Acanthodians Artiodactyls Backboned animals Carnivores Cenozoic Faunas Credonts Elephants and kinn Faunas, Cenozoic Fossils, Vertebrates Hagfishes Jawless Vertebrates Jaws, origin Mammal like reptiles Mammals Marsupials Ostracoderms Perissodactyls Placentals Placoderms Primates Primitive Ungulates Rabbits Reptiles, Mammal like Rodents Sharklike fishes Ungulates, Primitive Vetebrates Whales dolphins phylum Chordata, Classification