Amphibians: division into three orders
- The body of the apodas is cylindrical, elongated and smooth.
- They have stunted legs.
- Fertilization is internal.
- The body of apodas looks like a big worm.
- They have olfactory tentacles.
- Absorb oxygen through the mouth and skin. The breath is pulmonary.
Examples of apodas: blind snakes.
- Urodels, also known as caudados, have four short legs.
- Body with elongated tail.
- Possess the ability to regenerate the tail or body limbs when severed.
- During winter, many species of urodels go into hibernation.
- They live in humid regions or near rivers and lakes. They need moisture because their skin is very sensitive to dry weather.
Examples of urodels: newts, proteus and salamanders.
- The body of the anurans has no tail.
- Anurans have four legs (tetrapods). The hindquarters are elongated.
- They have bulging eyes.
- The vast majority of anuran species have complete metamorphosis.
Examples of frogs: frogs, frogs, tree frogs.