators from above.

4. Spines and Crests

• They have a row of spines running down their back and tail, which offer protection against predators. These spines also play a role in thermoregulation by increasing their surface area.

5. Skin Adaptations

• Their skin is tough and covered with scales, protecting them from injuries, dehydration, and UV radiation.
• Many iguanas have loose, flap-like skin under their throat called a dewlap, used for thermoregulation and communication.

6. Thermoregulation

• As ectothermic animals, iguanas rely on external heat sources to regulate their body temperature. They bask in the sun to warm up and seek shade or water to cool down.

7. Dietary Specialization

• Most iguanas are herbivores, feeding on leaves, fruits, and flowers. They have specialized teeth and a robust digestive system to process fibrous plant material.

8. Tail Autotomy

• Some iguanas can shed their tails when threatened by predators, a phenomenon known as autotomy. The detached tail distracts predators, allowing the iguana to escape.

9. Swimming Ability

• They, especially marine iguanas (Amblyrhynchus cristatus) found in the Galápagos Islands, are excellent swimmers. Marine iguanas can dive and feed on algae underwater.

10. Reproductive Features

• Lay eggs, and their clutch sizes can range from a few to over 50 eggs, depending on the species. Females often dig burrows to lay and protect their eggs.

11. Social Behavior

• Use visual signals, such as head-bobbing, to communicate with each other. Males often use their dewlap and head movements to display dominance or attract mates.

12. Longevity and Resilience

• They can live for 10-20 years in the wild and even longer in captivity. Their adaptability to various environments makes them resilient, though they are sensitive to habitat loss and environmental changes.

These features make iguanas well-suited for survival in their natural habitats and fascinating subjects for ecological and evolutionary studies.

Identification

• Since this lizard contains median row of spines on back and tail, besides above characters, hence it is Iguana.