Eleutherozoa
Eleutherozoa Temporal range:
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Pisaster ochraceaus | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Echinodermata |
Subphylum: | Eleutherozoa Bather, 1900 |
Classes[1] | |
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Eleutherozoa is a proposed subphylum of echinoderms. They are mobile animals with the mouth directed towards the substrate. They usually have a madreporite, tube feet, and moveable spines of some sort, and some have Tiedemann's bodies on the ring canal. All living echinoderms except Crinozoa and Blastozoa belong here.
Systematics
There are 2 main competing hypotheses about the internal subdivision, both about equally well supported by both molecular and morphological data. They differ in their placement of the
The "Cryptosyringida" hypothesis posits that the "sea-star"
The Asterozoa would have to be ranked as a superclass or treated as an unranked clade between the Cryptosyringida and the Eleutherozoa, depending on whether the "Asterozoa" or "Cryptosyringida" hypothesis eventually turns out to be correct.
Some old research favours the following classification:[3][4]
Echinodermata
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But more newer research with more advanced technology, favours this cladogram:[5][6]
Echinodermata
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Footnotes
- ^ Milsom (2010)
- ^ Wray (1999)
- ^ Smith, A. (2007). "Echinoderms: Attachment, torsion and the origins of a radical new body plan" (PDF). In Budd, G. E.; Streng, M.; Daley, A. C.; Willman, S. (eds.). Programme with Abstracts. Palaeontological Association Annual Meeting. Vol. 51. Uppsala, Sweden.
- doi:10.1002/gj.1018.
- PMID 24850925.
- PMID 25794146.
References
- Wray, Gregory A. (1999): Tree of Life Web Project: Echinodermata: Spiny-skinned animals: sea urchins, starfish, and their allies. Version of 1999-DEC-14. Retrieved 2008-FEB-02.
- Milsom, Clare. Fossils at a glance. Hoboken, NJ: Wiley-Blackwell, 2010.