Amphibian

Amphibians Fossil range: Upper Devonian – Recent
Eryops, a Carboniferous amphibian
Biological classification
Kingdom: Animalia Phylum: Chordata Subphylum: Vertebrata Superclass: Tetrapoda Class: Amphibia Linnaeus, 1758
Subclasses and Orders
Subclass Labyrinthodontia†, or Order Temnospondyli† and Subclass Lepospondyli† Subclass Lissamphibia Order Anura Order Caudata Order Gymnophiona †: extinct

Strawberry Poison dart frog, Oophaga pumilio. Like many living amphibia, poison and warning colouration protects it.

Amphibia are a class of four-legged animals (Amphi- = both; bios = life). They live in shallow water and on land, and must lay their eggs in water. They have a larval stage in water, and the adult stage usually lives mostly on land.

From the Upper Devonian are nine genera of animals which are as much amphibia as they are fish. The term fishapod has been used for them: they did move out onto land, but they were mainly water dwellers. They were descendants of the lobe-finned fish, the Sarcopterygii.

Early amphibia from the Carboniferous were quite large predators with flat skulls. The amphibia which survive today are much smaller and more specialised forms. Frogs and toads (Anura), newts and salamanders (Caudata) and caecilians are all amphibia.

As amphibians grow from a larva to an adult, they change shape. This is metamorphosis. They lose their gills and tails, and grow front and hind legs. Larval frogs, toads or salamanders are called tadpoles. They then grow appendages to become the amphibian they are today

Adult females lay as many as 4000 eggs, usually in the water or in wet places. They eat other animals, especially insects. Amphibians are cold blooded, which means that their body temperature does not adapt to the weather.

In terms of species numbers, amphibians are still quite successful. They are just limited in the habitats they can live in. There are about 5,700 living species of amphibia. For comparison, there are about 4,000 mammalian species.

Examples

• Newts
• Salamander
• Caecilian
• Frog
• Toad
• Olm
• Crab-eating Frog

Taxonomy

• Class Amphibia
  • Order Anura (Frogs)
  • Order Caudata (Salamanders)
  • Order Gymnophiona (Caecilians) (somewhat resemble snakes)