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MUCUS

Amphibians evolved from bonefish around 370 million years ago, and are considered a key evolutionary link between fish and land animals, specifically, mammals and reptiles. Before reptiles evolved, amphibians were the dominant land animal for about 60 million years.

Amphibians’ skin is water-permeable, so they regularly secrete mucus to keep from drying out—1 reason why most amphibians live near water. They also lay their eggs in water, and spend an early life stage in water as they go through metamorphosis. Salamanders and newts, frogs and toads, and caecilians (a limbless vertebrate) are the 3 families of amphibians.

 

Kingdom: Animalia
Phylum: Chordata
Clade: Batrachomorpha
Class: Amphibia