Urochordata

Colony of Salpa fusiformis, copyright Mark Rosenstein.

Belongs within: Chordata.
Contains: Enterogona, Pleurogona.

The Urochordata, tunicates, are spineless chordates that possess a notochord and postanal tail in the tadpole-like larval stage but usually loose them when they metamorphose into adults.

Characters (from Miller & Harley 1996): Notochord, nerve cord and postanal tail present in free-swimming larvae; adults sessile or planktonic, usually enclosed in a tunic containing some cellulose.

<==Urochordata
    |  i. s.: Octacnemus [Sorberacea] MH96
    |--Shankouclava Chen, Huang et al. 2003 EL11, CH03
    |    `--*S. anningense Chen, Huang et al. 2003 [=S. shankouense Chen, Huang et al. 2003 (n. n.)] CH03
    `--+--Oikopleura GD00 [Appendicularia C-S98, Larvacea]
       |    |--O. dioica LG03
       |    |--O. labradoriensis B26
       |    `--O. vanhoeffeni B26
       `--Tunicata C-S98
            |--Thaliacea [Thaliae] C-S98
            |    |  i. s.: Thalia democratica BN03
            |    |--Pyrosoma [Pyrosomatidae, Pyrosomida] MG-H11
            |    |    |--P. atlanticum Péron 1804 MG-H11
            |    |    `--P. spinosum MH96
            |    |--Doliolidae [Dolioloda] MG-H11
            |    |    |--Dolioletta gegenbauri (Uljanin 1884) MG-H11
            |    |    `--Doliolum W01
            |    |         |--D. mulleri Krohn 1852 W01
            |    |         `--D. nationalis CGS00
            |    `--Salpa [Salpida, Salpidae] MG-H11
            |         |--S. fusiformis B26
            |         |--S. maxima Forskål 1775 MG-H11
            |         |--S. tilesii B26
            |         `--S. zonaria B26
            `--Ascidiacea [Ascidiae] C-S98
                 |  i. s.: Clarelina molucensis RZ03
                 |         Phallusia CGS00
                 |           |--P. mamillata CGS00
                 |           `--P. nigra B79
                 |         Polyandrocarpa B79
                 |           |--P. gravei B79
                 |           |--P. tincta B79
                 |           `--P. zorritensis GO78
                 |         Symplegma viride B79
                 |         Diplosoma listerianum B79
                 |         Ctenicella appendiculata M62
                 |         Distomus variolosus M62
                 |         Asterocarpa coerulea HS01
                 |         Permosoma EL11
                 |         Cynthia melocactus H04
                 |         Fragarium elegans H04
                 |         Synoecum turgens H04
                 |         Polycyclus cyaneus H04
                 |--Enterogona S79
                 `--Pleurogona S79

*Type species of generic name indicated

REFERENCES

[B26] Bigelow, H. B. 1926. Plankton of the offshore waters of the Gulf of Maine. Bulletin of the Bureau of Fisheries 40 (2): 1–509.

[BN03] Bourlat, S. J., C. Nielsen, A. E. Lockyer, D. T. J. Littlewood & M. J. Telford. 2003. Xenoturbella is a deuterostome that eats molluscs. Nature 424: 925–928.

[B79] Buss, L. W. 1979. Habitat selection, directional growth and spatial refuges: why colonial animals have more hiding places. In: Larwood, G., & B. R. Rosen (eds) Biology and Systematics of Colonial Organisms pp. 459–497. Academic Press: London.

[CGS00] Cameron, C. B., J. R. Garey & B. J. Swalla. 2000. Evolution of the chordate body plan: new insights from phylogenetic analyses of deuterostome phyla. Proceedings of the National Academy of Sciences of the USA 97 (9): 4469–4474.

[C-S98] Cavalier-Smith, T. 1998. A revised six-kingdom system of life. Biological Reviews 73: 203–266.

[CH03] Chen, J.-Y., D.-Y. Huang, Q.-Q. Peng, H.-M. Chi, Z.-Q. Wang & M. Feng. 2003. The first tunicate from the Early Cambrian of South China. Proceedings of the National Academy of Sciences of the USA 100 (14): 8314–8318.

[EL11] Erwin, D. H., M. Laflamme, S. M. Tweedt, E. A. Sperling, D. Pisani & K. J. Peterson. 2011. The Cambrian conundrum: early divergence and later ecological success in the early history of animals. Science 334: 1091–1097.

[GO78] Gallardo S., C., & C. Osorio R. 1978. Hiatella solida (Sowerby, 1834) (Mollusca: Hiatellidae) on Concholepas concholepas (Bruguière, 1789) and other substrates. Veliger 20 (3): 274–278.

[GD00] Giribet, G., D. L. Distel, M. Polz, W. Sterrer & W. C. Wheeler. 2000. Triploblastic relationships with emphasis on the acoelomates and the position of Gnathostomulida, Cycliophora, Plathelminthes, and Chaetognatha: A combined approach of 18S rDNA sequences and morphology. Systematic Biology 49: 539–562.

[H04] Haeckel, E. 1899–1904. Kunstformen der Natur. Bibliographisches Institut: Leipzig und Wien.

[LG03] Lancelot, C., & R. Groben. 2003. Meeting report: Regional conference on the ecology and impact assessment of Phaeocystis blooms in the Eastern Channel and Southern Bight of the North Sea. Protist 154 (2): 173–176.

]MG-H11] McEnnulty, F. R., K. L. Gowlett-Holmes, A. Williams, F. Althaus, J. Fromont, G. C. B. Poore, T. D. O’Hara, L. Marsh, P. Kott, S. Slack-Smith, P. Alderslade & M. V. Kitahara. 2011. The deepwater megabenthic invertebrates on the western continental margin of Australia (100–1100 m depths): composition, distribution and novelty. Records of the Western Australian Museum Supplement 80: 1–191.

[MH96] Miller, S. A., & J. P. Harley. 1996. Zoology 3^rd ed. Wm. C. Brown Publishers: Dubuque (Iowa).

[M62] Monniot, F. 1962. Recherches sur les graviers a Amphioxus de la région de Banyuls-sur-Mer. Vie et Milieu 13: 231–322.

[RZ03] Romanenko, L. A., N. V. Zhukova, M. Rhode, A. M. Lysenko, V. M. Mikhailov & E. Stackebrandt. 2003. Pseudoalteromonas agarivorans sp. nov., a novel marine agarolytic bacterium. International Journal of Systematic and Evolutionary Microbiology 53: 125–131.

[S79] Sabbadin, A. 1979. Colonial structure and genetic patterns in ascidians. In: Larwood, G., & B. R. Rosen (eds) Biology and Systematics of Colonial Organisms pp. 433–444. Academic Press: London.

[W01] Williamson, D. I. 2001. Larval transfer and the origins of larvae. Zoological Journal of the Linnean Society 131: 111–122.