General Characters and Examples: Class Amphibia

Defination 

• Amphibian are class of  vertebrates that are cold blooded and found in both water and land.

General Characters 

• They can live in both aquatic and terrestrial habitat.

• Most of them have two pairs of limb.

• Body is divided into head and trunk. Some of the animals have tail.

• Their skin in moist due to presence of glands but have no any scale in body.

• Eyes👀 have eyelids and  also Nictating membrane while animal are in water.

• A tympanum represent the internal  ear👂.

• Cloaca is common chamber in which alimentary canal, Reproductive tract and urinary duct are opened.

• Heart has three chambers  Two auricle and one ventricle.

• Saxes are separate. Fertilization is external . Development is indirect . They are oviparous.

Example of Amphibia 

1. Bufo

• It is commonly called as Toad. Its skin is dry with small warts.

• It has large bulging eyes  👁️covered by nictitating membrane .

• Bufo has broad head with wide mouth with no teeth.

• It has short fore limb 🦵 with four digit and hind limb With five digits.

• Frog has two small nostril above the mouth.

• It has mucus glands to make skin moist 

• It has rounded tubercle on dorsal skin and sub articular tubercle on their  finger  and toes.

• It can change its color during breeding season 

• Male frog has  sound box and copon their fingers during breeding season. Sexual dimorphism is present .

• Bufotoxin is toxic substance released by toad to get protection from predator.

2. Rana

• It is commonly called as frog. Its skin is smooth and moist with presence of mucus. 

• It has large bulging  eyes  👁️ with nictitating membrane.

• Frog  has head with wide mouth with no teeth.

• It has short fore limb with four digits  🦵 and hind limb with five digits.

• Frog has two small nostril above the mouth. 

• It has parotid glands behind the ear.

• Frog never drinks water but absorb from the skin.

• It can change its  body color to get protection from enemy. It is called camouflage.

• Male frog  has copulatory pads pad on first finger of hind limb. Sexual dimorphism is present .

• Male frog also has vocal sac to produce some to attract the female during  copulation.

3. Hyla

• It is commonly called as tree  frog. It is an arboreal and spent most of the time on tree.  

• It's body is small and slender. It has round  adhesive disc on finger and toes.

• Its skin in smooth on back or front whereas dry skin in present in under side.

• Web is well developed in between the finger but less developed between the toes.

• Male Hyla produce sound during breeding season to attract the female.

• Hyla breed in water body like pond river etc and female lay egg in clumps.

• Eggs are developed into tadpole larva which are further developed into adult after metamorphosis.

• Some species of Hyla are poisonous .

4. Salamandra

• It is commonly called as Salamander.   

• It's body is covered by moist skin due to secretion of mucus. Some Salamander can respire by the moist skin.

• Salamander has four limb but in some  limb is reduced.

• They lack epidermal scale , Claws and external ear.

• They do not produce any sound due to lack of vocal sacs but make communication with touch and chemicals.

• Salamander has power of regeneration and it can regrow of its lost limb.

• Larva of salamander is carnivorous and possess developed external gills.

• Salamander has close relationship with  frog 🐸 and lizard 🦎.

• Salamander is nocturnal.

4. Icthyophis 

• It is a limbless Amphibian. It has slender body ,  Vestigial and short  tail.

• Icthyophis has small  eyes 👀 with compact skull with bony vertebrae.

• Transverse groove, slime glands and squirt glands are present.

• It's larva is aquatic with three pairs of external gills.

• Mouth is sub terminally located.