Classification of amphibia
- 3. GENERAL CHARACTERS OF AMPHIBIA Live both in land and water. Cold blooded animal. Body divided into head and trunk. Tail may or maynot present. Skin without scales. Mucous glands present in skin keeping it moist. External ear absent. Respiration through lungs, gills and buccopharyngeal cavity. Heart 3-chambered.
- 4. RBCs biconvex and nucleated. Bony Endoskeleton. Generally larva(/aquatic) ammonotelic and adult(/terrestial) ureotelic. Alimentary canal, excretory and urogenital tract all open to outside through cloaca. Generally oviparous. In many cases male shows parental care. Development includes larval stage.
- 5. Subclass Stegocephali Extinct Species Pentadactyl limbs. Skin with scales and bony plates. Order Labyrinthodontia Primitive amphibians. Also known as “Stem Amphibia”. Teeth large with folded dentine same as crossopterygian ancestors(fishes). Ex: Eryops (extinct)
- 6. Order Phyllospondyli Small salamander like. Notocord and spinal cord housed in common cavity. Ex: Branchiosaurs (extinct). Order Lepospondyli Small eel like. Vertebrae of single piece. Neural arch and centrum continuous. Ex: Diplocaulus (extinct).
- 7. Subclass lissiamphibia Modern aphibia. No scales present. Teeth small and simple. Order Apoda This order is also known as Gymnophiona. No limb or limb girdles. Blind In some dermal scales embedded in skin. Commonly known as Caecilians. Ex: Icthyophis, Uraeotysphlu
- 8. Order Urodela(/Caudata) Lizard like amphibians with distinct tail. Generally 2 pairs of limbs. Skin withot scales. Further subdivided into 5 suborders- Cryptobranchoidea, Ambystomatoidea, Salamandriodea, Proteidae, Meantes. Ex: Ambystoma, Siren. .
- 9. Order Anura(/Salientia) Tail absent in adult. Eyelids and tympanum present. Skin scaleless and loose. Further divided into 5suborders- Amphicoela, Opisthocoela, Anomcoela,Procoela, Diplasiocela Ex: Frog,Toad
- 10. The End