The phylum Chordata is a taxonomic group. All animals which have a  spine, or backbone, are classified in the phylum Chordata. There  are three subphylums in Chordata: Uroch … ordata (tunicates),  Cephalachordata (lancelets), and Vertebrata (vertebrates).hylum Chordata is the only phylum where all the members have a  backbone.   However, there is more to it than that, especially given that there  are two invertebrate ch … ordate groups-Urochordata (tunicates) and  Cephalachordata (lancelets) - whose backbone is not in the form of  actual vertebrae.