The arthropods, or crustaceans, were the ancestors of the first vertebrates. The forerunners of the fish family were two modified arthropod ancestors. [1] Air-breathing amphibians developed from the arthropods, whose swim bladders had evolved into lungs. [2]
The brachiopods early reached their climax, being succeeded by the arthropods, and barnacles made their first appearance. 110 millions years ago crabs, lobsters, and the modern types of crustaceans matured. [3] The trilobites existed in tens of thousands of patterns and were the predecessors of modern crustaceans. [4]