Lungfish are known for living in conditions where water is scarce or oxygen levels are low.

Habitat Conditions

Some lungfish can enter a dormant state called estivation to survive droughts.

Estivation Ability

Lungfish are a vital link in evolution, showing the transition from sea to land animals.

Evolutionary Importance

 writes about a universe in which many different von Neumann machines exist and proliferate simultaneously. Some are designed to greet young civilizations, others to locate and destroy them before they become a threat. In fact, in Brin's story "Lungfish,"

Could human civilization...

 from a pelican its legs from a flamingo and its head from an eagle the Shoebill stork lives in a Great Lakes region of Africa and feeds on frogs baby crocodiles and oh yes the Shoebill is the scourge of the lungfish it can catch

Shoebill Stork vs....

 it'll craw specially adapted fins allow the catfish to walk on its elbows like the lungfish it can also breathe air it may have to perform this trick many times as its habitable world gets smaller by the day