Rana catesbeinana

Amphibians are able to survive both in water and on land. Amphi + bios = double (biphasic) life

Class characteristics: Smooth, moist skin (no scales) Toes lack claws Gills, lungs, and skin used in respiration Metamorphosis from larval stage to adult Larvae heart 2 chambers,adult 3 chambers Eggs fertilized externally Amphibians are cold-blooded vertebrate animals. Frogs may be found anywhere in the world, although most frogs are found in the tropics.

Amphibian Fossils

Ichthyostega, prehistoric predecessor to the modern frog, lived 370 million years ago during the Devonian Period. Sometimes referred to as "the first four-legged fish," skeletal remains of this earliest known amphibian was first discovered in East Greenland.

The first true frogs evolved during the early Jurassic period, about 200 million years ago.

Anura Frogs Frogs – True frogs have smooth, moist skin and long hind legs.

Anura Toads – have bumpy, dry skin and short hind legs. They possess elevated ridges called cranial crests between and in back of the eyes.

Urodela Salamanders Salamanders – have elongated bodies with short legs and a smooth, moist skin. The tail is somewhat thick and flattened side to side to aid swimming.

Urodela - Newts and Mudpuppies Newts are large salamanders reaching total lengths almost up to 8 inches. They are characterized by warty skin that is not slimy, and are light brown to black above with a yellow to orange belly. Mudpuppies are large, permanently aquatic salamanders. Mudpuppies never form air-breathing lungs. They rely on the bushy red gills behind their heads to breathe under water, like fish.

Apoda Caecilians - legless amphibians (not found in the U.S.) Caecilians are rarely-seen amphibians that resemble giant earthworms. They spend most of their time underground, and on those rare occasions when they are seen, they are usually crossing roadways on rainy nights.

Frog Deformities Frogs in Peril UV radiation Acid rain Global warming Pathogens

Anura

Urodela

Urodela

Anura

Anura

Apoda