General Characters1-Reptiles represent the first class of vertebrates fully
adapted for life in dry places on land.
2- The study of reptiles is called Herpetology (Gr.,
herpeton, reptiles).
3- Predominantly terrestrial, creeping or burrowing,
mostly carnivorous, air-breathing, cold-blooded,
mostly oviparous and tetrapodal vertebrates.
4-Skin dry and devoid of glands.
5- Body bilaterally symmetrical.
6- Endoskeleton bony. Skull with one occipital condyle.
7- Exoskeleton of horny epidermal scales, shields, plates
and scutes.
8- The body consists of head, Neck, trunk and tail .
9- Mouth terminal. Jaws bear simple teeth.
10- Limbs 2 pairs, pentadactyle. Digits provided with
horny claws. However, limbs absent in a few lizards
and all snakes.
11- Heart usually 3-chambered, but 4-chambered in
crocodiles.
12- Respiration by lungs throughout life.
13-Lateral line system absent.
14- Sexes separate. Male usually with muscular
copulatory organ.
15- Fertilization internal. No metamorphosis. Young
resemble adults.
Subclass I. Anapsida
Subclass II. Eurvapsida (extinct)
Subclass III. Parapsida (extinct)
Subclass IV. Synapsida (extinct)
Subclass V. Diapsida
Class Reptilia usually divided into 5 subclasses;
three of them are extinct.
Order : Chelonia
1- Body short, broad and oval.
2- Limbs clawed – in aquatic types are webbed, paddle-like.
3- Body encased in a firm shell of dorsal carapace and ventral
plastron.
4-Thoracic vertebrae and ribs usually fused to carapace.
5-Teeth absent. Skull is Anapsida
Order :Squamata*(Squama = scale)
1- Advanced, small to medium, elongated reptilians.
2- Limbs clawed, absent in snakes and some lizards.
3- Exoskeleton of horny epidermal scales, shields and
spines.
4- Skull diapsida.
5- Male with eversible double copulatory organs.
** Squamata divided into 2 distinct suborders;
Lacertilia and Ophidia
Order : Crocodilia
1. Large-sized, carnivorous and aquatic reptiles.
2. Tail long, strong and laterally compressed.
3. Limbs are short but powerful, clawed and
webbed.
4. Skin thick with scales, bony plates and scutes.
5. Skull diapsida. Teeth numerous and strong
1- They are ancient reptiles that have remained
relatively unchanged for 175 million years.
2- They show the greatest departure from the typical
reptilian plan. However, they are easily identified by
their armored shell of bony plates.
3- Teeth are absent in all turtles being replaced by a
horny beak-like structure.
4-Their limbs are heavy as required for carrying the
unusually heavy body.
5- Aquatic forms (comparing to terrestrial forms)
have reduced shells and limbs modified as
flippers or paddles for swimming.
6- When the animal is threatened with danger, the
head, neck, limbs and tail are withdrawn into the
shell.
7- Although they breathe by lungs, they may remain
under water for a considerable time.
8- All turtles hibernate during colder days.
9- The leatherback turtle, Dermochelys coriacea, is
the largest turtle. It may reach a length of 2.5
meters and attain a weight of 600kg.
10- Carnivorous and attain age of 200 to 400 years.
Class : Reptilia
Subclass : Diapsida
Order : Squamata
Suborder : Lacertilia
Family : Gekkonidae
Genus : Hemidactylus
Hemidactylus
1-Common house or wall lizards are known, as geckos.
2- These are small lizards, about 30 cm in length having tails shorter than head and trunk.
3- Tongue is sticky and protrusible.
4- The underneath of fingers and toes have adhesive lamellae which aid in climbing vertical surfaces or walking across ceilings.
5- Unlike most lizards some geckos are vocal, making clicking sounds.
Class : Reptilia
Subclass : Diapsida
Order : Squamata
Suborder : Lacertilia
Family : Chamaeleonidae
Genus : Chamaeleon
Chameleon
1- Body is compressed, skin granulated and head with a prominent hood.
2- Feet with digits arranged in groups of 2 and 3 to grasp branches firmly. Additional security is provided by a prehensile tail.
3- The very large tongue can be projected forward with great speed to capture insects, which stick to its sticky tip.
4- The eyes are elevated and move independently.
5- Chameleons are famous to change their body colours rapidly to blend with their surroundings.
Class : Reptilia
Subclass : Diapsida
Order : Squamata
Suborder : Ophidia
Family : Elapidae
Genus : Naja
1- It known as (The Egyptian cobra) Poisonous snakes.
2- The body is cylindrical and stout with a long tail.
Length is about 1-2 metres.
3- The head is depressed and slightly distinct
from the neck.
4- Neck can dilatate supported by ribs.
5- This species prefers to eat toads, but it will prey on
small mammals, birds, eggs, lizards and other snakes.
Naja haje
Class : Reptilia
Subclass : Diapsida
Order : Crocodilia
Family : Crocodylidae
Genus : Crocodylus
Crocodilians
1- Include some of the largest living reptiles.
2- These are formidable carnivorous lizard-like
creatures.
3- live mainly in tropical freshwater rivers.
4- Their body is long, depressed.
5- The head elongated into a flat snout.
6- Massive tail is laterally compressed, forming
a powerful appendage.
7- Limbs are short but strong, pentadactyle, clawed and
webbed.
8- Skin is thick, with horny scutes.
9- It grows to 8-9 meters.
10- These large reptiles are well adapted for an aquatic
existence. Nostrils, eyes and ear openings are placed
high on the head and remain exposed even when the
whole animal is immersed in water. Thus, breathing,
seeing and hearing remain uninterrupted.