This interesting piece of anatomy first appeared on Earth in amphibians. It is not for just land dwellers however, since a primary tongue is in the mouth of Necturus and some aquatic frogs as well. It is an aid in swallowing and wetting food.
Most amphibians have a glandular portion to their tongue, and musculature.
Frog tongues are attached near the front of their jaws. When at rest it is folded on the floor of the mouth, tip pointed back toward the throat. They also can shoot it forward to trap insects. Both frogs and salamanders have mucous glands in the mouth to provide the sticky substance that snags the prey. Teeth are cone shaped.