Reptilia: Definition, Characteristics, Classification, and Example

Reptilia is a group of vertebrates that includes animals such as lizards, alligators, tortoises, turtles, crocodiles, and snakes. Animals of the class Reptilia are known as Reptiles. Reptilia can be found in various regions such as forests, deserts, freshwater, wetlands, and mangroves. They are cold-blooded animals and their skin is covered with scales.

The Mesozoic Era was the “Golden Age of Reptiles.” The study of snakes is known as Serpentology or Ophiology. They are mostly terrestrial and tetrapods. Reptilia is divided into anapsida, parapsida and diapsida. Reptilia has both ecological and economic importance.

What is Reptilia?

Reptilia is a class of cold-blooded vertebrates. It includes snakes, lizards, turtles, and crocodiles. Reptilia is characterized by scales, lungs, and laying shelled eggs. Reptiles have a diverse range of habitats. They live in deserts as well as rainforests. Many of the reptilians are predators and use adaptations like venom or powerful jaws for hunting their prey.

Characteristics of Reptilia

A few of the important characteristics of Reptilia are:

• They have a 3 chambered heart except crocodiles. Crocodiles have a 4 chambered heart.
• They are oviparous and development is direct. The eggs are yolky and soft-shelled.
• They have 12 pairs of cranial nerves in their nervous system.
• Internal fertilization.
• No external ear opening.
• They are uricotelic and excrete nitrogenous waste in the form of uric acid.
• They have scales on their bodies. Few of the reptiles shed scales. Scales have Beta keratin.
• They are ectotherms meaning heat is absorbed from the environment.
• They are burrowing terrestrial animals.
• They are cold-blooded animals.
• They use lungs for respiration.
• They are found in warmer regions of the world.
• They have dry and rough skin without the presence of glands.
• The body is divided into four parts i.e, head, neck, trunk and tail.
• Examples are turtles, lizards, snakes and crocodiles.
• They are tetrapods.

Examples of Reptilia

Here are some examples of reptiles:

• Snakes
• Lizards
• Turtles
• Crocodiles
• Alligators
• Chameleons
• Komodo dragons
• Geckos
• Iguanas
• Tuatara

Classification of Class Reptilia

There are three major subclasses:

Anapsida

Few characteristics of Anapsida are

• They are subdivided into Chelonia and Cotylosauria.
• The roof over the skull is formed by the dermal bones. No presence of temporal fossae.
• The roof of the skull is solid.
• Strong limbs.
• Examples are turtles and tortoises.

Parapsida

Few characteristics of Parapsida are:

• The presence of one temporal fossa, high up on the skull. Examples are Placodonts, Nothosaurs and Protosaurs.
• Ichthyosaurs and Plesiosaurs are two large groups.

Diapsida

Few characteristics of Diapsida are:

• The pterosaurs and dinosaurs are part of this group.
• The skull has two temporal vacuities.
• The two major groups are Lepidosauria and Archosauria.
• Examples are Chameleon and Crocodilus.

Groups of Reptiles

The classification of group of Reptiles is stated below:

Order	Examples
Order Squamata	Snakes , Lizards
Order Sphenodontia	Tuataras
Order Crocodilia	Alligators, Crocodiles
Order Testudines	Terrapins , Turtles, Tortoises

Extinct Groups of Reptilia

Extinct groups of Reptilia are:

• Ichthyopterygia: Ichthyopterygia is an extinct order of marine reptiles which lived during the mesozoic era. Ichthyopterygia resembled dolphins
• Archosauria: Archosauria were also known as ruling reptiles. They were the major group of diapsids. They are represented today only by crocodilians and birds
• Lepidosauria: Lepidosauria are ancestors of Squamata and the extant rhynchocephalian. The common features are overlapping scale and are also characterised by their scaly skin.
• Synapsida: Synapsids were the largest terrestrial vertebrates in the Permian period. A subclass of reptiles which includes the Pelycosauria and Therapsida.

Importance of Reptilia

The importance of Reptilia are:

• Lizards help in pest control by consuming insects from houses, gardens and other areas.
• Snake controls the population of Rodents.
• They help in biological research programs. Snake venom is used for the development of pain management drugs.
• Reptile skin is used in the leather industry.
• Alligators and crocodiles prevent the overpopulation of fish species.

Ecological Significance of Reptilia

The ecological significance are:

• It plays a crucial role in maintaining ecological balance and biodiversity.
• They also help to regulate prey species and prevent unchecked population growth.
• Many reptiles also act as keystone species.

Difference between Amphibia and Reptilia

The difference between Amphibia and Reptilia are as follows:

Characteristics	Amphibia	Reptilia
Skin	Skin is permeable to gases and water. Skin is moist.	Skin is dry and covered in scales.
Limbs	Webbed or unwebbed feet.	Well-developed limbs are present.
Reproduction	Eggs have a gel-like covering and are laid in water.	The eggs are hard and laid on nests or land.
Metamorphosis	They undergo metamorphosis in the larval stage.	No metamorphosis.
Habitat	They live in aquatic and terrestrial environments.	They are primarily terrestrial but some species are adapted to other habitats as well.
Examples	Frogs and Salamanders.	Lizards, turtles, snakes and crocodiles.

Conservation Challenges for Reptiles

Reptiles have many ecological importance but still face many conservation challenges:

• Habitat loss due to development.
• Climate change.
• Poaching and hunting.
• Illegal pet trade.

Conclusion – Reptilia

Reptiles are from the class reptilian and are tetrapod animals. Many researchers and scientists believe that reptiles are the first ones to adopt life on earth and they evolved from amphibians. The study of reptiles along with amphibians is known as herpetology. They are air-breathing vertebrates that use lungs. They undergo internal fertilisation and have scales on their skin.

FAQs on Reptilia

What Defines Reptilia?

Reptilia are members of the class Reptilia. They are a group of air-breathing vertebrates. They fertilised internally. Scales cover their body.

What is the Characteristic of Reptilia?

Characteristics of Reptilia are that they are creeping terrestrial animals. They have scales on their body and are cold-blooded animals. They have rough and dry skin.

What is Reptilia in Biology Class 11?

Reptiles are cold-blooded animals with three-chambered hearts except crocodiles. Crocodiles have a four-chambered heart. The body is divided into the head, neck, trunk and tail.

What is the Study of Reptilia?

The study of Reptilia is known as herpetology. Herpetology also includes the study of amphibians

What is the Class of Reptilia Based on?

The classification of reptiles is based on the temporal fossa or vaccuties on the skull. The Temporal fossa which is developed in reptiles to lighten the skull is a large hole on the sides of the skull.