The Terasquids are a group of cephalopods that are all terrestrial and come in many different shapes, sizes, habits, and species in 200 million AD, inhabiting much of Novopangea, in The Future is Wild. Despite their early emergence from the sea, invertebrates were not equipped to grow to any great size. They not only lacked the muscle power to support their weight, but diffusion was not an effective method of delivering oxygen into a large body. Vertebrates, with their strong internal skeletons and efficient lungs, had fewer restrictions on size. They dominated the land for 400 million years.