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Note

The phylogenetic relationships among the major groups of animals are currently the subject of a lively debate, and most scientists would agree that the elucidation of metazoan relationships is still very much a work in progress. A definitive, stable, and natural classification of animals at higher taxonomic levels is therefore at present premature. These limitations notwithstanding, suggestions for new or revised naming conventions continue to be published along with preliminary hypotheses of animal relationships. As a result, a host of different higher level names is tossed about in the zoological literature, and the usage of any given name may vary from author to author. This situation can create considerable confusion among fledgling students of zoology.

In order to make the reading of zoological literature a little easier, we provide here a list of commonly encountered names of higher level groups of animals along with information on how these names have been defined in some prominent zoological publications (full references are provided below). A name that appears in the literature is given in blue; the publication that used that name is referenced underneath the name in green. The groups listed following each reference are those groups (using group names found in Tree of Life pages) that are specified in the publication as belonging within the name being defined.

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Acanthognatha

Cavalier-Smith 1998: Gastrotricha, Gnathostomulida, Rotifera

Acoelomata

Hyman 1951a: Nemertea, Platyhelminthes

Acrosomata

Ax 1996: Ctenophora, Bilateria

Ambulacralia

Zrzavy & al. 1998: Echinodermata, Hemichordata

Ambulacraria

Peterson & Eernisse 2001: Echinodermata, Hemichordata

Animalia

Zrzavy & al. 1998: Choanoflagellates, Metazoa

Nielsen 2001: syn. Metazoa: Bilateria, Cnidaria, Ctenophora, Placozoa, Porifera

Arthropoda

Ax 2000: Arthropoda, Onychophora

Articulata

Ghiselin 1988: Articulata s. l.: Annelida, Arthropoda, Brachiopoda, Mollusca, Sipuncula

Ax 2000: Annelida, Arthropoda, Onychophora

Nielsen 2001: Annelida, Arthropoda, Mollusca, Onychophora, Tardigrada

Aschelminthes

Hyman 1951b: Gastrotricha, Kinorhyncha, Nematoda, Nematomorpha, Priapulida, Rotifera

Nielsen 1995: Chaetognatha, Gastrotricha, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida, Rotifera

Ehlers & al. 1996: syn. Nemathelminthes: Gastrotricha, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida

Kristensen & Funch 2000: syn. Pseudocoelomata: Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Micrognathozoa, Nematoda, Nematomorpha, Priapulida, Rotifera

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Bilateria

Nielsen 1995: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Ctenophora, Deuterostomia, Entoprocta, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Platyhelminthes, Priapulida, Rotifera, Sipuncula, Tardigrada

Zrzavy & al. 1998: syn. Triploblastica: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Cycliophora, Deuterostomia, Entoprocta, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Mesozoa, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Platyhelminthes, Priapulida, Rotifera, Sipuncula, Tardigrada

Nielsen 2001: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Deuterostomia, Entoprocta, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Micrognathozoa, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Platyhelminthes, Priapulida, Rotifera, Sipuncula, Tardigrada

Brachiozoa

Cavalier-Smith 1998: Brachiopoda, Phoronida

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Cephalorhyncha

Zrzavy & al. 1998, Nielsen 2001: Kinorhyncha, Loricifera, Priapulida

Chaetifera

Zrzavy & al. 1998, Nielsen 2001: Annelida, Echiura, Pogonophora

Coelenterata

Cavalier-Smith 1998: Cnidaria, Ctenophora

Cryptotreta

Nielsen 2001: Chordata, Enteropneusta

Cycloneuralia

Ehlers & al. 1996, Peterson & Eernisse 2001: Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida

Nielsen 2001: Gastrotricha, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida

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Deuterostomia

Hyman 1959: syn. Enterocoela: Chaetognatha (but inclusion considered doubtful), Chordata, Echinodermata, Hemichordata, Pogonophora

Zrzavy & al. 1998, Peterson & Eernisse 2001: Chordata, Echinodermata, Hemichordata

Nielsen 2001: Brachiopoda, Chordata, Echinodermata, Enteropneusta, Phoronida, Pterobranchia

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Ecdysozoa

Aguinaldo & al. 1997: Last common ancestor of Arthropoda, Kinorhyncha, Nematoda, Nematomorpha, Onychophora, Priapulida, Tardigrada and all the descendants of that common ancestor.

