Ichthyostega is an early genus of four-legged animals that lived during the Devonian Period, between about 360 and 370 million years ago. Equipped with lungs, a strong flat tail, and webbed feet which helped it both swim through shallow water in swamps and become one of the earliest animals to move onto land, Ichthostaga was a precursor of the first true amphibians which appeared in the Carboniferous Period.