Eusthenopteron fish anatomy, illustration. The areas highlighted here are the spine, the fins, and the shoulder girdle (red). This extinct prehistoric lobe-finned fish was closely related to tetrapods. Tetrapods are four-limbed animals that are similar to amphibians, that evolved from lobe-finned fishes, and then evolved further into reptiles and mammals. The earliest tetrapods evolved around 400 million years ago in the Devonian period, but the resulting vertebrate land invasion took many millions of years. Eusthenopteron lived during the Late Devonian, around 385 million years ago. For the anatomy of this animal's close relative the tetrapod Pederpes, see image C047/5512.