Cavalier-Smith 1998, Garey & Schmidt-Rhaesa 1998: Arthropoda, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Onychophora, Priapulida, Tardigrada

Zrzavy & al. 1998, Peterson & Eernisse 2001: Arthropoda, Chaetognatha, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Onychophora, Priapulida, Tardigrada

Ectoprocta

Hyman 1959, Nielsen 2001: Bryozoa

Enterocoela

Hyman 1959: syn. Deuterostomia: Chaetognatha (inclusion considered doubtful), Chordata, Echinodermata, Hemichordata, Pogonophora

Epitheliozoa

Ax 1996, Nielsen 2001, Peterson & Eernisse 2001: Bilateria, Cnidaria, Ctenophora, Placozoa

Euarticulata

Nielsen 2001: Annelida, Arthropoda, Onychophora, Tardigrada

Eucoelomata

Hyman 1940: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Chordata, Echinodermata, Hemichordata, Mollusca, Phoronida, Priapulida, Sipuncula

Zrzavy & al. 1998: Annelida, Brachiopoda, Bryozoa, Chordata, Cycliophora, Echinodermata, Entoprocta, Hemichordata, Mollusca, Nemertea, Phoronida, Sipuncula

Eumetazoa

Hyman 1940, Ax 1996, Nielsen 2001, Peterson & Eernisse 2001: Bilateria, Cnidaria, Ctenophora

Euspiralia

Ax 1996: Annelida, Arthropoda, Entoprocta, Mollusca, Nemertea, Onychophora, Sipuncula

Eutriploblastica

Zrzavy & al. 1998: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Cycliophora, Deuterostomia, Entoprocta, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Platyhelminthes (excluding Acoela & Nemertodermatida), Priapulida, Rotifera, Sipuncula, Tardigrada

Eutrochozoa

Ghiselin 1988: Annelida, Mollusca, Brachiopoda, Sipuncula

Zrzavy & al. 1998, Peterson & Eernisse 2001: Annelida, Mollusca, Nemertea, Sipuncula

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Gnathifera

Sørensen & al. 2000: Gnathostomulida, Micrognathozoa, Rotifera

Nielsen 2001: Chaetognatha, Gnathostomulida, Micrognathozoa, Rotifera

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Introverta

Nielsen 2001: Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida

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Lobopoda

Cavalier-Smith 1998: Onychophora, Tardigrada

Lophophorata

Hyman 1959: Brachiopoda, Bryozoa, Phoronida

Peterson & Eernisse 2001: Brachiopoda, Phoronida

Lophotrochozoa

Halanych & al. 1995: Last common ancestor of Annelida, Brachiopoda, Bryozoa, Mollusca, Phoronida and all the descendants of that common ancestor.

Garey & Schmidt-Rhaesa 1998: Annelida, Brachiopoda, Bryozoa, Entoprocta, Mollusca, Phoronida, Sipuncula

Peterson & Eernisse 2001: Annelida, Brachiopoda, Bryozoa, Cycliophora, Entoprocta, Gnathostomulida, Mollusca, Nemertea, Platyhelminthes, Phoronida, Rotifera, Sipuncula

Lophozoa

Cavalier-Smith 1998: Annelida, Brachiopoda, Bryozoa, Cycliophora, Entoprocta, Mollusca, Nemertea, Phoronida, Sipuncula

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Metazoa

Hyman 1940: Bilateria, Cnidaria, Ctenophora, Mesozoa, Porifera

Nielsen 2001: syn. Animalia: Bilateria, Cnidaria, Ctenophora, Placozoa, Porifera

Monokonta

Cavalier-Smith 1998: Gastrotricha, Gnathostomulida

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Nemathelminthes

Ehlers & al. 1996: syn. Aschelminthes: Gastrotricha, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida

Cavalier-Smith 1998: Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida

Nematoida

Cavalier-Smith 1998, Peterson & Eernisse 2001: Nematoda, Nematomorpha

Nematoidea

Ehlers & al. 1996: Nematoda, Nematomorpha

Nematozoa

Zrzavy & al. 1998: Nematoda, Nematomorpha

Nemertina

Cavalier-Smith 1998: Nemertea

Nemertini

Ax 1996, Nielsen 2001: Nemertea

Neorenalia

Nielsen 2001: Chordata, Echinodermata, Enteropneusta, Pterobranchia

Neotrichozoa

Zrzavy & al. 1998: Gastrotricha, Gnathostomulida

Neotrochozoa

Peterson & Eernisse 2001: Annelida, Mollusca, Sipuncula

Neotriploblastica

Zrzavy & al. 1998: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Chordata, Cycliophora, Echinodermata, Entoprocta, Gastrotricha, Gnathostomulida, Hemichordata, Kinorhyncha, Loricifera, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Priapulida, Rotifera, Sipuncula, Tardigrada

