Taxonomy
Urochordata is a junior synonym of Tunicata which was established by Lamarck in 1816. Balfour introduced the name Urochorda in 1881 in order to emphasize the affinity of the group to other chordates,. No doubt largely because of his influence, various authors supported the term, either as such, or as "Urochordata", but the usage is invalid because "Tunicata" has precedence and there never were grounds for superseding the name. Accordingly the current (formally correct) trend is to abandon the name Urochorda or Urochordata in favour of the original Tunicata, and the name Tunicata is almost invariably used in modern scientific works. It is accepted as valid by the World Register of Marine Species and by ITIS, the Integrated Taxonomic Information System.
Read more about this topic: Tunicate