Ichthyostega

Ichthyostega was an ancient, fish-like creature from about 370 million years ago, known as one of the earliest tetrapods—vertebrates with limbs. It had both aquatic features, like fins and a fish-like tail, and early limbs capable of supporting its weight on land. Its presence marks a key stage in the evolution of vertebrates moving from water to land, providing insight into how transition species adapted to terrestrial environments. Despite its primitive appearance, Ichthyostega was an important step in the evolution of amphibians and other land animals.