What role does the Clarias batrachus serve for scientists studying vertebrate history?

It serves as a living model illustrating ancient selective pressures encouraging exploitation of terrestrial resources

The walking catfish is highly valuable to evolutionary biologists studying the transition of vertebrates from water to land. It acts as a contemporary, tangible example that showcases the ancient, fundamental selective pressures that once acted upon early aquatic relatives. By observing the *Clarias batrachus*, scientists gain insight into the initial stages of adaptation, such as developing aerial respiration and utilizing paired fins for terrestrial movement, which foreshadowed the traits eventually seen in land-dwelling creatures like amphibians. It provides a living illustration of how the basic 'blueprint' for terrestrial locomotion was laid down in the aquatic realm millions of years ago.