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Platyzoa
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{{Taxobox
| color = pink
| name = Platyzoa
| image = Bedford's Flatworm.jpg
| image_width = 200px
| image_caption = Bedford's Flatworm (''Pseudobiceros bedfordi''), a Platyhelminth, or flatworm
| regnum =
Animalia
| subregnum =
Eumetazoa
| unranked_phylum =
Bilateria
| superphylum = '''Platyzoa'''
| superphylum_authority =
Thomas Cavalier-Smith Cavalier-Smith, 1998
| subdivision_ranks = Phyla
| subdivision =
*
flatworm Platyhelminthes
*
Gastrotricha
*'''Gnathifera'''
**
Rotifera
**
Acanthocephala
**
Gnathostomulida
**
Limnognathia Micrognathozoa
**
Symbion Cycliophora
}}
The '''Platyzoa''' are a group of
protostome animals proposed by
Thomas Cavalier-Smith in 1998. Cavalier-Smith included in Platyzoa the
Phylum flatworm Platyhelminthes or
flatworms, and a new phylum, Acanthognatha, into which he gathered several previously described phyla of microscopic animals. Subsequent studies have supported Platyzoa as a
clade, a
Monophyly monophyletic group of organisms with a common ancestor, while differing on the phyla included and on relationships within Platyzoa.
One current scheme places the following traditional phyla in Platyzoa:
* Platyhelminthes
*
Gastrotricha
* Gnathifera
**
Rotifera
**
Acanthocephala
**
Gnathostomulida
**
Limnognathia Micrognathozoa
**
Symbion Cycliophora
The Platyhelminthes and Gastrotricha are
body cavity acoelomate. The other phyla have a
Body cavity#Pseudocoel pseudocoel, and share characteristics such as the structure of their jaws and
pharynx, although these have been secondarily lost in the
Parasite parasitic Acanthocephala. They form a monophyletic subgroup called the Gnathifera.
The Platyzoa are close relatives of the
Lophotrochozoa, and are sometimes included in that group. Together the two make up the Spiralia.
References
-
The Taxonomicon - Taxon: Infrakingdom Platyzoa Cavalier-Smith, 1998 - retrieved
January 31 2006
-
The interrelationships of metazoan parasites: a review of phylum- and higher-level hypotheses from recent morphological and molecular phylogenetic analyses - retrieved
January 31 2006
-
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 - retrieved
January 31 2006
-
Myzostomida Are Not Annelids: Molecular and Morphological Support for a Clade of Animals with Anterior Sperm Flagella - retrieved
January 31 2006
-
Current advances in the phylogenetic reconstruction of metazoan evolution. A new paradigm for the Cambrian explosion? - retrieved
January 31 2006
Category:Animals
de:Plattwurmartige
zh:�蟲動物
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