Nematodes and Crustaceans but not sponges or leechs Mites, but not Orthopterans Basal animal groups notable for distinctive collar cells Wombats, but not bats Jellyfish and hydra, but not starfish Notochord and post-anal tail are shared ancestral traits Birds, crocodiles and aardvarks, but not frogs sea cucumbers, but not sea squirts or beetles Sea sponges but not sea squirts, sea lilies or barnacles Frogs and finches, but not fishes.