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Panarthropoda

Nielsen 2001, Peterson & Eernisse 2001: Arthropoda, Onychophora, Tardigrada

Paracoelomata

Zrzavy & al. 1998: Arthropoda, Chaetognatha, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Onychophora, Priapulida, Rotifera, Tardigrada

Parazoa

Hyman 1940: syn. Porifera

Parenchymia

Nielsen 2001: Nemertea, Platyhelminthes

Phoronozoa

Zrzavy & al. 1998: Brachiopoda, Phoronida

Platyhelminthomorpha

Ax 1996: Gnathostomulida, Platyhelminthes

Platyzoa

Cavalier-Smith 1998: Gastrotricha, Gnathostomulida, Platyhelminthes, Rotifera

Peterson & Eernisse 2001: Cycliophora, Gnathostomulida, Platyhelminthes, Rotifera

Polyzoa

Cavalier-Smith 1998: Bryozoa, Entoprocta

Priapozoa

Cavalier-Smith 1998: Loricifera, Priapulida

Proctozoa

Ghiselin 1988: Bilateria excluding Platyhelminthes

Protostomia

Hyman 1940: Annelida, Arthropoda, Brachiopoda, Bryozoa, Entoprocta, Gastrotricha, Kinorhyncha, Mollusca, Nematoda, Nematomorpha, Nemertea, Phoronida, Platyhelminthes, Priapulida, Rotifera, Sipuncula

Nielsen 2001: Annelida, Arthropoda, Bryozoa, Chaetognatha, Entoprocta, Gastrotricha, Gnathostimulida, Kinorhyncha, Loricifera, Micrognathozoa, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Platyhelminthes, Priapulida, Rotifera, Sipuncula, Tardigrada

Peterson & Eernisse 2001: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Cycliophora, Entoprocta, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Platyhelminthes, Priapulida, Rotifera, Sipuncula, Tardigrada

Pseudocoelomata

Hyman 1951b: Entoprocta, Gastrotricha, Kinorhyncha, Nematoda, Nematomorpha, Priapulida, Rotifera

Lorenzen 1985: Gastrotricha, Kinorhyncha, Loricifera, Nematoda, Nematomorpha, Priapulida, Rotifera

Kristensen & Funch 2000: syn. Aschelminthes: Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Micrognathozoa, Nematoda, Nematomorpha, Priapulida, Rotifera

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Radialia

Ax 1996: Brachiopoda, Bryozoa, Deuterostomia, Phoronida

Radiata

Hyman 1940: Cnidaria, Ctenophora

Cavalier-Smith 1998: Cnidaria, Ctenophora, Placozoa, Porifera

Rhynchocoela

Hyman 1951a: Nemertea

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Scalidophora

Ehlers & al. 1996, Peterson & Eernisse 2001: Kinorhyncha, Loricifera, Priapulida

Scalidorhyncha

Cavalier-Smith 1998: Kinorhyncha, Loricifera, Priapulida

Schizocoela

Hyman 1940: Annelida, Arthropoda, Brachiopoda, Bryozoa, Mollusca, Phoronida, Priapulida, Sipuncula

Schizocoelia

Nielsen 2001: syn. Teloblastica: Annelida, Arthropoda, Mollusca, Onychophora, Sipuncula, Tardigrada

Spiralia

Nielsen 1995: Annelida, Arthropoda, Bryozoa, Entoprocta, Gnathostomulida, Mollusca, Nemertea, Onychophora, Platyhelminthes, Sipuncula, Tardigrada

Ax 1996: Annelida, Arthropoda, Entoprocta, Gnathostomulida, Mollusca, Nemertea, Onychophora, Platyhelminthes, Sipuncula

Garey & Schmidt-Rhaesa 1998: Annelida, Brachiopoda, Bryozoa, Entoprocta, Gastrotricha, Gnathostomulida, Mollusca, Phoronida, Platyhelminthes, Rotifera, Sipuncula

Nielsen 2001: Annelida, Arthropoda, Bryozoa, Chaetognatha, Entoprocta, Gnathostomulida, Micrognathozoa, Mollusca, Nemertea, Onychophora, Platyhelminthes, Rotifera, Sipuncula, Tardigrada

Peterson & Eernisse 2001: Annelida, Bryozoa, Cycliophora, Entoprocta, Gnathostomulida, Mollusca, Nemertea, Platyhelminthes, Rotifera, Sipuncula

Syndermata

Zrzavy & al. 1998: Rotifera including Acanthocephala

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Teloblastica

Nielsen 2001: syn. Schizocoelia: Annelida, Arthropoda, Mollusca, Onychophora, Sipuncula, Tardigrada

