By the Devonian period two major animal groups dominated the land, the tetrapods or 4-legged terrestrial vertebrates and the arthropods, including arachnids and wingless insects. Lobe-finned fish or Eusthenopteron had a number of exaptations that pre-adapted it to life on land: it had limbs that allowed it to move around on the bottom of pools, lungs, which meant it could gulp air at the surface, and the beginnings of a neck. This last is important as a terrestrial predator cannot rely on water current to bring food into its mouth, but must move its head to catch prey. And the bones in Eusthenopteron's fins are almost identical to those in the limbs of the earliest amphibians, an example of homology. All modern tetrapods have a maximum of 5
