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Amphibian Classification

Amphibian Classification. Amphibian Classification Notes. Amphibians occur on all continents except Antarctica . There are about 4 000 living species of amphibian. These species belong to 3 orders: 1. Caudata 2. Gymnophiona 3. Anura. ORDER CAUDATA.

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Amphibian Classification

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  1. Amphibian Classification

  2. Amphibian Classification Notes • Amphibians occur on all continents except Antarctica. • There are about 4000 living species of amphibian. • These species belong to 3 orders: 1. Caudata 2. Gymnophiona 3. Anura

  3. ORDER CAUDATA • Members of this order are the salamanders. • They possess a tail throughout their life and may or may not have legs.

  4. ORDER CAUDATA • There are about 350 species of salamander and almost half of these live in North America. • Most salamanders that live on land (terrestrial) live on the forest floor and have aquatic larvae.

  5. ORDER CAUDATA • Members of the family Salamandridae are commonly called newts. • They spend most of their time in water and will often keep their fins.

  6. ORDER CAUDATA • Salamanders range in length from a few centimeters to 1.5 meters (Japanese giant salamander) • The largest North American salamander is the hellbender, which gets about 65 centimeters.

  7. ORDER CAUDATA • Most salamanders have internal fertilization. • Males produce a jelly-like substance that contains their sperm and the females pick up and store the sperm in a special pouch called the spermatheca. • Eggs are deposited in clumps or strings. • Larvae are similar to adults but smaller. • Many salamanders will undergo incomplete metamorphosis and are paedomorphic—become sexually active while still having larval characteristics.

  8. ORDER GYMNOPHIONA • Members of this order are the caecilians. • There are about 160 species, found mostly in tropical regions.

  9. ORDER GYMNOPHIONA • Caecilians are wormlike burrowers that feed on worms and other invertebrates in the soil. • Caecilians appear segmented because of folds of skin that cover separations between muscles.

  10. ORDER GYMNOPHIONA • They have a retracting tentacle between their eyes and nostrils that may transport chemicals from the environment to sensory cells in the roof of the mouth. • Skin covers their eyes so they are nearly blind.

  11. ORDER GYMNOPHIONA • Fertilization is internal. • Larval stages often occur inside the female. • The young emerge from the female as miniature adults. • Some caecilians will lay eggs that develop into aquatic larvae.

  12. ORDER ANURA • This order contains frogs and toads. • There are about 3500 species. • Anurans live in moist environments, except in high latitudes. • Adults do not have tails. • Hindlimbs are long and muscular and end in webbed feet.

  13. ORDER ANURA • Fertilization is almost always external, and eggs and larvae are usually aquatic. • The larval stage is called a tadpole and has a well-developed tail.

  14. ORDER ANURA • They have no limbs until almost the end of the larval stage. • Larvae are herbivores and have a beaklike structure for feeding. • These larvae undergo a drastic and rapid metamorphosis to the adult body form.

  15. ORDER ANURA • The distinction between “frog” and “toad” is not very scientific. • “Toad” usually refers to anurans with dry and warty skin and are more terrestrial than other members of this order.

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