Tentaculata

Ax 1996: group not considered monophyletic: Brachiopoda, Bryozoa, Phoronida

Triploblastica

Zrzavy & al. 1998: syn. Bilateria: Annelida, Arthropoda, Brachiopoda, Bryozoa, Chaetognatha, Cycliophora, Deuterostomia, Entoprocta, Gastrotricha, Gnathostomulida, Kinorhyncha, Loricifera, Mesozoa, Mollusca, Nematoda, Nematomorpha, Nemertea, Onychophora, Phoronida, Platyhelminthes, Priapulida, Rotifera, Sipuncula, Tardigrada

Nielsen 2001: Bilateria, Ctenophora

Trochozoa

Zrzavy & al. 1998: Annelida, Cycliophora, Entoprocta, Mollusca, Nemertea, Sipuncula

Ax 2000: Annelida, Arthropoda, Entoprocta, Mollusca, Sipuncula

Peterson & Eernisse 2001: Annelida, Entoprocta, Mollusca, Nemertea, Sipuncula

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Vermizoa

Cavalier-Smith 1998: Annelida, Nemertea

References

Aguinaldo, A. M. A., J. M. Turbeville, L. S. Linford, M. C. Rivera, J. R. Garey, R. A. Raff, and J. A. Lake. 1997. Evidence for a clade of nematodes, arthropods and other moulting animals. Nature 387:489-493.

Ax, P. 1996. Multicellular Animals. A New Approach to the Phylogenetic Order in Nature. Volume I. Springer Verlag, Berlin, Heidelberg, New York.

Ax, P. 2000. Multicellular Animals. The Phylogenetic System of the Metazoa. Volume II. Springer Verlag, Berlin, Heidelberg, New York.

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

Ehlers, U., W. Ahlrichs, C. Lemburg and A. Schmidt-Rhaesa. 1996. Phylogenetic systematization of the Nemathelminthes (Aschelminthes). Verhandlungen der Deutschen Zoologischen Gesellschaft 89:8.

Garey, J. R. and A. Schmidt-Rhaesa. 1998. The essential role of "minor" phyla in molecular studies of animal evolution. American Zoologist 38:907-917.

Ghiselin, M. T. 1988. The origin of molluscs in the light of molecular evidence. Oxford Surveys in Evolutionary Biology 5:66-95.

Halanych, K. M., J. D. Bacheller, A. M. A. Aguinaldo, S. M. Liva, D. M. Hillis and J. A. Lake. 1995. Evidence from 18S ribosomal DNA that the lophophorates are protostome animals. Science 267:1641-1643.

Hyman, L. H. 1940. The Invertebrates. Volume 1, Protozoa through Ctenophora. McGraw-Hill Book Company, Inc., New York and London.

Hyman, L. H. 1951a. The Invertebrates. Volume 2, Platyhelminthes and Rhynchocoela. McGraw-Hill Book Company, Inc., New York and London.

Hyman, L. H. 1951b. The Invertebrates. Volume 3, Acanthocephala, Aschelminthes, and Entoprocta. McGraw-Hill Book Company, Inc., New York and London.

Hyman, L. H. 1959. The Invertebrates. Volume 5, Smaller coelomate groups. McGraw-Hill Book Company, Inc., New York and London.

Kristensen, R. M. and P. Funch. 2000. Micrognathozoa: A new class with complicated jaws like those of Rotifera and Gnathostomulida. Journal of Morphology 246:1-49.

Lorenzen, S. 1985. Phylogenetic aspects of pseudocoelomate evolution. Pages 210-223 in The Origins and Relationships of Lower Invertebrates. S. C. Morris, J. D. George, R. Gibson and H. M. Platt, eds. Oxford University Press, Oxford.

Nielsen, C. 1995. Animal Evolution: Interrelationships of the Living Phyla. First Edition. Oxford University Press, Oxford.

Nielsen, C. 2001. Animal Evolution: Interrelationships of the Living Phyla. Second Edition. Oxford University Press, Oxford.

Peterson, K. J. and D. J. Eernisse. 2001. Animal phylogeny and the ancestry of bilaterians: inferences from morphology and 18S rDNA gene sequences. Evolution & Development 3:170-205.

Sørensen, M. V., P. Funch, E. Willerslev, A. J. Hansen, and J. Olesen. 2000. On the phylogeny of the Metazoa in light of Cycliophora and Micrognathozoa. Zoologischer Anzeiger 239:297-318.

Zrzavy, J., S. Mihulka, P. Kepka, A. Bezdek, and D. Tietz. 1998. Phylogeny of the Metazoa based on morphological and 18S ribosomal DNA evidence. Cladistics 14:249-285.