Presentation by-Deepak Rawal

Assistant ProfessorMohanlal Sukhadia University

Udaipur India

AMPHIBIA CLASSIFICATION

General characters• Amphi- double; bios- life; living on land and breeding in water• Respiration by lungs, skin and buccopharynx• Larval forms with lateral line system• Exclusively fresh-water; no marine forms• Poikilothermic(cold-blooded)• Exoskeleton absent• Soft, moist and glandular skin without scales• Homodont teeth• Skull is dicondylic• Protrusible tongue• Cloaca present• 3-chambered heart(2atrium+1ventricle)• R.B.C. large oval and nucleated• Mesonephric kidneys• Amphibians are ureotelic• Middle ear with single rod like bone collumella auris• Cranial nerves 10 pairs• Sexual dimorphism found• Oviparous and external fertilization• Indirect development through tadpole larva mostly• Anamniotes(extra-embryonic membrane amnion absent)• Batrachology-study of amphibian• Evolved from crossopterygian fishes

Order- † Labyrinthodontia

• Maze-toothed• Aquatic forms• Large crocodile like• Stem amphibians(first

evolved amphibians)• Teeth like

crossopterygian fishes• Evolved from

crossopterygian fishes• Example- †Eryops

T.S. OF TOOTH

Order- † Phyllospondyli

• Leaf like thin vertebrae

• Small salamander like• Ancestors of modern

anuran and urodels• Example-

†Ichthyostega

Order- † Lepospondyli

• Ring like vertebrae• Ancestor of modern

caecilians• Example-

†Diplocaulus

Subclass-lissamphibia

Order-apoda Order-urodela Order-anura

Order-Apoda

• Also called gymnophiona or caecilians

• Burrowing forms• Snake like• Without limbs• Blind• Tail absent• Limb girdles present• Example- Ichthyophis

Order-Urodela

• Also called caudata• Lizard like with tail• Larva aquatic• Neoteny may found• Larva breaths through

gills which lost in adults

• Example-Ambystoma(tiger salamander)

Axolotl larva of salamander

Order-Anura

• Also called salientia• Frogs and toads• Tail absent in adults• Vocal sacs present in males• Leaping locomotion• 5 to 9 vertebrae with urostyle• Mandible toothless• Vomer teeth present• Metamorphosis found in most• Tadpole larva• Example- Hoplobatrachus

(Rana)

Metamorphosis of frog shown in time interval

PARENTAL CARE IN AMPHIBIAN

• Parents give food shelter and protection to their eggs or offspring is called parental care.

• Parental care increase the rate of survival of offspring.

• MATERNAL CARE- caring by mother.

• PATERNAL CARE-caring by father.

• INDIRECT CARING

Tree nests

• Eggs laid on overhanging leaves which protect them from predator

• Example- Rhacophorus (flying frog)

Mud nests

• Dig a hole in mud and lay eggs in it

• example- Hyla faber

Defending eggs

• Many species of amphibians guard eggs and attack the invading intruders

• Example- Autodax

Foam nests

• Many species of amphibians convert their mucus secretion to foam nests.

• Example- Leptodactylus

Gelatinous bags

• Some make transparent gelatinous bag by their mucus secretion

• Example- Salamandra keyserlingi

Direct development

• No metamorphosis occurs in some species

• Eggs hatch directly into little frogs

• Example- Hylodes

DIRECT CARING

Coiling around eggs

• Some dig a hole in mud and lay their eggs in that and coiled around them to protect them.

• Example- Ichthyophis

Eggs glued to body

• Many species glued their eggs to neck, thigh and other parts of body

• Example- Desmognathus glued their eggs to neck

• Example- Alytes glued their eggs to thigh

Eggs in back pouches• In breeding season skin become thick vascular

glandular• Male presses eggs on female back• Amphibian with this characteristic is called

marsupials• Example- Pipa (surinam toad)

Eggs develop and hatch in different organ of body

• Some use buccal cavity. example- Hylambates

• Some use stomach. example- Rheobatrachus

• Some use vocal sacs. example- Rhinoderma

ovoviviparity

• Eggs laid but retain in oviduct and give birth to young ones.

• Exampke- Dermophis