What is Reptilia?
Class Reptilia comprise of vertebrates which are held to have evolved from amphibians. These animals belong to the phylum Chordata under animal taxonomy.
There are some general characteristics of reptiles which can be found in almost all members of the class. It includes dry skin without any gland, cold-blood, and scales on their body, among others. Examples of reptiles are – lizard, turtle, snake, chameleon, crocodile etc.
Read on to know more about the main characteristics of reptiles.
Characteristics of Reptiles
While there can be variations in the general features of reptiles, there exist certain common characteristics. The unique features of reptiles have been mentioned below.
Reptiles are cold-blooded, also known as Ectothermic, and are mostly terrestrial
There are epidermal scales on the body of reptiles
Their skull comprises of a single occipital condyle
Heart of reptiles usually includes two auricles which are separated by a ventricle. An exception is a crocodile with a four-chambered heart
There are 12 pairs of cranial nerves
Barring snakes, ears of reptiles have 3 parts – internal, middle and external
Cloaca is present in reptiles
Reptiles are mostly oviparous. It lays eggs as opposed to giving birth to young ones.
Snakes and lizards are most common examples of reptile animals. Even though those have slits for nostrils, they use their tongue to smell. They flick out their tongue and pass it on to Jacobson’s Organ. The chemicals that stick at their tongues impart smell.
Reptilia can be further divided into Subclasses and Orders
(1) Reptilia Sub-Classes
The different Reptilia subclasses are – Anapsida, Parapsida, Diapsida. The characteristics of reptiles under these subclasses are elucidated below.
There are certain groups which have gone extinct under class Reptilia. Those are – Cotylosauria, Ichthyopterygia, Archosauria, and Synaptosauria. Dinosaurs primarily belonged to these orders.
Test Your Knowledge
i. Among which types of reptiles, Typhlop belong?
(a) False snake
(b) True snake
(d) True worm
ii. Most highly advanced feature of the Reptilia, crocodile is –
(b) 4-chambered heart
(c) Shelled eggs
(d) Powerful jaws
[See the solutions to the quiz at the end of the article]
(2) Reptilia orders
The different Reptilia orders are – Chelonia, Rhyncocephalia, Squamata, Crocodilia. The characteristics of reptiles under these orders are indicated below.
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1. What characteristics do reptiles have?
One of the major class reptilia characteristics is having vertebra. These are mostly oviparous, that is, lays eggs. Reptiles also have scales or scutes that form the dermis.
2. Name any two reptiles.
Snakes and lizards are common examples of Reptiles. This classification of reptiles shares the common features of movable quadrate bones and scales.
3. What animals are reptiles?
The members of class Reptilia, exhibiting characteristics of internal fertilisation, presence of vertebra, epidermal scales and amniotic development etc. are called reptiles.
i. (b) True snake
ii. (b) 4-chambered heart